prom_init.c

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/*
 * Procedures for interfacing to Open Firmware.
 *
 * Paul Mackerras   August 1996.
 * Copyright (C) 1996-2005 Paul Mackerras.
 * 
 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
 *    {engebret|bergner}@us.ibm.com 
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#undef DEBUG_PROM

#include <stdarg.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/threads.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/proc_fs.h>
#include <linux/stringify.h>
#include <linux/delay.h>
#include <linux/initrd.h>
#include <linux/bitops.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/page.h>
#include <asm/processor.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/pci.h>
#include <asm/iommu.h>
#include <asm/btext.h>
#include <asm/sections.h>
#include <asm/machdep.h>
#include <asm/opal.h>

#include <linux/linux_logo.h>

/*
 * Eventually bump that one up
 */
#define DEVTREE_CHUNK_SIZE  0x100000

/*
 * This is the size of the local memory reserve map that gets copied
 * into the boot params passed to the kernel. That size is totally
 * flexible as the kernel just reads the list until it encounters an
 * entry with size 0, so it can be changed without breaking binary
 * compatibility
 */
#define MEM_RESERVE_MAP_SIZE    8

/*
 * prom_init() is called very early on, before the kernel text
 * and data have been mapped to KERNELBASE.  At this point the code
 * is running at whatever address it has been loaded at.
 * On ppc32 we compile with -mrelocatable, which means that references
 * to extern and static variables get relocated automatically.
 * On ppc64 we have to relocate the references explicitly with
 * RELOC.  (Note that strings count as static variables.)
 *
 * Because OF may have mapped I/O devices into the area starting at
 * KERNELBASE, particularly on CHRP machines, we can't safely call
 * OF once the kernel has been mapped to KERNELBASE.  Therefore all
 * OF calls must be done within prom_init().
 *
 * ADDR is used in calls to call_prom.  The 4th and following
 * arguments to call_prom should be 32-bit values.
 * On ppc64, 64 bit values are truncated to 32 bits (and
 * fortunately don't get interpreted as two arguments).
 */
#ifdef CONFIG_PPC64
#define RELOC(x)        (*PTRRELOC(&(x)))
#define ADDR(x)     (u32) add_reloc_offset((unsigned long)(x))
#define OF_WORKAROUNDS  0
#else
#define RELOC(x)    (x)
#define ADDR(x)     (u32) (x)
#define OF_WORKAROUNDS  of_workarounds
int of_workarounds;
#endif

#define OF_WA_CLAIM 1   /* do phys/virt claim separately, then map */
#define OF_WA_LONGTRAIL 2   /* work around longtrail bugs */

#define PROM_BUG() do {                     \
        prom_printf("kernel BUG at %s line 0x%x!\n",        \
            RELOC(__FILE__), __LINE__);         \
        __asm__ __volatile__(".long " BUG_ILLEGAL_INSTR);   \
} while (0)

#ifdef DEBUG_PROM
#define prom_debug(x...)    prom_printf(x)
#else
#define prom_debug(x...)
#endif


typedef u32 prom_arg_t;

struct prom_args {
        u32 service;
        u32 nargs;
        u32 nret;
        prom_arg_t args[10];
};

struct prom_t {
    ihandle root;
    phandle chosen;
    int cpu;
    ihandle stdout;
    ihandle mmumap;
    ihandle memory;
};

struct mem_map_entry {
    u64 base;
    u64 size;
};

typedef u32 cell_t;

extern void __start(unsigned long r3, unsigned long r4, unsigned long r5,
            unsigned long r6, unsigned long r7, unsigned long r8,
            unsigned long r9);

#ifdef CONFIG_PPC64
extern int enter_prom(struct prom_args *args, unsigned long entry);
#else
static inline int enter_prom(struct prom_args *args, unsigned long entry)
{
    return ((int (*)(struct prom_args *))entry)(args);
}
#endif

extern void copy_and_flush(unsigned long dest, unsigned long src,
               unsigned long size, unsigned long offset);

/* prom structure */
static struct prom_t __initdata prom;

static unsigned long prom_entry __initdata;

#define PROM_SCRATCH_SIZE 256

static char __initdata of_stdout_device[256];
static char __initdata prom_scratch[PROM_SCRATCH_SIZE];

static unsigned long __initdata dt_header_start;
static unsigned long __initdata dt_struct_start, dt_struct_end;
static unsigned long __initdata dt_string_start, dt_string_end;

static unsigned long __initdata prom_initrd_start, prom_initrd_end;

#ifdef CONFIG_PPC64
static int __initdata prom_iommu_force_on;
static int __initdata prom_iommu_off;
static unsigned long __initdata prom_tce_alloc_start;
static unsigned long __initdata prom_tce_alloc_end;
#endif

/* Platforms codes are now obsolete in the kernel. Now only used within this
 * file and ultimately gone too. Feel free to change them if you need, they
 * are not shared with anything outside of this file anymore
 */
#define PLATFORM_PSERIES    0x0100
#define PLATFORM_PSERIES_LPAR   0x0101
#define PLATFORM_LPAR       0x0001
#define PLATFORM_POWERMAC   0x0400
#define PLATFORM_GENERIC    0x0500
#define PLATFORM_OPAL       0x0600

static int __initdata of_platform;

static char __initdata prom_cmd_line[COMMAND_LINE_SIZE];

static unsigned long __initdata prom_memory_limit;

static unsigned long __initdata alloc_top;
static unsigned long __initdata alloc_top_high;
static unsigned long __initdata alloc_bottom;
static unsigned long __initdata rmo_top;
static unsigned long __initdata ram_top;

static struct mem_map_entry __initdata mem_reserve_map[MEM_RESERVE_MAP_SIZE];
static int __initdata mem_reserve_cnt;

static cell_t __initdata regbuf[1024];


/*
 * Error results ... some OF calls will return "-1" on error, some
 * will return 0, some will return either. To simplify, here are
 * macros to use with any ihandle or phandle return value to check if
 * it is valid
 */

#define PROM_ERROR      (-1u)
#define PHANDLE_VALID(p)    ((p) != 0 && (p) != PROM_ERROR)
#define IHANDLE_VALID(i)    ((i) != 0 && (i) != PROM_ERROR)


/* This is the one and *ONLY* place where we actually call open
 * firmware.
 */

static int __init call_prom(const char *service, int nargs, int nret, ...)
{
    int i;
    struct prom_args args;
    va_list list;

    args.service = ADDR(service);
    args.nargs = nargs;
    args.nret = nret;

    va_start(list, nret);
    for (i = 0; i < nargs; i++)
        args.args[i] = va_arg(list, prom_arg_t);
    va_end(list);

    for (i = 0; i < nret; i++)
        args.args[nargs+i] = 0;

    if (enter_prom(&args, RELOC(prom_entry)) < 0)
        return PROM_ERROR;

    return (nret > 0) ? args.args[nargs] : 0;
}

static int __init call_prom_ret(const char *service, int nargs, int nret,
                prom_arg_t *rets, ...)
{
    int i;
    struct prom_args args;
    va_list list;

    args.service = ADDR(service);
    args.nargs = nargs;
    args.nret = nret;

    va_start(list, rets);
    for (i = 0; i < nargs; i++)
        args.args[i] = va_arg(list, prom_arg_t);
    va_end(list);

    for (i = 0; i < nret; i++)
        args.args[nargs+i] = 0;

    if (enter_prom(&args, RELOC(prom_entry)) < 0)
        return PROM_ERROR;

    if (rets != NULL)
        for (i = 1; i < nret; ++i)
            rets[i-1] = args.args[nargs+i];

    return (nret > 0) ? args.args[nargs] : 0;
}


static void __init prom_print(const char *msg)
{
    const char *p, *q;
    struct prom_t *_prom = &RELOC(prom);

    if (_prom->stdout == 0)
        return;

    for (p = msg; *p != 0; p = q) {
        for (q = p; *q != 0 && *q != '\n'; ++q)
            ;
        if (q > p)
            call_prom("write", 3, 1, _prom->stdout, p, q - p);
        if (*q == 0)
            break;
        ++q;
        call_prom("write", 3, 1, _prom->stdout, ADDR("\r\n"), 2);
    }
}


static void __init prom_print_hex(unsigned long val)
{
    int i, nibbles = sizeof(val)*2;
    char buf[sizeof(val)*2+1];
    struct prom_t *_prom = &RELOC(prom);

    for (i = nibbles-1;  i >= 0;  i--) {
        buf[i] = (val & 0xf) + '0';
        if (buf[i] > '9')
            buf[i] += ('a'-'0'-10);
        val >>= 4;
    }
    buf[nibbles] = '\0';
    call_prom("write", 3, 1, _prom->stdout, buf, nibbles);
}

/* max number of decimal digits in an unsigned long */
#define UL_DIGITS 21
static void __init prom_print_dec(unsigned long val)
{
    int i, size;
    char buf[UL_DIGITS+1];
    struct prom_t *_prom = &RELOC(prom);

    for (i = UL_DIGITS-1; i >= 0;  i--) {
        buf[i] = (val % 10) + '0';
        val = val/10;
        if (val == 0)
            break;
    }
    /* shift stuff down */
    size = UL_DIGITS - i;
    call_prom("write", 3, 1, _prom->stdout, buf+i, size);
}

static void __init prom_printf(const char *format, ...)
{
    const char *p, *q, *s;
    va_list args;
    unsigned long v;
    long vs;
    struct prom_t *_prom = &RELOC(prom);

    va_start(args, format);
#ifdef CONFIG_PPC64
    format = PTRRELOC(format);
#endif
    for (p = format; *p != 0; p = q) {
        for (q = p; *q != 0 && *q != '\n' && *q != '%'; ++q)
            ;
        if (q > p)
            call_prom("write", 3, 1, _prom->stdout, p, q - p);
        if (*q == 0)
            break;
        if (*q == '\n') {
            ++q;
            call_prom("write", 3, 1, _prom->stdout,
                  ADDR("\r\n"), 2);
            continue;
        }
        ++q;
        if (*q == 0)
            break;
        switch (*q) {
        case 's':
            ++q;
            s = va_arg(args, const char *);
            prom_print(s);
            break;
        case 'x':
            ++q;
            v = va_arg(args, unsigned long);
            prom_print_hex(v);
            break;
        case 'd':
            ++q;
            vs = va_arg(args, int);
            if (vs < 0) {
                prom_print(RELOC("-"));
                vs = -vs;
            }
            prom_print_dec(vs);
            break;
        case 'l':
            ++q;
            if (*q == 0)
                break;
            else if (*q == 'x') {
                ++q;
                v = va_arg(args, unsigned long);
                prom_print_hex(v);
            } else if (*q == 'u') { /* '%lu' */
                ++q;
                v = va_arg(args, unsigned long);
                prom_print_dec(v);
            } else if (*q == 'd') { /* %ld */
                ++q;
                vs = va_arg(args, long);
                if (vs < 0) {
                    prom_print(RELOC("-"));
                    vs = -vs;
                }
                prom_print_dec(vs);
            }
            break;
        }
    }
}


static unsigned int __init prom_claim(unsigned long virt, unsigned long size,
                unsigned long align)
{
    struct prom_t *_prom = &RELOC(prom);

    if (align == 0 && (OF_WORKAROUNDS & OF_WA_CLAIM)) {
        /*
         * Old OF requires we claim physical and virtual separately
         * and then map explicitly (assuming virtual mode)
         */
        int ret;
        prom_arg_t result;

        ret = call_prom_ret("call-method", 5, 2, &result,
                    ADDR("claim"), _prom->memory,
                    align, size, virt);
        if (ret != 0 || result == -1)
            return -1;
        ret = call_prom_ret("call-method", 5, 2, &result,
                    ADDR("claim"), _prom->mmumap,
                    align, size, virt);
        if (ret != 0) {
            call_prom("call-method", 4, 1, ADDR("release"),
                  _prom->memory, size, virt);
            return -1;
        }
        /* the 0x12 is M (coherence) + PP == read/write */
        call_prom("call-method", 6, 1,
              ADDR("map"), _prom->mmumap, 0x12, size, virt, virt);
        return virt;
    }
    return call_prom("claim", 3, 1, (prom_arg_t)virt, (prom_arg_t)size,
             (prom_arg_t)align);
}

static void __init __attribute__((noreturn)) prom_panic(const char *reason)
{
#ifdef CONFIG_PPC64
    reason = PTRRELOC(reason);
#endif
    prom_print(reason);
    /* Do not call exit because it clears the screen on pmac
     * it also causes some sort of double-fault on early pmacs */
    if (RELOC(of_platform) == PLATFORM_POWERMAC)
        asm("trap\n");

