/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * 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/seq_file.h>
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/root_dev.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/of_fdt.h>
#include <linux/cache.h>
#include <asm/sections.h>
#include <asm/arcregs.h>
#include <asm/tlb.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/irq.h>
#include <asm/unwind.h>
#include <asm/clk.h>
#include <asm/mach_desc.h>

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

int running_on_hw = 1;  /* vs. on ISS */

/* Part of U-boot ABI: see head.S */
int __initdata uboot_tag;
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 void read_arc_build_cfg_regs(void)
{
        struct bcr_perip uncached_space;
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
        FIX_PTR(cpu);

        READ_BCR(AUX_IDENTITY, cpu->core);

        cpu->timers = read_aux_reg(ARC_REG_TIMERS_BCR);
        cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);

        READ_BCR(ARC_REG_D_UNCACH_BCR, uncached_space);
        cpu->uncached_base = uncached_space.start << 24;

        cpu->extn.mul = read_aux_reg(ARC_REG_MUL_BCR);
        cpu->extn.swap = read_aux_reg(ARC_REG_SWAP_BCR);
        cpu->extn.norm = read_aux_reg(ARC_REG_NORM_BCR);
        cpu->extn.minmax = read_aux_reg(ARC_REG_MIXMAX_BCR);
        cpu->extn.barrel = read_aux_reg(ARC_REG_BARREL_BCR);
        READ_BCR(ARC_REG_MAC_BCR, cpu->extn_mac_mul);

        cpu->extn.ext_arith = read_aux_reg(ARC_REG_EXTARITH_BCR);
        cpu->extn.crc = read_aux_reg(ARC_REG_CRC_BCR);

        /* Note that we read the CCM BCRs independent of kernel config
         * This is to catch the cases where user doesn't know that
         * CCMs are present in hardware build
         */
        {
                struct bcr_iccm iccm;
                struct bcr_dccm dccm;
                struct bcr_dccm_base dccm_base;
                unsigned int bcr_32bit_val;

                bcr_32bit_val = read_aux_reg(ARC_REG_ICCM_BCR);
                if (bcr_32bit_val) {
                        iccm = *((struct bcr_iccm *)&bcr_32bit_val);
                        cpu->iccm.base_addr = iccm.base << 16;
                        cpu->iccm.sz = 0x2000 << (iccm.sz - 1);
                }

                bcr_32bit_val = read_aux_reg(ARC_REG_DCCM_BCR);
                if (bcr_32bit_val) {
                        dccm = *((struct bcr_dccm *)&bcr_32bit_val);
                        cpu->dccm.sz = 0x800 << (dccm.sz);

                        READ_BCR(ARC_REG_DCCMBASE_BCR, dccm_base);
                        cpu->dccm.base_addr = dccm_base.addr << 8;
                }
        }

        READ_BCR(ARC_REG_XY_MEM_BCR, cpu->extn_xymem);

        read_decode_mmu_bcr();
        read_decode_cache_bcr();

        READ_BCR(ARC_REG_FP_BCR, cpu->fp);
        READ_BCR(ARC_REG_DPFP_BCR, cpu->dpfp);
}

static const struct cpuinfo_data arc_cpu_tbl[] = {
        { {0x10, "ARCTangent A5"}, 0x1F},
        { {0x20, "ARC 600"      }, 0x2F},
        { {0x30, "ARC 700"      }, 0x33},
        { {0x34, "ARC 700 R4.10"}, 0x34},
        { {0x00, NULL           } }
};

static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
{
        int n = 0;
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
        struct bcr_identity *core = &cpu->core;
        const struct cpuinfo_data *tbl;
        int be = 0;
#ifdef CONFIG_CPU_BIG_ENDIAN
        be = 1;
#endif
        FIX_PTR(cpu);

        n += scnprintf(buf + n, len - n,
                       "\nARC IDENTITY\t: Family [%#02x]"
                       " Cpu-id [%#02x] Chip-id [%#4x]\n",
                       core->family, core->cpu_id,
                       core->chip_id);

        for (tbl = &arc_cpu_tbl[0]; tbl->info.id != 0; tbl++) {
                if ((core->family >= tbl->info.id) &&
                    (core->family <= tbl->up_range)) {
                        n += scnprintf(buf + n, len - n,
                                       "processor\t: %s %s\n",
                                       tbl->info.str,
                                       be ? "[Big Endian]" : "");
                        break;
                }
        }

        if (tbl->info.id == 0)
                n += scnprintf(buf + n, len - n, "UNKNOWN ARC Processor\n");

        n += scnprintf(buf + n, len - n, "CPU speed\t: %u.%02u Mhz\n",
                       (unsigned int)(arc_get_core_freq() / 1000000),
                       (unsigned int)(arc_get_core_freq() / 10000) % 100);

        n += scnprintf(buf + n, len - n, "Timers\t\t: %s %s\n",
                       (cpu->timers & 0x200) ? "TIMER1" : "",
                       (cpu->timers & 0x100) ? "TIMER0" : "");

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

        n += scnprintf(buf + n, len - n, "UNCACHED Base\t: %#x\n",
                       cpu->uncached_base);

        return buf;
}

static const struct id_to_str mul_type_nm[] = {
        { 0x0, "N/A"},
        { 0x1, "32x32 (spl Result Reg)" },
        { 0x2, "32x32 (ANY Result Reg)" }
};

static const struct id_to_str mac_mul_nm[] = {
        {0x0, "N/A"},
        {0x1, "N/A"},
        {0x2, "Dual 16 x 16"},
        {0x3, "N/A"},
        {0x4, "32x16"},
        {0x5, "N/A"},
        {0x6, "Dual 16x16 and 32x16"}
};

