of/flattree: merge find_flat_dt_string and initial_boot_params

[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / kernel / prom.c

/*
 * 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/module.h>
#include <linux/kexec.h>
#include <linux/debugfs.h>
#include <linux/irq.h>
#include <linux/lmb.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/system.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/pSeries_reconfig.h>
#include <asm/pci-bridge.h>
#include <asm/phyp_dump.h>
#include <asm/kexec.h>
#include <mm/mmu_decl.h>

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


static int __initdata dt_root_addr_cells;
static int __initdata dt_root_size_cells;

#ifdef CONFIG_PPC64
int __initdata iommu_is_off;
int __initdata iommu_force_on;
unsigned long tce_alloc_start, tce_alloc_end;
#endif

typedef u32 cell_t;

extern struct device_node *allnodes;    /* temporary while merging */

extern rwlock_t devtree_lock;   /* temporary while merging */

/* export that to outside world */
struct device_node *of_chosen;

/**
 * This function is used to scan the flattened device-tree, it is
 * used to extract the memory informations at boot before we can
 * unflatten the tree
 */
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) +
                initial_boot_params->off_dt_struct;
        int rc = 0;
        int depth = -1;

        do {
                u32 tag = *((u32 *)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 = *((u32 *)p);
                        p += 8;
                        if (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) {
                        printk(KERN_WARNING "Invalid tag %x scanning flattened"
                               " 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) +
                initial_boot_params->off_dt_struct;

        while(*((u32 *)p) == OF_DT_NOP)
                p += 4;
        BUG_ON (*((u32 *)p) != OF_DT_BEGIN_NODE);
        p += 4;
        return _ALIGN(p + strlen((char *)p) + 1, 4);
}

/**
 * This  function can be used within scan_flattened_dt callback to get
 * access to properties
 */
void* __init of_get_flat_dt_prop(unsigned long node, const char *name,
                                 unsigned long *size)
{
        unsigned long p = node;

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

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

                sz = *((u32 *)p);
                noff = *((u32 *)(p + 4));
                p += 8;
                if (initial_boot_params->version < 0x10)
                        p = _ALIGN(p, sz >= 8 ? 8 : 4);

                nstr = find_flat_dt_string(noff);
                if (nstr == NULL) {
                        printk(KERN_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 __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
{
        const char* cp;
        unsigned long cplen, l;

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

        return 0;
}

static void *__init 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 __init unflatten_dt_node(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 = *((u32 *)(*p));
        if (tag != OF_DT_BEGIN_NODE) {
                printk("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 *p = np->full_name;
                        /* rebuild full path for new format */
                        if (dad && dad->parent) {
                                strcpy(p, dad->full_name);
#ifdef DEBUG
                                if ((strlen(p) + l + 1) != allocl) {
                                        DBG("%s: p: %d, l: %d, a: %d\n",
                                            pathp, (int)strlen(p), l, allocl);
                                }
#endif
                                p += strlen(p);
                        }
                        *(p++) = '/';
                        memcpy(p, 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 == 0)
                                dad->child = np;
                        else
                                dad->next->sibling = np;
                        dad->next = np;
                }
                kref_init(&np->kref);
        }
        while(1) {
                u32 sz, noff;
                char *pname;

                tag = *((u32 *)(*p));
                if (tag == OF_DT_NOP) {
                        *p += 4;
                        continue;
                }
                if (tag != OF_DT_PROP)
                        break;
                *p += 4;
                sz = *((u32 *)(*p));
                noff = *((u32 *)((*p) + 4));
                *p += 8;
                if (initial_boot_params->version < 0x10)
                        *p = _ALIGN(*p, sz >= 8 ? 8 : 4);

                pname = find_flat_dt_string(noff);
                if (pname == NULL) {
                        printk("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) {
                        if (strcmp(pname, "linux,phandle") == 0) {
                                np->node = *((u32 *)*p);
                                if (np->linux_phandle == 0)
                                        np->linux_phandle = np->node;
                        }
                        if (strcmp(pname, "ibm,phandle") == 0)
                                np->linux_phandle = *((u32 *)*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 *p = pathp, *ps = pathp, *pa = NULL;
                int sz;

                while (*p) {
                        if ((*p) == '@')
                                pa = p;
                        if ((*p) == '/')
                                ps = p + 1;
                        p++;
                }
                if (pa < ps)
                        pa = p;
                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;
                        DBG("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) {
                mem = unflatten_dt_node(mem, p, np, allnextpp, fpsize);
                tag = *((u32 *)(*p));
        }
        if (tag != OF_DT_END_NODE) {
                printk("Weird tag at end of node: %x\n", tag);
                return mem;
        }
        *p += 4;
        return mem;
}

