/*
 *  linux/arch/arm/kernel/setup.c
 *
 *  Copyright (C) 1995-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/efi.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/utsname.h>
#include <linux/initrd.h>
#include <linux/console.h>
#include <linux/bootmem.h>
#include <linux/seq_file.h>
#include <linux/screen_info.h>
#include <linux/of_platform.h>
#include <linux/init.h>
#include <linux/kexec.h>
#include <linux/of_fdt.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/proc_fs.h>
#include <linux/memblock.h>
#include <linux/bug.h>
#include <linux/compiler.h>
#include <linux/sort.h>
#include <linux/psci.h>

#include <asm/unified.h>
#include <asm/cp15.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/efi.h>
#include <asm/elf.h>
#include <asm/early_ioremap.h>
#include <asm/fixmap.h>
#include <asm/procinfo.h>
#include <asm/psci.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/smp_plat.h>
#include <asm/mach-types.h>
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/tlbflush.h>
#include <asm/xen/hypervisor.h>

#include <asm/prom.h>
#include <asm/mach/arch.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <asm/system_info.h>
#include <asm/system_misc.h>
#include <asm/traps.h>
#include <asm/unwind.h>
#include <asm/memblock.h>
#include <asm/virt.h>

#include "atags.h"


#if defined(CONFIG_FPE_NWFPE) || defined(CONFIG_FPE_FASTFPE)
char fpe_type[8];

static int __init fpe_setup(char *line)
{
        memcpy(fpe_type, line, 8);
        return 1;
}

__setup("fpe=", fpe_setup);
#endif

extern void init_default_cache_policy(unsigned long);
extern void paging_init(const struct machine_desc *desc);
extern void early_mm_init(const struct machine_desc *);
extern void adjust_lowmem_bounds(void);
extern enum reboot_mode reboot_mode;
extern void setup_dma_zone(const struct machine_desc *desc);

unsigned int processor_id;
EXPORT_SYMBOL(processor_id);
unsigned int __machine_arch_type __read_mostly;
EXPORT_SYMBOL(__machine_arch_type);
unsigned int cacheid __read_mostly;
EXPORT_SYMBOL(cacheid);

unsigned int __atags_pointer __initdata;

unsigned int system_rev;
EXPORT_SYMBOL(system_rev);

const char *system_serial;
EXPORT_SYMBOL(system_serial);

unsigned int system_serial_low;
EXPORT_SYMBOL(system_serial_low);

unsigned int system_serial_high;
EXPORT_SYMBOL(system_serial_high);

unsigned int elf_hwcap __read_mostly;
EXPORT_SYMBOL(elf_hwcap);

unsigned int elf_hwcap2 __read_mostly;
EXPORT_SYMBOL(elf_hwcap2);


#ifdef MULTI_CPU
struct processor processor __ro_after_init;
#endif
#ifdef MULTI_TLB
struct cpu_tlb_fns cpu_tlb __ro_after_init;
#endif
#ifdef MULTI_USER
struct cpu_user_fns cpu_user __ro_after_init;
#endif
#ifdef MULTI_CACHE
struct cpu_cache_fns cpu_cache __ro_after_init;
#endif
#ifdef CONFIG_OUTER_CACHE
struct outer_cache_fns outer_cache __ro_after_init;
EXPORT_SYMBOL(outer_cache);
#endif

/*
 * Cached cpu_architecture() result for use by assembler code.
 * C code should use the cpu_architecture() function instead of accessing this
 * variable directly.
 */
int __cpu_architecture __read_mostly = CPU_ARCH_UNKNOWN;

struct stack {
        u32 irq[3];
        u32 abt[3];
        u32 und[3];
        u32 fiq[3];
} ____cacheline_aligned;

#ifndef CONFIG_CPU_V7M
static struct stack stacks[NR_CPUS];
#endif

char elf_platform[ELF_PLATFORM_SIZE];
EXPORT_SYMBOL(elf_platform);

static const char *cpu_name;
static const char *machine_name;
static char __initdata cmd_line[COMMAND_LINE_SIZE];
const struct machine_desc *machine_desc __initdata;

static union { char c[4]; unsigned long l; } endian_test __initdata = { { 'l', '?', '?', 'b' } };
#define ENDIANNESS ((char)endian_test.l)

DEFINE_PER_CPU(struct cpuinfo_arm, cpu_data);

/*
 * Standard memory resources
 */
static struct resource mem_res[] = {
        {
                .name = "Video RAM",
                .start = 0,
                .end = 0,
                .flags = IORESOURCE_MEM
        },
        {
                .name = "Kernel code",
                .start = 0,
                .end = 0,
                .flags = IORESOURCE_SYSTEM_RAM
        },
        {
                .name = "Kernel data",
                .start = 0,
                .end = 0,
                .flags = IORESOURCE_SYSTEM_RAM
        }
};

