// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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 
 */

#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/delay.h>
#include <linux/initrd.h>
#include <linux/bitops.h>
#include <linux/export.h>
#include <linux/kexec.h>
#include <linux/irq.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <linux/cpu.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/powernv.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/epapr_hcalls.h>
#include <asm/firmware.h>
#include <asm/dt_cpu_ftrs.h>
#include <asm/drmem.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 = fdt_totalsize(initial_boot_params);

        if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
            !memblock_is_memory(start + size - 1) ||
            overlaps_crashkernel(start, size) || overlaps_initrd(start, size)) {
                p = memblock_alloc_raw(size, PAGE_SIZE);
                if (!p)
                        panic("Failed to allocate %lu bytes to move device tree\n",
                              size);
                memcpy(p, initial_boot_params, size);
                initial_boot_params = p;
                DBG("Moved device tree to 0x%px\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 int    cpu_user_ftrs2; /* PPC_FEATURE2_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 = {
        { .pabyte = 0,  .pabit = 0, .cpu_user_ftrs = PPC_FEATURE_HAS_MMU },
        { .pabyte = 0,  .pabit = 1, .cpu_user_ftrs = PPC_FEATURE_HAS_FPU },
        { .pabyte = 0,  .pabit = 3, .cpu_features  = CPU_FTR_CTRL },
        { .pabyte = 0,  .pabit = 6, .cpu_features  = CPU_FTR_NOEXECUTE },
        { .pabyte = 1,  .pabit = 2, .mmu_features  = MMU_FTR_CI_LARGE_PAGE },
#ifdef CONFIG_PPC_RADIX_MMU
        { .pabyte = 40, .pabit = 0, .mmu_features  = MMU_FTR_TYPE_RADIX },
#endif
        { .pabyte = 1,  .pabit = 1, .invert = 1, .cpu_features = CPU_FTR_NODSISRALIGN },
        { .pabyte = 5,  .pabit = 0, .cpu_features  = CPU_FTR_REAL_LE,
                                    .cpu_user_ftrs = PPC_FEATURE_TRUE_LE },
        /*
         * If the kernel doesn't support TM (ie CONFIG_PPC_TRANSACTIONAL_MEM=n),
         * we don't want to turn on TM here, so we use the *_COMP versions
         * which are 0 if the kernel doesn't support TM.
         */
        { .pabyte = 22, .pabit = 0, .cpu_features = CPU_FTR_TM_COMP,
          .cpu_user_ftrs2 = PPC_FEATURE2_HTM_COMP | PPC_FEATURE2_HTM_NOSC_COMP },
};

static void __init scan_features(unsigned long node, const 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->cpu_user_features2 |= fp->cpu_user_ftrs2;
                        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->cpu_user_features2 &= ~fp->cpu_user_ftrs2;
                        cur_cpu_spec->mmu_features &= ~fp->mmu_features;
                }
        }
}

static void __init check_cpu_pa_features(unsigned long node)
{
        const unsigned char *pa_ftrs;
        int 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_BOOK3S_64
static void __init init_mmu_slb_size(unsigned long node)
{
        const __be32 *slb_size_ptr;

        slb_size_ptr = of_get_flat_dt_prop(node, "slb-size", NULL) ? :
                        of_get_flat_dt_prop(node, "ibm,slb-size", NULL);

        if (slb_size_ptr)
                mmu_slb_size = be32_to_cpup(slb_size_ptr);
}
#else
#define init_mmu_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;
        const 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)
{
        int i;
        struct feature_property *fp = feature_properties;
        const __be32 *prop;

        for (i = 0; i < (int)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)
{
        const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
        const __be32 *prop;
        const __be32 *intserv;
        int i, nthreads;
        int 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)
                intserv = of_get_flat_dt_prop(node, "reg", &len);

        nthreads = len / sizeof(int);

        /*
         * 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++) {
                if (be32_to_cpu(intserv[i]) ==
                        fdt_boot_cpuid_phys(initial_boot_params)) {
                        found = boot_cpu_count;
                        found_thread = i;
                }
#ifdef CONFIG_SMP
                /* logical cpu id is always 0 on UP kernels */
                boot_cpu_count++;
#endif
        }

