prom.c

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/*
 * Procedures for creating, accessing and interpreting the device tree.
 *
 * 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

#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/stringify.h>
#include <linux/delay.h>
#include <linux/initrd.h>
#include <linux/bitops.h>
#include <linux/export.h>
#include <linux/kexec.h>
#include <linux/debugfs.h>
#include <linux/irq.h>
#include <linux/memblock.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/kdump.h>
#include <asm/smp.h>
#include <asm/mmu.h>
#include <asm/paca.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/pSeries_reconfig.h>
#include <asm/pci-bridge.h>
#include <asm/kexec.h>
#include <asm/opal.h>
#include <asm/fadump.h>

#include <mm/mmu_decl.h>

#ifdef DEBUG
#define DBG(fmt...) printk(KERN_ERR fmt)
#else
#define DBG(fmt...)
#endif

#ifdef CONFIG_PPC64
int __initdata iommu_is_off;
int __initdata iommu_force_on;
unsigned long tce_alloc_start, tce_alloc_end;
u64 ppc64_rma_size;
#endif
static phys_addr_t first_memblock_size;
static int __initdata boot_cpu_count;

static int __init early_parse_mem(char *p)
{
    if (!p)
        return 1;

    memory_limit = PAGE_ALIGN(memparse(p, &p));
    DBG("memory limit = 0x%llx\n", memory_limit);

    return 0;
}
early_param("mem", early_parse_mem);

/*
 * overlaps_initrd - check for overlap with page aligned extension of
 * initrd.
 */
static inline int overlaps_initrd(unsigned long start, unsigned long size)
{
#ifdef CONFIG_BLK_DEV_INITRD
    if (!initrd_start)
        return 0;

    return  (start + size) > _ALIGN_DOWN(initrd_start, PAGE_SIZE) &&
            start <= _ALIGN_UP(initrd_end, PAGE_SIZE);
#else
    return 0;
#endif
}

static void __init move_device_tree(void)
{
    unsigned long start, size;
    void *p;

    DBG("-> move_device_tree\n");

    start = __pa(initial_boot_params);
    size = be32_to_cpu(initial_boot_params->totalsize);

    if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
            overlaps_crashkernel(start, size) ||
            overlaps_initrd(start, size)) {
        p = __va(memblock_alloc(size, PAGE_SIZE));
        memcpy(p, initial_boot_params, size);
        initial_boot_params = (struct boot_param_header *)p;
        DBG("Moved device tree to 0x%p\n", p);
    }

    DBG("<- move_device_tree\n");
}

/*
 * ibm,pa-features is a per-cpu property that contains a string of
 * attribute descriptors, each of which has a 2 byte header plus up
 * to 254 bytes worth of processor attribute bits.  First header
 * byte specifies the number of bytes following the header.
 * Second header byte is an "attribute-specifier" type, of which
 * zero is the only currently-defined value.
 * Implementation:  Pass in the byte and bit offset for the feature
 * that we are interested in.  The function will return -1 if the
 * pa-features property is missing, or a 1/0 to indicate if the feature
 * is supported/not supported.  Note that the bit numbers are
 * big-endian to match the definition in PAPR.
 */
static struct ibm_pa_feature {
    unsigned long   cpu_features;   /* CPU_FTR_xxx bit */
    unsigned long   mmu_features;   /* MMU_FTR_xxx bit */
    unsigned int    cpu_user_ftrs;  /* PPC_FEATURE_xxx bit */
    unsigned char   pabyte;     /* byte number in ibm,pa-features */
    unsigned char   pabit;      /* bit number (big-endian) */
    unsigned char   invert;     /* if 1, pa bit set => clear feature */
} ibm_pa_features[] __initdata = {
    {0, 0, PPC_FEATURE_HAS_MMU, 0, 0, 0},
    {0, 0, PPC_FEATURE_HAS_FPU, 0, 1, 0},
    {0, MMU_FTR_SLB, 0,     0, 2, 0},
    {CPU_FTR_CTRL, 0, 0,        0, 3, 0},
    {CPU_FTR_NOEXECUTE, 0, 0,   0, 6, 0},
    {CPU_FTR_NODSISRALIGN, 0, 0,    1, 1, 1},
    {0, MMU_FTR_CI_LARGE_PAGE, 0,   1, 2, 0},
    {CPU_FTR_REAL_LE, PPC_FEATURE_TRUE_LE, 5, 0, 0},
};

