arm/dt: probe for platforms via the device tree

[mirror_ubuntu-zesty-kernel.git] / arch / arm / kernel / setup.c

/*
 *  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/module.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/init.h>
#include <linux/kexec.h>
#include <linux/of_fdt.h>
#include <linux/crash_dump.h>
#include <linux/root_dev.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/memblock.h>

#include <asm/unified.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/elf.h>
#include <asm/procinfo.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/prom.h>
#include <asm/mach/arch.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <asm/traps.h>
#include <asm/unwind.h>

#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
#include "compat.h"
#endif
#include "atags.h"
#include "tcm.h"

#ifndef MEM_SIZE
#define MEM_SIZE        (16*1024*1024)
#endif

#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 paging_init(struct machine_desc *desc);
extern void reboot_setup(char *str);

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);

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);


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

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

static struct stack stacks[NR_CPUS];

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];
struct machine_desc *machine_desc __initdata;

static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
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 text",
                .start = 0,
                .end = 0,
                .flags = IORESOURCE_MEM
        },
        {
                .name = "Kernel data",
                .start = 0,
                .end = 0,
                .flags = IORESOURCE_MEM
        }
};

#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",
        "?(11)",
        "?(12)",
        "?(13)",
        "?(14)",
        "?(15)",
        "?(16)",
        "?(17)",
};

int 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) {
                unsigned int mmfr0;

                /* Revised CPUID format. Read the Memory Model Feature
                 * Register 0 and check for VMSAv7 or PMSAv7 */
                asm("mrc        p15, 0, %0, c0, c1, 4"
                    : "=r" (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;
}

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

        /* arch specifies the register format */
        switch (arch) {
        case CPU_ARCH_ARMv7:
                asm("mcr        p15, 2, %0, c0, c0, 0 @ set CSSELR"
                    : /* No output operands */
                    : "r" (1));
                isb();
                asm("mrc        p15, 1, %0, c0, c0, 0 @ read CCSIDR"
                    : "=r" (id_reg));
                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 cachetype = read_cpuid_cachetype();
        unsigned int arch = cpu_architecture();

        if (arch >= CPU_ARCH_ARMv6) {
                if ((cachetype & (7 << 29)) == 4 << 29) {
                        /* ARMv7 register format */
                        cacheid = CACHEID_VIPT_NONALIASING;
                        if ((cachetype & (3 << 14)) == 1 << 14)
                                cacheid |= CACHEID_ASID_TAGGED;
                        else if (cpu_has_aliasing_icache(CPU_ARCH_ARMv7))
                                cacheid |= CACHEID_VIPT_I_ALIASING;
                } else if (cachetype & (1 << 23)) {
                        cacheid = CACHEID_VIPT_ALIASING;
                } else {
                        cacheid = CACHEID_VIPT_NONALIASING;
                        if (cpu_has_aliasing_icache(CPU_ARCH_ARMv6))
                                cacheid |= CACHEID_VIPT_I_ALIASING;
                }
        } else {
                cacheid = CACHEID_VIVT;
        }

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

static void __init feat_v6_fixup(void)
{
        int id = read_cpuid_id();

        if ((id & 0xff0f0000) != 0x41070000)
                return;

        /*
         * HWCAP_TLS is available only on 1136 r1p0 and later,
         * see also kuser_get_tls_init.
         */
        if ((((id >> 4) & 0xfff) == 0xb36) && (((id >> 20) & 3) == 0))
                elf_hwcap &= ~HWCAP_TLS;
}

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) {
                printk("CPU configuration botched (ID %08x), unable "
                       "to continue.\n", read_cpuid_id());
                while (1);
        }

        cpu_name = list->cpu_name;

#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

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

        sprintf(init_utsname()->machine, "%s%c", list->arch_name, ENDIANNESS);
        sprintf(elf_platform, "%s%c", list->elf_name, ENDIANNESS);
        elf_hwcap = list->elf_hwcap;
#ifndef CONFIG_ARM_THUMB
        elf_hwcap &= ~HWCAP_THUMB;
#endif

        feat_v6_fixup();

        cacheid_init();
        cpu_proc_init();
}

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

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

        /*
         * 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"
            :
            : "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 | SVC_MODE)
            : "r14");
}

void __init dump_machine_table(void)
{
        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(phys_addr_t start, unsigned long size)
{
        struct membank *bank = &meminfo.bank[meminfo.nr_banks];

        if (meminfo.nr_banks >= NR_BANKS) {
                printk(KERN_CRIT "NR_BANKS too low, "
                        "ignoring memory at 0x%08llx\n", (long long)start);
                return -EINVAL;
        }

        /*
         * Ensure that start/size are aligned to a page boundary.
         * Size is appropriately rounded down, start is rounded up.
         */
        size -= start & ~PAGE_MASK;
        bank->start = PAGE_ALIGN(start);
        bank->size  = size & PAGE_MASK;

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

        meminfo.nr_banks++;
        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;
        unsigned long size;
        phys_addr_t start;
        char *endp;

