// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 */

#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/root_dev.h>
#include <linux/clk.h>
#include <linux/clocksource.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/sizes.h>
#include <linux/cpu.h>
#include <linux/of_clk.h>
#include <linux/of_fdt.h>
#include <linux/of.h>
#include <linux/cache.h>
#include <uapi/linux/mount.h>
#include <asm/sections.h>
#include <asm/arcregs.h>
#include <asm/asserts.h>
#include <asm/tlb.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/irq.h>
#include <asm/unwind.h>
#include <asm/mach_desc.h>
#include <asm/smp.h>
#include <asm/dsp-impl.h>

#define FIX_PTR(x)  __asm__ __volatile__(";" : "+r"(x))

unsigned int intr_to_DE_cnt;

/* Part of U-boot ABI: see head.S */
int __initdata uboot_tag;
int __initdata uboot_magic;
char __initdata *uboot_arg;

const struct machine_desc *machine_desc;

struct task_struct *_current_task[NR_CPUS];     /* For stack switching */

struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];

static const struct id_to_str arc_legacy_rel[] = {
        /* ID.ARCVER,   Release */
#ifdef CONFIG_ISA_ARCOMPACT
        { 0x34,         "R4.10"},
        { 0x35,         "R4.11"},
#else
        { 0x51,         "R2.0" },
        { 0x52,         "R2.1" },
        { 0x53,         "R3.0" },
#endif
        { 0x00,         NULL   }
};

static const struct id_to_str arc_hs_ver54_rel[] = {
        /* UARCH.MAJOR, Release */
        {  0,           "R3.10a"},
        {  1,           "R3.50a"},
        {  2,           "R3.60a"},
        {  3,           "R4.00a"},
        {  0xFF,        NULL   }
};

static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
{
        if (is_isa_arcompact()) {
                struct bcr_iccm_arcompact iccm;
                struct bcr_dccm_arcompact dccm;

                READ_BCR(ARC_REG_ICCM_BUILD, iccm);
                if (iccm.ver) {
                        cpu->iccm.sz = 4096 << iccm.sz; /* 8K to 512K */
                        cpu->iccm.base_addr = iccm.base << 16;
                }

                READ_BCR(ARC_REG_DCCM_BUILD, dccm);
                if (dccm.ver) {
                        unsigned long base;
                        cpu->dccm.sz = 2048 << dccm.sz; /* 2K to 256K */

                        base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
                        cpu->dccm.base_addr = base & ~0xF;
                }
        } else {
                struct bcr_iccm_arcv2 iccm;
                struct bcr_dccm_arcv2 dccm;
                unsigned long region;

                READ_BCR(ARC_REG_ICCM_BUILD, iccm);
                if (iccm.ver) {
                        cpu->iccm.sz = 256 << iccm.sz00;        /* 512B to 16M */
                        if (iccm.sz00 == 0xF && iccm.sz01 > 0)
                                cpu->iccm.sz <<= iccm.sz01;

                        region = read_aux_reg(ARC_REG_AUX_ICCM);
                        cpu->iccm.base_addr = region & 0xF0000000;
                }

                READ_BCR(ARC_REG_DCCM_BUILD, dccm);
                if (dccm.ver) {
                        cpu->dccm.sz = 256 << dccm.sz0;
                        if (dccm.sz0 == 0xF && dccm.sz1 > 0)
                                cpu->dccm.sz <<= dccm.sz1;

                        region = read_aux_reg(ARC_REG_AUX_DCCM);
                        cpu->dccm.base_addr = region & 0xF0000000;
                }
        }
}

static void decode_arc_core(struct cpuinfo_arc *cpu)
{
        struct bcr_uarch_build_arcv2 uarch;
        const struct id_to_str *tbl;

        if (cpu->core.family < 0x54) { /* includes arc700 */

                for (tbl = &arc_legacy_rel[0]; tbl->id != 0; tbl++) {
                        if (cpu->core.family == tbl->id) {
                                cpu->release = tbl->str;
                                break;
                        }
                }

                if (is_isa_arcompact())
                        cpu->name = "ARC700";
                else if (tbl->str)
                        cpu->name = "HS38";
                else
                        cpu->name = cpu->release = "Unknown";

                return;
        }

        /*
         * Initial HS cores bumped AUX IDENTITY.ARCVER for each release until
         * ARCVER 0x54 which introduced AUX MICRO_ARCH_BUILD and subsequent
         * releases only update it.
         */
        READ_BCR(ARC_REG_MICRO_ARCH_BCR, uarch);

        if (uarch.prod == 4) {
                cpu->name = "HS48";
                cpu->extn.dual = 1;