static void __init scan_features(unsigned long node, unsigned char *ftrs,
                 unsigned long tablelen,
                 struct ibm_pa_feature *fp,
                 unsigned long ft_size)
{
    unsigned long i, len, bit;

    /* find descriptor with type == 0 */
    for (;;) {
        if (tablelen < 3)
            return;
        len = 2 + ftrs[0];
        if (tablelen < len)
            return;     /* descriptor 0 not found */
        if (ftrs[1] == 0)
            break;
        tablelen -= len;
        ftrs += len;
    }

    /* loop over bits we know about */
    for (i = 0; i < ft_size; ++i, ++fp) {
        if (fp->pabyte >= ftrs[0])
            continue;
        bit = (ftrs[2 + fp->pabyte] >> (7 - fp->pabit)) & 1;
        if (bit ^ fp->invert) {
            cur_cpu_spec->cpu_features |= fp->cpu_features;
            cur_cpu_spec->cpu_user_features |= fp->cpu_user_ftrs;
            cur_cpu_spec->mmu_features |= fp->mmu_features;
        } else {
            cur_cpu_spec->cpu_features &= ~fp->cpu_features;
            cur_cpu_spec->cpu_user_features &= ~fp->cpu_user_ftrs;
            cur_cpu_spec->mmu_features &= ~fp->mmu_features;
        }
    }
}

static void __init check_cpu_pa_features(unsigned long node)
{
    unsigned char *pa_ftrs;
    unsigned long tablelen;

    pa_ftrs = of_get_flat_dt_prop(node, "ibm,pa-features", &tablelen);
    if (pa_ftrs == NULL)
        return;

    scan_features(node, pa_ftrs, tablelen,
              ibm_pa_features, ARRAY_SIZE(ibm_pa_features));
}

#ifdef CONFIG_PPC_STD_MMU_64
static void __init check_cpu_slb_size(unsigned long node)
{
    u32 *slb_size_ptr;

    slb_size_ptr = of_get_flat_dt_prop(node, "slb-size", NULL);
    if (slb_size_ptr != NULL) {
        mmu_slb_size = *slb_size_ptr;
        return;
    }
    slb_size_ptr = of_get_flat_dt_prop(node, "ibm,slb-size", NULL);
    if (slb_size_ptr != NULL) {
        mmu_slb_size = *slb_size_ptr;
    }
}
#else
#define check_cpu_slb_size(node) do { } while(0)
#endif

static struct feature_property {
    const char *name;
    u32 min_value;
    unsigned long cpu_feature;
    unsigned long cpu_user_ftr;
} feature_properties[] __initdata = {
#ifdef CONFIG_ALTIVEC
    {"altivec", 0, CPU_FTR_ALTIVEC, PPC_FEATURE_HAS_ALTIVEC},
    {"ibm,vmx", 1, CPU_FTR_ALTIVEC, PPC_FEATURE_HAS_ALTIVEC},
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
    /* Yes, this _really_ is ibm,vmx == 2 to enable VSX */
    {"ibm,vmx", 2, CPU_FTR_VSX, PPC_FEATURE_HAS_VSX},
#endif /* CONFIG_VSX */
#ifdef CONFIG_PPC64
    {"ibm,dfp", 1, 0, PPC_FEATURE_HAS_DFP},
    {"ibm,purr", 1, CPU_FTR_PURR, 0},
    {"ibm,spurr", 1, CPU_FTR_SPURR, 0},
#endif /* CONFIG_PPC64 */
};

#if defined(CONFIG_44x) && defined(CONFIG_PPC_FPU)
static inline void identical_pvr_fixup(unsigned long node)
{
    unsigned int pvr;
    char *model = of_get_flat_dt_prop(node, "model", NULL);