    /* ToDo: should put up an SRC here on pSeries */
    call_prom("exit", 0, 0);

    for (;;)            /* should never get here */
        ;
}


static int __init prom_next_node(phandle *nodep)
{
    phandle node;

    if ((node = *nodep) != 0
        && (*nodep = call_prom("child", 1, 1, node)) != 0)
        return 1;
    if ((*nodep = call_prom("peer", 1, 1, node)) != 0)
        return 1;
    for (;;) {
        if ((node = call_prom("parent", 1, 1, node)) == 0)
            return 0;
        if ((*nodep = call_prom("peer", 1, 1, node)) != 0)
            return 1;
    }
}

static int inline prom_getprop(phandle node, const char *pname,
                   void *value, size_t valuelen)
{
    return call_prom("getprop", 4, 1, node, ADDR(pname),
             (u32)(unsigned long) value, (u32) valuelen);
}

static int inline prom_getproplen(phandle node, const char *pname)
{
    return call_prom("getproplen", 2, 1, node, ADDR(pname));
}

static void add_string(char **str, const char *q)
{
    char *p = *str;

    while (*q)
        *p++ = *q++;
    *p++ = ' ';
    *str = p;
}

static char *tohex(unsigned int x)
{
    static char digits[] = "0123456789abcdef";
    static char result[9];
    int i;

    result[8] = 0;
    i = 8;
    do {
        --i;
        result[i] = digits[x & 0xf];
        x >>= 4;
    } while (x != 0 && i > 0);
    return &result[i];
}

static int __init prom_setprop(phandle node, const char *nodename,
                   const char *pname, void *value, size_t valuelen)
{
    char cmd[256], *p;

    if (!(OF_WORKAROUNDS & OF_WA_LONGTRAIL))
        return call_prom("setprop", 4, 1, node, ADDR(pname),
                 (u32)(unsigned long) value, (u32) valuelen);

    /* gah... setprop doesn't work on longtrail, have to use interpret */
    p = cmd;
    add_string(&p, "dev");
    add_string(&p, nodename);
    add_string(&p, tohex((u32)(unsigned long) value));
    add_string(&p, tohex(valuelen));
    add_string(&p, tohex(ADDR(pname)));
    add_string(&p, tohex(strlen(RELOC(pname))));
    add_string(&p, "property");
    *p = 0;
    return call_prom("interpret", 1, 1, (u32)(unsigned long) cmd);
}

/* We can't use the standard versions because of RELOC headaches. */
#define isxdigit(c) (('0' <= (c) && (c) <= '9') \
             || ('a' <= (c) && (c) <= 'f') \
             || ('A' <= (c) && (c) <= 'F'))

#define isdigit(c)  ('0' <= (c) && (c) <= '9')
#define islower(c)  ('a' <= (c) && (c) <= 'z')
#define toupper(c)  (islower(c) ? ((c) - 'a' + 'A') : (c))

unsigned long prom_strtoul(const char *cp, const char **endp)
{
    unsigned long result = 0, base = 10, value;

    if (*cp == '0') {
        base = 8;
        cp++;
        if (toupper(*cp) == 'X') {
            cp++;
            base = 16;
        }
    }

    while (isxdigit(*cp) &&
           (value = isdigit(*cp) ? *cp - '0' : toupper(*cp) - 'A' + 10) < base) {
        result = result * base + value;
        cp++;
    }

    if (endp)
        *endp = cp;

    return result;
}

unsigned long prom_memparse(const char *ptr, const char **retptr)
{
    unsigned long ret = prom_strtoul(ptr, retptr);
    int shift = 0;

    /*
     * We can't use a switch here because GCC *may* generate a
     * jump table which won't work, because we're not running at
     * the address we're linked at.
     */
    if ('G' == **retptr || 'g' == **retptr)
        shift = 30;

    if ('M' == **retptr || 'm' == **retptr)
        shift = 20;

    if ('K' == **retptr || 'k' == **retptr)
        shift = 10;

    if (shift) {
        ret <<= shift;
        (*retptr)++;
    }

    return ret;
}

/*
 * Early parsing of the command line passed to the kernel, used for
 * "mem=x" and the options that affect the iommu
 */
static void __init early_cmdline_parse(void)
{
    struct prom_t *_prom = &RELOC(prom);
    const char *opt;

    char *p;
    int l = 0;

    RELOC(prom_cmd_line[0]) = 0;
    p = RELOC(prom_cmd_line);
    if ((long)_prom->chosen > 0)
        l = prom_getprop(_prom->chosen, "bootargs", p, COMMAND_LINE_SIZE-1);
#ifdef CONFIG_CMDLINE
    if (l <= 0 || p[0] == '\0') /* dbl check */
        strlcpy(RELOC(prom_cmd_line),
            RELOC(CONFIG_CMDLINE), sizeof(prom_cmd_line));
#endif /* CONFIG_CMDLINE */
    prom_printf("command line: %s\n", RELOC(prom_cmd_line));

#ifdef CONFIG_PPC64
    opt = strstr(RELOC(prom_cmd_line), RELOC("iommu="));
    if (opt) {
        prom_printf("iommu opt is: %s\n", opt);
        opt += 6;
        while (*opt && *opt == ' ')
            opt++;
        if (!strncmp(opt, RELOC("off"), 3))
            RELOC(prom_iommu_off) = 1;
        else if (!strncmp(opt, RELOC("force"), 5))
            RELOC(prom_iommu_force_on) = 1;
    }
#endif
    opt = strstr(RELOC(prom_cmd_line), RELOC("mem="));
    if (opt) {
        opt += 4;
        RELOC(prom_memory_limit) = prom_memparse(opt, (const char **)&opt);
#ifdef CONFIG_PPC64
        /* Align to 16 MB == size of ppc64 large page */
        RELOC(prom_memory_limit) = ALIGN(RELOC(prom_memory_limit), 0x1000000);
#endif
    }
}

#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
/*
 * There are two methods for telling firmware what our capabilities are.
 * Newer machines have an "ibm,client-architecture-support" method on the
 * root node.  For older machines, we have to call the "process-elf-header"
 * method in the /packages/elf-loader node, passing it a fake 32-bit
 * ELF header containing a couple of PT_NOTE sections that contain
 * structures that contain various information.
 */

/*
 * New method - extensible architecture description vector.
 *
 * Because the description vector contains a mix of byte and word
 * values, we declare it as an unsigned char array, and use this
 * macro to put word values in.
 */
#define W(x)    ((x) >> 24) & 0xff, ((x) >> 16) & 0xff, \
        ((x) >> 8) & 0xff, (x) & 0xff

/* Option vector bits - generic bits in byte 1 */
#define OV_IGNORE       0x80    /* ignore this vector */
#define OV_CESSATION_POLICY 0x40    /* halt if unsupported option present*/

/* Option vector 1: processor architectures supported */
#define OV1_PPC_2_00        0x80    /* set if we support PowerPC 2.00 */
#define OV1_PPC_2_01        0x40    /* set if we support PowerPC 2.01 */
#define OV1_PPC_2_02        0x20    /* set if we support PowerPC 2.02 */
#define OV1_PPC_2_03        0x10    /* set if we support PowerPC 2.03 */
#define OV1_PPC_2_04        0x08    /* set if we support PowerPC 2.04 */
#define OV1_PPC_2_05        0x04    /* set if we support PowerPC 2.05 */
#define OV1_PPC_2_06        0x02    /* set if we support PowerPC 2.06 */

/* Option vector 2: Open Firmware options supported */
#define OV2_REAL_MODE       0x20    /* set if we want OF in real mode */

/* Option vector 3: processor options supported */
#define OV3_FP          0x80    /* floating point */
#define OV3_VMX         0x40    /* VMX/Altivec */
#define OV3_DFP         0x20    /* decimal FP */

/* Option vector 4: IBM PAPR implementation */
#define OV4_MIN_ENT_CAP     0x01    /* minimum VP entitled capacity */

/* Option vector 5: PAPR/OF options supported */
#define OV5_LPAR        0x80    /* logical partitioning supported */
#define OV5_SPLPAR      0x40    /* shared-processor LPAR supported */
/* ibm,dynamic-reconfiguration-memory property supported */
#define OV5_DRCONF_MEMORY   0x20
#define OV5_LARGE_PAGES     0x10    /* large pages supported */
#define OV5_DONATE_DEDICATE_CPU 0x02    /* donate dedicated CPU support */
/* PCIe/MSI support.  Without MSI full PCIe is not supported */
#ifdef CONFIG_PCI_MSI
#define OV5_MSI         0x01    /* PCIe/MSI support */
#else
#define OV5_MSI         0x00
#endif /* CONFIG_PCI_MSI */
#ifdef CONFIG_PPC_SMLPAR
#define OV5_CMO         0x80    /* Cooperative Memory Overcommitment */
#define OV5_XCMO            0x40    /* Page Coalescing */
#else
#define OV5_CMO         0x00
#define OV5_XCMO            0x00
#endif
#define OV5_TYPE1_AFFINITY  0x80    /* Type 1 NUMA affinity */
#define OV5_PFO_HW_RNG      0x80    /* PFO Random Number Generator */
#define OV5_PFO_HW_842      0x40    /* PFO Compression Accelerator */
#define OV5_PFO_HW_ENCR     0x20    /* PFO Encryption Accelerator */

/* Option Vector 6: IBM PAPR hints */
#define OV6_LINUX       0x02    /* Linux is our OS */

/*
 * The architecture vector has an array of PVR mask/value pairs,
 * followed by # option vectors - 1, followed by the option vectors.
 */
static unsigned char ibm_architecture_vec[] = {
    W(0xfffe0000), W(0x003a0000),   /* POWER5/POWER5+ */
    W(0xffff0000), W(0x003e0000),   /* POWER6 */
    W(0xffff0000), W(0x003f0000),   /* POWER7 */
    W(0xffffffff), W(0x0f000003),   /* all 2.06-compliant */
    W(0xffffffff), W(0x0f000002),   /* all 2.05-compliant */
    W(0xfffffffe), W(0x0f000001),   /* all 2.04-compliant and earlier */
    6 - 1,              /* 6 option vectors */

    /* option vector 1: processor architectures supported */
    3 - 2,              /* length */
    0,              /* don't ignore, don't halt */
    OV1_PPC_2_00 | OV1_PPC_2_01 | OV1_PPC_2_02 | OV1_PPC_2_03 |
    OV1_PPC_2_04 | OV1_PPC_2_05 | OV1_PPC_2_06,

    /* option vector 2: Open Firmware options supported */
    34 - 2,             /* length */
    OV2_REAL_MODE,
    0, 0,
    W(0xffffffff),          /* real_base */
    W(0xffffffff),          /* real_size */
    W(0xffffffff),          /* virt_base */
    W(0xffffffff),          /* virt_size */
    W(0xffffffff),          /* load_base */
    W(256),             /* 256MB min RMA */
    W(0xffffffff),          /* full client load */
    0,              /* min RMA percentage of total RAM */
    48,             /* max log_2(hash table size) */

    /* option vector 3: processor options supported */
    3 - 2,              /* length */
    0,              /* don't ignore, don't halt */
    OV3_FP | OV3_VMX | OV3_DFP,

    /* option vector 4: IBM PAPR implementation */
    3 - 2,              /* length */
    0,              /* don't halt */
    OV4_MIN_ENT_CAP,        /* minimum VP entitled capacity */

    /* option vector 5: PAPR/OF options */
    18 - 2,             /* length */
    0,              /* don't ignore, don't halt */
    OV5_LPAR | OV5_SPLPAR | OV5_LARGE_PAGES | OV5_DRCONF_MEMORY |
    OV5_DONATE_DEDICATE_CPU | OV5_MSI,
    0,
    OV5_CMO | OV5_XCMO,
    OV5_TYPE1_AFFINITY,
    0,
    0,
    0,
    /* WARNING: The offset of the "number of cores" field below
     * must match by the macro below. Update the definition if
     * the structure layout changes.
     */
#define IBM_ARCH_VEC_NRCORES_OFFSET 101
    W(NR_CPUS),         /* number of cores supported */
    0,
    0,
    0,
    0,
    OV5_PFO_HW_RNG | OV5_PFO_HW_ENCR | OV5_PFO_HW_842,
    /* option vector 6: IBM PAPR hints */
    4 - 2,              /* length */
    0,
    0,
    OV6_LINUX,

};