        /* Not the boot CPU */
        if (found < 0)
                return 0;

        DBG("boot cpu: logical %d physical %d\n", found,
            be32_to_cpu(intserv[found_thread]));
        boot_cpuid = found;

        /*
         * 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.
         *
         * If we're using device tree CPU feature discovery then we don't
         * support the cpu-version property, and it's the responsibility of the
         * firmware/hypervisor to provide the correct feature set for the
         * architecture level via the ibm,powerpc-cpu-features binding.
         */
        if (!dt_cpu_ftrs_in_use()) {
                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));

                check_cpu_feature_properties(node);
                check_cpu_pa_features(node);
        }

        identical_pvr_fixup(node);
        init_mmu_slb_size(node);

#ifdef CONFIG_PPC64
        if (nthreads == 1)
                cur_cpu_spec->cpu_features &= ~CPU_FTR_SMT;
        else if (!dt_cpu_ftrs_in_use())
                cur_cpu_spec->cpu_features |= CPU_FTR_SMT;
        allocate_paca(boot_cpuid);
#endif
        set_hard_smp_processor_id(found, be32_to_cpu(intserv[found_thread]));

        return 0;
}

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

/*
 * Compare the range against max mem limit and update
 * size if it cross the limit.
 */

#ifdef CONFIG_SPARSEMEM
static bool validate_mem_limit(u64 base, u64 *size)
{
        u64 max_mem = 1UL << (MAX_PHYSMEM_BITS);

        if (base >= max_mem)
                return false;
        if ((base + *size) > max_mem)
                *size = max_mem - base;
        return true;
}
#else
static bool validate_mem_limit(u64 base, u64 *size)
{
        return true;
}
#endif

#ifdef CONFIG_PPC_PSERIES
/*
 * Interpret the ibm dynamic reconfiguration memory LMBs.
 * This contains a list of memory blocks along with NUMA affinity
 * information.
 */
static void __init early_init_drmem_lmb(struct drmem_lmb *lmb,
                                        const __be32 **usm)
{
        u64 base, size;
        int is_kexec_kdump = 0, rngs;

        base = lmb->base_addr;
        size = drmem_lmb_size();
        rngs = 1;

        /*
         * Skip this block if the reserved bit is set in flags
         * or if the block is not assigned to this partition.
         */
        if ((lmb->flags & DRCONF_MEM_RESERVED) ||
            !(lmb->flags & DRCONF_MEM_ASSIGNED))
                return;

        if (*usm)
                is_kexec_kdump = 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 */
                        return;
        }

        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;
                }

                DBG("Adding: %llx -> %llx\n", base, size);
                if (validate_mem_limit(base, &size))
                        memblock_add(base, size);
        } while (--rngs);
}
#endif /* CONFIG_PPC_PSERIES */

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

/*
 * For a relocatable kernel, we need to get the memstart_addr first,
 * then use it to calculate the virtual kernel start address. This has
 * to happen at a very early stage (before machine_init). In this case,
 * we just want to get the memstart_address and would not like to mess the
 * memblock at this stage. So introduce a variable to skip the memblock_add()
 * for this reason.
 */
#ifdef CONFIG_RELOCATABLE
static int add_mem_to_memblock = 1;
#else
#define add_mem_to_memblock 1
#endif

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 */
        if (add_mem_to_memblock) {
                if (validate_mem_limit(base, &size))
                        memblock_add(base, size);
        }
}

static void __init early_reserve_mem_dt(void)
{
        unsigned long i, dt_root;
        int len;
        const __be32 *prop;

        early_init_fdt_reserve_self();
        early_init_fdt_scan_reserved_mem();

        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)
{
        __be64 *reserve_map;

        reserve_map = (__be64 *)(((unsigned long)initial_boot_params) +
                        fdt_off_mem_rsvmap(initial_boot_params));