        } else {
                cpu->name = "HS38";
        }

        for (tbl = &arc_hs_ver54_rel[0]; tbl->id != 0xFF; tbl++) {
                if (uarch.maj == tbl->id) {
                        cpu->release = tbl->str;
                        break;
                }
        }
}

static void read_arc_build_cfg_regs(void)
{
        struct bcr_timer timer;
        struct bcr_generic bcr;
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
        struct bcr_isa_arcv2 isa;
        struct bcr_actionpoint ap;

        FIX_PTR(cpu);

        READ_BCR(AUX_IDENTITY, cpu->core);
        decode_arc_core(cpu);

        READ_BCR(ARC_REG_TIMERS_BCR, timer);
        cpu->extn.timer0 = timer.t0;
        cpu->extn.timer1 = timer.t1;
        cpu->extn.rtc = timer.rtc;

        cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);

        READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);

        /* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
        read_decode_ccm_bcr(cpu);

        read_decode_mmu_bcr();
        read_decode_cache_bcr();

        if (is_isa_arcompact()) {
                struct bcr_fp_arcompact sp, dp;
                struct bcr_bpu_arcompact bpu;

                READ_BCR(ARC_REG_FP_BCR, sp);
                READ_BCR(ARC_REG_DPFP_BCR, dp);
                cpu->extn.fpu_sp = sp.ver ? 1 : 0;
                cpu->extn.fpu_dp = dp.ver ? 1 : 0;

                READ_BCR(ARC_REG_BPU_BCR, bpu);
                cpu->bpu.ver = bpu.ver;
                cpu->bpu.full = bpu.fam ? 1 : 0;
                if (bpu.ent) {
                        cpu->bpu.num_cache = 256 << (bpu.ent - 1);
                        cpu->bpu.num_pred = 256 << (bpu.ent - 1);
                }
        } else {
                struct bcr_fp_arcv2 spdp;
                struct bcr_bpu_arcv2 bpu;

                READ_BCR(ARC_REG_FP_V2_BCR, spdp);
                cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
                cpu->extn.fpu_dp = spdp.dp ? 1 : 0;

                READ_BCR(ARC_REG_BPU_BCR, bpu);
                cpu->bpu.ver = bpu.ver;
                cpu->bpu.full = bpu.ft;
                cpu->bpu.num_cache = 256 << bpu.bce;
                cpu->bpu.num_pred = 2048 << bpu.pte;
                cpu->bpu.ret_stk = 4 << bpu.rse;

                /* if dual issue hardware, is it enabled ? */
                if (cpu->extn.dual) {
                        unsigned int exec_ctrl;

                        READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
                        cpu->extn.dual_enb = !(exec_ctrl & 1);
                }
        }

        READ_BCR(ARC_REG_AP_BCR, ap);
        if (ap.ver) {
                cpu->extn.ap_num = 2 << ap.num;
                cpu->extn.ap_full = !ap.min;
        }

        READ_BCR(ARC_REG_SMART_BCR, bcr);
        cpu->extn.smart = bcr.ver ? 1 : 0;

        READ_BCR(ARC_REG_RTT_BCR, bcr);
        cpu->extn.rtt = bcr.ver ? 1 : 0;

        READ_BCR(ARC_REG_ISA_CFG_BCR, isa);

        /* some hacks for lack of feature BCR info in old ARC700 cores */
        if (is_isa_arcompact()) {
                if (!isa.ver)   /* ISA BCR absent, use Kconfig info */
                        cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
                else {
                        /* ARC700_BUILD only has 2 bits of isa info */
                        struct bcr_generic bcr = *(struct bcr_generic *)&isa;
                        cpu->isa.atomic = bcr.info & 1;
                }

                cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);