#define video_ram   mem_res[0]
#define kernel_code mem_res[1]
#define kernel_data mem_res[2]

static struct resource io_res[] = {
        {
                .name = "reserved",
                .start = 0x3bc,
                .end = 0x3be,
                .flags = IORESOURCE_IO | IORESOURCE_BUSY
        },
        {
                .name = "reserved",
                .start = 0x378,
                .end = 0x37f,
                .flags = IORESOURCE_IO | IORESOURCE_BUSY
        },
        {
                .name = "reserved",
                .start = 0x278,
                .end = 0x27f,
                .flags = IORESOURCE_IO | IORESOURCE_BUSY
        }
};

#define lp0 io_res[0]
#define lp1 io_res[1]
#define lp2 io_res[2]

static const char *proc_arch[] = {
        "undefined/unknown",
        "3",
        "4",
        "4T",
        "5",
        "5T",
        "5TE",
        "5TEJ",
        "6TEJ",
        "7",
        "7M",
        "?(12)",
        "?(13)",
        "?(14)",
        "?(15)",
        "?(16)",
        "?(17)",
};

#ifdef CONFIG_CPU_V7M
static int __get_cpu_architecture(void)
{
        return CPU_ARCH_ARMv7M;
}
#else
static int __get_cpu_architecture(void)
{
        int cpu_arch;

        if ((read_cpuid_id() & 0x0008f000) == 0) {
                cpu_arch = CPU_ARCH_UNKNOWN;
        } else if ((read_cpuid_id() & 0x0008f000) == 0x00007000) {
                cpu_arch = (read_cpuid_id() & (1 << 23)) ? CPU_ARCH_ARMv4T : CPU_ARCH_ARMv3;
        } else if ((read_cpuid_id() & 0x00080000) == 0x00000000) {
                cpu_arch = (read_cpuid_id() >> 16) & 7;
                if (cpu_arch)
                        cpu_arch += CPU_ARCH_ARMv3;
        } else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
                /* Revised CPUID format. Read the Memory Model Feature
                 * Register 0 and check for VMSAv7 or PMSAv7 */
                unsigned int mmfr0 = read_cpuid_ext(CPUID_EXT_MMFR0);
                if ((mmfr0 & 0x0000000f) >= 0x00000003 ||
                    (mmfr0 & 0x000000f0) >= 0x00000030)
                        cpu_arch = CPU_ARCH_ARMv7;
                else if ((mmfr0 & 0x0000000f) == 0x00000002 ||
                         (mmfr0 & 0x000000f0) == 0x00000020)
                        cpu_arch = CPU_ARCH_ARMv6;
                else
                        cpu_arch = CPU_ARCH_UNKNOWN;
        } else
                cpu_arch = CPU_ARCH_UNKNOWN;

        return cpu_arch;
}
#endif

int __pure cpu_architecture(void)
{
        BUG_ON(__cpu_architecture == CPU_ARCH_UNKNOWN);

        return __cpu_architecture;
}

static int cpu_has_aliasing_icache(unsigned int arch)
{
        int aliasing_icache;
        unsigned int id_reg, num_sets, line_size;

        /* PIPT caches never alias. */
        if (icache_is_pipt())
                return 0;

        /* arch specifies the register format */
        switch (arch) {
        case CPU_ARCH_ARMv7:
                set_csselr(CSSELR_ICACHE | CSSELR_L1);
                isb();
                id_reg = read_ccsidr();
                line_size = 4 << ((id_reg & 0x7) + 2);
                num_sets = ((id_reg >> 13) & 0x7fff) + 1;
                aliasing_icache = (line_size * num_sets) > PAGE_SIZE;
                break;
        case CPU_ARCH_ARMv6:
                aliasing_icache = read_cpuid_cachetype() & (1 << 11);
                break;
        default:
                /* I-cache aliases will be handled by D-cache aliasing code */
                aliasing_icache = 0;
        }

        return aliasing_icache;
}

static void __init cacheid_init(void)
{
        unsigned int arch = cpu_architecture();

        if (arch >= CPU_ARCH_ARMv6) {
                unsigned int cachetype = read_cpuid_cachetype();

                if ((arch == CPU_ARCH_ARMv7M) && !(cachetype & 0xf000f)) {
                        cacheid = 0;
                } else if ((cachetype & (7 << 29)) == 4 << 29) {
                        /* ARMv7 register format */
                        arch = CPU_ARCH_ARMv7;
                        cacheid = CACHEID_VIPT_NONALIASING;
                        switch (cachetype & (3 << 14)) {
                        case (1 << 14):
                                cacheid |= CACHEID_ASID_TAGGED;
                                break;
                        case (3 << 14):
                                cacheid |= CACHEID_PIPT;
                                break;
                        }
                } else {
                        arch = CPU_ARCH_ARMv6;
                        if (cachetype & (1 << 23))
                                cacheid = CACHEID_VIPT_ALIASING;
                        else
                                cacheid = CACHEID_VIPT_NONALIASING;
                }
                if (cpu_has_aliasing_icache(arch))
                        cacheid |= CACHEID_VIPT_I_ALIASING;
        } else {
                cacheid = CACHEID_VIVT;
        }

        pr_info("CPU: %s data cache, %s instruction cache\n",
                cache_is_vivt() ? "VIVT" :
                cache_is_vipt_aliasing() ? "VIPT aliasing" :
                cache_is_vipt_nonaliasing() ? "PIPT / VIPT nonaliasing" : "unknown",
                cache_is_vivt() ? "VIVT" :
                icache_is_vivt_asid_tagged() ? "VIVT ASID tagged" :
                icache_is_vipt_aliasing() ? "VIPT aliasing" :
                icache_is_pipt() ? "PIPT" :
                cache_is_vipt_nonaliasing() ? "VIPT nonaliasing" : "unknown");
}