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

        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
setup_ramdisk(int doload, int prompt, int image_start, unsigned int rd_sz)
{
#ifdef CONFIG_BLK_DEV_RAM
        extern int rd_size, rd_image_start, rd_prompt, rd_doload;

        rd_image_start = image_start;
        rd_prompt = prompt;
        rd_doload = doload;

        if (rd_sz)
                rd_size = rd_sz;
#endif
}

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

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

        for_each_memblock(memory, region) {
                res = alloc_bootmem_low(sizeof(*res));
                res->name  = "System RAM";
                res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
                res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
                res->flags = IORESOURCE_MEM | 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);
}

/*
 *  Tag parsing.
 *
 * This is the new way of passing data to the kernel at boot time.  Rather
 * than passing a fixed inflexible structure to the kernel, we pass a list
 * of variable-sized tags to the kernel.  The first tag must be a ATAG_CORE
 * tag for the list to be recognised (to distinguish the tagged list from
 * a param_struct).  The list is terminated with a zero-length tag (this tag
 * is not parsed in any way).
 */
static int __init parse_tag_core(const struct tag *tag)
{
        if (tag->hdr.size > 2) {
                if ((tag->u.core.flags & 1) == 0)
                        root_mountflags &= ~MS_RDONLY;
                ROOT_DEV = old_decode_dev(tag->u.core.rootdev);
        }
        return 0;
}

__tagtable(ATAG_CORE, parse_tag_core);

static int __init parse_tag_mem32(const struct tag *tag)
{
        return arm_add_memory(tag->u.mem.start, tag->u.mem.size);
}

__tagtable(ATAG_MEM, parse_tag_mem32);

#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
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
};

static int __init parse_tag_videotext(const struct tag *tag)
{
        screen_info.orig_x            = tag->u.videotext.x;
        screen_info.orig_y            = tag->u.videotext.y;
        screen_info.orig_video_page   = tag->u.videotext.video_page;
        screen_info.orig_video_mode   = tag->u.videotext.video_mode;
        screen_info.orig_video_cols   = tag->u.videotext.video_cols;
        screen_info.orig_video_ega_bx = tag->u.videotext.video_ega_bx;
        screen_info.orig_video_lines  = tag->u.videotext.video_lines;
        screen_info.orig_video_isVGA  = tag->u.videotext.video_isvga;
        screen_info.orig_video_points = tag->u.videotext.video_points;
        return 0;
}

__tagtable(ATAG_VIDEOTEXT, parse_tag_videotext);
#endif

static int __init parse_tag_ramdisk(const struct tag *tag)
{
        setup_ramdisk((tag->u.ramdisk.flags & 1) == 0,
                      (tag->u.ramdisk.flags & 2) == 0,
                      tag->u.ramdisk.start, tag->u.ramdisk.size);
        return 0;
}

__tagtable(ATAG_RAMDISK, parse_tag_ramdisk);

static int __init parse_tag_serialnr(const struct tag *tag)
{
        system_serial_low = tag->u.serialnr.low;
        system_serial_high = tag->u.serialnr.high;
        return 0;
}

__tagtable(ATAG_SERIAL, parse_tag_serialnr);

static int __init parse_tag_revision(const struct tag *tag)
{
        system_rev = tag->u.revision.rev;
        return 0;
}

__tagtable(ATAG_REVISION, parse_tag_revision);

static int __init parse_tag_cmdline(const struct tag *tag)
{
#ifndef CONFIG_CMDLINE_FORCE
        strlcpy(default_command_line, tag->u.cmdline.cmdline, COMMAND_LINE_SIZE);
#else
        pr_warning("Ignoring tag cmdline (using the default kernel command line)\n");
#endif /* CONFIG_CMDLINE_FORCE */
        return 0;
}

__tagtable(ATAG_CMDLINE, parse_tag_cmdline);

/*
 * Scan the tag table for this tag, and call its parse function.
 * The tag table is built by the linker from all the __tagtable
 * declarations.
 */
static int __init parse_tag(const struct tag *tag)
{
        extern struct tagtable __tagtable_begin, __tagtable_end;
        struct tagtable *t;

        for (t = &__tagtable_begin; t < &__tagtable_end; t++)
                if (tag->hdr.tag == t->tag) {
                        t->parse(tag);
                        break;
                }

        return t < &__tagtable_end;
}

/*
 * Parse all tags in the list, checking both the global and architecture
 * specific tag tables.
 */
static void __init parse_tags(const struct tag *t)
{
        for (; t->hdr.size; t = tag_next(t))
                if (!parse_tag(t))
                        printk(KERN_WARNING
                                "Ignoring unrecognised tag 0x%08x\n",
                                t->hdr.tag);
}