                 /* there's no direct way to distinguish 750 vs. 770 */
                if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
                        cpu->name = "ARC750";
        } else {
                cpu->isa = isa;
        }
}

static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
{
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
        struct bcr_identity *core = &cpu->core;
        char mpy_opt[16];
        int n = 0;

        FIX_PTR(cpu);

        n += scnprintf(buf + n, len - n,
                       "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
                       core->family, core->cpu_id, core->chip_id);

        n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s%s%s\n",
                       cpu_id, cpu->name, cpu->release,
                       is_isa_arcompact() ? "ARCompact" : "ARCv2",
                       IS_AVAIL1(cpu->isa.be, "[Big-Endian]"),
                       IS_AVAIL3(cpu->extn.dual, cpu->extn.dual_enb, " Dual-Issue "));

        n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
                       IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
                       IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
                       IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
                       IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));

        if (cpu->extn_mpy.ver) {
                if (is_isa_arcompact()) {
                        scnprintf(mpy_opt, 16, "mpy");
                } else {

                        int opt = 2;    /* stock MPY/MPYH */

                        if (cpu->extn_mpy.dsp)  /* OPT 7-9 */
                                opt = cpu->extn_mpy.dsp + 6;

                        scnprintf(mpy_opt, 16, "mpy[opt %d] ", opt);
                }
        }

        n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
                       IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
                       IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
                       IS_AVAIL2(cpu->isa.unalign, "unalign ", CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS),
                       IS_AVAIL1(cpu->extn_mpy.ver, mpy_opt),
                       IS_AVAIL1(cpu->isa.div_rem, "div_rem "));

        if (cpu->bpu.ver) {
                n += scnprintf(buf + n, len - n,
                              "BPU\t\t: %s%s match, cache:%d, Predict Table:%d Return stk: %d",
                              IS_AVAIL1(cpu->bpu.full, "full"),
                              IS_AVAIL1(!cpu->bpu.full, "partial"),
                              cpu->bpu.num_cache, cpu->bpu.num_pred, cpu->bpu.ret_stk);

                if (is_isa_arcv2()) {
                        struct bcr_lpb lpb;

                        READ_BCR(ARC_REG_LPB_BUILD, lpb);
                        if (lpb.ver) {
                                unsigned int ctl;
                                ctl = read_aux_reg(ARC_REG_LPB_CTRL);

                                n += scnprintf(buf + n, len - n, " Loop Buffer:%d %s",
                                               lpb.entries,
                                               IS_DISABLED_RUN(!ctl));
                        }
                }
                n += scnprintf(buf + n, len - n, "\n");
        }

        return buf;
}

static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
{
        int n = 0;
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];

        FIX_PTR(cpu);

        n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);

        if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
                n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
                               IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
                               IS_AVAIL1(cpu->extn.fpu_dp, "DP "));

        if (cpu->extn.ap_num | cpu->extn.smart | cpu->extn.rtt) {
                n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s",
                               IS_AVAIL1(cpu->extn.smart, "smaRT "),
                               IS_AVAIL1(cpu->extn.rtt, "RTT "));
                if (cpu->extn.ap_num) {
                        n += scnprintf(buf + n, len - n, "ActionPoint %d/%s",
                                       cpu->extn.ap_num,
                                       cpu->extn.ap_full ? "full":"min");
                }
                n += scnprintf(buf + n, len - n, "\n");
        }

        if (cpu->dccm.sz || cpu->iccm.sz)
                n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
                               cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
                               cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));

        if (is_isa_arcv2()) {

                /* Error Protection: ECC/Parity */
                struct bcr_erp erp;
                READ_BCR(ARC_REG_ERP_BUILD, erp);

                if (erp.ver) {
                        struct  ctl_erp ctl;
                        READ_BCR(ARC_REG_ERP_CTRL, ctl);