/*
 * These functions re-use the assembly code in head.S, which
 * already provide the required functionality.
 */
extern struct proc_info_list *lookup_processor_type(unsigned int);

void __init early_print(const char *str, ...)
{
        extern void printascii(const char *);
        char buf[256];
        va_list ap;

        va_start(ap, str);
        vsnprintf(buf, sizeof(buf), str, ap);
        va_end(ap);

#ifdef CONFIG_DEBUG_LL
        printascii(buf);
#endif
        printk("%s", buf);
}

#ifdef CONFIG_ARM_PATCH_IDIV

static inline u32 __attribute_const__ sdiv_instruction(void)
{
        if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
                /* "sdiv r0, r0, r1" */
                u32 insn = __opcode_thumb32_compose(0xfb90, 0xf0f1);
                return __opcode_to_mem_thumb32(insn);
        }

        /* "sdiv r0, r0, r1" */
        return __opcode_to_mem_arm(0xe710f110);
}

static inline u32 __attribute_const__ udiv_instruction(void)
{
        if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
                /* "udiv r0, r0, r1" */
                u32 insn = __opcode_thumb32_compose(0xfbb0, 0xf0f1);
                return __opcode_to_mem_thumb32(insn);
        }

        /* "udiv r0, r0, r1" */
        return __opcode_to_mem_arm(0xe730f110);
}

static inline u32 __attribute_const__ bx_lr_instruction(void)
{
        if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
                /* "bx lr; nop" */
                u32 insn = __opcode_thumb32_compose(0x4770, 0x46c0);
                return __opcode_to_mem_thumb32(insn);
        }

        /* "bx lr" */
        return __opcode_to_mem_arm(0xe12fff1e);
}

static void __init patch_aeabi_idiv(void)
{
        extern void __aeabi_uidiv(void);
        extern void __aeabi_idiv(void);
        uintptr_t fn_addr;
        unsigned int mask;

        mask = IS_ENABLED(CONFIG_THUMB2_KERNEL) ? HWCAP_IDIVT : HWCAP_IDIVA;
        if (!(elf_hwcap & mask))
                return;

        pr_info("CPU: div instructions available: patching division code\n");

        fn_addr = ((uintptr_t)&__aeabi_uidiv) & ~1;
        asm ("" : "+g" (fn_addr));
        ((u32 *)fn_addr)[0] = udiv_instruction();
        ((u32 *)fn_addr)[1] = bx_lr_instruction();
        flush_icache_range(fn_addr, fn_addr + 8);

        fn_addr = ((uintptr_t)&__aeabi_idiv) & ~1;
        asm ("" : "+g" (fn_addr));
        ((u32 *)fn_addr)[0] = sdiv_instruction();
        ((u32 *)fn_addr)[1] = bx_lr_instruction();
        flush_icache_range(fn_addr, fn_addr + 8);
}

#else
static inline void patch_aeabi_idiv(void) { }
#endif

static void __init cpuid_init_hwcaps(void)
{
        int block;
        u32 isar5;

        if (cpu_architecture() < CPU_ARCH_ARMv7)
                return;

        block = cpuid_feature_extract(CPUID_EXT_ISAR0, 24);
        if (block >= 2)
                elf_hwcap |= HWCAP_IDIVA;
        if (block >= 1)
                elf_hwcap |= HWCAP_IDIVT;

        /* LPAE implies atomic ldrd/strd instructions */
        block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
        if (block >= 5)
                elf_hwcap |= HWCAP_LPAE;

        /* check for supported v8 Crypto instructions */
        isar5 = read_cpuid_ext(CPUID_EXT_ISAR5);

        block = cpuid_feature_extract_field(isar5, 4);
        if (block >= 2)
                elf_hwcap2 |= HWCAP2_PMULL;
        if (block >= 1)
                elf_hwcap2 |= HWCAP2_AES;

        block = cpuid_feature_extract_field(isar5, 8);
        if (block >= 1)
                elf_hwcap2 |= HWCAP2_SHA1;

        block = cpuid_feature_extract_field(isar5, 12);
        if (block >= 1)
                elf_hwcap2 |= HWCAP2_SHA2;

        block = cpuid_feature_extract_field(isar5, 16);
        if (block >= 1)
                elf_hwcap2 |= HWCAP2_CRC32;
}

static void __init elf_hwcap_fixup(void)
{
        unsigned id = read_cpuid_id();

        /*
         * HWCAP_TLS is available only on 1136 r1p0 and later,
         * see also kuser_get_tls_init.
         */
        if (read_cpuid_part() == ARM_CPU_PART_ARM1136 &&
            ((id >> 20) & 3) == 0) {
                elf_hwcap &= ~HWCAP_TLS;
                return;
        }