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", (unsigned long long)memory_limit);

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

/**
 * move_device_tree - move tree to an unused area, if needed.
 *
 * The device tree may be allocated beyond our memory limit, or inside the
 * crash kernel region for kdump. If so, move it out of the way.
 */
static void __init move_device_tree(void)
{
        unsigned long start, size;
        void *p;

        DBG("-> move_device_tree\n");

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

        if ((memory_limit && (start + size) > memory_limit) ||
                        overlaps_crashkernel(start, size)) {
                p = __va(lmb_alloc_base(size, PAGE_SIZE, lmb.rmo_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");
}

/**
 * unflattens the device-tree passed by the firmware, creating the
 * tree of struct device_node. It also fills the "name" and "type"
 * pointers of the nodes so the normal device-tree walking functions
 * can be used (this used to be done by finish_device_tree)
 */
void __init unflatten_device_tree(void)
{
        unsigned long start, mem, size;
        struct device_node **allnextp = &allnodes;

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

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

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

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

        ((u32 *)mem)[size / 4] = 0xdeadbeef;

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

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

        /* Get pointer to OF "/chosen" node for use everywhere */
        of_chosen = of_find_node_by_path("/chosen");
        if (of_chosen == NULL)
                of_chosen = of_find_node_by_path("/chosen@0");

        DBG(" <- unflatten_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 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, PPC_FEATURE_HAS_MMU,        0, 0, 0},
        {0, PPC_FEATURE_HAS_FPU,        0, 1, 0},
        {CPU_FTR_SLB, 0,                0, 2, 0},
        {CPU_FTR_CTRL, 0,               0, 3, 0},
        {CPU_FTR_NOEXECUTE, 0,          0, 6, 0},
        {CPU_FTR_NODSISRALIGN, 0,       1, 1, 1},
        {CPU_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;
                } else {
                        cur_cpu_spec->cpu_features &= ~fp->cpu_features;
                        cur_cpu_spec->cpu_user_features &= ~fp->cpu_user_ftrs;
                }
        }
}

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)
{
        static int logical_cpuid = 0;
        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 = 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 && initial_boot_params->version >= 2) {
                        if (intserv[i] ==
                                        initial_boot_params->boot_cpuid_phys) {
                                found = 1;
                                break;
                        }
                } 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 = 1;
                                break;
                        }
                }

#ifdef CONFIG_SMP
                /* logical cpu id is always 0 on UP kernels */
                logical_cpuid++;
#endif
        }

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

                /*
                 * 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;
}

#ifdef CONFIG_BLK_DEV_INITRD
static void __init early_init_dt_check_for_initrd(unsigned long node)
{
        unsigned long l;
        u32 *prop;

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

        prop = of_get_flat_dt_prop(node, "linux,initrd-start", &l);
        if (prop) {
                initrd_start = (unsigned long)__va(of_read_ulong(prop, l/4));

                prop = of_get_flat_dt_prop(node, "linux,initrd-end", &l);
                if (prop) {
                        initrd_end = (unsigned long)
                                        __va(of_read_ulong(prop, l/4));
                        initrd_below_start_ok = 1;
                } else {
                        initrd_start = 0;
                }
        }

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

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

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

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

        early_init_dt_check_for_initrd(node);

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

#ifdef CONFIG_CMDLINE
        if (p == NULL || l == 0 || (l == 1 && (*p) == 0))
                strlcpy(cmd_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
#endif /* CONFIG_CMDLINE */

        DBG("Command line is: %s\n", cmd_line);

        /* break now */
        return 1;
}

static int __init early_init_dt_scan_root(unsigned long node,
                                          const char *uname, int depth, void *data)
{
        u32 *prop;

        if (depth != 0)
                return 0;

        prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
        dt_root_size_cells = (prop == NULL) ? 1 : *prop;
        DBG("dt_root_size_cells = %x\n", dt_root_size_cells);

        prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
        dt_root_addr_cells = (prop == NULL) ? 2 : *prop;
        DBG("dt_root_addr_cells = %x\n", dt_root_addr_cells);
        