                        /* inverted bits: 0 means enabled */
                        n += scnprintf(buf + n, len - n, "Extn [ECC]\t: %s%s%s%s%s%s\n",
                                IS_AVAIL3(erp.ic,  !ctl.dpi, "IC "),
                                IS_AVAIL3(erp.dc,  !ctl.dpd, "DC "),
                                IS_AVAIL3(erp.mmu, !ctl.mpd, "MMU "));
                }
        }

        return buf;
}

void chk_opt_strict(char *opt_name, bool hw_exists, bool opt_ena)
{
        if (hw_exists && !opt_ena)
                pr_warn(" ! Enable %s for working apps\n", opt_name);
        else if (!hw_exists && opt_ena)
                panic("Disable %s, hardware NOT present\n", opt_name);
}

void chk_opt_weak(char *opt_name, bool hw_exists, bool opt_ena)
{
        if (!hw_exists && opt_ena)
                panic("Disable %s, hardware NOT present\n", opt_name);
}

static void arc_chk_core_config(void)
{
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
        int present = 0;

        if (!cpu->extn.timer0)
                panic("Timer0 is not present!\n");

        if (!cpu->extn.timer1)
                panic("Timer1 is not present!\n");

#ifdef CONFIG_ARC_HAS_DCCM
        /*
         * DCCM can be arbit placed in hardware.
         * Make sure it's placement/sz matches what Linux is built with
         */
        if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
                panic("Linux built with incorrect DCCM Base address\n");

        if (CONFIG_ARC_DCCM_SZ * SZ_1K != cpu->dccm.sz)
                panic("Linux built with incorrect DCCM Size\n");
#endif

#ifdef CONFIG_ARC_HAS_ICCM
        if (CONFIG_ARC_ICCM_SZ * SZ_1K != cpu->iccm.sz)
                panic("Linux built with incorrect ICCM Size\n");
#endif

        /*
         * FP hardware/software config sanity
         * -If hardware present, kernel needs to save/restore FPU state
         * -If not, it will crash trying to save/restore the non-existant regs
         */

        if (is_isa_arcompact()) {
                /* only DPDP checked since SP has no arch visible regs */
                present = cpu->extn.fpu_dp;
                CHK_OPT_STRICT(CONFIG_ARC_FPU_SAVE_RESTORE, present);
        } else {
                /* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
                present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
                CHK_OPT_STRICT(CONFIG_ARC_HAS_ACCL_REGS, present);

                dsp_config_check();
        }
}

/*
 * Initialize and setup the processor core
 * This is called by all the CPUs thus should not do special case stuff
 *    such as only for boot CPU etc
 */

void setup_processor(void)
{
        char str[512];
        int cpu_id = smp_processor_id();

        read_arc_build_cfg_regs();
        arc_init_IRQ();

        pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));

        arc_mmu_init();
        arc_cache_init();

        pr_info("%s", arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
        pr_info("%s", arc_platform_smp_cpuinfo());

        arc_chk_core_config();
}

static inline bool uboot_arg_invalid(unsigned long addr)
{
        /*
         * Check that it is a untranslated address (although MMU is not enabled
         * yet, it being a high address ensures this is not by fluke)
         */
        if (addr < PAGE_OFFSET)
                return true;

        /* Check that address doesn't clobber resident kernel image */
        return addr >= (unsigned long)_stext && addr <= (unsigned long)_end;
}

#define IGNORE_ARGS             "Ignore U-boot args: "

/* uboot_tag values for U-boot - kernel ABI revision 0; see head.S */
#define UBOOT_TAG_NONE          0
#define UBOOT_TAG_CMDLINE       1
#define UBOOT_TAG_DTB           2
/* We always pass 0 as magic from U-boot */
#define UBOOT_MAGIC_VALUE       0

void __init handle_uboot_args(void)
{
        bool use_embedded_dtb = true;
        bool append_cmdline = false;

        /* check that we know this tag */
        if (uboot_tag != UBOOT_TAG_NONE &&
            uboot_tag != UBOOT_TAG_CMDLINE &&
            uboot_tag != UBOOT_TAG_DTB) {
                pr_warn(IGNORE_ARGS "invalid uboot tag: '%08x'\n", uboot_tag);
                goto ignore_uboot_args;
        }

        if (uboot_magic != UBOOT_MAGIC_VALUE) {
                pr_warn(IGNORE_ARGS "non zero uboot magic\n");
                goto ignore_uboot_args;
        }

        if (uboot_tag != UBOOT_TAG_NONE &&
            uboot_arg_invalid((unsigned long)uboot_arg)) {
                pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg);
                goto ignore_uboot_args;
        }