        /* Verify if CPUID scheme is implemented */
        if ((id & 0x000f0000) != 0x000f0000)
                return;

        /*
         * If the CPU supports LDREX/STREX and LDREXB/STREXB,
         * avoid advertising SWP; it may not be atomic with
         * multiprocessing cores.
         */
        if (cpuid_feature_extract(CPUID_EXT_ISAR3, 12) > 1 ||
            (cpuid_feature_extract(CPUID_EXT_ISAR3, 12) == 1 &&
             cpuid_feature_extract(CPUID_EXT_ISAR4, 20) >= 3))
                elf_hwcap &= ~HWCAP_SWP;
}

/*
 * cpu_init - initialise one CPU.
 *
 * cpu_init sets up the per-CPU stacks.
 */
void notrace cpu_init(void)
{
#ifndef CONFIG_CPU_V7M
        unsigned int cpu = smp_processor_id();
        struct stack *stk = &stacks[cpu];

        if (cpu >= NR_CPUS) {
                pr_crit("CPU%u: bad primary CPU number\n", cpu);
                BUG();
        }

        /*
         * This only works on resume and secondary cores. For booting on the
         * boot cpu, smp_prepare_boot_cpu is called after percpu area setup.
         */
        set_my_cpu_offset(per_cpu_offset(cpu));

        cpu_proc_init();

        /*
         * Define the placement constraint for the inline asm directive below.
         * In Thumb-2, msr with an immediate value is not allowed.
         */
#ifdef CONFIG_THUMB2_KERNEL
#define PLC     "r"
#else
#define PLC     "I"
#endif

        /*
         * setup stacks for re-entrant exception handlers
         */
        __asm__ (
        "msr    cpsr_c, %1\n\t"
        "add    r14, %0, %2\n\t"
        "mov    sp, r14\n\t"
        "msr    cpsr_c, %3\n\t"
        "add    r14, %0, %4\n\t"
        "mov    sp, r14\n\t"
        "msr    cpsr_c, %5\n\t"
        "add    r14, %0, %6\n\t"
        "mov    sp, r14\n\t"
        "msr    cpsr_c, %7\n\t"
        "add    r14, %0, %8\n\t"
        "mov    sp, r14\n\t"
        "msr    cpsr_c, %9"
            :
            : "r" (stk),
              PLC (PSR_F_BIT | PSR_I_BIT | IRQ_MODE),
              "I" (offsetof(struct stack, irq[0])),
              PLC (PSR_F_BIT | PSR_I_BIT | ABT_MODE),
              "I" (offsetof(struct stack, abt[0])),
              PLC (PSR_F_BIT | PSR_I_BIT | UND_MODE),
              "I" (offsetof(struct stack, und[0])),
              PLC (PSR_F_BIT | PSR_I_BIT | FIQ_MODE),
              "I" (offsetof(struct stack, fiq[0])),
              PLC (PSR_F_BIT | PSR_I_BIT | SVC_MODE)
            : "r14");
#endif
}

u32 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };

void __init smp_setup_processor_id(void)
{
        int i;
        u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
        u32 cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);

        cpu_logical_map(0) = cpu;
        for (i = 1; i < nr_cpu_ids; ++i)
                cpu_logical_map(i) = i == cpu ? 0 : i;

        /*
         * clear __my_cpu_offset on boot CPU to avoid hang caused by
         * using percpu variable early, for example, lockdep will
         * access percpu variable inside lock_release
         */
        set_my_cpu_offset(0);

        pr_info("Booting Linux on physical CPU 0x%x\n", mpidr);
}

struct mpidr_hash mpidr_hash;
#ifdef CONFIG_SMP
/**
 * smp_build_mpidr_hash - Pre-compute shifts required at each affinity
 *                        level in order to build a linear index from an
 *                        MPIDR value. Resulting algorithm is a collision
 *                        free hash carried out through shifting and ORing
 */
static void __init smp_build_mpidr_hash(void)
{
        u32 i, affinity;
        u32 fs[3], bits[3], ls, mask = 0;
        /*
         * Pre-scan the list of MPIDRS and filter out bits that do
         * not contribute to affinity levels, ie they never toggle.
         */
        for_each_possible_cpu(i)
                mask |= (cpu_logical_map(i) ^ cpu_logical_map(0));
        pr_debug("mask of set bits 0x%x\n", mask);
        /*
         * Find and stash the last and first bit set at all affinity levels to
         * check how many bits are required to represent them.
         */
        for (i = 0; i < 3; i++) {
                affinity = MPIDR_AFFINITY_LEVEL(mask, i);
                /*
                 * Find the MSB bit and LSB bits position
                 * to determine how many bits are required
                 * to express the affinity level.
                 */
                ls = fls(affinity);
                fs[i] = affinity ? ffs(affinity) - 1 : 0;
                bits[i] = ls - fs[i];
        }
        /*
         * An index can be created from the MPIDR by isolating the
         * significant bits at each affinity level and by shifting
         * them in order to compress the 24 bits values space to a
         * compressed set of values. This is equivalent to hashing
         * the MPIDR through shifting and ORing. It is a collision free
         * hash though not minimal since some levels might contain a number
         * of CPUs that is not an exact power of 2 and their bit
         * representation might contain holes, eg MPIDR[7:0] = {0x2, 0x80}.
         */
        mpidr_hash.shift_aff[0] = fs[0];
        mpidr_hash.shift_aff[1] = MPIDR_LEVEL_BITS + fs[1] - bits[0];
        mpidr_hash.shift_aff[2] = 2*MPIDR_LEVEL_BITS + fs[2] -
                                                (bits[1] + bits[0]);
        mpidr_hash.mask = mask;
        mpidr_hash.bits = bits[2] + bits[1] + bits[0];
        pr_debug("MPIDR hash: aff0[%u] aff1[%u] aff2[%u] mask[0x%x] bits[%u]\n",
                                mpidr_hash.shift_aff[0],
                                mpidr_hash.shift_aff[1],
                                mpidr_hash.shift_aff[2],
                                mpidr_hash.mask,
                                mpidr_hash.bits);
        /*
         * 4x is an arbitrary value used to warn on a hash table much bigger
         * than expected on most systems.
         */
        if (mpidr_hash_size() > 4 * num_possible_cpus())
                pr_warn("Large number of MPIDR hash buckets detected\n");
        sync_cache_w(&mpidr_hash);
}
#endif

