fdt.c

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/*
 * Functions for working with the Flattened Device Tree data format
 *
 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
 * [email protected]
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/initrd.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/slab.h>

#include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
#ifdef CONFIG_PPC
#include <asm/machdep.h>
#endif /* CONFIG_PPC */

#include <asm/page.h>

char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
{
    return ((char *)blob) +
        be32_to_cpu(blob->off_dt_strings) + offset;
}

void *of_fdt_get_property(struct boot_param_header *blob,
               unsigned long node, const char *name,
               unsigned long *size)
{
    unsigned long p = node;

    do {
        u32 tag = be32_to_cpup((__be32 *)p);
        u32 sz, noff;
        const char *nstr;

        p += 4;
        if (tag == OF_DT_NOP)
            continue;
        if (tag != OF_DT_PROP)
            return NULL;

        sz = be32_to_cpup((__be32 *)p);
        noff = be32_to_cpup((__be32 *)(p + 4));
        p += 8;
        if (be32_to_cpu(blob->version) < 0x10)
            p = ALIGN(p, sz >= 8 ? 8 : 4);

        nstr = of_fdt_get_string(blob, noff);
        if (nstr == NULL) {
            pr_warning("Can't find property index name !\n");
            return NULL;
        }
        if (strcmp(name, nstr) == 0) {
            if (size)
                *size = sz;
            return (void *)p;
        }
        p += sz;
        p = ALIGN(p, 4);
    } while (1);
}

int of_fdt_is_compatible(struct boot_param_header *blob,
              unsigned long node, const char *compat)
{
    const char *cp;
    unsigned long cplen, l, score = 0;

    cp = of_fdt_get_property(blob, node, "compatible", &cplen);
    if (cp == NULL)
        return 0;
    while (cplen > 0) {
        score++;
        if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
            return score;
        l = strlen(cp) + 1;
        cp += l;
        cplen -= l;
    }

    return 0;
}

int of_fdt_match(struct boot_param_header *blob, unsigned long node,
                 const char *const *compat)
{
    unsigned int tmp, score = 0;

    if (!compat)
        return 0;

    while (*compat) {
        tmp = of_fdt_is_compatible(blob, node, *compat);
        if (tmp && (score == 0 || (tmp < score)))
            score = tmp;
        compat++;
    }

    return score;
}

static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
                       unsigned long align)
{
    void *res;

    *mem = ALIGN(*mem, align);
    res = (void *)*mem;
    *mem += size;

    return res;
}

static unsigned long unflatten_dt_node(struct boot_param_header *blob,
                unsigned long mem,
                unsigned long *p,
                struct device_node *dad,
                struct device_node ***allnextpp,
                unsigned long fpsize)
{
    struct device_node *np;
    struct property *pp, **prev_pp = NULL;
    char *pathp;
    u32 tag;
    unsigned int l, allocl;
    int has_name = 0;
    int new_format = 0;

    tag = be32_to_cpup((__be32 *)(*p));
    if (tag != OF_DT_BEGIN_NODE) {
        pr_err("Weird tag at start of node: %x\n", tag);
        return mem;
    }
    *p += 4;
    pathp = (char *)*p;
    l = allocl = strlen(pathp) + 1;
    *p = ALIGN(*p + l, 4);

    /* version 0x10 has a more compact unit name here instead of the full
     * path. we accumulate the full path size using "fpsize", we'll rebuild
     * it later. We detect this because the first character of the name is
     * not '/'.
     */
    if ((*pathp) != '/') {
        new_format = 1;
        if (fpsize == 0) {
            /* root node: special case. fpsize accounts for path
             * plus terminating zero. root node only has '/', so
             * fpsize should be 2, but we want to avoid the first
             * level nodes to have two '/' so we use fpsize 1 here
             */
            fpsize = 1;
            allocl = 2;
        } else {
            /* account for '/' and path size minus terminal 0
             * already in 'l'
             */
            fpsize += l;
            allocl = fpsize;
        }
    }