/*
 * This holds our defaults.
 */
static struct init_tags {
        struct tag_header hdr1;
        struct tag_core   core;
        struct tag_header hdr2;
        struct tag_mem32  mem;
        struct tag_header hdr3;
} init_tags __initdata = {
        { tag_size(tag_core), ATAG_CORE },
        { 1, PAGE_SIZE, 0xff },
        { tag_size(tag_mem32), ATAG_MEM },
        { MEM_SIZE },
        { 0, ATAG_NONE }
};

static int __init customize_machine(void)
{
        /* customizes platform devices, or adds new ones */
        if (machine_desc->init_machine)
                machine_desc->init_machine();
        return 0;
}
arch_initcall(customize_machine);

#ifdef CONFIG_KEXEC
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;

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

        printk(KERN_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));

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

static void __init squash_mem_tags(struct tag *tag)
{
        for (; tag->hdr.size; tag = tag_next(tag))
                if (tag->hdr.tag == ATAG_MEM)
                        tag->hdr.tag = ATAG_NONE;
}

static struct machine_desc * __init setup_machine_tags(unsigned int nr)
{
        struct tag *tags = (struct tag *)&init_tags;
        struct machine_desc *mdesc = NULL, *p;
        char *from = default_command_line;

        init_tags.mem.start = PHYS_OFFSET;

        /*
         * locate machine in the list of supported machines.
         */
        for_each_machine_desc(p)
                if (nr == p->nr) {
                        printk("Machine: %s\n", p->name);
                        mdesc = p;
                        break;
                }

        if (!mdesc) {
                early_print("\nError: unrecognized/unsupported machine ID"
                        " (r1 = 0x%08x).\n\n", nr);
                dump_machine_table(); /* does not return */
        }

        if (__atags_pointer)
                tags = phys_to_virt(__atags_pointer);
        else if (mdesc->boot_params) {
#ifdef CONFIG_MMU
                /*
                 * We still are executing with a minimal MMU mapping created
                 * with the presumption that the machine default for this
                 * is located in the first MB of RAM.  Anything else will
                 * fault and silently hang the kernel at this point.
                 */
                if (mdesc->boot_params < PHYS_OFFSET ||
                    mdesc->boot_params >= PHYS_OFFSET + SZ_1M) {
                        printk(KERN_WARNING
                               "Default boot params at physical 0x%08lx out of reach\n",
                               mdesc->boot_params);
                } else
#endif
                {
                        tags = phys_to_virt(mdesc->boot_params);
                }
        }

#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
        /*
         * If we have the old style parameters, convert them to
         * a tag list.
         */
        if (tags->hdr.tag != ATAG_CORE)
                convert_to_tag_list(tags);
#endif

        if (tags->hdr.tag != ATAG_CORE) {
#if defined(CONFIG_OF)
                /*
                 * If CONFIG_OF is set, then assume this is a reasonably
                 * modern system that should pass boot parameters
                 */
                early_print("Warning: Neither atags nor dtb found\n");
#endif
                tags = (struct tag *)&init_tags;
        }

        if (mdesc->fixup)
                mdesc->fixup(mdesc, tags, &from, &meminfo);

        if (tags->hdr.tag == ATAG_CORE) {
                if (meminfo.nr_banks != 0)
                        squash_mem_tags(tags);
                save_atags(tags);
                parse_tags(tags);
        }

        /* parse_early_param needs a boot_command_line */
        strlcpy(boot_command_line, from, COMMAND_LINE_SIZE);

        return mdesc;
}


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

        unwind_init();

        setup_processor();
        mdesc = setup_machine_fdt(__atags_pointer);
        if (!mdesc)
                mdesc = setup_machine_tags(machine_arch_type);
        machine_desc = mdesc;
        machine_name = mdesc->name;

        if (mdesc->soft_reboot)
                reboot_setup("s");

        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;

        parse_early_param();

        arm_memblock_init(&meminfo, mdesc);

        paging_init(mdesc);
        request_standard_resources(mdesc);

        unflatten_device_tree();

#ifdef CONFIG_SMP
        if (is_smp())
                smp_init_cpus();
#endif
        reserve_crashkernel();

        cpu_init();
        tcm_init();

#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
        early_trap_init();

        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 = 1;
                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",
        NULL
};

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

        seq_printf(m, "Processor\t: %s rev %d (%s)\n",
                   cpu_name, read_cpuid_id() & 15, elf_platform);

#if defined(CONFIG_SMP)
        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);
                seq_printf(m, "BogoMIPS\t: %lu.%02lu\n\n",
                           per_cpu(cpu_data, i).loops_per_jiffy / (500000UL/HZ),
                           (per_cpu(cpu_data, i).loops_per_jiffy / (5000UL/HZ)) % 100);
        }
#else /* CONFIG_SMP */
        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 (i = 0; hwcap_str[i]; i++)
                if (elf_hwcap & (1 << i))
                        seq_printf(m, "%s ", hwcap_str[i]);

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

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

        seq_puts(m, "\n");

        seq_printf(m, "Hardware\t: %s\n", machine_name);
        seq_printf(m, "Revision\t: %04x\n", system_rev);
        seq_printf(m, "Serial\t\t: %08x%08x\n",
                   system_serial_high, system_serial_low);

        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
};