        /* break now */
        return 1;
}

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

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

#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)
{
        cell_t *dm, *ls, *usm;
        unsigned long l, n, flags;
        u64 base, size, lmb_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(cell_t))
                return 0;
        lmb_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(cell_t))
                return 0;

        n = *dm++;      /* number of entries */
        if (l < (n * (dt_root_addr_cells + 4) + 1) * sizeof(cell_t))
                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 = lmb_size;
                rngs = 1;
                if (is_kexec_kdump) {
                        /*
                         * For each lmb 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;
                        }
                        lmb_add(base, size);
                } while (--rngs);
        }
        lmb_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(unsigned long node,
                                            const char *uname, int depth, void *data)
{
        char *type = of_get_flat_dt_prop(node, "device_type", NULL);
        cell_t *reg, *endp;
        unsigned long l;

        /* Look for the ibm,dynamic-reconfiguration-memory node */
        if (depth == 1 &&
            strcmp(uname, "ibm,dynamic-reconfiguration-memory") == 0)
                return early_init_dt_scan_drconf_memory(node);

        /* 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(cell_t));

        DBG("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;
                DBG(" - %llx ,  %llx\n", (unsigned long long)base,
                    (unsigned long long)size);
#ifdef CONFIG_PPC64
                if (iommu_is_off) {
                        if (base >= 0x80000000ul)
                                continue;
                        if ((base + size) > 0x80000000ul)
                                size = 0x80000000ul - base;
                }
#endif
                lmb_add(base, size);

                memstart_addr = min((u64)memstart_addr, base);
        }

        return 0;
}

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;
        lmb_reserve(self_base, self_size);

#ifdef CONFIG_BLK_DEV_INITRD
        /* then reserve the initrd, if any */
        if (initrd_start && (initrd_end > initrd_start))
                lmb_reserve(__pa(initrd_start), initrd_end - initrd_start);
#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);
                        lmb_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);
                lmb_reserve(base, size);
        }
}

#ifdef CONFIG_PHYP_DUMP
/**
 * phyp_dump_calculate_reserve_size() - reserve variable boot area 5% or arg
 *
 * Function to find the largest size we need to reserve
 * during early boot process.
 *
 * It either looks for boot param and returns that OR
 * returns larger of 256 or 5% rounded down to multiples of 256MB.
 *
 */
static inline unsigned long phyp_dump_calculate_reserve_size(void)
{
        unsigned long tmp;

        if (phyp_dump_info->reserve_bootvar)
                return phyp_dump_info->reserve_bootvar;

        /* divide by 20 to get 5% of value */
        tmp = lmb_end_of_DRAM();
        do_div(tmp, 20);

        /* round it down in multiples of 256 */
        tmp = tmp & ~0x0FFFFFFFUL;

        return (tmp > PHYP_DUMP_RMR_END ? tmp : PHYP_DUMP_RMR_END);
}

/**
 * phyp_dump_reserve_mem() - reserve all not-yet-dumped mmemory
 *
 * This routine may reserve memory regions in the kernel only
 * if the system is supported and a dump was taken in last
 * boot instance or if the hardware is supported and the
 * scratch area needs to be setup. In other instances it returns
 * without reserving anything. The memory in case of dump being
 * active is freed when the dump is collected (by userland tools).
 */
static void __init phyp_dump_reserve_mem(void)
{
        unsigned long base, size;
        unsigned long variable_reserve_size;

        if (!phyp_dump_info->phyp_dump_configured) {
                printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
                return;
        }

        if (!phyp_dump_info->phyp_dump_at_boot) {
                printk(KERN_INFO "Phyp-dump disabled at boot time\n");
                return;
        }

        variable_reserve_size = phyp_dump_calculate_reserve_size();

        if (phyp_dump_info->phyp_dump_is_active) {
                /* Reserve *everything* above RMR.Area freed by userland tools*/
                base = variable_reserve_size;
                size = lmb_end_of_DRAM() - base;

                /* XXX crashed_ram_end is wrong, since it may be beyond
                 * the memory_limit, it will need to be adjusted. */
                lmb_reserve(base, size);

                phyp_dump_info->init_reserve_start = base;
                phyp_dump_info->init_reserve_size = size;
        } else {
                size = phyp_dump_info->cpu_state_size +
                        phyp_dump_info->hpte_region_size +
                        variable_reserve_size;
                base = lmb_end_of_DRAM() - size;
                lmb_reserve(base, size);
                phyp_dump_info->init_reserve_start = base;
                phyp_dump_info->init_reserve_size = size;
        }
}
#else
static inline void __init phyp_dump_reserve_mem(void) {}
#endif /* CONFIG_PHYP_DUMP  && CONFIG_PPC_RTAS */