    /*
     * Since 440GR(x)/440EP(x) processors have the same pvr,
     * we check the node path and set bit 28 in the cur_cpu_spec
     * pvr for EP(x) processor version. This bit is always 0 in
     * the "real" pvr. Then we call identify_cpu again with
     * the new logical pvr to enable FPU support.
     */
    if (model && strstr(model, "440EP")) {
        pvr = cur_cpu_spec->pvr_value | 0x8;
        identify_cpu(0, pvr);
        DBG("Using logical pvr %x for %s\n", pvr, model);
    }
}
#else
#define identical_pvr_fixup(node) do { } while(0)
#endif

static void __init check_cpu_feature_properties(unsigned long node)
{
    unsigned long i;
    struct feature_property *fp = feature_properties;
    const u32 *prop;

    for (i = 0; i < ARRAY_SIZE(feature_properties); ++i, ++fp) {
        prop = of_get_flat_dt_prop(node, fp->name, NULL);
        if (prop && *prop >= fp->min_value) {
            cur_cpu_spec->cpu_features |= fp->cpu_feature;
            cur_cpu_spec->cpu_user_features |= fp->cpu_user_ftr;
        }
    }
}

static int __init early_init_dt_scan_cpus(unsigned long node,
                      const char *uname, int depth,
                      void *data)
{
    char *type = of_get_flat_dt_prop(node, "device_type", NULL);
    const u32 *prop;
    const u32 *intserv;
    int i, nthreads;
    unsigned long len;
    int found = -1;
    int found_thread = 0;

    /* We are scanning "cpu" nodes only */
    if (type == NULL || strcmp(type, "cpu") != 0)
        return 0;

    /* Get physical cpuid */
    intserv = of_get_flat_dt_prop(node, "ibm,ppc-interrupt-server#s", &len);
    if (intserv) {
        nthreads = len / sizeof(int);
    } else {
        intserv = of_get_flat_dt_prop(node, "reg", NULL);
        nthreads = 1;
    }

    /*
     * Now see if any of these threads match our boot cpu.
     * NOTE: This must match the parsing done in smp_setup_cpu_maps.
     */
    for (i = 0; i < nthreads; i++) {
        /*
         * version 2 of the kexec param format adds the phys cpuid of
         * booted proc.
         */
        if (initial_boot_params->version >= 2) {
            if (intserv[i] == initial_boot_params->boot_cpuid_phys) {
                found = boot_cpu_count;
                found_thread = i;
            }
        } else {
            /*
             * Check if it's the boot-cpu, set it's hw index now,
             * unfortunately this format did not support booting
             * off secondary threads.
             */
            if (of_get_flat_dt_prop(node,
                    "linux,boot-cpu", NULL) != NULL)
                found = boot_cpu_count;
        }
#ifdef CONFIG_SMP
        /* logical cpu id is always 0 on UP kernels */
        boot_cpu_count++;
#endif
    }

    if (found >= 0) {
        DBG("boot cpu: logical %d physical %d\n", found,
            intserv[found_thread]);
        boot_cpuid = found;
        set_hard_smp_processor_id(found, intserv[found_thread]);

        /*
         * PAPR defines "logical" PVR values for cpus that
         * meet various levels of the architecture:
         * 0x0f000001   Architecture version 2.04
         * 0x0f000002   Architecture version 2.05
         * If the cpu-version property in the cpu node contains
         * such a value, we call identify_cpu again with the
         * logical PVR value in order to use the cpu feature
         * bits appropriate for the architecture level.
         *
         * A POWER6 partition in "POWER6 architected" mode
         * uses the 0x0f000002 PVR value; in POWER5+ mode
         * it uses 0x0f000001.
         */
        prop = of_get_flat_dt_prop(node, "cpu-version", NULL);
        if (prop && (*prop & 0xff000000) == 0x0f000000)
            identify_cpu(0, *prop);

        identical_pvr_fixup(node);
    }

    check_cpu_feature_properties(node);
    check_cpu_pa_features(node);
    check_cpu_slb_size(node);