/* Old method - ELF header with PT_NOTE sections */
static struct fake_elf {
    Elf32_Ehdr  elfhdr;
    Elf32_Phdr  phdr[2];
    struct chrpnote {
        u32 namesz;
        u32 descsz;
        u32 type;
        char    name[8];    /* "PowerPC" */
        struct chrpdesc {
            u32 real_mode;
            u32 real_base;
            u32 real_size;
            u32 virt_base;
            u32 virt_size;
            u32 load_base;
        } chrpdesc;
    } chrpnote;
    struct rpanote {
        u32 namesz;
        u32 descsz;
        u32 type;
        char    name[24];   /* "IBM,RPA-Client-Config" */
        struct rpadesc {
            u32 lpar_affinity;
            u32 min_rmo_size;
            u32 min_rmo_percent;
            u32 max_pft_size;
            u32 splpar;
            u32 min_load;
            u32 new_mem_def;
            u32 ignore_me;
        } rpadesc;
    } rpanote;
} fake_elf = {
    .elfhdr = {
        .e_ident = { 0x7f, 'E', 'L', 'F',
                 ELFCLASS32, ELFDATA2MSB, EV_CURRENT },
        .e_type = ET_EXEC,  /* yeah right */
        .e_machine = EM_PPC,
        .e_version = EV_CURRENT,
        .e_phoff = offsetof(struct fake_elf, phdr),
        .e_phentsize = sizeof(Elf32_Phdr),
        .e_phnum = 2
    },
    .phdr = {
        [0] = {
            .p_type = PT_NOTE,
            .p_offset = offsetof(struct fake_elf, chrpnote),
            .p_filesz = sizeof(struct chrpnote)
        }, [1] = {
            .p_type = PT_NOTE,
            .p_offset = offsetof(struct fake_elf, rpanote),
            .p_filesz = sizeof(struct rpanote)
        }
    },
    .chrpnote = {
        .namesz = sizeof("PowerPC"),
        .descsz = sizeof(struct chrpdesc),
        .type = 0x1275,
        .name = "PowerPC",
        .chrpdesc = {
            .real_mode = ~0U,   /* ~0 means "don't care" */
            .real_base = ~0U,
            .real_size = ~0U,
            .virt_base = ~0U,
            .virt_size = ~0U,
            .load_base = ~0U
        },
    },
    .rpanote = {
        .namesz = sizeof("IBM,RPA-Client-Config"),
        .descsz = sizeof(struct rpadesc),
        .type = 0x12759999,
        .name = "IBM,RPA-Client-Config",
        .rpadesc = {
            .lpar_affinity = 0,
            .min_rmo_size = 64, /* in megabytes */
            .min_rmo_percent = 0,
            .max_pft_size = 48, /* 2^48 bytes max PFT size */
            .splpar = 1,
            .min_load = ~0U,
            .new_mem_def = 0
        }
    }
};

static int __init prom_count_smt_threads(void)
{
    phandle node;
    char type[64];
    unsigned int plen;

    /* Pick up th first CPU node we can find */
    for (node = 0; prom_next_node(&node); ) {
        type[0] = 0;
        prom_getprop(node, "device_type", type, sizeof(type));

        if (strcmp(type, RELOC("cpu")))
            continue;
        /*
         * There is an entry for each smt thread, each entry being
         * 4 bytes long.  All cpus should have the same number of
         * smt threads, so return after finding the first.
         */
        plen = prom_getproplen(node, "ibm,ppc-interrupt-server#s");
        if (plen == PROM_ERROR)
            break;
        plen >>= 2;
        prom_debug("Found %lu smt threads per core\n", (unsigned long)plen);

        /* Sanity check */
        if (plen < 1 || plen > 64) {
            prom_printf("Threads per core %lu out of bounds, assuming 1\n",
                    (unsigned long)plen);
            return 1;
        }
        return plen;
    }
    prom_debug("No threads found, assuming 1 per core\n");

    return 1;

}


static void __init prom_send_capabilities(void)
{
    ihandle elfloader, root;
    prom_arg_t ret;
    u32 *cores;

    root = call_prom("open", 1, 1, ADDR("/"));
    if (root != 0) {
        /* We need to tell the FW about the number of cores we support.
         *
         * To do that, we count the number of threads on the first core
         * (we assume this is the same for all cores) and use it to
         * divide NR_CPUS.
         */
        cores = (u32 *)PTRRELOC(&ibm_architecture_vec[IBM_ARCH_VEC_NRCORES_OFFSET]);
        if (*cores != NR_CPUS) {
            prom_printf("WARNING ! "
                    "ibm_architecture_vec structure inconsistent: %lu!\n",
                    *cores);
        } else {
            *cores = DIV_ROUND_UP(NR_CPUS, prom_count_smt_threads());
            prom_printf("Max number of cores passed to firmware: %lu (NR_CPUS = %lu)\n",
                    *cores, NR_CPUS);
        }

        /* try calling the ibm,client-architecture-support method */
        prom_printf("Calling ibm,client-architecture-support...");
        if (call_prom_ret("call-method", 3, 2, &ret,
                  ADDR("ibm,client-architecture-support"),
                  root,
                  ADDR(ibm_architecture_vec)) == 0) {
            /* the call exists... */
            if (ret)
                prom_printf("\nWARNING: ibm,client-architecture"
                        "-support call FAILED!\n");
            call_prom("close", 1, 0, root);
            prom_printf(" done\n");
            return;
        }
        call_prom("close", 1, 0, root);
        prom_printf(" not implemented\n");
    }

    /* no ibm,client-architecture-support call, try the old way */
    elfloader = call_prom("open", 1, 1, ADDR("/packages/elf-loader"));
    if (elfloader == 0) {
        prom_printf("couldn't open /packages/elf-loader\n");
        return;
    }
    call_prom("call-method", 3, 1, ADDR("process-elf-header"),
            elfloader, ADDR(&fake_elf));
    call_prom("close", 1, 0, elfloader);
}
#endif

/*
 * Memory allocation strategy... our layout is normally:
 *
 *  at 14Mb or more we have vmlinux, then a gap and initrd.  In some
 *  rare cases, initrd might end up being before the kernel though.
 *  We assume this won't override the final kernel at 0, we have no
 *  provision to handle that in this version, but it should hopefully
 *  never happen.
 *
 *  alloc_top is set to the top of RMO, eventually shrink down if the
 *  TCEs overlap
 *
 *  alloc_bottom is set to the top of kernel/initrd
 *
 *  from there, allocations are done this way : rtas is allocated
 *  topmost, and the device-tree is allocated from the bottom. We try
 *  to grow the device-tree allocation as we progress. If we can't,
 *  then we fail, we don't currently have a facility to restart
 *  elsewhere, but that shouldn't be necessary.
 *
 *  Note that calls to reserve_mem have to be done explicitly, memory
 *  allocated with either alloc_up or alloc_down isn't automatically
 *  reserved.
 */


/*
 * Allocates memory in the RMO upward from the kernel/initrd
 *
 * When align is 0, this is a special case, it means to allocate in place
 * at the current location of alloc_bottom or fail (that is basically
 * extending the previous allocation). Used for the device-tree flattening
 */
static unsigned long __init alloc_up(unsigned long size, unsigned long align)
{
    unsigned long base = RELOC(alloc_bottom);
    unsigned long addr = 0;

    if (align)
        base = _ALIGN_UP(base, align);
    prom_debug("alloc_up(%x, %x)\n", size, align);
    if (RELOC(ram_top) == 0)
        prom_panic("alloc_up() called with mem not initialized\n");

    if (align)
        base = _ALIGN_UP(RELOC(alloc_bottom), align);
    else
        base = RELOC(alloc_bottom);

    for(; (base + size) <= RELOC(alloc_top); 
        base = _ALIGN_UP(base + 0x100000, align)) {
        prom_debug("    trying: 0x%x\n\r", base);
        addr = (unsigned long)prom_claim(base, size, 0);
        if (addr != PROM_ERROR && addr != 0)
            break;
        addr = 0;
        if (align == 0)
            break;
    }
    if (addr == 0)
        return 0;
    RELOC(alloc_bottom) = addr + size;

    prom_debug(" -> %x\n", addr);
    prom_debug("  alloc_bottom : %x\n", RELOC(alloc_bottom));
    prom_debug("  alloc_top    : %x\n", RELOC(alloc_top));
    prom_debug("  alloc_top_hi : %x\n", RELOC(alloc_top_high));
    prom_debug("  rmo_top      : %x\n", RELOC(rmo_top));
    prom_debug("  ram_top      : %x\n", RELOC(ram_top));

    return addr;
}

/*
 * Allocates memory downward, either from top of RMO, or if highmem
 * is set, from the top of RAM.  Note that this one doesn't handle
 * failures.  It does claim memory if highmem is not set.
 */
static unsigned long __init alloc_down(unsigned long size, unsigned long align,
                       int highmem)
{
    unsigned long base, addr = 0;

    prom_debug("alloc_down(%x, %x, %s)\n", size, align,
           highmem ? RELOC("(high)") : RELOC("(low)"));
    if (RELOC(ram_top) == 0)
        prom_panic("alloc_down() called with mem not initialized\n");

    if (highmem) {
        /* Carve out storage for the TCE table. */
        addr = _ALIGN_DOWN(RELOC(alloc_top_high) - size, align);
        if (addr <= RELOC(alloc_bottom))
            return 0;
        /* Will we bump into the RMO ? If yes, check out that we
         * didn't overlap existing allocations there, if we did,
         * we are dead, we must be the first in town !
         */
        if (addr < RELOC(rmo_top)) {
            /* Good, we are first */
            if (RELOC(alloc_top) == RELOC(rmo_top))
                RELOC(alloc_top) = RELOC(rmo_top) = addr;
            else
                return 0;
        }
        RELOC(alloc_top_high) = addr;
        goto bail;
    }

    base = _ALIGN_DOWN(RELOC(alloc_top) - size, align);
    for (; base > RELOC(alloc_bottom);
         base = _ALIGN_DOWN(base - 0x100000, align))  {
        prom_debug("    trying: 0x%x\n\r", base);
        addr = (unsigned long)prom_claim(base, size, 0);
        if (addr != PROM_ERROR && addr != 0)
            break;
        addr = 0;
    }
    if (addr == 0)
        return 0;
    RELOC(alloc_top) = addr;

 bail:
    prom_debug(" -> %x\n", addr);
    prom_debug("  alloc_bottom : %x\n", RELOC(alloc_bottom));
    prom_debug("  alloc_top    : %x\n", RELOC(alloc_top));
    prom_debug("  alloc_top_hi : %x\n", RELOC(alloc_top_high));
    prom_debug("  rmo_top      : %x\n", RELOC(rmo_top));
    prom_debug("  ram_top      : %x\n", RELOC(ram_top));

    return addr;
}

/*
 * Parse a "reg" cell
 */
static unsigned long __init prom_next_cell(int s, cell_t **cellp)
{
    cell_t *p = *cellp;
    unsigned long r = 0;

    /* Ignore more than 2 cells */
    while (s > sizeof(unsigned long) / 4) {
        p++;
        s--;
    }
    r = *p++;
#ifdef CONFIG_PPC64
    if (s > 1) {
        r <<= 32;
        r |= *(p++);
    }
#endif
    *cellp = p;
    return r;
}

/*
 * Very dumb function for adding to the memory reserve list, but
 * we don't need anything smarter at this point
 *
 * XXX Eventually check for collisions.  They should NEVER happen.
 * If problems seem to show up, it would be a good start to track
 * them down.
 */
static void __init reserve_mem(u64 base, u64 size)
{
    u64 top = base + size;
    unsigned long cnt = RELOC(mem_reserve_cnt);

    if (size == 0)
        return;

    /* We need to always keep one empty entry so that we
     * have our terminator with "size" set to 0 since we are
     * dumb and just copy this entire array to the boot params
     */
    base = _ALIGN_DOWN(base, PAGE_SIZE);
    top = _ALIGN_UP(top, PAGE_SIZE);
    size = top - base;

    if (cnt >= (MEM_RESERVE_MAP_SIZE - 1))
        prom_panic("Memory reserve map exhausted !\n");
    RELOC(mem_reserve_map)[cnt].base = base;
    RELOC(mem_reserve_map)[cnt].size = size;
    RELOC(mem_reserve_cnt) = cnt + 1;
}

/*
 * Initialize memory allocation mechanism, parse "memory" nodes and
 * obtain that way the top of memory and RMO to setup out local allocator
 */
static void __init prom_init_mem(void)
{
    phandle node;
    char *path, type[64];
    unsigned int plen;
    cell_t *p, *endp;
    struct prom_t *_prom = &RELOC(prom);
    u32 rac, rsc;

    /*
     * We iterate the memory nodes to find
     * 1) top of RMO (first node)
     * 2) top of memory
     */
    rac = 2;
    prom_getprop(_prom->root, "#address-cells", &rac, sizeof(rac));
    rsc = 1;
    prom_getprop(_prom->root, "#size-cells", &rsc, sizeof(rsc));
    prom_debug("root_addr_cells: %x\n", (unsigned long) rac);
    prom_debug("root_size_cells: %x\n", (unsigned long) rsc);

    prom_debug("scanning memory:\n");
    path = RELOC(prom_scratch);

    for (node = 0; prom_next_node(&node); ) {
        type[0] = 0;
        prom_getprop(node, "device_type", type, sizeof(type));

        if (type[0] == 0) {
            /*
             * CHRP Longtrail machines have no device_type
             * on the memory node, so check the name instead...
             */
            prom_getprop(node, "name", type, sizeof(type));
        }
        if (strcmp(type, RELOC("memory")))
            continue;

        plen = prom_getprop(node, "reg", RELOC(regbuf), sizeof(regbuf));
        if (plen > sizeof(regbuf)) {
            prom_printf("memory node too large for buffer !\n");
            plen = sizeof(regbuf);
        }
        p = RELOC(regbuf);
        endp = p + (plen / sizeof(cell_t));

#ifdef DEBUG_PROM
        memset(path, 0, PROM_SCRATCH_SIZE);
        call_prom("package-to-path", 3, 1, node, path, PROM_SCRATCH_SIZE-1);
        prom_debug("  node %s :\n", path);
#endif /* DEBUG_PROM */

        while ((endp - p) >= (rac + rsc)) {
            unsigned long base, size;

            base = prom_next_cell(rac, &p);
            size = prom_next_cell(rsc, &p);

            if (size == 0)
                continue;
            prom_debug("    %x %x\n", base, size);
            if (base == 0 && (RELOC(of_platform) & PLATFORM_LPAR))
                RELOC(rmo_top) = size;
            if ((base + size) > RELOC(ram_top))
                RELOC(ram_top) = base + size;
        }
    }