    np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
                __alignof__(struct device_node));
    if (allnextpp) {
        memset(np, 0, sizeof(*np));
        np->full_name = ((char *)np) + sizeof(struct device_node);
        if (new_format) {
            char *fn = np->full_name;
            /* rebuild full path for new format */
            if (dad && dad->parent) {
                strcpy(fn, dad->full_name);
#ifdef DEBUG
                if ((strlen(fn) + l + 1) != allocl) {
                    pr_debug("%s: p: %d, l: %d, a: %d\n",
                        pathp, (int)strlen(fn),
                        l, allocl);
                }
#endif
                fn += strlen(fn);
            }
            *(fn++) = '/';
            memcpy(fn, pathp, l);
        } else
            memcpy(np->full_name, pathp, l);
        prev_pp = &np->properties;
        **allnextpp = np;
        *allnextpp = &np->allnext;
        if (dad != NULL) {
            np->parent = dad;
            /* we temporarily use the next field as `last_child'*/
            if (dad->next == NULL)
                dad->child = np;
            else
                dad->next->sibling = np;
            dad->next = np;
        }
        kref_init(&np->kref);
    }
    /* process properties */
    while (1) {
        u32 sz, noff;
        char *pname;

        tag = be32_to_cpup((__be32 *)(*p));
        if (tag == OF_DT_NOP) {
            *p += 4;
            continue;
        }
        if (tag != OF_DT_PROP)
            break;
        *p += 4;
        sz = be32_to_cpup((__be32 *)(*p));
        noff = be32_to_cpup((__be32 *)((*p) + 4));
        *p += 8;
        if (be32_to_cpu(blob->version) < 0x10)
            *p = ALIGN(*p, sz >= 8 ? 8 : 4);

        pname = of_fdt_get_string(blob, noff);
        if (pname == NULL) {
            pr_info("Can't find property name in list !\n");
            break;
        }
        if (strcmp(pname, "name") == 0)
            has_name = 1;
        l = strlen(pname) + 1;
        pp = unflatten_dt_alloc(&mem, sizeof(struct property),
                    __alignof__(struct property));
        if (allnextpp) {
            /* We accept flattened tree phandles either in
             * ePAPR-style "phandle" properties, or the
             * legacy "linux,phandle" properties.  If both
             * appear and have different values, things
             * will get weird.  Don't do that. */
            if ((strcmp(pname, "phandle") == 0) ||
                (strcmp(pname, "linux,phandle") == 0)) {
                if (np->phandle == 0)
                    np->phandle = be32_to_cpup((__be32*)*p);
            }
            /* And we process the "ibm,phandle" property
             * used in pSeries dynamic device tree
             * stuff */
            if (strcmp(pname, "ibm,phandle") == 0)
                np->phandle = be32_to_cpup((__be32 *)*p);
            pp->name = pname;
            pp->length = sz;
            pp->value = (void *)*p;
            *prev_pp = pp;
            prev_pp = &pp->next;
        }
        *p = ALIGN((*p) + sz, 4);
    }
    /* with version 0x10 we may not have the name property, recreate
     * it here from the unit name if absent
     */
    if (!has_name) {
        char *p1 = pathp, *ps = pathp, *pa = NULL;
        int sz;

        while (*p1) {
            if ((*p1) == '@')
                pa = p1;
            if ((*p1) == '/')
                ps = p1 + 1;
            p1++;
        }
        if (pa < ps)
            pa = p1;
        sz = (pa - ps) + 1;
        pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
                    __alignof__(struct property));
        if (allnextpp) {
            pp->name = "name";
            pp->length = sz;
            pp->value = pp + 1;
            *prev_pp = pp;
            prev_pp = &pp->next;
            memcpy(pp->value, ps, sz - 1);
            ((char *)pp->value)[sz - 1] = 0;
            pr_debug("fixed up name for %s -> %s\n", pathp,
                (char *)pp->value);
        }
    }
    if (allnextpp) {
        *prev_pp = NULL;
        np->name = of_get_property(np, "name", NULL);
        np->type = of_get_property(np, "device_type", NULL);

        if (!np->name)
            np->name = "<NULL>";
        if (!np->type)
            np->type = "<NULL>";
    }
    while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
        if (tag == OF_DT_NOP)
            *p += 4;
        else
            mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
                        fpsize);
        tag = be32_to_cpup((__be32 *)(*p));
    }
    if (tag != OF_DT_END_NODE) {
        pr_err("Weird tag at end of node: %x\n", tag);
        return mem;
    }
    *p += 4;
    return mem;
}