#ifdef CONFIG_PPC_PSERIES
    if (nthreads > 1)
        cur_cpu_spec->cpu_features |= CPU_FTR_SMT;
    else
        cur_cpu_spec->cpu_features &= ~CPU_FTR_SMT;
#endif

    return 0;
}

int __init early_init_dt_scan_chosen_ppc(unsigned long node, const char *uname,
                     int depth, void *data)
{
    unsigned long *lprop;

    /* Use common scan routine to determine if this is the chosen node */
    if (early_init_dt_scan_chosen(node, uname, depth, data) == 0)
        return 0;

#ifdef CONFIG_PPC64
    /* check if iommu is forced on or off */
    if (of_get_flat_dt_prop(node, "linux,iommu-off", NULL) != NULL)
        iommu_is_off = 1;
    if (of_get_flat_dt_prop(node, "linux,iommu-force-on", NULL) != NULL)
        iommu_force_on = 1;
#endif

    /* mem=x on the command line is the preferred mechanism */
    lprop = of_get_flat_dt_prop(node, "linux,memory-limit", NULL);
    if (lprop)
        memory_limit = *lprop;

#ifdef CONFIG_PPC64
    lprop = of_get_flat_dt_prop(node, "linux,tce-alloc-start", NULL);
    if (lprop)
        tce_alloc_start = *lprop;
    lprop = of_get_flat_dt_prop(node, "linux,tce-alloc-end", NULL);
    if (lprop)
        tce_alloc_end = *lprop;
#endif

#ifdef CONFIG_KEXEC
    lprop = of_get_flat_dt_prop(node, "linux,crashkernel-base", NULL);
    if (lprop)
        crashk_res.start = *lprop;

    lprop = of_get_flat_dt_prop(node, "linux,crashkernel-size", NULL);
    if (lprop)
        crashk_res.end = crashk_res.start + *lprop - 1;
#endif

    /* break now */
    return 1;
}

#ifdef CONFIG_PPC_PSERIES
/*
 * Interpret the ibm,dynamic-memory property in the
 * /ibm,dynamic-reconfiguration-memory node.
 * This contains a list of memory blocks along with NUMA affinity
 * information.
 */
static int __init early_init_dt_scan_drconf_memory(unsigned long node)
{
    __be32 *dm, *ls, *usm;
    unsigned long l, n, flags;
    u64 base, size, memblock_size;
    unsigned int is_kexec_kdump = 0, rngs;

    ls = of_get_flat_dt_prop(node, "ibm,lmb-size", &l);
    if (ls == NULL || l < dt_root_size_cells * sizeof(__be32))
        return 0;
    memblock_size = dt_mem_next_cell(dt_root_size_cells, &ls);

    dm = of_get_flat_dt_prop(node, "ibm,dynamic-memory", &l);
    if (dm == NULL || l < sizeof(__be32))
        return 0;

    n = *dm++;  /* number of entries */
    if (l < (n * (dt_root_addr_cells + 4) + 1) * sizeof(__be32))
        return 0;

    /* check if this is a kexec/kdump kernel. */
    usm = of_get_flat_dt_prop(node, "linux,drconf-usable-memory",
                         &l);
    if (usm != NULL)
        is_kexec_kdump = 1;