    RELOC(alloc_bottom) = PAGE_ALIGN((unsigned long)&RELOC(_end) + 0x4000);

    /*
     * If prom_memory_limit is set we reduce the upper limits *except* for
     * alloc_top_high. This must be the real top of RAM so we can put
     * TCE's up there.
     */

    RELOC(alloc_top_high) = RELOC(ram_top);

    if (RELOC(prom_memory_limit)) {
        if (RELOC(prom_memory_limit) <= RELOC(alloc_bottom)) {
            prom_printf("Ignoring mem=%x <= alloc_bottom.\n",
                RELOC(prom_memory_limit));
            RELOC(prom_memory_limit) = 0;
        } else if (RELOC(prom_memory_limit) >= RELOC(ram_top)) {
            prom_printf("Ignoring mem=%x >= ram_top.\n",
                RELOC(prom_memory_limit));
            RELOC(prom_memory_limit) = 0;
        } else {
            RELOC(ram_top) = RELOC(prom_memory_limit);
            RELOC(rmo_top) = min(RELOC(rmo_top), RELOC(prom_memory_limit));
        }
    }

    /*
     * Setup our top alloc point, that is top of RMO or top of
     * segment 0 when running non-LPAR.
     * Some RS64 machines have buggy firmware where claims up at
     * 1GB fail.  Cap at 768MB as a workaround.
     * Since 768MB is plenty of room, and we need to cap to something
     * reasonable on 32-bit, cap at 768MB on all machines.
     */
    if (!RELOC(rmo_top))
        RELOC(rmo_top) = RELOC(ram_top);
    RELOC(rmo_top) = min(0x30000000ul, RELOC(rmo_top));
    RELOC(alloc_top) = RELOC(rmo_top);
    RELOC(alloc_top_high) = RELOC(ram_top);

    /*
     * Check if we have an initrd after the kernel but still inside
     * the RMO.  If we do move our bottom point to after it.
     */
    if (RELOC(prom_initrd_start) &&
        RELOC(prom_initrd_start) < RELOC(rmo_top) &&
        RELOC(prom_initrd_end) > RELOC(alloc_bottom))
        RELOC(alloc_bottom) = PAGE_ALIGN(RELOC(prom_initrd_end));

    prom_printf("memory layout at init:\n");
    prom_printf("  memory_limit : %x (16 MB aligned)\n", RELOC(prom_memory_limit));
    prom_printf("  alloc_bottom : %x\n", RELOC(alloc_bottom));
    prom_printf("  alloc_top    : %x\n", RELOC(alloc_top));
    prom_printf("  alloc_top_hi : %x\n", RELOC(alloc_top_high));
    prom_printf("  rmo_top      : %x\n", RELOC(rmo_top));
    prom_printf("  ram_top      : %x\n", RELOC(ram_top));
}

static void __init prom_close_stdin(void)
{
    struct prom_t *_prom = &RELOC(prom);
    ihandle val;

    if (prom_getprop(_prom->chosen, "stdin", &val, sizeof(val)) > 0)
        call_prom("close", 1, 0, val);
}

#ifdef CONFIG_PPC_POWERNV

static u64 __initdata prom_opal_size;
static u64 __initdata prom_opal_align;
static int __initdata prom_rtas_start_cpu;
static u64 __initdata prom_rtas_data;
static u64 __initdata prom_rtas_entry;

#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL
static u64 __initdata prom_opal_base;
static u64 __initdata prom_opal_entry;
#endif

/* XXX Don't change this structure without updating opal-takeover.S */
static struct opal_secondary_data {
    s64             ack;    /*  0 */
    u64             go; /*  8 */
    struct opal_takeover_args   args;   /* 16 */
} opal_secondary_data;

extern char opal_secondary_entry;

static void __init prom_query_opal(void)
{
    long rc;

    /* We must not query for OPAL presence on a machine that
     * supports TNK takeover (970 blades), as this uses the same
     * h-call with different arguments and will crash
     */
    if (PHANDLE_VALID(call_prom("finddevice", 1, 1,
                    ADDR("/tnk-memory-map")))) {
        prom_printf("TNK takeover detected, skipping OPAL check\n");
        return;
    }

    prom_printf("Querying for OPAL presence... ");
    rc = opal_query_takeover(&RELOC(prom_opal_size),
                 &RELOC(prom_opal_align));
    prom_debug("(rc = %ld) ", rc);
    if (rc != 0) {
        prom_printf("not there.\n");
        return;
    }
    RELOC(of_platform) = PLATFORM_OPAL;
    prom_printf(" there !\n");
    prom_debug("  opal_size  = 0x%lx\n", RELOC(prom_opal_size));
    prom_debug("  opal_align = 0x%lx\n", RELOC(prom_opal_align));
    if (RELOC(prom_opal_align) < 0x10000)
        RELOC(prom_opal_align) = 0x10000;
}

static int prom_rtas_call(int token, int nargs, int nret, int *outputs, ...)
{
    struct rtas_args rtas_args;
    va_list list;
    int i;

    rtas_args.token = token;
    rtas_args.nargs = nargs;
    rtas_args.nret  = nret;
    rtas_args.rets  = (rtas_arg_t *)&(rtas_args.args[nargs]);
    va_start(list, outputs);
    for (i = 0; i < nargs; ++i)
        rtas_args.args[i] = va_arg(list, rtas_arg_t);
    va_end(list);

    for (i = 0; i < nret; ++i)
        rtas_args.rets[i] = 0;

    opal_enter_rtas(&rtas_args, RELOC(prom_rtas_data),
            RELOC(prom_rtas_entry));

    if (nret > 1 && outputs != NULL)
        for (i = 0; i < nret-1; ++i)
            outputs[i] = rtas_args.rets[i+1];
    return (nret > 0)? rtas_args.rets[0]: 0;
}

static void __init prom_opal_hold_cpus(void)
{
    int i, cnt, cpu, rc;
    long j;
    phandle node;
    char type[64];
    u32 servers[8];
    struct prom_t *_prom = &RELOC(prom);
    void *entry = (unsigned long *)&RELOC(opal_secondary_entry);
    struct opal_secondary_data *data = &RELOC(opal_secondary_data);

    prom_debug("prom_opal_hold_cpus: start...\n");
    prom_debug("    - entry       = 0x%x\n", entry);
    prom_debug("    - data        = 0x%x\n", data);

    data->ack = -1;
    data->go = 0;

    /* look for cpus */
    for (node = 0; prom_next_node(&node); ) {
        type[0] = 0;
        prom_getprop(node, "device_type", type, sizeof(type));
        if (strcmp(type, RELOC("cpu")) != 0)
            continue;

        /* Skip non-configured cpus. */
        if (prom_getprop(node, "status", type, sizeof(type)) > 0)
            if (strcmp(type, RELOC("okay")) != 0)
                continue;

        cnt = prom_getprop(node, "ibm,ppc-interrupt-server#s", servers,
                 sizeof(servers));
        if (cnt == PROM_ERROR)
            break;
        cnt >>= 2;
        for (i = 0; i < cnt; i++) {
            cpu = servers[i];
            prom_debug("CPU %d ... ", cpu);
            if (cpu == _prom->cpu) {
                prom_debug("booted !\n");
                continue;
            }
            prom_debug("starting ... ");

            /* Init the acknowledge var which will be reset by
             * the secondary cpu when it awakens from its OF
             * spinloop.
             */
            data->ack = -1;
            rc = prom_rtas_call(RELOC(prom_rtas_start_cpu), 3, 1,
                        NULL, cpu, entry, data);
            prom_debug("rtas rc=%d ...", rc);

            for (j = 0; j < 100000000 && data->ack == -1; j++) {
                HMT_low();
                mb();
            }
            HMT_medium();
            if (data->ack != -1)
                prom_debug("done, PIR=0x%x\n", data->ack);
            else
                prom_debug("timeout !\n");
        }
    }
    prom_debug("prom_opal_hold_cpus: end...\n");
}

static void __init prom_opal_takeover(void)
{
    struct opal_secondary_data *data = &RELOC(opal_secondary_data);
    struct opal_takeover_args *args = &data->args;
    u64 align = RELOC(prom_opal_align);
    u64 top_addr, opal_addr;

    args->k_image   = (u64)RELOC(_stext);
    args->k_size    = _end - _stext;
    args->k_entry   = 0;
    args->k_entry2  = 0x60;

    top_addr = _ALIGN_UP(args->k_size, align);

    if (RELOC(prom_initrd_start) != 0) {
        args->rd_image = RELOC(prom_initrd_start);
        args->rd_size = RELOC(prom_initrd_end) - args->rd_image;
        args->rd_loc = top_addr;
        top_addr = _ALIGN_UP(args->rd_loc + args->rd_size, align);
    }

    /* Pickup an address for the HAL. We want to go really high
     * up to avoid problem with future kexecs. On the other hand
     * we don't want to be all over the TCEs on P5IOC2 machines
     * which are going to be up there too. We assume the machine
     * has plenty of memory, and we ask for the HAL for now to
     * be just below the 1G point, or above the initrd
     */
    opal_addr = _ALIGN_DOWN(0x40000000 - RELOC(prom_opal_size), align);
    if (opal_addr < top_addr)
        opal_addr = top_addr;
    args->hal_addr = opal_addr;

    /* Copy the command line to the kernel image */
    strlcpy(RELOC(boot_command_line), RELOC(prom_cmd_line),
        COMMAND_LINE_SIZE);

    prom_debug("  k_image    = 0x%lx\n", args->k_image);
    prom_debug("  k_size     = 0x%lx\n", args->k_size);
    prom_debug("  k_entry    = 0x%lx\n", args->k_entry);
    prom_debug("  k_entry2   = 0x%lx\n", args->k_entry2);
    prom_debug("  hal_addr   = 0x%lx\n", args->hal_addr);
    prom_debug("  rd_image   = 0x%lx\n", args->rd_image);
    prom_debug("  rd_size    = 0x%lx\n", args->rd_size);
    prom_debug("  rd_loc     = 0x%lx\n", args->rd_loc);
    prom_printf("Performing OPAL takeover,this can take a few minutes..\n");
    prom_close_stdin();
    mb();
    data->go = 1;
    for (;;)
        opal_do_takeover(args);
}

/*
 * Allocate room for and instantiate OPAL
 */
static void __init prom_instantiate_opal(void)
{
    phandle opal_node;
    ihandle opal_inst;
    u64 base, entry;
    u64 size = 0, align = 0x10000;
    u32 rets[2];

    prom_debug("prom_instantiate_opal: start...\n");

    opal_node = call_prom("finddevice", 1, 1, ADDR("/ibm,opal"));
    prom_debug("opal_node: %x\n", opal_node);
    if (!PHANDLE_VALID(opal_node))
        return;

    prom_getprop(opal_node, "opal-runtime-size", &size, sizeof(size));
    if (size == 0)
        return;
    prom_getprop(opal_node, "opal-runtime-alignment", &align,
             sizeof(align));

    base = alloc_down(size, align, 0);
    if (base == 0) {
        prom_printf("OPAL allocation failed !\n");
        return;
    }

    opal_inst = call_prom("open", 1, 1, ADDR("/ibm,opal"));
    if (!IHANDLE_VALID(opal_inst)) {
        prom_printf("opening opal package failed (%x)\n", opal_inst);
        return;
    }

    prom_printf("instantiating opal at 0x%x...", base);

    if (call_prom_ret("call-method", 4, 3, rets,
              ADDR("load-opal-runtime"),
              opal_inst,
              base >> 32, base & 0xffffffff) != 0
        || (rets[0] == 0 && rets[1] == 0)) {
        prom_printf(" failed\n");
        return;
    }
    entry = (((u64)rets[0]) << 32) | rets[1];

    prom_printf(" done\n");

    reserve_mem(base, size);

    prom_debug("opal base     = 0x%x\n", base);
    prom_debug("opal align    = 0x%x\n", align);
    prom_debug("opal entry    = 0x%x\n", entry);
    prom_debug("opal size     = 0x%x\n", (long)size);

    prom_setprop(opal_node, "/ibm,opal", "opal-base-address",
             &base, sizeof(base));
    prom_setprop(opal_node, "/ibm,opal", "opal-entry-address",
             &entry, sizeof(entry));

#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL
    RELOC(prom_opal_base) = base;
    RELOC(prom_opal_entry) = entry;
#endif
    prom_debug("prom_instantiate_opal: end...\n");
}