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_PHYP_DUMP
        /* scan tree to see if dump occured during last boot */
        of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
#endif

        /* 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, NULL);

        /* Scan memory nodes and rebuild LMBs */
        lmb_init();
        of_scan_flat_dt(early_init_dt_scan_root, NULL);
        of_scan_flat_dt(early_init_dt_scan_memory, NULL);

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

        /* Reserve LMB regions used by kernel, initrd, dt, etc... */
        lmb_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);
        /* If relocatable, reserve first 32k for interrupt vectors etc. */
        if (PHYSICAL_START > MEMORY_START)
                lmb_reserve(MEMORY_START, 0x8000);
        reserve_kdump_trampoline();
        reserve_crashkernel();
        early_reserve_mem();
        phyp_dump_reserve_mem();

        limit = memory_limit;
        if (! limit) {
                phys_addr_t memsize;

                /* Ensure that total memory size is page-aligned, because
                 * otherwise mark_bootmem() gets upset. */
                lmb_analyze();
                memsize = lmb_phys_mem_size();
                if ((memsize & PAGE_MASK) != memsize)
                        limit = memsize & PAGE_MASK;
        }
        lmb_enforce_memory_limit(limit);

        lmb_analyze();
        lmb_dump_all();

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

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

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

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

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


/**
 * Indicates whether the root node has a given value in its
 * compatible property.
 */
int machine_is_compatible(const char *compat)
{
        struct device_node *root;
        int rc = 0;

        root = of_find_node_by_path("/");
        if (root) {
                rc = of_device_is_compatible(root, compat);
                of_node_put(root);
        }
        return rc;
}
EXPORT_SYMBOL(machine_is_compatible);

/*******
 *
 * 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.
 *
 *******/

/**
 *      of_find_node_by_phandle - Find a node given a phandle
 *      @handle:        phandle of the node to find
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_find_node_by_phandle(phandle handle)
{
        struct device_node *np;

        read_lock(&devtree_lock);
        for (np = allnodes; np != 0; np = np->allnext)
                if (np->linux_phandle == handle)
                        break;
        of_node_get(np);
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_find_node_by_phandle);

/**
 *      of_find_next_cache_node - Find a node's subsidiary cache
 *      @np:    node of type "cpu" or "cache"
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.  Caller should hold a reference
 *      to np.
 */
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;
}

/**
 *      of_node_get - Increment refcount of a node
 *      @node:  Node to inc refcount, NULL is supported to
 *              simplify writing of callers
 *
 *      Returns node.
 */
struct device_node *of_node_get(struct device_node *node)
{
        if (node)
                kref_get(&node->kref);
        return node;
}
EXPORT_SYMBOL(of_node_get);

static inline struct device_node * kref_to_device_node(struct kref *kref)
{
        return container_of(kref, struct device_node, kref);
}

/**
 *      of_node_release - release a dynamically allocated node
 *      @kref:  kref element of the node to be released
 *
 *      In of_node_put() this function is passed to kref_put()
 *      as the destructor.
 */
static void of_node_release(struct kref *kref)
{
        struct device_node *node = kref_to_device_node(kref);
        struct property *prop = node->properties;

        /* We should never be releasing nodes that haven't been detached. */
        if (!of_node_check_flag(node, OF_DETACHED)) {
                printk("WARNING: Bad of_node_put() on %s\n", node->full_name);
                dump_stack();
                kref_init(&node->kref);
                return;
        }

        if (!of_node_check_flag(node, OF_DYNAMIC))
                return;

        while (prop) {
                struct property *next = prop->next;
                kfree(prop->name);
                kfree(prop->value);
                kfree(prop);
                prop = next;

                if (!prop) {
                        prop = node->deadprops;
                        node->deadprops = NULL;
                }
        }
        kfree(node->full_name);
        kfree(node->data);
        kfree(node);
}

/**
 *      of_node_put - Decrement refcount of a node
 *      @node:  Node to dec refcount, NULL is supported to
 *              simplify writing of callers
 *
 */
void of_node_put(struct device_node *node)
{
        if (node)
                kref_put(&node->kref, of_node_release);
}
EXPORT_SYMBOL(of_node_put);

/*
 * Plug a device node into the tree and global list.
 */
void of_attach_node(struct device_node *np)
{
        unsigned long flags;

        write_lock_irqsave(&devtree_lock, flags);
        np->sibling = np->parent->child;
        np->allnext = allnodes;
        np->parent->child = np;
        allnodes = np;
        write_unlock_irqrestore(&devtree_lock, flags);
}