    for (; n != 0; --n) {
        base = dt_mem_next_cell(dt_root_addr_cells, &dm);
        flags = dm[3];
        /* skip DRC index, pad, assoc. list index, flags */
        dm += 4;
        /* skip this block if the reserved bit is set in flags (0x80)
           or if the block is not assigned to this partition (0x8) */
        if ((flags & 0x80) || !(flags & 0x8))
            continue;
        size = memblock_size;
        rngs = 1;
        if (is_kexec_kdump) {
            /*
             * For each memblock in ibm,dynamic-memory, a corresponding
             * entry in linux,drconf-usable-memory property contains
             * a counter 'p' followed by 'p' (base, size) duple.
             * Now read the counter from
             * linux,drconf-usable-memory property
             */
            rngs = dt_mem_next_cell(dt_root_size_cells, &usm);
            if (!rngs) /* there are no (base, size) duple */
                continue;
        }
        do {
            if (is_kexec_kdump) {
                base = dt_mem_next_cell(dt_root_addr_cells,
                             &usm);
                size = dt_mem_next_cell(dt_root_size_cells,
                             &usm);
            }
            if (iommu_is_off) {
                if (base >= 0x80000000ul)
                    continue;
                if ((base + size) > 0x80000000ul)
                    size = 0x80000000ul - base;
            }
            memblock_add(base, size);
        } while (--rngs);
    }
    memblock_dump_all();
    return 0;
}
#else
#define early_init_dt_scan_drconf_memory(node)  0
#endif /* CONFIG_PPC_PSERIES */

static int __init early_init_dt_scan_memory_ppc(unsigned long node,
                        const char *uname,
                        int depth, void *data)
{
    if (depth == 1 &&
        strcmp(uname, "ibm,dynamic-reconfiguration-memory") == 0)
        return early_init_dt_scan_drconf_memory(node);
    
    return early_init_dt_scan_memory(node, uname, depth, data);
}

void __init early_init_dt_add_memory_arch(u64 base, u64 size)
{
#ifdef CONFIG_PPC64
    if (iommu_is_off) {
        if (base >= 0x80000000ul)
            return;
        if ((base + size) > 0x80000000ul)
            size = 0x80000000ul - base;
    }
#endif
    /* Keep track of the beginning of memory -and- the size of
     * the very first block in the device-tree as it represents
     * the RMA on ppc64 server
     */
    if (base < memstart_addr) {
        memstart_addr = base;
        first_memblock_size = size;
    }

    /* Add the chunk to the MEMBLOCK list */
    memblock_add(base, size);
}

void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
{
    return __va(memblock_alloc(size, align));
}

#ifdef CONFIG_BLK_DEV_INITRD
void __init early_init_dt_setup_initrd_arch(unsigned long start,
        unsigned long end)
{
    initrd_start = (unsigned long)__va(start);
    initrd_end = (unsigned long)__va(end);
    initrd_below_start_ok = 1;
}
#endif

static void __init early_reserve_mem(void)
{
    u64 base, size;
    u64 *reserve_map;
    unsigned long self_base;
    unsigned long self_size;

    reserve_map = (u64 *)(((unsigned long)initial_boot_params) +
                    initial_boot_params->off_mem_rsvmap);

    /* before we do anything, lets reserve the dt blob */
    self_base = __pa((unsigned long)initial_boot_params);
    self_size = initial_boot_params->totalsize;
    memblock_reserve(self_base, self_size);

#ifdef CONFIG_BLK_DEV_INITRD
    /* then reserve the initrd, if any */
    if (initrd_start && (initrd_end > initrd_start))
        memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE),
            _ALIGN_UP(initrd_end, PAGE_SIZE) -
            _ALIGN_DOWN(initrd_start, PAGE_SIZE));
#endif /* CONFIG_BLK_DEV_INITRD */

#ifdef CONFIG_PPC32
    /* 
     * Handle the case where we might be booting from an old kexec
     * image that setup the mem_rsvmap as pairs of 32-bit values
     */
    if (*reserve_map > 0xffffffffull) {
        u32 base_32, size_32;
        u32 *reserve_map_32 = (u32 *)reserve_map;

        while (1) {
            base_32 = *(reserve_map_32++);
            size_32 = *(reserve_map_32++);
            if (size_32 == 0)
                break;
            /* skip if the reservation is for the blob */
            if (base_32 == self_base && size_32 == self_size)
                continue;
            DBG("reserving: %x -> %x\n", base_32, size_32);
            memblock_reserve(base_32, size_32);
        }
        return;
    }
#endif
    while (1) {
        base = *(reserve_map++);
        size = *(reserve_map++);
        if (size == 0)
            break;
        DBG("reserving: %llx -> %llx\n", base, size);
        memblock_reserve(base, size);
    }
}

void __init early_init_devtree(void *params)
{
    phys_addr_t limit;