static void __init setup_processor(void)
{
        struct proc_info_list *list;

        /*
         * locate processor in the list of supported processor
         * types.  The linker builds this table for us from the
         * entries in arch/arm/mm/proc-*.S
         */
        list = lookup_processor_type(read_cpuid_id());
        if (!list) {
                pr_err("CPU configuration botched (ID %08x), unable to continue.\n",
                       read_cpuid_id());
                while (1);
        }

        cpu_name = list->cpu_name;
        __cpu_architecture = __get_cpu_architecture();

#ifdef MULTI_CPU
        processor = *list->proc;
#endif
#ifdef MULTI_TLB
        cpu_tlb = *list->tlb;
#endif
#ifdef MULTI_USER
        cpu_user = *list->user;
#endif
#ifdef MULTI_CACHE
        cpu_cache = *list->cache;
#endif

        pr_info("CPU: %s [%08x] revision %d (ARMv%s), cr=%08lx\n",
                cpu_name, read_cpuid_id(), read_cpuid_id() & 15,
                proc_arch[cpu_architecture()], get_cr());

        snprintf(init_utsname()->machine, __NEW_UTS_LEN + 1, "%s%c",
                 list->arch_name, ENDIANNESS);
        snprintf(elf_platform, ELF_PLATFORM_SIZE, "%s%c",
                 list->elf_name, ENDIANNESS);
        elf_hwcap = list->elf_hwcap;

        cpuid_init_hwcaps();
        patch_aeabi_idiv();

#ifndef CONFIG_ARM_THUMB
        elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT);
#endif
#ifdef CONFIG_MMU
        init_default_cache_policy(list->__cpu_mm_mmu_flags);
#endif
        erratum_a15_798181_init();

        elf_hwcap_fixup();

        cacheid_init();
        cpu_init();
}

void __init dump_machine_table(void)
{
        const struct machine_desc *p;

        early_print("Available machine support:\n\nID (hex)\tNAME\n");
        for_each_machine_desc(p)
                early_print("%08x\t%s\n", p->nr, p->name);

        early_print("\nPlease check your kernel config and/or bootloader.\n");

        while (true)
                /* can't use cpu_relax() here as it may require MMU setup */;
}

int __init arm_add_memory(u64 start, u64 size)
{
        u64 aligned_start;

        /*
         * Ensure that start/size are aligned to a page boundary.
         * Size is rounded down, start is rounded up.
         */
        aligned_start = PAGE_ALIGN(start);
        if (aligned_start > start + size)
                size = 0;
        else
                size -= aligned_start - start;

#ifndef CONFIG_ARCH_PHYS_ADDR_T_64BIT
        if (aligned_start > ULONG_MAX) {
                pr_crit("Ignoring memory at 0x%08llx outside 32-bit physical address space\n",
                        (long long)start);
                return -EINVAL;
        }

        if (aligned_start + size > ULONG_MAX) {
                pr_crit("Truncating memory at 0x%08llx to fit in 32-bit physical address space\n",
                        (long long)start);
                /*
                 * To ensure bank->start + bank->size is representable in
                 * 32 bits, we use ULONG_MAX as the upper limit rather than 4GB.
                 * This means we lose a page after masking.
                 */
                size = ULONG_MAX - aligned_start;
        }
#endif

        if (aligned_start < PHYS_OFFSET) {
                if (aligned_start + size <= PHYS_OFFSET) {
                        pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
                                aligned_start, aligned_start + size);
                        return -EINVAL;
                }

                pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
                        aligned_start, (u64)PHYS_OFFSET);

                size -= PHYS_OFFSET - aligned_start;
                aligned_start = PHYS_OFFSET;
        }

        start = aligned_start;
        size = size & ~(phys_addr_t)(PAGE_SIZE - 1);