#endif /* CONFIG_PPC_POWERNV */

/*
 * Allocate room for and instantiate RTAS
 */
static void __init prom_instantiate_rtas(void)
{
    phandle rtas_node;
    ihandle rtas_inst;
    u32 base, entry = 0;
    u32 size = 0;

    prom_debug("prom_instantiate_rtas: start...\n");

    rtas_node = call_prom("finddevice", 1, 1, ADDR("/rtas"));
    prom_debug("rtas_node: %x\n", rtas_node);
    if (!PHANDLE_VALID(rtas_node))
        return;

    prom_getprop(rtas_node, "rtas-size", &size, sizeof(size));
    if (size == 0)
        return;

    base = alloc_down(size, PAGE_SIZE, 0);
    if (base == 0)
        prom_panic("Could not allocate memory for RTAS\n");

    rtas_inst = call_prom("open", 1, 1, ADDR("/rtas"));
    if (!IHANDLE_VALID(rtas_inst)) {
        prom_printf("opening rtas package failed (%x)\n", rtas_inst);
        return;
    }

    prom_printf("instantiating rtas at 0x%x...", base);

    if (call_prom_ret("call-method", 3, 2, &entry,
              ADDR("instantiate-rtas"),
              rtas_inst, base) != 0
        || entry == 0) {
        prom_printf(" failed\n");
        return;
    }
    prom_printf(" done\n");

    reserve_mem(base, size);

    prom_setprop(rtas_node, "/rtas", "linux,rtas-base",
             &base, sizeof(base));
    prom_setprop(rtas_node, "/rtas", "linux,rtas-entry",
             &entry, sizeof(entry));

#ifdef CONFIG_PPC_POWERNV
    /* PowerVN takeover hack */
    RELOC(prom_rtas_data) = base;
    RELOC(prom_rtas_entry) = entry;
    prom_getprop(rtas_node, "start-cpu", &RELOC(prom_rtas_start_cpu), 4);
#endif
    prom_debug("rtas base     = 0x%x\n", base);
    prom_debug("rtas entry    = 0x%x\n", entry);
    prom_debug("rtas size     = 0x%x\n", (long)size);

    prom_debug("prom_instantiate_rtas: end...\n");
}

#ifdef CONFIG_PPC64
/*
 * Allocate room for and instantiate Stored Measurement Log (SML)
 */
static void __init prom_instantiate_sml(void)
{
    phandle ibmvtpm_node;
    ihandle ibmvtpm_inst;
    u32 entry = 0, size = 0;
    u64 base;

    prom_debug("prom_instantiate_sml: start...\n");

    ibmvtpm_node = call_prom("finddevice", 1, 1, ADDR("/ibm,vtpm"));
    prom_debug("ibmvtpm_node: %x\n", ibmvtpm_node);
    if (!PHANDLE_VALID(ibmvtpm_node))
        return;

    ibmvtpm_inst = call_prom("open", 1, 1, ADDR("/ibm,vtpm"));
    if (!IHANDLE_VALID(ibmvtpm_inst)) {
        prom_printf("opening vtpm package failed (%x)\n", ibmvtpm_inst);
        return;
    }

    if (call_prom_ret("call-method", 2, 2, &size,
              ADDR("sml-get-handover-size"),
              ibmvtpm_inst) != 0 || size == 0) {
        prom_printf("SML get handover size failed\n");
        return;
    }

    base = alloc_down(size, PAGE_SIZE, 0);
    if (base == 0)
        prom_panic("Could not allocate memory for sml\n");

    prom_printf("instantiating sml at 0x%x...", base);

    if (call_prom_ret("call-method", 4, 2, &entry,
              ADDR("sml-handover"),
              ibmvtpm_inst, size, base) != 0 || entry == 0) {
        prom_printf("SML handover failed\n");
        return;
    }
    prom_printf(" done\n");

    reserve_mem(base, size);

    prom_setprop(ibmvtpm_node, "/ibm,vtpm", "linux,sml-base",
             &base, sizeof(base));
    prom_setprop(ibmvtpm_node, "/ibm,vtpm", "linux,sml-size",
             &size, sizeof(size));

    prom_debug("sml base     = 0x%x\n", base);
    prom_debug("sml size     = 0x%x\n", (long)size);

    prom_debug("prom_instantiate_sml: end...\n");
}

/*
 * Allocate room for and initialize TCE tables
 */
static void __init prom_initialize_tce_table(void)
{
    phandle node;
    ihandle phb_node;
    char compatible[64], type[64], model[64];
    char *path = RELOC(prom_scratch);
    u64 base, align;
    u32 minalign, minsize;
    u64 tce_entry, *tce_entryp;
    u64 local_alloc_top, local_alloc_bottom;
    u64 i;

    if (RELOC(prom_iommu_off))
        return;

    prom_debug("starting prom_initialize_tce_table\n");

    /* Cache current top of allocs so we reserve a single block */
    local_alloc_top = RELOC(alloc_top_high);
    local_alloc_bottom = local_alloc_top;

    /* Search all nodes looking for PHBs. */
    for (node = 0; prom_next_node(&node); ) {
        compatible[0] = 0;
        type[0] = 0;
        model[0] = 0;
        prom_getprop(node, "compatible",
                 compatible, sizeof(compatible));
        prom_getprop(node, "device_type", type, sizeof(type));
        prom_getprop(node, "model", model, sizeof(model));

        if ((type[0] == 0) || (strstr(type, RELOC("pci")) == NULL))
            continue;

        /* Keep the old logic intact to avoid regression. */
        if (compatible[0] != 0) {
            if ((strstr(compatible, RELOC("python")) == NULL) &&
                (strstr(compatible, RELOC("Speedwagon")) == NULL) &&
                (strstr(compatible, RELOC("Winnipeg")) == NULL))
                continue;
        } else if (model[0] != 0) {
            if ((strstr(model, RELOC("ython")) == NULL) &&
                (strstr(model, RELOC("peedwagon")) == NULL) &&
                (strstr(model, RELOC("innipeg")) == NULL))
                continue;
        }

        if (prom_getprop(node, "tce-table-minalign", &minalign,
                 sizeof(minalign)) == PROM_ERROR)
            minalign = 0;
        if (prom_getprop(node, "tce-table-minsize", &minsize,
                 sizeof(minsize)) == PROM_ERROR)
            minsize = 4UL << 20;

        /*
         * Even though we read what OF wants, we just set the table
         * size to 4 MB.  This is enough to map 2GB of PCI DMA space.
         * By doing this, we avoid the pitfalls of trying to DMA to
         * MMIO space and the DMA alias hole.
         *
         * On POWER4, firmware sets the TCE region by assuming
         * each TCE table is 8MB. Using this memory for anything
         * else will impact performance, so we always allocate 8MB.
         * Anton
         */
        if (pvr_version_is(PVR_POWER4) || pvr_version_is(PVR_POWER4p))
            minsize = 8UL << 20;
        else
            minsize = 4UL << 20;

        /* Align to the greater of the align or size */
        align = max(minalign, minsize);
        base = alloc_down(minsize, align, 1);
        if (base == 0)
            prom_panic("ERROR, cannot find space for TCE table.\n");
        if (base < local_alloc_bottom)
            local_alloc_bottom = base;

        /* It seems OF doesn't null-terminate the path :-( */
        memset(path, 0, PROM_SCRATCH_SIZE);
        /* Call OF to setup the TCE hardware */
        if (call_prom("package-to-path", 3, 1, node,
                  path, PROM_SCRATCH_SIZE-1) == PROM_ERROR) {
            prom_printf("package-to-path failed\n");
        }

        /* Save away the TCE table attributes for later use. */
        prom_setprop(node, path, "linux,tce-base", &base, sizeof(base));
        prom_setprop(node, path, "linux,tce-size", &minsize, sizeof(minsize));

        prom_debug("TCE table: %s\n", path);
        prom_debug("\tnode = 0x%x\n", node);
        prom_debug("\tbase = 0x%x\n", base);
        prom_debug("\tsize = 0x%x\n", minsize);

        /* Initialize the table to have a one-to-one mapping
         * over the allocated size.
         */
        tce_entryp = (u64 *)base;
        for (i = 0; i < (minsize >> 3) ;tce_entryp++, i++) {
            tce_entry = (i << PAGE_SHIFT);
            tce_entry |= 0x3;
            *tce_entryp = tce_entry;
        }

        prom_printf("opening PHB %s", path);
        phb_node = call_prom("open", 1, 1, path);
        if (phb_node == 0)
            prom_printf("... failed\n");
        else
            prom_printf("... done\n");

        call_prom("call-method", 6, 0, ADDR("set-64-bit-addressing"),
              phb_node, -1, minsize,
              (u32) base, (u32) (base >> 32));
        call_prom("close", 1, 0, phb_node);
    }

    reserve_mem(local_alloc_bottom, local_alloc_top - local_alloc_bottom);

    /* These are only really needed if there is a memory limit in
     * effect, but we don't know so export them always. */
    RELOC(prom_tce_alloc_start) = local_alloc_bottom;
    RELOC(prom_tce_alloc_end) = local_alloc_top;

    /* Flag the first invalid entry */
    prom_debug("ending prom_initialize_tce_table\n");
}
#endif

/*
 * With CHRP SMP we need to use the OF to start the other processors.
 * We can't wait until smp_boot_cpus (the OF is trashed by then)
 * so we have to put the processors into a holding pattern controlled
 * by the kernel (not OF) before we destroy the OF.
 *
 * This uses a chunk of low memory, puts some holding pattern
 * code there and sends the other processors off to there until
 * smp_boot_cpus tells them to do something.  The holding pattern
 * checks that address until its cpu # is there, when it is that
 * cpu jumps to __secondary_start().  smp_boot_cpus() takes care
 * of setting those values.
 *
 * We also use physical address 0x4 here to tell when a cpu
 * is in its holding pattern code.
 *
 * -- Cort
 */
/*
 * We want to reference the copy of __secondary_hold_* in the
 * 0 - 0x100 address range
 */
#define LOW_ADDR(x) (((unsigned long) &(x)) & 0xff)

static void __init prom_hold_cpus(void)
{
    unsigned long i;
    unsigned int reg;
    phandle node;
    char type[64];
    struct prom_t *_prom = &RELOC(prom);
    unsigned long *spinloop
        = (void *) LOW_ADDR(__secondary_hold_spinloop);
    unsigned long *acknowledge
        = (void *) LOW_ADDR(__secondary_hold_acknowledge);
    unsigned long secondary_hold = LOW_ADDR(__secondary_hold);

    prom_debug("prom_hold_cpus: start...\n");
    prom_debug("    1) spinloop       = 0x%x\n", (unsigned long)spinloop);
    prom_debug("    1) *spinloop      = 0x%x\n", *spinloop);
    prom_debug("    1) acknowledge    = 0x%x\n",
           (unsigned long)acknowledge);
    prom_debug("    1) *acknowledge   = 0x%x\n", *acknowledge);
    prom_debug("    1) secondary_hold = 0x%x\n", secondary_hold);

    /* Set the common spinloop variable, so all of the secondary cpus
     * will block when they are awakened from their OF spinloop.
     * This must occur for both SMP and non SMP kernels, since OF will
     * be trashed when we move the kernel.
     */
    *spinloop = 0;

    /* look for cpus */
    for (node = 0; prom_next_node(&node); ) {
        type[0] = 0;
        prom_getprop(node, "device_type", type, sizeof(type));
        if (strcmp(type, RELOC("cpu")) != 0)
            continue;

        /* Skip non-configured cpus. */
        if (prom_getprop(node, "status", type, sizeof(type)) > 0)
            if (strcmp(type, RELOC("okay")) != 0)
                continue;

        reg = -1;
        prom_getprop(node, "reg", &reg, sizeof(reg));

        prom_debug("cpu hw idx   = %lu\n", reg);

        /* Init the acknowledge var which will be reset by
         * the secondary cpu when it awakens from its OF
         * spinloop.
         */
        *acknowledge = (unsigned long)-1;

        if (reg != _prom->cpu) {
            /* Primary Thread of non-boot cpu or any thread */
            prom_printf("starting cpu hw idx %lu... ", reg);
            call_prom("start-cpu", 3, 0, node,
                  secondary_hold, reg);

            for (i = 0; (i < 100000000) && 
                 (*acknowledge == ((unsigned long)-1)); i++ )
                mb();

            if (*acknowledge == reg)
                prom_printf("done\n");
            else
                prom_printf("failed: %x\n", *acknowledge);
        }
#ifdef CONFIG_SMP
        else
            prom_printf("boot cpu hw idx %lu\n", reg);
#endif /* CONFIG_SMP */
    }

    prom_debug("prom_hold_cpus: end...\n");
}


static void __init prom_init_client_services(unsigned long pp)
{
    struct prom_t *_prom = &RELOC(prom);

    /* Get a handle to the prom entry point before anything else */
    RELOC(prom_entry) = pp;

    /* get a handle for the stdout device */
    _prom->chosen = call_prom("finddevice", 1, 1, ADDR("/chosen"));
    if (!PHANDLE_VALID(_prom->chosen))
        prom_panic("cannot find chosen"); /* msg won't be printed :( */

    /* get device tree root */
    _prom->root = call_prom("finddevice", 1, 1, ADDR("/"));
    if (!PHANDLE_VALID(_prom->root))
        prom_panic("cannot find device tree root"); /* msg won't be printed :( */