    DBG(" -> early_init_devtree(%p)\n", params);

    /* Setup flat device-tree pointer */
    initial_boot_params = params;

#ifdef CONFIG_PPC_RTAS
    /* Some machines might need RTAS info for debugging, grab it now. */
    of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
#endif

#ifdef CONFIG_PPC_POWERNV
    /* Some machines might need OPAL info for debugging, grab it now. */
    of_scan_flat_dt(early_init_dt_scan_opal, NULL);
#endif

#ifdef CONFIG_FA_DUMP
    /* scan tree to see if dump is active during last boot */
    of_scan_flat_dt(early_init_dt_scan_fw_dump, NULL);
#endif

    /* Pre-initialize the cmd_line with the content of boot_commmand_line,
     * which will be empty except when the content of the variable has
     * been overriden by a bootloading mechanism. This happens typically
     * with HAL takeover
     */
    strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);

    /* Retrieve various informations from the /chosen node of the
     * device-tree, including the platform type, initrd location and
     * size, TCE reserve, and more ...
     */
    of_scan_flat_dt(early_init_dt_scan_chosen_ppc, cmd_line);

    /* Scan memory nodes and rebuild MEMBLOCKs */
    of_scan_flat_dt(early_init_dt_scan_root, NULL);
    of_scan_flat_dt(early_init_dt_scan_memory_ppc, NULL);

    /* Save command line for /proc/cmdline and then parse parameters */
    strlcpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE);
    parse_early_param();

    /* make sure we've parsed cmdline for mem= before this */
    if (memory_limit)
        first_memblock_size = min_t(u64, first_memblock_size, memory_limit);
    setup_initial_memory_limit(memstart_addr, first_memblock_size);
    /* Reserve MEMBLOCK regions used by kernel, initrd, dt, etc... */
    memblock_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);
    /* If relocatable, reserve first 32k for interrupt vectors etc. */
    if (PHYSICAL_START > MEMORY_START)
        memblock_reserve(MEMORY_START, 0x8000);
    reserve_kdump_trampoline();
#ifdef CONFIG_FA_DUMP
    /*
     * If we fail to reserve memory for firmware-assisted dump then
     * fallback to kexec based kdump.
     */
    if (fadump_reserve_mem() == 0)
#endif
        reserve_crashkernel();
    early_reserve_mem();

    /*
     * Ensure that total memory size is page-aligned, because otherwise
     * mark_bootmem() gets upset.
     */
    limit = ALIGN(memory_limit ?: memblock_phys_mem_size(), PAGE_SIZE);
    memblock_enforce_memory_limit(limit);

    memblock_allow_resize();
    memblock_dump_all();

    DBG("Phys. mem: %llx\n", memblock_phys_mem_size());

    /* We may need to relocate the flat tree, do it now.
     * FIXME .. and the initrd too? */
    move_device_tree();

    allocate_pacas();

    DBG("Scanning CPUs ...\n");

    /* Retrieve CPU related informations from the flat tree
     * (altivec support, boot CPU ID, ...)
     */
    of_scan_flat_dt(early_init_dt_scan_cpus, NULL);

#if defined(CONFIG_SMP) && defined(CONFIG_PPC64)
    /* We'll later wait for secondaries to check in; there are
     * NCPUS-1 non-boot CPUs  :-)
     */
    spinning_secondaries = boot_cpu_count - 1;
#endif

    DBG(" <- early_init_devtree()\n");
}

/*******
 *
 * New implementation of the OF "find" APIs, return a refcounted
 * object, call of_node_put() when done.  The device tree and list
 * are protected by a rw_lock.
 *
 * Note that property management will need some locking as well,
 * this isn't dealt with yet.
 *
 *******/

struct device_node *of_find_next_cache_node(struct device_node *np)
{
    struct device_node *child;
    const phandle *handle;

    handle = of_get_property(np, "l2-cache", NULL);
    if (!handle)
        handle = of_get_property(np, "next-level-cache", NULL);

    if (handle)
        return of_find_node_by_phandle(*handle);