static void __unflatten_device_tree(struct boot_param_header *blob,
                 struct device_node **mynodes,
                 void * (*dt_alloc)(u64 size, u64 align))
{
    unsigned long start, mem, size;
    struct device_node **allnextp = mynodes;

    pr_debug(" -> unflatten_device_tree()\n");

    if (!blob) {
        pr_debug("No device tree pointer\n");
        return;
    }

    pr_debug("Unflattening device tree:\n");
    pr_debug("magic: %08x\n", be32_to_cpu(blob->magic));
    pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize));
    pr_debug("version: %08x\n", be32_to_cpu(blob->version));

    if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
        pr_err("Invalid device tree blob header\n");
        return;
    }

    /* First pass, scan for size */
    start = ((unsigned long)blob) +
        be32_to_cpu(blob->off_dt_struct);
    size = unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
    size = (size | 3) + 1;

    pr_debug("  size is %lx, allocating...\n", size);

    /* Allocate memory for the expanded device tree */
    mem = (unsigned long)
        dt_alloc(size + 4, __alignof__(struct device_node));

    ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);

    pr_debug("  unflattening %lx...\n", mem);

    /* Second pass, do actual unflattening */
    start = ((unsigned long)blob) +
        be32_to_cpu(blob->off_dt_struct);
    unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
    if (be32_to_cpup((__be32 *)start) != OF_DT_END)
        pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
    if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
        pr_warning("End of tree marker overwritten: %08x\n",
               be32_to_cpu(((__be32 *)mem)[size / 4]));
    *allnextp = NULL;

    pr_debug(" <- unflatten_device_tree()\n");
}

static void *kernel_tree_alloc(u64 size, u64 align)
{
    return kzalloc(size, GFP_KERNEL);
}

void of_fdt_unflatten_tree(unsigned long *blob,
            struct device_node **mynodes)
{
    struct boot_param_header *device_tree =
        (struct boot_param_header *)blob;
    __unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
}
EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);

/* Everything below here references initial_boot_params directly. */
int __initdata dt_root_addr_cells;
int __initdata dt_root_size_cells;

struct boot_param_header *initial_boot_params;

#ifdef CONFIG_OF_EARLY_FLATTREE

int __init of_scan_flat_dt(int (*it)(unsigned long node,
                     const char *uname, int depth,
                     void *data),
               void *data)
{
    unsigned long p = ((unsigned long)initial_boot_params) +
        be32_to_cpu(initial_boot_params->off_dt_struct);
    int rc = 0;
    int depth = -1;

    do {
        u32 tag = be32_to_cpup((__be32 *)p);
        char *pathp;

        p += 4;
        if (tag == OF_DT_END_NODE) {
            depth--;
            continue;
        }
        if (tag == OF_DT_NOP)
            continue;
        if (tag == OF_DT_END)
            break;
        if (tag == OF_DT_PROP) {
            u32 sz = be32_to_cpup((__be32 *)p);
            p += 8;
            if (be32_to_cpu(initial_boot_params->version) < 0x10)
                p = ALIGN(p, sz >= 8 ? 8 : 4);
            p += sz;
            p = ALIGN(p, 4);
            continue;
        }
        if (tag != OF_DT_BEGIN_NODE) {
            pr_err("Invalid tag %x in flat device tree!\n", tag);
            return -EINVAL;
        }
        depth++;
        pathp = (char *)p;
        p = ALIGN(p + strlen(pathp) + 1, 4);
        if ((*pathp) == '/') {
            char *lp, *np;
            for (lp = NULL, np = pathp; *np; np++)
                if ((*np) == '/')
                    lp = np+1;
            if (lp != NULL)
                pathp = lp;
        }
        rc = it(p, pathp, depth, data);
        if (rc != 0)
            break;
    } while (1);

    return rc;
}

unsigned long __init of_get_flat_dt_root(void)
{
    unsigned long p = ((unsigned long)initial_boot_params) +
        be32_to_cpu(initial_boot_params->off_dt_struct);

    while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
        p += 4;
    BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
    p += 4;
    return ALIGN(p + strlen((char *)p) + 1, 4);
}

void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
                 unsigned long *size)
{
    return of_fdt_get_property(initial_boot_params, node, name, size);
}

int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
{
    return of_fdt_is_compatible(initial_boot_params, node, compat);
}

int __init of_flat_dt_match(unsigned long node, const char *const *compat)
{
    return of_fdt_match(initial_boot_params, node, compat);
}