    _prom->mmumap = 0;
}

#ifdef CONFIG_PPC32
/*
 * For really old powermacs, we need to map things we claim.
 * For that, we need the ihandle of the mmu.
 * Also, on the longtrail, we need to work around other bugs.
 */
static void __init prom_find_mmu(void)
{
    struct prom_t *_prom = &RELOC(prom);
    phandle oprom;
    char version[64];

    oprom = call_prom("finddevice", 1, 1, ADDR("/openprom"));
    if (!PHANDLE_VALID(oprom))
        return;
    if (prom_getprop(oprom, "model", version, sizeof(version)) <= 0)
        return;
    version[sizeof(version) - 1] = 0;
    /* XXX might need to add other versions here */
    if (strcmp(version, "Open Firmware, 1.0.5") == 0)
        of_workarounds = OF_WA_CLAIM;
    else if (strncmp(version, "FirmWorks,3.", 12) == 0) {
        of_workarounds = OF_WA_CLAIM | OF_WA_LONGTRAIL;
        call_prom("interpret", 1, 1, "dev /memory 0 to allow-reclaim");
    } else
        return;
    _prom->memory = call_prom("open", 1, 1, ADDR("/memory"));
    prom_getprop(_prom->chosen, "mmu", &_prom->mmumap,
             sizeof(_prom->mmumap));
    if (!IHANDLE_VALID(_prom->memory) || !IHANDLE_VALID(_prom->mmumap))
        of_workarounds &= ~OF_WA_CLAIM;     /* hmmm */
}
#else
#define prom_find_mmu()
#endif

static void __init prom_init_stdout(void)
{
    struct prom_t *_prom = &RELOC(prom);
    char *path = RELOC(of_stdout_device);
    char type[16];
    u32 val;

    if (prom_getprop(_prom->chosen, "stdout", &val, sizeof(val)) <= 0)
        prom_panic("cannot find stdout");

    _prom->stdout = val;

    /* Get the full OF pathname of the stdout device */
    memset(path, 0, 256);
    call_prom("instance-to-path", 3, 1, _prom->stdout, path, 255);
    val = call_prom("instance-to-package", 1, 1, _prom->stdout);
    prom_setprop(_prom->chosen, "/chosen", "linux,stdout-package",
             &val, sizeof(val));
    prom_printf("OF stdout device is: %s\n", RELOC(of_stdout_device));
    prom_setprop(_prom->chosen, "/chosen", "linux,stdout-path",
             path, strlen(path) + 1);

    /* If it's a display, note it */
    memset(type, 0, sizeof(type));
    prom_getprop(val, "device_type", type, sizeof(type));
    if (strcmp(type, RELOC("display")) == 0)
        prom_setprop(val, path, "linux,boot-display", NULL, 0);
}

static int __init prom_find_machine_type(void)
{
    struct prom_t *_prom = &RELOC(prom);
    char compat[256];
    int len, i = 0;
#ifdef CONFIG_PPC64
    phandle rtas;
    int x;
#endif

    /* Look for a PowerMac or a Cell */
    len = prom_getprop(_prom->root, "compatible",
               compat, sizeof(compat)-1);
    if (len > 0) {
        compat[len] = 0;
        while (i < len) {
            char *p = &compat[i];
            int sl = strlen(p);
            if (sl == 0)
                break;
            if (strstr(p, RELOC("Power Macintosh")) ||
                strstr(p, RELOC("MacRISC")))
                return PLATFORM_POWERMAC;
#ifdef CONFIG_PPC64
            /* We must make sure we don't detect the IBM Cell
             * blades as pSeries due to some firmware issues,
             * so we do it here.
             */
            if (strstr(p, RELOC("IBM,CBEA")) ||
                strstr(p, RELOC("IBM,CPBW-1.0")))
                return PLATFORM_GENERIC;
#endif /* CONFIG_PPC64 */
            i += sl + 1;
        }
    }
#ifdef CONFIG_PPC64
    /* Try to detect OPAL */
    if (PHANDLE_VALID(call_prom("finddevice", 1, 1, ADDR("/ibm,opal"))))
        return PLATFORM_OPAL;

    /* Try to figure out if it's an IBM pSeries or any other
     * PAPR compliant platform. We assume it is if :
     *  - /device_type is "chrp" (please, do NOT use that for future
     *    non-IBM designs !
     *  - it has /rtas
     */
    len = prom_getprop(_prom->root, "device_type",
               compat, sizeof(compat)-1);
    if (len <= 0)
        return PLATFORM_GENERIC;
    if (strcmp(compat, RELOC("chrp")))
        return PLATFORM_GENERIC;

    /* Default to pSeries. We need to know if we are running LPAR */
    rtas = call_prom("finddevice", 1, 1, ADDR("/rtas"));
    if (!PHANDLE_VALID(rtas))
        return PLATFORM_GENERIC;
    x = prom_getproplen(rtas, "ibm,hypertas-functions");
    if (x != PROM_ERROR) {
        prom_debug("Hypertas detected, assuming LPAR !\n");
        return PLATFORM_PSERIES_LPAR;
    }
    return PLATFORM_PSERIES;
#else
    return PLATFORM_GENERIC;
#endif
}

static int __init prom_set_color(ihandle ih, int i, int r, int g, int b)
{
    return call_prom("call-method", 6, 1, ADDR("color!"), ih, i, b, g, r);
}

/*
 * If we have a display that we don't know how to drive,
 * we will want to try to execute OF's open method for it
 * later.  However, OF will probably fall over if we do that
 * we've taken over the MMU.
 * So we check whether we will need to open the display,
 * and if so, open it now.
 */
static void __init prom_check_displays(void)
{
    char type[16], *path;
    phandle node;
    ihandle ih;
    int i;

    static unsigned char default_colors[] = {
        0x00, 0x00, 0x00,
        0x00, 0x00, 0xaa,
        0x00, 0xaa, 0x00,
        0x00, 0xaa, 0xaa,
        0xaa, 0x00, 0x00,
        0xaa, 0x00, 0xaa,
        0xaa, 0xaa, 0x00,
        0xaa, 0xaa, 0xaa,
        0x55, 0x55, 0x55,
        0x55, 0x55, 0xff,
        0x55, 0xff, 0x55,
        0x55, 0xff, 0xff,
        0xff, 0x55, 0x55,
        0xff, 0x55, 0xff,
        0xff, 0xff, 0x55,
        0xff, 0xff, 0xff
    };
    const unsigned char *clut;

    prom_debug("Looking for displays\n");
    for (node = 0; prom_next_node(&node); ) {
        memset(type, 0, sizeof(type));
        prom_getprop(node, "device_type", type, sizeof(type));
        if (strcmp(type, RELOC("display")) != 0)
            continue;

        /* It seems OF doesn't null-terminate the path :-( */
        path = RELOC(prom_scratch);
        memset(path, 0, PROM_SCRATCH_SIZE);

        /*
         * leave some room at the end of the path for appending extra
         * arguments
         */
        if (call_prom("package-to-path", 3, 1, node, path,
                  PROM_SCRATCH_SIZE-10) == PROM_ERROR)
            continue;
        prom_printf("found display   : %s, opening... ", path);
        
        ih = call_prom("open", 1, 1, path);
        if (ih == 0) {
            prom_printf("failed\n");
            continue;
        }

        /* Success */
        prom_printf("done\n");
        prom_setprop(node, path, "linux,opened", NULL, 0);

        /* Setup a usable color table when the appropriate
         * method is available. Should update this to set-colors */
        clut = RELOC(default_colors);
        for (i = 0; i < 16; i++, clut += 3)
            if (prom_set_color(ih, i, clut[0], clut[1],
                       clut[2]) != 0)
                break;

#ifdef CONFIG_LOGO_LINUX_CLUT224
        clut = PTRRELOC(RELOC(logo_linux_clut224.clut));
        for (i = 0; i < RELOC(logo_linux_clut224.clutsize); i++, clut += 3)
            if (prom_set_color(ih, i + 32, clut[0], clut[1],
                       clut[2]) != 0)
                break;
#endif /* CONFIG_LOGO_LINUX_CLUT224 */
    }
}


/* Return (relocated) pointer to this much memory: moves initrd if reqd. */
static void __init *make_room(unsigned long *mem_start, unsigned long *mem_end,
                  unsigned long needed, unsigned long align)
{
    void *ret;

    *mem_start = _ALIGN(*mem_start, align);
    while ((*mem_start + needed) > *mem_end) {
        unsigned long room, chunk;

        prom_debug("Chunk exhausted, claiming more at %x...\n",
               RELOC(alloc_bottom));
        room = RELOC(alloc_top) - RELOC(alloc_bottom);
        if (room > DEVTREE_CHUNK_SIZE)
            room = DEVTREE_CHUNK_SIZE;
        if (room < PAGE_SIZE)
            prom_panic("No memory for flatten_device_tree "
                   "(no room)\n");
        chunk = alloc_up(room, 0);
        if (chunk == 0)
            prom_panic("No memory for flatten_device_tree "
                   "(claim failed)\n");
        *mem_end = chunk + room;
    }

    ret = (void *)*mem_start;
    *mem_start += needed;

    return ret;
}

#define dt_push_token(token, mem_start, mem_end) \
    do { *((u32 *)make_room(mem_start, mem_end, 4, 4)) = token; } while(0)

static unsigned long __init dt_find_string(char *str)
{
    char *s, *os;

    s = os = (char *)RELOC(dt_string_start);
    s += 4;
    while (s <  (char *)RELOC(dt_string_end)) {
        if (strcmp(s, str) == 0)
            return s - os;
        s += strlen(s) + 1;
    }
    return 0;
}

/*
 * The Open Firmware 1275 specification states properties must be 31 bytes or
 * less, however not all firmwares obey this. Make it 64 bytes to be safe.
 */
#define MAX_PROPERTY_NAME 64

static void __init scan_dt_build_strings(phandle node,
                     unsigned long *mem_start,
                     unsigned long *mem_end)
{
    char *prev_name, *namep, *sstart;
    unsigned long soff;
    phandle child;

    sstart =  (char *)RELOC(dt_string_start);

    /* get and store all property names */
    prev_name = RELOC("");
    for (;;) {
        /* 64 is max len of name including nul. */
        namep = make_room(mem_start, mem_end, MAX_PROPERTY_NAME, 1);
        if (call_prom("nextprop", 3, 1, node, prev_name, namep) != 1) {
            /* No more nodes: unwind alloc */
            *mem_start = (unsigned long)namep;
            break;
        }

        /* skip "name" */
        if (strcmp(namep, RELOC("name")) == 0) {
            *mem_start = (unsigned long)namep;
            prev_name = RELOC("name");
            continue;
        }
        /* get/create string entry */
        soff = dt_find_string(namep);
        if (soff != 0) {
            *mem_start = (unsigned long)namep;
            namep = sstart + soff;
        } else {
            /* Trim off some if we can */
            *mem_start = (unsigned long)namep + strlen(namep) + 1;
            RELOC(dt_string_end) = *mem_start;
        }
        prev_name = namep;
    }

    /* do all our children */
    child = call_prom("child", 1, 1, node);
    while (child != 0) {
        scan_dt_build_strings(child, mem_start, mem_end);
        child = call_prom("peer", 1, 1, child);
    }
}

static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
                    unsigned long *mem_end)
{
    phandle child;
    char *namep, *prev_name, *sstart, *p, *ep, *lp, *path;
    unsigned long soff;
    unsigned char *valp;
    static char pname[MAX_PROPERTY_NAME];
    int l, room, has_phandle = 0;

    dt_push_token(OF_DT_BEGIN_NODE, mem_start, mem_end);

    /* get the node's full name */
    namep = (char *)*mem_start;
    room = *mem_end - *mem_start;
    if (room > 255)
        room = 255;
    l = call_prom("package-to-path", 3, 1, node, namep, room);
    if (l >= 0) {
        /* Didn't fit?  Get more room. */
        if (l >= room) {
            if (l >= *mem_end - *mem_start)
                namep = make_room(mem_start, mem_end, l+1, 1);
            call_prom("package-to-path", 3, 1, node, namep, l);
        }
        namep[l] = '\0';

        /* Fixup an Apple bug where they have bogus \0 chars in the
         * middle of the path in some properties, and extract
         * the unit name (everything after the last '/').
         */
        for (lp = p = namep, ep = namep + l; p < ep; p++) {
            if (*p == '/')
                lp = namep;
            else if (*p != 0)
                *lp++ = *p;
        }
        *lp = 0;
        *mem_start = _ALIGN((unsigned long)lp + 1, 4);
    }

    /* get it again for debugging */
    path = RELOC(prom_scratch);
    memset(path, 0, PROM_SCRATCH_SIZE);
    call_prom("package-to-path", 3, 1, node, path, PROM_SCRATCH_SIZE-1);

    /* get and store all properties */
    prev_name = RELOC("");
    sstart = (char *)RELOC(dt_string_start);
    for (;;) {
        if (call_prom("nextprop", 3, 1, node, prev_name,
                  RELOC(pname)) != 1)
            break;

        /* skip "name" */
        if (strcmp(RELOC(pname), RELOC("name")) == 0) {
            prev_name = RELOC("name");
            continue;
        }

        /* find string offset */
        soff = dt_find_string(RELOC(pname));
        if (soff == 0) {
            prom_printf("WARNING: Can't find string index for"
                    " <%s>, node %s\n", RELOC(pname), path);
            break;
        }
        prev_name = sstart + soff;

        /* get length */
        l = call_prom("getproplen", 2, 1, node, RELOC(pname));

        /* sanity checks */
        if (l == PROM_ERROR)
            continue;