/*
 * "Unplug" a node from the device tree.  The caller must hold
 * a reference to the node.  The memory associated with the node
 * is not freed until its refcount goes to zero.
 */
void of_detach_node(struct device_node *np)
{
        struct device_node *parent;
        unsigned long flags;

        write_lock_irqsave(&devtree_lock, flags);

        parent = np->parent;
        if (!parent)
                goto out_unlock;

        if (allnodes == np)
                allnodes = np->allnext;
        else {
                struct device_node *prev;
                for (prev = allnodes;
                     prev->allnext != np;
                     prev = prev->allnext)
                        ;
                prev->allnext = np->allnext;
        }

        if (parent->child == np)
                parent->child = np->sibling;
        else {
                struct device_node *prevsib;
                for (prevsib = np->parent->child;
                     prevsib->sibling != np;
                     prevsib = prevsib->sibling)
                        ;
                prevsib->sibling = np->sibling;
        }

        of_node_set_flag(np, OF_DETACHED);

out_unlock:
        write_unlock_irqrestore(&devtree_lock, flags);
}

#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 linux_phandle field */
        if ((ibm_phandle = of_get_property(node, "ibm,phandle", NULL)))
                node->linux_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);
                        err = NOTIFY_BAD;
                }
                break;
        default:
                err = NOTIFY_DONE;
                break;
        }
        return 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

/*
 * Add a property to a node
 */
int prom_add_property(struct device_node* np, struct property* prop)
{
        struct property **next;
        unsigned long flags;

        prop->next = NULL;      
        write_lock_irqsave(&devtree_lock, flags);
        next = &np->properties;
        while (*next) {
                if (strcmp(prop->name, (*next)->name) == 0) {
                        /* duplicate ! don't insert it */
                        write_unlock_irqrestore(&devtree_lock, flags);
                        return -1;
                }
                next = &(*next)->next;
        }
        *next = prop;
        write_unlock_irqrestore(&devtree_lock, flags);

#ifdef CONFIG_PROC_DEVICETREE
        /* try to add to proc as well if it was initialized */
        if (np->pde)
                proc_device_tree_add_prop(np->pde, prop);
#endif /* CONFIG_PROC_DEVICETREE */

        return 0;
}

/*
 * Remove a property from a node.  Note that we don't actually
 * remove it, since we have given out who-knows-how-many pointers
 * to the data using get-property.  Instead we just move the property
 * to the "dead properties" list, so it won't be found any more.
 */
int prom_remove_property(struct device_node *np, struct property *prop)
{
        struct property **next;
        unsigned long flags;
        int found = 0;

        write_lock_irqsave(&devtree_lock, flags);
        next = &np->properties;
        while (*next) {
                if (*next == prop) {
                        /* found the node */
                        *next = prop->next;
                        prop->next = np->deadprops;
                        np->deadprops = prop;
                        found = 1;
                        break;
                }
                next = &(*next)->next;
        }
        write_unlock_irqrestore(&devtree_lock, flags);

        if (!found)
                return -ENODEV;

#ifdef CONFIG_PROC_DEVICETREE
        /* try to remove the proc node as well */
        if (np->pde)
                proc_device_tree_remove_prop(np->pde, prop);
#endif /* CONFIG_PROC_DEVICETREE */

        return 0;
}

/*
 * Update a property in a node.  Note that we don't actually
 * remove it, since we have given out who-knows-how-many pointers
 * to the data using get-property.  Instead we just move the property
 * to the "dead properties" list, and add the new property to the
 * property list
 */
int prom_update_property(struct device_node *np,
                         struct property *newprop,
                         struct property *oldprop)
{
        struct property **next;
        unsigned long flags;
        int found = 0;

        write_lock_irqsave(&devtree_lock, flags);
        next = &np->properties;
        while (*next) {
                if (*next == oldprop) {
                        /* found the node */
                        newprop->next = oldprop->next;
                        *next = newprop;
                        oldprop->next = np->deadprops;
                        np->deadprops = oldprop;
                        found = 1;
                        break;
                }
                next = &(*next)->next;
        }
        write_unlock_irqrestore(&devtree_lock, flags);

        if (!found)
                return -ENODEV;

#ifdef CONFIG_PROC_DEVICETREE
        /* try to add to proc as well if it was initialized */
        if (np->pde)
                proc_device_tree_update_prop(np->pde, newprop, oldprop);
#endif /* CONFIG_PROC_DEVICETREE */

        return 0;
}


/* 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