    /* OF on pmac has nodes instead of properties named "l2-cache"
     * beneath CPU nodes.
     */
    if (!strcmp(np->type, "cpu"))
        for_each_child_of_node(np, child)
            if (!strcmp(child->type, "cache"))
                return child;

    return NULL;
}

#ifdef CONFIG_PPC_PSERIES
/*
 * Fix up the uninitialized fields in a new device node:
 * name, type and pci-specific fields
 */

static int of_finish_dynamic_node(struct device_node *node)
{
    struct device_node *parent = of_get_parent(node);
    int err = 0;
    const phandle *ibm_phandle;

    node->name = of_get_property(node, "name", NULL);
    node->type = of_get_property(node, "device_type", NULL);

    if (!node->name)
        node->name = "<NULL>";
    if (!node->type)
        node->type = "<NULL>";

    if (!parent) {
        err = -ENODEV;
        goto out;
    }

    /* We don't support that function on PowerMac, at least
     * not yet
     */
    if (machine_is(powermac))
        return -ENODEV;

    /* fix up new node's phandle field */
    if ((ibm_phandle = of_get_property(node, "ibm,phandle", NULL)))
        node->phandle = *ibm_phandle;

out:
    of_node_put(parent);
    return err;
}

static int prom_reconfig_notifier(struct notifier_block *nb,
                  unsigned long action, void *node)
{
    int err;

    switch (action) {
    case PSERIES_RECONFIG_ADD:
        err = of_finish_dynamic_node(node);
        if (err < 0)
            printk(KERN_ERR "finish_node returned %d\n", err);
        break;
    default:
        err = 0;
        break;
    }
    return notifier_from_errno(err);
}

static struct notifier_block prom_reconfig_nb = {
    .notifier_call = prom_reconfig_notifier,
    .priority = 10, /* This one needs to run first */
};

static int __init prom_reconfig_setup(void)
{
    return pSeries_reconfig_notifier_register(&prom_reconfig_nb);
}
__initcall(prom_reconfig_setup);
#endif

/* Find the device node for a given logical cpu number, also returns the cpu
 * local thread number (index in ibm,interrupt-server#s) if relevant and
 * asked for (non NULL)
 */
struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
{
    int hardid;
    struct device_node *np;

    hardid = get_hard_smp_processor_id(cpu);

    for_each_node_by_type(np, "cpu") {
        const u32 *intserv;
        unsigned int plen, t;

        /* Check for ibm,ppc-interrupt-server#s. If it doesn't exist
         * fallback to "reg" property and assume no threads
         */
        intserv = of_get_property(np, "ibm,ppc-interrupt-server#s",
                &plen);
        if (intserv == NULL) {
            const u32 *reg = of_get_property(np, "reg", NULL);
            if (reg == NULL)
                continue;
            if (*reg == hardid) {
                if (thread)
                    *thread = 0;
                return np;
            }
        } else {
            plen /= sizeof(u32);
            for (t = 0; t < plen; t++) {
                if (hardid == intserv[t]) {
                    if (thread)
                        *thread = t;
                    return np;
                }
            }
        }
    }
    return NULL;
}
EXPORT_SYMBOL(of_get_cpu_node);

#if defined(CONFIG_DEBUG_FS) && defined(DEBUG)
static struct debugfs_blob_wrapper flat_dt_blob;

static int __init export_flat_device_tree(void)
{
    struct dentry *d;

    flat_dt_blob.data = initial_boot_params;
    flat_dt_blob.size = initial_boot_params->totalsize;

    d = debugfs_create_blob("flat-device-tree", S_IFREG | S_IRUSR,
                powerpc_debugfs_root, &flat_dt_blob);
    if (!d)
        return 1;

    return 0;
}
__initcall(export_flat_device_tree);
#endif