        /*
         * Check whether this memory region has non-zero size or
         * invalid node number.
         */
        if (size == 0)
                return -EINVAL;

        memblock_add(start, size);
        return 0;
}

/*
 * Pick out the memory size.  We look for mem=size@start,
 * where start and size are "size[KkMm]"
 */

static int __init early_mem(char *p)
{
        static int usermem __initdata = 0;
        u64 size;
        u64 start;
        char *endp;

        /*
         * If the user specifies memory size, we
         * blow away any automatically generated
         * size.
         */
        if (usermem == 0) {
                usermem = 1;
                memblock_remove(memblock_start_of_DRAM(),
                        memblock_end_of_DRAM() - memblock_start_of_DRAM());
        }

        start = PHYS_OFFSET;
        size  = memparse(p, &endp);
        if (*endp == '@')
                start = memparse(endp + 1, NULL);

        arm_add_memory(start, size);

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

static void __init request_standard_resources(const struct machine_desc *mdesc)
{
        struct memblock_region *region;
        struct resource *res;

        kernel_code.start   = virt_to_phys(_text);
        kernel_code.end     = virt_to_phys(__init_begin - 1);
        kernel_data.start   = virt_to_phys(_sdata);
        kernel_data.end     = virt_to_phys(_end - 1);

        for_each_memblock(memory, region) {
                phys_addr_t start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
                phys_addr_t end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
                unsigned long boot_alias_start;

                /*
                 * Some systems have a special memory alias which is only
                 * used for booting.  We need to advertise this region to
                 * kexec-tools so they know where bootable RAM is located.
                 */
                boot_alias_start = phys_to_idmap(start);
                if (arm_has_idmap_alias() && boot_alias_start != IDMAP_INVALID_ADDR) {
                        res = memblock_virt_alloc(sizeof(*res), 0);
                        res->name = "System RAM (boot alias)";
                        res->start = boot_alias_start;
                        res->end = phys_to_idmap(end);
                        res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
                        request_resource(&iomem_resource, res);
                }

                res = memblock_virt_alloc(sizeof(*res), 0);
                res->name  = "System RAM";
                res->start = start;
                res->end = end;
                res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;

                request_resource(&iomem_resource, res);

                if (kernel_code.start >= res->start &&
                    kernel_code.end <= res->end)
                        request_resource(res, &kernel_code);
                if (kernel_data.start >= res->start &&
                    kernel_data.end <= res->end)
                        request_resource(res, &kernel_data);
        }

        if (mdesc->video_start) {
                video_ram.start = mdesc->video_start;
                video_ram.end   = mdesc->video_end;
                request_resource(&iomem_resource, &video_ram);
        }

        /*
         * Some machines don't have the possibility of ever
         * possessing lp0, lp1 or lp2
         */
        if (mdesc->reserve_lp0)
                request_resource(&ioport_resource, &lp0);
        if (mdesc->reserve_lp1)
                request_resource(&ioport_resource, &lp1);
        if (mdesc->reserve_lp2)
                request_resource(&ioport_resource, &lp2);
}

#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) || \
    defined(CONFIG_EFI)
struct screen_info screen_info = {
 .orig_video_lines      = 30,
 .orig_video_cols       = 80,
 .orig_video_mode       = 0,
 .orig_video_ega_bx     = 0,
 .orig_video_isVGA      = 1,
 .orig_video_points     = 8
};
#endif

static int __init customize_machine(void)
{
        /*
         * customizes platform devices, or adds new ones
         * On DT based machines, we fall back to populating the
         * machine from the device tree, if no callback is provided,
         * otherwise we would always need an init_machine callback.
         */
        if (machine_desc->init_machine)
                machine_desc->init_machine();

        return 0;
}
arch_initcall(customize_machine);

static int __init init_machine_late(void)
{
        struct device_node *root;
        int ret;

        if (machine_desc->init_late)
                machine_desc->init_late();

        root = of_find_node_by_path("/");
        if (root) {
                ret = of_property_read_string(root, "serial-number",
                                              &system_serial);
                if (ret)
                        system_serial = NULL;
        }

        if (!system_serial)
                system_serial = kasprintf(GFP_KERNEL, "%08x%08x",
                                          system_serial_high,
                                          system_serial_low);

        return 0;
}
late_initcall(init_machine_late);

#ifdef CONFIG_KEXEC
/*
 * The crash region must be aligned to 128MB to avoid
 * zImage relocating below the reserved region.
 */
#define CRASH_ALIGN     (128 << 20)

static inline unsigned long long get_total_mem(void)
{
        unsigned long total;

        total = max_low_pfn - min_low_pfn;
        return total << PAGE_SHIFT;
}

/**
 * reserve_crashkernel() - reserves memory are for crash kernel
 *
 * This function reserves memory area given in "crashkernel=" kernel command
 * line parameter. The memory reserved is used by a dump capture kernel when
 * primary kernel is crashing.
 */
static void __init reserve_crashkernel(void)
{
        unsigned long long crash_size, crash_base;
        unsigned long long total_mem;
        int ret;