        /* push property head */
        dt_push_token(OF_DT_PROP, mem_start, mem_end);
        dt_push_token(l, mem_start, mem_end);
        dt_push_token(soff, mem_start, mem_end);

        /* push property content */
        valp = make_room(mem_start, mem_end, l, 4);
        call_prom("getprop", 4, 1, node, RELOC(pname), valp, l);
        *mem_start = _ALIGN(*mem_start, 4);

        if (!strcmp(RELOC(pname), RELOC("phandle")))
            has_phandle = 1;
    }

    /* Add a "linux,phandle" property if no "phandle" property already
     * existed (can happen with OPAL)
     */
    if (!has_phandle) {
        soff = dt_find_string(RELOC("linux,phandle"));
        if (soff == 0)
            prom_printf("WARNING: Can't find string index for"
                    " <linux-phandle> node %s\n", path);
        else {
            dt_push_token(OF_DT_PROP, mem_start, mem_end);
            dt_push_token(4, mem_start, mem_end);
            dt_push_token(soff, mem_start, mem_end);
            valp = make_room(mem_start, mem_end, 4, 4);
            *(u32 *)valp = node;
        }
    }

    /* do all our children */
    child = call_prom("child", 1, 1, node);
    while (child != 0) {
        scan_dt_build_struct(child, mem_start, mem_end);
        child = call_prom("peer", 1, 1, child);
    }

    dt_push_token(OF_DT_END_NODE, mem_start, mem_end);
}

static void __init flatten_device_tree(void)
{
    phandle root;
    unsigned long mem_start, mem_end, room;
    struct boot_param_header *hdr;
    struct prom_t *_prom = &RELOC(prom);
    char *namep;
    u64 *rsvmap;

    /*
     * Check how much room we have between alloc top & bottom (+/- a
     * few pages), crop to 1MB, as this is our "chunk" size
     */
    room = RELOC(alloc_top) - RELOC(alloc_bottom) - 0x4000;
    if (room > DEVTREE_CHUNK_SIZE)
        room = DEVTREE_CHUNK_SIZE;
    prom_debug("starting device tree allocs at %x\n", RELOC(alloc_bottom));

    /* Now try to claim that */
    mem_start = (unsigned long)alloc_up(room, PAGE_SIZE);
    if (mem_start == 0)
        prom_panic("Can't allocate initial device-tree chunk\n");
    mem_end = mem_start + room;

    /* Get root of tree */
    root = call_prom("peer", 1, 1, (phandle)0);
    if (root == (phandle)0)
        prom_panic ("couldn't get device tree root\n");

    /* Build header and make room for mem rsv map */ 
    mem_start = _ALIGN(mem_start, 4);
    hdr = make_room(&mem_start, &mem_end,
            sizeof(struct boot_param_header), 4);
    RELOC(dt_header_start) = (unsigned long)hdr;
    rsvmap = make_room(&mem_start, &mem_end, sizeof(mem_reserve_map), 8);

    /* Start of strings */
    mem_start = PAGE_ALIGN(mem_start);
    RELOC(dt_string_start) = mem_start;
    mem_start += 4; /* hole */

    /* Add "linux,phandle" in there, we'll need it */
    namep = make_room(&mem_start, &mem_end, 16, 1);
    strcpy(namep, RELOC("linux,phandle"));
    mem_start = (unsigned long)namep + strlen(namep) + 1;

    /* Build string array */
    prom_printf("Building dt strings...\n"); 
    scan_dt_build_strings(root, &mem_start, &mem_end);
    RELOC(dt_string_end) = mem_start;

    /* Build structure */
    mem_start = PAGE_ALIGN(mem_start);
    RELOC(dt_struct_start) = mem_start;
    prom_printf("Building dt structure...\n"); 
    scan_dt_build_struct(root, &mem_start, &mem_end);
    dt_push_token(OF_DT_END, &mem_start, &mem_end);
    RELOC(dt_struct_end) = PAGE_ALIGN(mem_start);

    /* Finish header */
    hdr->boot_cpuid_phys = _prom->cpu;
    hdr->magic = OF_DT_HEADER;
    hdr->totalsize = RELOC(dt_struct_end) - RELOC(dt_header_start);
    hdr->off_dt_struct = RELOC(dt_struct_start) - RELOC(dt_header_start);
    hdr->off_dt_strings = RELOC(dt_string_start) - RELOC(dt_header_start);
    hdr->dt_strings_size = RELOC(dt_string_end) - RELOC(dt_string_start);
    hdr->off_mem_rsvmap = ((unsigned long)rsvmap) - RELOC(dt_header_start);
    hdr->version = OF_DT_VERSION;
    /* Version 16 is not backward compatible */
    hdr->last_comp_version = 0x10;

    /* Copy the reserve map in */
    memcpy(rsvmap, RELOC(mem_reserve_map), sizeof(mem_reserve_map));

#ifdef DEBUG_PROM
    {
        int i;
        prom_printf("reserved memory map:\n");
        for (i = 0; i < RELOC(mem_reserve_cnt); i++)
            prom_printf("  %x - %x\n",
                    RELOC(mem_reserve_map)[i].base,
                    RELOC(mem_reserve_map)[i].size);
    }
#endif
    /* Bump mem_reserve_cnt to cause further reservations to fail
     * since it's too late.
     */
    RELOC(mem_reserve_cnt) = MEM_RESERVE_MAP_SIZE;

    prom_printf("Device tree strings 0x%x -> 0x%x\n",
            RELOC(dt_string_start), RELOC(dt_string_end)); 
    prom_printf("Device tree struct  0x%x -> 0x%x\n",
            RELOC(dt_struct_start), RELOC(dt_struct_end));

}

#ifdef CONFIG_PPC_MAPLE
/* PIBS Version 1.05.0000 04/26/2005 has an incorrect /ht/isa/ranges property.
 * The values are bad, and it doesn't even have the right number of cells. */
static void __init fixup_device_tree_maple(void)
{
    phandle isa;
    u32 rloc = 0x01002000; /* IO space; PCI device = 4 */
    u32 isa_ranges[6];
    char *name;

    name = "/ht@0/isa@4";
    isa = call_prom("finddevice", 1, 1, ADDR(name));
    if (!PHANDLE_VALID(isa)) {
        name = "/ht@0/isa@6";
        isa = call_prom("finddevice", 1, 1, ADDR(name));
        rloc = 0x01003000; /* IO space; PCI device = 6 */
    }
    if (!PHANDLE_VALID(isa))
        return;

    if (prom_getproplen(isa, "ranges") != 12)
        return;
    if (prom_getprop(isa, "ranges", isa_ranges, sizeof(isa_ranges))
        == PROM_ERROR)
        return;

    if (isa_ranges[0] != 0x1 ||
        isa_ranges[1] != 0xf4000000 ||
        isa_ranges[2] != 0x00010000)
        return;

    prom_printf("Fixing up bogus ISA range on Maple/Apache...\n");

    isa_ranges[0] = 0x1;
    isa_ranges[1] = 0x0;
    isa_ranges[2] = rloc;
    isa_ranges[3] = 0x0;
    isa_ranges[4] = 0x0;
    isa_ranges[5] = 0x00010000;
    prom_setprop(isa, name, "ranges",
            isa_ranges, sizeof(isa_ranges));
}

#define CPC925_MC_START     0xf8000000
#define CPC925_MC_LENGTH    0x1000000
/* The values for memory-controller don't have right number of cells */
static void __init fixup_device_tree_maple_memory_controller(void)
{
    phandle mc;
    u32 mc_reg[4];
    char *name = "/hostbridge@f8000000";
    struct prom_t *_prom = &RELOC(prom);
    u32 ac, sc;

    mc = call_prom("finddevice", 1, 1, ADDR(name));
    if (!PHANDLE_VALID(mc))
        return;

    if (prom_getproplen(mc, "reg") != 8)
        return;

    prom_getprop(_prom->root, "#address-cells", &ac, sizeof(ac));
    prom_getprop(_prom->root, "#size-cells", &sc, sizeof(sc));
    if ((ac != 2) || (sc != 2))
        return;

    if (prom_getprop(mc, "reg", mc_reg, sizeof(mc_reg)) == PROM_ERROR)
        return;

    if (mc_reg[0] != CPC925_MC_START || mc_reg[1] != CPC925_MC_LENGTH)
        return;

    prom_printf("Fixing up bogus hostbridge on Maple...\n");

    mc_reg[0] = 0x0;
    mc_reg[1] = CPC925_MC_START;
    mc_reg[2] = 0x0;
    mc_reg[3] = CPC925_MC_LENGTH;
    prom_setprop(mc, name, "reg", mc_reg, sizeof(mc_reg));
}
#else
#define fixup_device_tree_maple()
#define fixup_device_tree_maple_memory_controller()
#endif

#ifdef CONFIG_PPC_CHRP
/*
 * Pegasos and BriQ lacks the "ranges" property in the isa node
 * Pegasos needs decimal IRQ 14/15, not hexadecimal
 * Pegasos has the IDE configured in legacy mode, but advertised as native
 */
static void __init fixup_device_tree_chrp(void)
{
    phandle ph;
    u32 prop[6];
    u32 rloc = 0x01006000; /* IO space; PCI device = 12 */
    char *name;
    int rc;

    name = "/pci@80000000/isa@c";
    ph = call_prom("finddevice", 1, 1, ADDR(name));
    if (!PHANDLE_VALID(ph)) {
        name = "/pci@ff500000/isa@6";
        ph = call_prom("finddevice", 1, 1, ADDR(name));
        rloc = 0x01003000; /* IO space; PCI device = 6 */
    }
    if (PHANDLE_VALID(ph)) {
        rc = prom_getproplen(ph, "ranges");
        if (rc == 0 || rc == PROM_ERROR) {
            prom_printf("Fixing up missing ISA range on Pegasos...\n");

            prop[0] = 0x1;
            prop[1] = 0x0;
            prop[2] = rloc;
            prop[3] = 0x0;
            prop[4] = 0x0;
            prop[5] = 0x00010000;
            prom_setprop(ph, name, "ranges", prop, sizeof(prop));
        }
    }

    name = "/pci@80000000/ide@C,1";
    ph = call_prom("finddevice", 1, 1, ADDR(name));
    if (PHANDLE_VALID(ph)) {
        prom_printf("Fixing up IDE interrupt on Pegasos...\n");
        prop[0] = 14;
        prop[1] = 0x0;
        prom_setprop(ph, name, "interrupts", prop, 2*sizeof(u32));
        prom_printf("Fixing up IDE class-code on Pegasos...\n");
        rc = prom_getprop(ph, "class-code", prop, sizeof(u32));
        if (rc == sizeof(u32)) {
            prop[0] &= ~0x5;
            prom_setprop(ph, name, "class-code", prop, sizeof(u32));
        }
    }
}
#else
#define fixup_device_tree_chrp()
#endif

#if defined(CONFIG_PPC64) && defined(CONFIG_PPC_PMAC)
static void __init fixup_device_tree_pmac(void)
{
    phandle u3, i2c, mpic;
    u32 u3_rev;
    u32 interrupts[2];
    u32 parent;

    /* Some G5s have a missing interrupt definition, fix it up here */
    u3 = call_prom("finddevice", 1, 1, ADDR("/u3@0,f8000000"));
    if (!PHANDLE_VALID(u3))
        return;
    i2c = call_prom("finddevice", 1, 1, ADDR("/u3@0,f8000000/i2c@f8001000"));
    if (!PHANDLE_VALID(i2c))
        return;
    mpic = call_prom("finddevice", 1, 1, ADDR("/u3@0,f8000000/mpic@f8040000"));
    if (!PHANDLE_VALID(mpic))
        return;

    /* check if proper rev of u3 */
    if (prom_getprop(u3, "device-rev", &u3_rev, sizeof(u3_rev))
        == PROM_ERROR)
        return;
    if (u3_rev < 0x35 || u3_rev > 0x39)
        return;
    /* does it need fixup ? */
    if (prom_getproplen(i2c, "interrupts") > 0)
        return;

    prom_printf("fixing up bogus interrupts for u3 i2c...\n");

    /* interrupt on this revision of u3 is number 0 and level */
    interrupts[0] = 0;
    interrupts[1] = 1;
    prom_setprop(i2c, "/u3@0,f8000000/i2c@f8001000", "interrupts",
             &interrupts, sizeof(interrupts));
    parent = (u32)mpic;
    prom_setprop(i2c, "/u3@0,f8000000/i2c@f8001000", "interrupt-parent",
             &parent, sizeof(parent));
}
#else
#define fixup_device_tree_pmac()
#endif

#ifdef CONFIG_PPC_EFIKA
/*
 * The MPC5200 FEC driver requires an phy-handle property to tell it how
 * to talk to the phy.  If the phy-handle property is missing, then this
 * function is called to add the appropriate nodes and link it to the
 * ethernet node.
 */
static void __init fixup_device_tree_efika_add_phy(void)
{
    u32 node;
    char prop[64];
    int rv;

    /* Check if /builtin/ethernet exists - bail if it doesn't */
    node = call_prom("finddevice", 1, 1, ADDR("/builtin/ethernet"));
    if (!PHANDLE_VALID(node))
        return;