#ifdef CONFIG_BLK_DEV_INITRD

void __init early_init_dt_check_for_initrd(unsigned long node)
{
    unsigned long start, end, len;
    __be32 *prop;

    pr_debug("Looking for initrd properties... ");

    prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
    if (!prop)
        return;
    start = of_read_ulong(prop, len/4);

    prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
    if (!prop)
        return;
    end = of_read_ulong(prop, len/4);

    early_init_dt_setup_initrd_arch(start, end);
    pr_debug("initrd_start=0x%lx  initrd_end=0x%lx\n", start, end);
}
#else
inline void early_init_dt_check_for_initrd(unsigned long node)
{
}
#endif /* CONFIG_BLK_DEV_INITRD */

int __init early_init_dt_scan_root(unsigned long node, const char *uname,
                   int depth, void *data)
{
    __be32 *prop;

    if (depth != 0)
        return 0;

    dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
    dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;

    prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
    if (prop)
        dt_root_size_cells = be32_to_cpup(prop);
    pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);

    prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
    if (prop)
        dt_root_addr_cells = be32_to_cpup(prop);
    pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);

    /* break now */
    return 1;
}

u64 __init dt_mem_next_cell(int s, __be32 **cellp)
{
    __be32 *p = *cellp;

    *cellp = p + s;
    return of_read_number(p, s);
}

int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
                     int depth, void *data)
{
    char *type = of_get_flat_dt_prop(node, "device_type", NULL);
    __be32 *reg, *endp;
    unsigned long l;

    /* We are scanning "memory" nodes only */
    if (type == NULL) {
        /*
         * The longtrail doesn't have a device_type on the
         * /memory node, so look for the node called /memory@0.
         */
        if (depth != 1 || strcmp(uname, "memory@0") != 0)
            return 0;
    } else if (strcmp(type, "memory") != 0)
        return 0;

    reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
    if (reg == NULL)
        reg = of_get_flat_dt_prop(node, "reg", &l);
    if (reg == NULL)
        return 0;

    endp = reg + (l / sizeof(__be32));

    pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
        uname, l, reg[0], reg[1], reg[2], reg[3]);

    while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
        u64 base, size;

        base = dt_mem_next_cell(dt_root_addr_cells, &reg);
        size = dt_mem_next_cell(dt_root_size_cells, &reg);

        if (size == 0)
            continue;
        pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
            (unsigned long long)size);

        early_init_dt_add_memory_arch(base, size);
    }

    return 0;
}

int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
                     int depth, void *data)
{
    unsigned long l;
    char *p;

    pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);

    if (depth != 1 || !data ||
        (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
        return 0;

    early_init_dt_check_for_initrd(node);

    /* Retrieve command line */
    p = of_get_flat_dt_prop(node, "bootargs", &l);
    if (p != NULL && l > 0)
        strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));

    /*
     * CONFIG_CMDLINE is meant to be a default in case nothing else
     * managed to set the command line, unless CONFIG_CMDLINE_FORCE
     * is set in which case we override whatever was found earlier.
     */
#ifdef CONFIG_CMDLINE
#ifndef CONFIG_CMDLINE_FORCE
    if (!((char *)data)[0])
#endif
        strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
#endif /* CONFIG_CMDLINE */

    pr_debug("Command line is: %s\n", (char*)data);

    /* break now */
    return 1;
}

void __init unflatten_device_tree(void)
{
    __unflatten_device_tree(initial_boot_params, &allnodes,
                early_init_dt_alloc_memory_arch);

    /* Get pointer to "/chosen" and "/aliasas" nodes for use everywhere */
    of_alias_scan(early_init_dt_alloc_memory_arch);
}

#endif /* CONFIG_OF_EARLY_FLATTREE */