        total_mem = get_total_mem();
        ret = parse_crashkernel(boot_command_line, total_mem,
                                &crash_size, &crash_base);
        if (ret)
                return;

        if (crash_base <= 0) {
                unsigned long long crash_max = idmap_to_phys((u32)~0);
                unsigned long long lowmem_max = __pa(high_memory - 1) + 1;
                if (crash_max > lowmem_max)
                        crash_max = lowmem_max;
                crash_base = memblock_find_in_range(CRASH_ALIGN, crash_max,
                                                    crash_size, CRASH_ALIGN);
                if (!crash_base) {
                        pr_err("crashkernel reservation failed - No suitable area found.\n");
                        return;
                }
        } else {
                unsigned long long start;

                start = memblock_find_in_range(crash_base,
                                               crash_base + crash_size,
                                               crash_size, SECTION_SIZE);
                if (start != crash_base) {
                        pr_err("crashkernel reservation failed - memory is in use.\n");
                        return;
                }
        }

        ret = memblock_reserve(crash_base, crash_size);
        if (ret < 0) {
                pr_warn("crashkernel reservation failed - memory is in use (0x%lx)\n",
                        (unsigned long)crash_base);
                return;
        }

        pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
                (unsigned long)(crash_size >> 20),
                (unsigned long)(crash_base >> 20),
                (unsigned long)(total_mem >> 20));

        /* The crashk resource must always be located in normal mem */
        crashk_res.start = crash_base;
        crashk_res.end = crash_base + crash_size - 1;
        insert_resource(&iomem_resource, &crashk_res);

        if (arm_has_idmap_alias()) {
                /*
                 * If we have a special RAM alias for use at boot, we
                 * need to advertise to kexec tools where the alias is.
                 */
                static struct resource crashk_boot_res = {
                        .name = "Crash kernel (boot alias)",
                        .flags = IORESOURCE_BUSY | IORESOURCE_MEM,
                };

                crashk_boot_res.start = phys_to_idmap(crash_base);
                crashk_boot_res.end = crashk_boot_res.start + crash_size - 1;
                insert_resource(&iomem_resource, &crashk_boot_res);
        }
}
#else
static inline void reserve_crashkernel(void) {}
#endif /* CONFIG_KEXEC */

void __init hyp_mode_check(void)
{
#ifdef CONFIG_ARM_VIRT_EXT
        sync_boot_mode();

        if (is_hyp_mode_available()) {
                pr_info("CPU: All CPU(s) started in HYP mode.\n");
                pr_info("CPU: Virtualization extensions available.\n");
        } else if (is_hyp_mode_mismatched()) {
                pr_warn("CPU: WARNING: CPU(s) started in wrong/inconsistent modes (primary CPU mode 0x%x)\n",
                        __boot_cpu_mode & MODE_MASK);
                pr_warn("CPU: This may indicate a broken bootloader or firmware.\n");
        } else
                pr_info("CPU: All CPU(s) started in SVC mode.\n");
#endif
}

void __init setup_arch(char **cmdline_p)
{
        const struct machine_desc *mdesc;

        setup_processor();
        mdesc = setup_machine_fdt(__atags_pointer);
        if (!mdesc)
                mdesc = setup_machine_tags(__atags_pointer, __machine_arch_type);
        if (!mdesc) {
                early_print("\nError: invalid dtb and unrecognized/unsupported machine ID\n");
                early_print("  r1=0x%08x, r2=0x%08x\n", __machine_arch_type,
                            __atags_pointer);
                if (__atags_pointer)
                        early_print("  r2[]=%*ph\n", 16,
                                    phys_to_virt(__atags_pointer));
                dump_machine_table();
        }

        machine_desc = mdesc;
        machine_name = mdesc->name;
        dump_stack_set_arch_desc("%s", mdesc->name);

        if (mdesc->reboot_mode != REBOOT_HARD)
                reboot_mode = mdesc->reboot_mode;

        init_mm.start_code = (unsigned long) _text;
        init_mm.end_code   = (unsigned long) _etext;
        init_mm.end_data   = (unsigned long) _edata;
        init_mm.brk        = (unsigned long) _end;

        /* populate cmd_line too for later use, preserving boot_command_line */
        strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
        *cmdline_p = cmd_line;

        early_fixmap_init();
        early_ioremap_init();

        parse_early_param();

#ifdef CONFIG_MMU
        early_mm_init(mdesc);
#endif
        setup_dma_zone(mdesc);
        xen_early_init();
        efi_init();
        /*
         * Make sure the calculation for lowmem/highmem is set appropriately
         * before reserving/allocating any mmeory
         */
        adjust_lowmem_bounds();
        arm_memblock_init(mdesc);
        /* Memory may have been removed so recalculate the bounds. */
        adjust_lowmem_bounds();

        early_ioremap_reset();

        paging_init(mdesc);
        request_standard_resources(mdesc);

        if (mdesc->restart)
                arm_pm_restart = mdesc->restart;

        unflatten_device_tree();

        arm_dt_init_cpu_maps();
        psci_dt_init();
#ifdef CONFIG_SMP
        if (is_smp()) {
                if (!mdesc->smp_init || !mdesc->smp_init()) {
                        if (psci_smp_available())
                                smp_set_ops(&psci_smp_ops);
                        else if (mdesc->smp)
                                smp_set_ops(mdesc->smp);
                }
                smp_init_cpus();
                smp_build_mpidr_hash();
        }
#endif

        if (!is_smp())
                hyp_mode_check();

        reserve_crashkernel();