    /* Check if the phy-handle property exists - bail if it does */
    rv = prom_getprop(node, "phy-handle", prop, sizeof(prop));
    if (!rv)
        return;

    /*
     * At this point the ethernet device doesn't have a phy described.
     * Now we need to add the missing phy node and linkage
     */

    /* Check for an MDIO bus node - if missing then create one */
    node = call_prom("finddevice", 1, 1, ADDR("/builtin/mdio"));
    if (!PHANDLE_VALID(node)) {
        prom_printf("Adding Ethernet MDIO node\n");
        call_prom("interpret", 1, 1,
            " s\" /builtin\" find-device"
            " new-device"
                " 1 encode-int s\" #address-cells\" property"
                " 0 encode-int s\" #size-cells\" property"
                " s\" mdio\" device-name"
                " s\" fsl,mpc5200b-mdio\" encode-string"
                " s\" compatible\" property"
                " 0xf0003000 0x400 reg"
                " 0x2 encode-int"
                " 0x5 encode-int encode+"
                " 0x3 encode-int encode+"
                " s\" interrupts\" property"
            " finish-device");
    };

    /* Check for a PHY device node - if missing then create one and
     * give it's phandle to the ethernet node */
    node = call_prom("finddevice", 1, 1,
             ADDR("/builtin/mdio/ethernet-phy"));
    if (!PHANDLE_VALID(node)) {
        prom_printf("Adding Ethernet PHY node\n");
        call_prom("interpret", 1, 1,
            " s\" /builtin/mdio\" find-device"
            " new-device"
                " s\" ethernet-phy\" device-name"
                " 0x10 encode-int s\" reg\" property"
                " my-self"
                " ihandle>phandle"
            " finish-device"
            " s\" /builtin/ethernet\" find-device"
                " encode-int"
                " s\" phy-handle\" property"
            " device-end");
    }
}

static void __init fixup_device_tree_efika(void)
{
    int sound_irq[3] = { 2, 2, 0 };
    int bcomm_irq[3*16] = { 3,0,0, 3,1,0, 3,2,0, 3,3,0,
                3,4,0, 3,5,0, 3,6,0, 3,7,0,
                3,8,0, 3,9,0, 3,10,0, 3,11,0,
                3,12,0, 3,13,0, 3,14,0, 3,15,0 };
    u32 node;
    char prop[64];
    int rv, len;

    /* Check if we're really running on a EFIKA */
    node = call_prom("finddevice", 1, 1, ADDR("/"));
    if (!PHANDLE_VALID(node))
        return;

    rv = prom_getprop(node, "model", prop, sizeof(prop));
    if (rv == PROM_ERROR)
        return;
    if (strcmp(prop, "EFIKA5K2"))
        return;

    prom_printf("Applying EFIKA device tree fixups\n");

    /* Claiming to be 'chrp' is death */
    node = call_prom("finddevice", 1, 1, ADDR("/"));
    rv = prom_getprop(node, "device_type", prop, sizeof(prop));
    if (rv != PROM_ERROR && (strcmp(prop, "chrp") == 0))
        prom_setprop(node, "/", "device_type", "efika", sizeof("efika"));

    /* CODEGEN,description is exposed in /proc/cpuinfo so
       fix that too */
    rv = prom_getprop(node, "CODEGEN,description", prop, sizeof(prop));
    if (rv != PROM_ERROR && (strstr(prop, "CHRP")))
        prom_setprop(node, "/", "CODEGEN,description",
                 "Efika 5200B PowerPC System",
                 sizeof("Efika 5200B PowerPC System"));

    /* Fixup bestcomm interrupts property */
    node = call_prom("finddevice", 1, 1, ADDR("/builtin/bestcomm"));
    if (PHANDLE_VALID(node)) {
        len = prom_getproplen(node, "interrupts");
        if (len == 12) {
            prom_printf("Fixing bestcomm interrupts property\n");
            prom_setprop(node, "/builtin/bestcom", "interrupts",
                     bcomm_irq, sizeof(bcomm_irq));
        }
    }

    /* Fixup sound interrupts property */
    node = call_prom("finddevice", 1, 1, ADDR("/builtin/sound"));
    if (PHANDLE_VALID(node)) {
        rv = prom_getprop(node, "interrupts", prop, sizeof(prop));
        if (rv == PROM_ERROR) {
            prom_printf("Adding sound interrupts property\n");
            prom_setprop(node, "/builtin/sound", "interrupts",
                     sound_irq, sizeof(sound_irq));
        }
    }

    /* Make sure ethernet phy-handle property exists */
    fixup_device_tree_efika_add_phy();
}
#else
#define fixup_device_tree_efika()
#endif

static void __init fixup_device_tree(void)
{
    fixup_device_tree_maple();
    fixup_device_tree_maple_memory_controller();
    fixup_device_tree_chrp();
    fixup_device_tree_pmac();
    fixup_device_tree_efika();
}

static void __init prom_find_boot_cpu(void)
{
    struct prom_t *_prom = &RELOC(prom);
    u32 getprop_rval;
    ihandle prom_cpu;
    phandle cpu_pkg;

    _prom->cpu = 0;
    if (prom_getprop(_prom->chosen, "cpu", &prom_cpu, sizeof(prom_cpu)) <= 0)
        return;

    cpu_pkg = call_prom("instance-to-package", 1, 1, prom_cpu);

    prom_getprop(cpu_pkg, "reg", &getprop_rval, sizeof(getprop_rval));
    _prom->cpu = getprop_rval;

    prom_debug("Booting CPU hw index = %lu\n", _prom->cpu);
}

static void __init prom_check_initrd(unsigned long r3, unsigned long r4)
{
#ifdef CONFIG_BLK_DEV_INITRD
    struct prom_t *_prom = &RELOC(prom);

    if (r3 && r4 && r4 != 0xdeadbeef) {
        unsigned long val;

        RELOC(prom_initrd_start) = is_kernel_addr(r3) ? __pa(r3) : r3;
        RELOC(prom_initrd_end) = RELOC(prom_initrd_start) + r4;

        val = RELOC(prom_initrd_start);
        prom_setprop(_prom->chosen, "/chosen", "linux,initrd-start",
                 &val, sizeof(val));
        val = RELOC(prom_initrd_end);
        prom_setprop(_prom->chosen, "/chosen", "linux,initrd-end",
                 &val, sizeof(val));

        reserve_mem(RELOC(prom_initrd_start),
                RELOC(prom_initrd_end) - RELOC(prom_initrd_start));

        prom_debug("initrd_start=0x%x\n", RELOC(prom_initrd_start));
        prom_debug("initrd_end=0x%x\n", RELOC(prom_initrd_end));
    }
#endif /* CONFIG_BLK_DEV_INITRD */
}


/*
 * We enter here early on, when the Open Firmware prom is still
 * handling exceptions and the MMU hash table for us.
 */

unsigned long __init prom_init(unsigned long r3, unsigned long r4,
                   unsigned long pp,
                   unsigned long r6, unsigned long r7,
                   unsigned long kbase)
{   
    struct prom_t *_prom;
    unsigned long hdr;

#ifdef CONFIG_PPC32
    unsigned long offset = reloc_offset();
    reloc_got2(offset);
#endif

    _prom = &RELOC(prom);

    /*
     * First zero the BSS
     */
    memset(&RELOC(__bss_start), 0, __bss_stop - __bss_start);

    /*
     * Init interface to Open Firmware, get some node references,
     * like /chosen
     */
    prom_init_client_services(pp);

    /*
     * See if this OF is old enough that we need to do explicit maps
     * and other workarounds
     */
    prom_find_mmu();

    /*
     * Init prom stdout device
     */
    prom_init_stdout();

    prom_printf("Preparing to boot %s", RELOC(linux_banner));

    /*
     * Get default machine type. At this point, we do not differentiate
     * between pSeries SMP and pSeries LPAR
     */
    RELOC(of_platform) = prom_find_machine_type();
    prom_printf("Detected machine type: %x\n", RELOC(of_platform));

#ifndef CONFIG_NONSTATIC_KERNEL
    /* Bail if this is a kdump kernel. */
    if (PHYSICAL_START > 0)
        prom_panic("Error: You can't boot a kdump kernel from OF!\n");
#endif

    /*
     * Check for an initrd
     */
    prom_check_initrd(r3, r4);

#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
    /*
     * On pSeries, inform the firmware about our capabilities
     */
    if (RELOC(of_platform) == PLATFORM_PSERIES ||
        RELOC(of_platform) == PLATFORM_PSERIES_LPAR)
        prom_send_capabilities();
#endif

    /*
     * Copy the CPU hold code
     */
    if (RELOC(of_platform) != PLATFORM_POWERMAC)
        copy_and_flush(0, kbase, 0x100, 0);

    /*
     * Do early parsing of command line
     */
    early_cmdline_parse();

    /*
     * Initialize memory management within prom_init
     */
    prom_init_mem();

    /*
     * Determine which cpu is actually running right _now_
     */
    prom_find_boot_cpu();

    /* 
     * Initialize display devices
     */
    prom_check_displays();

#ifdef CONFIG_PPC64
    /*
     * Initialize IOMMU (TCE tables) on pSeries. Do that before anything else
     * that uses the allocator, we need to make sure we get the top of memory
     * available for us here...
     */
    if (RELOC(of_platform) == PLATFORM_PSERIES)
        prom_initialize_tce_table();
#endif

    /*
     * On non-powermacs, try to instantiate RTAS. PowerMacs don't
     * have a usable RTAS implementation.
     */
    if (RELOC(of_platform) != PLATFORM_POWERMAC &&
        RELOC(of_platform) != PLATFORM_OPAL)
        prom_instantiate_rtas();

#ifdef CONFIG_PPC_POWERNV
    /* Detect HAL and try instanciating it & doing takeover */
    if (RELOC(of_platform) == PLATFORM_PSERIES_LPAR) {
        prom_query_opal();
        if (RELOC(of_platform) == PLATFORM_OPAL) {
            prom_opal_hold_cpus();
            prom_opal_takeover();
        }
    } else if (RELOC(of_platform) == PLATFORM_OPAL)
        prom_instantiate_opal();
#endif

#ifdef CONFIG_PPC64
    /* instantiate sml */
    prom_instantiate_sml();
#endif

    /*
     * On non-powermacs, put all CPUs in spin-loops.
     *
     * PowerMacs use a different mechanism to spin CPUs
     */
    if (RELOC(of_platform) != PLATFORM_POWERMAC &&
        RELOC(of_platform) != PLATFORM_OPAL)
        prom_hold_cpus();

    /*
     * Fill in some infos for use by the kernel later on
     */
    if (RELOC(prom_memory_limit))
        prom_setprop(_prom->chosen, "/chosen", "linux,memory-limit",
                 &RELOC(prom_memory_limit),
                 sizeof(prom_memory_limit));
#ifdef CONFIG_PPC64
    if (RELOC(prom_iommu_off))
        prom_setprop(_prom->chosen, "/chosen", "linux,iommu-off",
                 NULL, 0);

    if (RELOC(prom_iommu_force_on))
        prom_setprop(_prom->chosen, "/chosen", "linux,iommu-force-on",
                 NULL, 0);

    if (RELOC(prom_tce_alloc_start)) {
        prom_setprop(_prom->chosen, "/chosen", "linux,tce-alloc-start",
                 &RELOC(prom_tce_alloc_start),
                 sizeof(prom_tce_alloc_start));
        prom_setprop(_prom->chosen, "/chosen", "linux,tce-alloc-end",
                 &RELOC(prom_tce_alloc_end),
                 sizeof(prom_tce_alloc_end));
    }
#endif

    /*
     * Fixup any known bugs in the device-tree
     */
    fixup_device_tree();

    /*
     * Now finally create the flattened device-tree
     */
    prom_printf("copying OF device tree...\n");
    flatten_device_tree();

    /*
     * in case stdin is USB and still active on IBM machines...
     * Unfortunately quiesce crashes on some powermacs if we have
     * closed stdin already (in particular the powerbook 101). It
     * appears that the OPAL version of OFW doesn't like it either.
     */
    if (RELOC(of_platform) != PLATFORM_POWERMAC &&
        RELOC(of_platform) != PLATFORM_OPAL)
        prom_close_stdin();

    /*
     * Call OF "quiesce" method to shut down pending DMA's from
     * devices etc...
     */
    prom_printf("Calling quiesce...\n");
    call_prom("quiesce", 0, 0);

    /*
     * And finally, call the kernel passing it the flattened device
     * tree and NULL as r5, thus triggering the new entry point which
     * is common to us and kexec
     */
    hdr = RELOC(dt_header_start);

    /* Don't print anything after quiesce under OPAL, it crashes OFW */
    if (RELOC(of_platform) != PLATFORM_OPAL) {
        prom_printf("returning from prom_init\n");
        prom_debug("->dt_header_start=0x%x\n", hdr);
    }

#ifdef CONFIG_PPC32
    reloc_got2(-offset);
#endif

#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL
    /* OPAL early debug gets the OPAL base & entry in r8 and r9 */
    __start(hdr, kbase, 0, 0, 0,
        RELOC(prom_opal_base), RELOC(prom_opal_entry));
#else
    __start(hdr, kbase, 0, 0, 0, 0, 0);
#endif

    return 0;
}