powerpc: More little endian fixes for prom.c

[mirror_ubuntu-zesty-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/export.h>
#include <linux/kexec.h>
#include <linux/debugfs.h>
#include <linux/irq.h>
#include <linux/memblock.h>
#include <linux/of.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/pci-bridge.h>
#include <asm/kexec.h>
#include <asm/opal.h>
#include <asm/fadump.h>
#include <asm/debug.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
}

/**
 * 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, or within the page aligned range of initrd.
 * 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 = 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)
{
        __be32 *slb_size_ptr;

        slb_size_ptr = of_get_flat_dt_prop(node, "slb-size", NULL);
        if (slb_size_ptr != NULL) {
                mmu_slb_size = be32_to_cpup(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 = be32_to_cpup(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 __be32 *prop;

        for (i = 0; i < ARRAY_SIZE(feature_properties); ++i, ++fp) {
                prop = of_get_flat_dt_prop(node, fp->name, NULL);
                if (prop && be32_to_cpup(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 __be32 *prop;
        const __be32 *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 (be32_to_cpu(initial_boot_params->version) >= 2) {
                        if (be32_to_cpu(intserv[i]) ==
                            be32_to_cpu(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,
                        be32_to_cpu(intserv[found_thread]));
                boot_cpuid = found;
                set_hard_smp_processor_id(found,
                        be32_to_cpu(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 && (be32_to_cpup(prop) & 0xff000000) == 0x0f000000)
                        identify_cpu(0, be32_to_cpup(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; /* All these set by kernel, so no need to convert endian */

        /* 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 = of_read_number(dm++, 1);    /* 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 = of_read_number(&dm[3], 1);
                /* 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_dt(void)
{
        unsigned long i, len, dt_root;
        const __be32 *prop;

        dt_root = of_get_flat_dt_root();

        prop = of_get_flat_dt_prop(dt_root, "reserved-ranges", &len);

        if (!prop)
                return;

        DBG("Found new-style reserved-ranges\n");

        /* Each reserved range is an (address,size) pair, 2 cells each,
         * totalling 4 cells per range. */
        for (i = 0; i < len / (sizeof(*prop) * 4); i++) {
                u64 base, size;

                base = of_read_number(prop + (i * 4) + 0, 2);
                size = of_read_number(prop + (i * 4) + 2, 2);

                if (size) {
                        DBG("reserving: %llx -> %llx\n", base, size);
                        memblock_reserve(base, size);
                }
        }
}

static void __init early_reserve_mem(void)
{
        u64 base, size;
        __be64 *reserve_map;
        unsigned long self_base;
        unsigned long self_size;

        reserve_map = (__be64 *)(((unsigned long)initial_boot_params) +
                        be32_to_cpu(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 = be32_to_cpu(initial_boot_params->totalsize);
        memblock_reserve(self_base, self_size);

        /* Look for the new "reserved-regions" property in the DT */
        early_reserve_mem_dt();

#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 (be64_to_cpup(reserve_map) > 0xffffffffull) {
                u32 base_32, size_32;
                __be32 *reserve_map_32 = (__be32 *)reserve_map;

                DBG("Found old 32-bit reserve map\n");

                while (1) {
                        base_32 = be32_to_cpup(reserve_map_32++);
                        size_32 = be32_to_cpup(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
        DBG("Processing reserve map\n");

        /* Handle the reserve map in the fdt blob if it exists */
        while (1) {
                base = be64_to_cpup(reserve_map++);
                size = be64_to_cpup(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.
 *
 *******/

/**
 *      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_get_ibm_chip_id - Returns the IBM "chip-id" of a device
 * @np: device node of the device
 *
 * This looks for a property "ibm,chip-id" in the node or any
 * of its parents and returns its content, or -1 if it cannot
 * be found.
 */
int of_get_ibm_chip_id(struct device_node *np)
{
        of_node_get(np);
        while(np) {
                struct device_node *old = np;
                const __be32 *prop;

                prop = of_get_property(np, "ibm,chip-id", NULL);
                if (prop) {
                        of_node_put(np);
                        return be32_to_cpup(prop);
                }
                np = of_get_parent(np);
                of_node_put(old);
        }
        return -1;
}

#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 OF_RECONFIG_ATTACH_NODE:
                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 of_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 __be32 *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 __be32 *reg = of_get_property(np, "reg", NULL);
                        if (reg == NULL)
                                continue;
                        if (be32_to_cpup(reg) == hardid) {
                                if (thread)
                                        *thread = 0;
                                return np;
                        }
                } else {
                        plen /= sizeof(u32);
                        for (t = 0; t < plen; t++) {
                                if (hardid == be32_to_cpu(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 = be32_to_cpu(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