        /* 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;
                        DBG("reserving: %x -> %x\n", base_32, size_32);
                        memblock_reserve(base_32, size_32);
                }
                return;
        }
#endif
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
static bool tm_disabled __initdata;

static int __init parse_ppc_tm(char *str)
{
        bool res;

        if (kstrtobool(str, &res))
                return -EINVAL;

        tm_disabled = !res;

        return 0;
}
early_param("ppc_tm", parse_ppc_tm);

static void __init tm_init(void)
{
        if (tm_disabled) {
                pr_info("Disabling hardware transactional memory (HTM)\n");
                cur_cpu_spec->cpu_user_features2 &=
                        ~(PPC_FEATURE2_HTM_NOSC | PPC_FEATURE2_HTM);
                cur_cpu_spec->cpu_features &= ~CPU_FTR_TM;
                return;
        }

        pnv_tm_init();
}
#else
static void tm_init(void) { }
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */

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

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

        /* Too early to BUG_ON(), do it by hand */
        if (!early_init_dt_verify(params))
                panic("BUG: Failed verifying flat device tree, bad version?");

#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

        /* 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, boot_command_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);

        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. */
        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", (unsigned long long)memblock_phys_mem_size());

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

        allocate_paca_ptrs();

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

        dt_cpu_ftrs_scan();

        /* Retrieve CPU related informations from the flat tree
         * (altivec support, boot CPU ID, ...)
         */
        of_scan_flat_dt(early_init_dt_scan_cpus, NULL);
        if (boot_cpuid < 0) {
                printk("Failed to identify boot CPU !\n");
                BUG();
        }

#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

        mmu_early_init_devtree();

#ifdef CONFIG_PPC_POWERNV
        /* Scan and build the list of machine check recoverable ranges */
        of_scan_flat_dt(early_init_dt_scan_recoverable_ranges, NULL);
#endif
        epapr_paravirt_early_init();

        /* Now try to figure out if we are running on LPAR and so on */
        pseries_probe_fw_features();

#ifdef CONFIG_PPC_PS3
        /* Identify PS3 firmware */
        if (of_flat_dt_is_compatible(of_get_flat_dt_root(), "sony,ps3"))
                powerpc_firmware_features |= FW_FEATURE_PS3_POSSIBLE;
#endif

        tm_init();

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

#ifdef CONFIG_RELOCATABLE
/*
 * This function run before early_init_devtree, so we have to init
 * initial_boot_params.
 */
void __init early_get_first_memblock_info(void *params, phys_addr_t *size)
{
        /* Setup flat device-tree pointer */
        initial_boot_params = params;

        /*
         * Scan the memory nodes and set add_mem_to_memblock to 0 to avoid
         * mess the memblock.
         */
        add_mem_to_memblock = 0;
        of_scan_flat_dt(early_init_dt_scan_root, NULL);
        of_scan_flat_dt(early_init_dt_scan_memory_ppc, NULL);
        add_mem_to_memblock = 1;

        if (size)
                *size = first_memblock_size;
}
#endif

/*******
 *
 * 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_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) {
                u32 chip_id;

                /*
                 * Skiboot may produce memory nodes that contain more than one
                 * cell in chip-id, we only read the first one here.
                 */
                if (!of_property_read_u32(np, "ibm,chip-id", &chip_id)) {
                        of_node_put(np);
                        return chip_id;
                }

                np = of_get_next_parent(np);
        }
        return -1;
}
EXPORT_SYMBOL(of_get_ibm_chip_id);

/**
 * cpu_to_chip_id - Return the cpus chip-id
 * @cpu: The logical cpu number.
 *
 * Return the value of the ibm,chip-id property corresponding to the given
 * logical cpu number. If the chip-id can not be found, returns -1.
 */
int cpu_to_chip_id(int cpu)
{
        struct device_node *np;

        np = of_get_cpu_node(cpu, NULL);
        if (!np)
                return -1;

        of_node_put(np);
        return of_get_ibm_chip_id(np);
}
EXPORT_SYMBOL(cpu_to_chip_id);

bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
{
#ifdef CONFIG_SMP
        /*
         * Early firmware scanning must use this rather than
         * get_hard_smp_processor_id because we don't have pacas allocated
         * until memory topology is discovered.
         */
        if (cpu_to_phys_id != NULL)
                return (int)phys_id == cpu_to_phys_id[cpu];
#endif

        return (int)phys_id == get_hard_smp_processor_id(cpu);
}