#ifdef CONFIG_MULTI_IRQ_HANDLER
        handle_arch_irq = mdesc->handle_irq;
#endif

#ifdef CONFIG_VT
#if defined(CONFIG_VGA_CONSOLE)
        conswitchp = &vga_con;
#elif defined(CONFIG_DUMMY_CONSOLE)
        conswitchp = &dummy_con;
#endif
#endif

        if (mdesc->init_early)
                mdesc->init_early();
}


static int __init topology_init(void)
{
        int cpu;

        for_each_possible_cpu(cpu) {
                struct cpuinfo_arm *cpuinfo = &per_cpu(cpu_data, cpu);
                cpuinfo->cpu.hotpluggable = platform_can_hotplug_cpu(cpu);
                register_cpu(&cpuinfo->cpu, cpu);
        }

        return 0;
}
subsys_initcall(topology_init);

#ifdef CONFIG_HAVE_PROC_CPU
static int __init proc_cpu_init(void)
{
        struct proc_dir_entry *res;

        res = proc_mkdir("cpu", NULL);
        if (!res)
                return -ENOMEM;
        return 0;
}
fs_initcall(proc_cpu_init);
#endif

static const char *hwcap_str[] = {
        "swp",
        "half",
        "thumb",
        "26bit",
        "fastmult",
        "fpa",
        "vfp",
        "edsp",
        "java",
        "iwmmxt",
        "crunch",
        "thumbee",
        "neon",
        "vfpv3",
        "vfpv3d16",
        "tls",
        "vfpv4",
        "idiva",
        "idivt",
        "vfpd32",
        "lpae",
        "evtstrm",
        NULL
};

static const char *hwcap2_str[] = {
        "aes",
        "pmull",
        "sha1",
        "sha2",
        "crc32",
        NULL
};

static int c_show(struct seq_file *m, void *v)
{
        int i, j;
        u32 cpuid;

        for_each_online_cpu(i) {
                /*
                 * glibc reads /proc/cpuinfo to determine the number of
                 * online processors, looking for lines beginning with
                 * "processor".  Give glibc what it expects.
                 */
                seq_printf(m, "processor\t: %d\n", i);
                cpuid = is_smp() ? per_cpu(cpu_data, i).cpuid : read_cpuid_id();
                seq_printf(m, "model name\t: %s rev %d (%s)\n",
                           cpu_name, cpuid & 15, elf_platform);

#if defined(CONFIG_SMP)
                seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
                           per_cpu(cpu_data, i).loops_per_jiffy / (500000UL/HZ),
                           (per_cpu(cpu_data, i).loops_per_jiffy / (5000UL/HZ)) % 100);
#else
                seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
                           loops_per_jiffy / (500000/HZ),
                           (loops_per_jiffy / (5000/HZ)) % 100);
#endif
                /* dump out the processor features */
                seq_puts(m, "Features\t: ");

                for (j = 0; hwcap_str[j]; j++)
                        if (elf_hwcap & (1 << j))
                                seq_printf(m, "%s ", hwcap_str[j]);

                for (j = 0; hwcap2_str[j]; j++)
                        if (elf_hwcap2 & (1 << j))
                                seq_printf(m, "%s ", hwcap2_str[j]);

                seq_printf(m, "\nCPU implementer\t: 0x%02x\n", cpuid >> 24);
                seq_printf(m, "CPU architecture: %s\n",
                           proc_arch[cpu_architecture()]);

                if ((cpuid & 0x0008f000) == 0x00000000) {
                        /* pre-ARM7 */
                        seq_printf(m, "CPU part\t: %07x\n", cpuid >> 4);
                } else {
                        if ((cpuid & 0x0008f000) == 0x00007000) {
                                /* ARM7 */
                                seq_printf(m, "CPU variant\t: 0x%02x\n",
                                           (cpuid >> 16) & 127);
                        } else {
                                /* post-ARM7 */
                                seq_printf(m, "CPU variant\t: 0x%x\n",
                                           (cpuid >> 20) & 15);
                        }
                        seq_printf(m, "CPU part\t: 0x%03x\n",
                                   (cpuid >> 4) & 0xfff);
                }
                seq_printf(m, "CPU revision\t: %d\n\n", cpuid & 15);
        }

        seq_printf(m, "Hardware\t: %s\n", machine_name);
        seq_printf(m, "Revision\t: %04x\n", system_rev);
        seq_printf(m, "Serial\t\t: %s\n", system_serial);

        return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
        return *pos < 1 ? (void *)1 : NULL;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
        ++*pos;
        return NULL;
}

static void c_stop(struct seq_file *m, void *v)
{
}

const struct seq_operations cpuinfo_op = {
        .start  = c_start,
        .next   = c_next,
        .stop   = c_stop,
        .show   = c_show
};