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);
#define IS_AVAIL1(var, str)     ((var) ? str : "")
#define IS_AVAIL2(var, str)     ((var == 0x2) ? str : "")
#define IS_USED(cfg)            (IS_ENABLED(cfg) ? "(in-use)" : "(not used)")

        n += scnprintf(buf + n, len - n,
                       "Extn [700-Base]\t: %s %s %s %s %s %s\n",
                       IS_AVAIL2(cpu->extn.norm, "norm,"),
                       IS_AVAIL2(cpu->extn.barrel, "barrel-shift,"),
                       IS_AVAIL1(cpu->extn.swap, "swap,"),
                       IS_AVAIL2(cpu->extn.minmax, "minmax,"),
                       IS_AVAIL1(cpu->extn.crc, "crc,"),
                       IS_AVAIL2(cpu->extn.ext_arith, "ext-arith"));

        n += scnprintf(buf + n, len - n, "Extn [700-MPY]\t: %s",
                       mul_type_nm[cpu->extn.mul].str);

        n += scnprintf(buf + n, len - n, "   MAC MPY: %s\n",
                       mac_mul_nm[cpu->extn_mac_mul.type].str);

        if (cpu->core.family == 0x34) {
                n += scnprintf(buf + n, len - n,
                "Extn [700-4.10]\t: LLOCK/SCOND %s, SWAPE %s, RTSC %s\n",
                               IS_USED(CONFIG_ARC_HAS_LLSC),
                               IS_USED(CONFIG_ARC_HAS_SWAPE),
                               IS_USED(CONFIG_ARC_HAS_RTSC));
        }

        n += scnprintf(buf + n, len - n, "Extn [CCM]\t: %s",
                       !(cpu->dccm.sz || cpu->iccm.sz) ? "N/A" : "");

        if (cpu->dccm.sz)
                n += scnprintf(buf + n, len - n, "DCCM: @ %x, %d KB ",
                               cpu->dccm.base_addr, TO_KB(cpu->dccm.sz));

        if (cpu->iccm.sz)
                n += scnprintf(buf + n, len - n, "ICCM: @ %x, %d KB",
                               cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));

        n += scnprintf(buf + n, len - n, "\nExtn [FPU]\t: %s",
                       !(cpu->fp.ver || cpu->dpfp.ver) ? "N/A" : "");

        if (cpu->fp.ver)
                n += scnprintf(buf + n, len - n, "SP [v%d] %s",
                               cpu->fp.ver, cpu->fp.fast ? "(fast)" : "");

        if (cpu->dpfp.ver)
                n += scnprintf(buf + n, len - n, "DP [v%d] %s",
                               cpu->dpfp.ver, cpu->dpfp.fast ? "(fast)" : "");

        n += scnprintf(buf + n, len - n, "\n");

        n += scnprintf(buf + n, len - n,
                       "OS ABI [v3]\t: no-legacy-syscalls\n");

        return buf;
}

static void arc_chk_ccms(void)
{
#if defined(CONFIG_ARC_HAS_DCCM) || defined(CONFIG_ARC_HAS_ICCM)
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];

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

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

/*
 * Ensure that FP hardware and kernel config match
 * -If hardware contains DPFP, kernel needs to save/restore FPU state
 *  across context switches
 * -If hardware lacks DPFP, but kernel configured to save FPU state then
 *  kernel trying to access non-existant DPFP regs will crash
 *
 * We only check for Dbl precision Floating Point, because only DPFP
 * hardware has dedicated regs which need to be saved/restored on ctx-sw
 * (Single Precision uses core regs), thus kernel is kind of oblivious to it
 */
static void arc_chk_fpu(void)
{
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];

        if (cpu->dpfp.ver) {
#ifndef CONFIG_ARC_FPU_SAVE_RESTORE
                pr_warn("DPFP support broken in this kernel...\n");
#endif
        } else {
#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
                panic("H/w lacks DPFP support, apps won't work\n");
#endif
        }
}

/*
 * 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();

        printk(arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));

        arc_mmu_init();
        arc_cache_init();
        arc_chk_ccms();

        printk(arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));

#ifdef CONFIG_SMP
        printk(arc_platform_smp_cpuinfo());
#endif

        arc_chk_fpu();
}

static inline int is_kernel(unsigned long addr)
{
        if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
                return 1;
        return 0;
}

void __init setup_arch(char **cmdline_p)
{
        /* make sure that uboot passed pointer to cmdline/dtb is valid */
        if (uboot_tag && is_kernel((unsigned long)uboot_arg))
                panic("Invalid uboot arg\n");

        /* See if u-boot passed an external Device Tree blob */
        machine_desc = setup_machine_fdt(uboot_arg);    /* uboot_tag == 2 */
        if (!machine_desc) {
                /* No, so try the embedded one */
                machine_desc = setup_machine_fdt(__dtb_start);
                if (!machine_desc)
                        panic("Embedded DT invalid\n");

                /*
                 * If we are here, it is established that @uboot_arg didn't
                 * point to DT blob. Instead if u-boot says it is cmdline,
                 * Appent to embedded DT cmdline.
                 * setup_machine_fdt() would have populated @boot_command_line
                 */
                if (uboot_tag == 1) {
                        /* Ensure a whitespace between the 2 cmdlines */
                        strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
                        strlcat(boot_command_line, uboot_arg,
                                COMMAND_LINE_SIZE);
                }
        }

        /* 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();

        setup_processor();

#ifdef CONFIG_SMP
        smp_init_cpus();
#endif

        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;

#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
        conswitchp = &dummy_con;
#endif

        arc_unwind_init();
        arc_unwind_setup();
}

static int __init customize_machine(void)
{
        /* Add platform devices */
        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);

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

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

        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));

#ifdef CONFIG_SMP
        seq_printf(m, arc_platform_smp_cpuinfo());
#endif

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