        /* see if U-boot passed an external Device Tree blob */
        if (uboot_tag == UBOOT_TAG_DTB) {
                machine_desc = setup_machine_fdt((void *)uboot_arg);

                /* external Device Tree blob is invalid - use embedded one */
                use_embedded_dtb = !machine_desc;
        }

        if (uboot_tag == UBOOT_TAG_CMDLINE)
                append_cmdline = true;

ignore_uboot_args:

        if (use_embedded_dtb) {
                machine_desc = setup_machine_fdt(__dtb_start);
                if (!machine_desc)
                        panic("Embedded DT invalid\n");
        }

        /*
         * NOTE: @boot_command_line is populated by setup_machine_fdt() so this
         * append processing can only happen after.
         */
        if (append_cmdline) {
                /* Ensure a whitespace between the 2 cmdlines */
                strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
                strlcat(boot_command_line, uboot_arg, COMMAND_LINE_SIZE);
        }
}

void __init setup_arch(char **cmdline_p)
{
        handle_uboot_args();

        /* Save unparsed command line copy for /proc/cmdline */
        *cmdline_p = boot_command_line;

        /* To force early parsing of things like mem=xxx */
        parse_early_param();

        /* Platform/board specific: e.g. early console registration */
        if (machine_desc->init_early)
                machine_desc->init_early();

        smp_init_cpus();

        setup_processor();
        setup_arch_memory();

        /* copy flat DT out of .init and then unflatten it */
        unflatten_and_copy_device_tree();

        /* Can be issue if someone passes cmd line arg "ro"
         * But that is unlikely so keeping it as it is
         */
        root_mountflags &= ~MS_RDONLY;

        arc_unwind_init();
}

/*
 * Called from start_kernel() - boot CPU only
 */
void __init time_init(void)
{
        of_clk_init(NULL);
        timer_probe();
}

static int __init customize_machine(void)
{
        if (machine_desc->init_machine)
                machine_desc->init_machine();

        return 0;
}
arch_initcall(customize_machine);

static int __init init_late_machine(void)
{
        if (machine_desc->init_late)
                machine_desc->init_late();

        return 0;
}
late_initcall(init_late_machine);
/*
 *  Get CPU information for use by the procfs.
 */

#define cpu_to_ptr(c)   ((void *)(0xFFFF0000 | (unsigned int)(c)))
#define ptr_to_cpu(p)   (~0xFFFF0000UL & (unsigned int)(p))

static int show_cpuinfo(struct seq_file *m, void *v)
{
        char *str;
        int cpu_id = ptr_to_cpu(v);
        struct device *cpu_dev = get_cpu_device(cpu_id);
        struct clk *cpu_clk;
        unsigned long freq = 0;

        if (!cpu_online(cpu_id)) {
                seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
                goto done;
        }

        str = (char *)__get_free_page(GFP_KERNEL);
        if (!str)
                goto done;

        seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));

        cpu_clk = clk_get(cpu_dev, NULL);
        if (IS_ERR(cpu_clk)) {
                seq_printf(m, "CPU speed \t: Cannot get clock for processor [%d]\n",
                           cpu_id);
        } else {
                freq = clk_get_rate(cpu_clk);
        }
        if (freq)
                seq_printf(m, "CPU speed\t: %lu.%02lu Mhz\n",
                           freq / 1000000, (freq / 10000) % 100);

        seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
                   loops_per_jiffy / (500000 / HZ),
                   (loops_per_jiffy / (5000 / HZ)) % 100);

        seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
        seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
        seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
        seq_printf(m, arc_platform_smp_cpuinfo());

        free_page((unsigned long)str);
done:
        seq_printf(m, "\n");

        return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
        /*
         * Callback returns cpu-id to iterator for show routine, NULL to stop.
         * However since NULL is also a valid cpu-id (0), we use a round-about
         * way to pass it w/o having to kmalloc/free a 2 byte string.
         * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
         */
        return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
}

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

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   = show_cpuinfo
};

static DEFINE_PER_CPU(struct cpu, cpu_topology);

static int __init topology_init(void)
{
        int cpu;

        for_each_present_cpu(cpu)
            register_cpu(&per_cpu(cpu_topology, cpu), cpu);

        return 0;
}

subsys_initcall(topology_init);