// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2008-2011
 * Graeme Russ, <graeme.russ@gmail.com>
 *
 * (C) Copyright 2002
 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <mgroeger@sysgo.de>
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Alex Zuepke <azu@sysgo.de>
 *
 * Part of this file is adapted from coreboot
 * src/arch/x86/lib/cpu.c
 */

#include <common.h>
#include <malloc.h>
#include <asm/control_regs.h>
#include <asm/cpu.h>
#include <asm/mp.h>
#include <asm/msr.h>
#include <asm/mtrr.h>
#include <asm/processor-flags.h>

DECLARE_GLOBAL_DATA_PTR;

/*
 * Constructor for a conventional segment GDT (or LDT) entry
 * This is a macro so it can be used in initialisers
 */
#define GDT_ENTRY(flags, base, limit)                   \
        ((((base)  & 0xff000000ULL) << (56-24)) |       \
         (((flags) & 0x0000f0ffULL) << 40) |            \
         (((limit) & 0x000f0000ULL) << (48-16)) |       \
         (((base)  & 0x00ffffffULL) << 16) |            \
         (((limit) & 0x0000ffffULL)))

struct gdt_ptr {
        u16 len;
        u32 ptr;
} __packed;

struct cpu_device_id {
        unsigned vendor;
        unsigned device;
};

struct cpuinfo_x86 {
        uint8_t x86;            /* CPU family */
        uint8_t x86_vendor;     /* CPU vendor */
        uint8_t x86_model;
        uint8_t x86_mask;
};

/*
 * List of cpu vendor strings along with their normalized
 * id values.
 */
static const struct {
        int vendor;
        const char *name;
} x86_vendors[] = {
        { X86_VENDOR_INTEL,     "GenuineIntel", },
        { X86_VENDOR_CYRIX,     "CyrixInstead", },
        { X86_VENDOR_AMD,       "AuthenticAMD", },
        { X86_VENDOR_UMC,       "UMC UMC UMC ", },
        { X86_VENDOR_NEXGEN,    "NexGenDriven", },
        { X86_VENDOR_CENTAUR,   "CentaurHauls", },
        { X86_VENDOR_RISE,      "RiseRiseRise", },
        { X86_VENDOR_TRANSMETA, "GenuineTMx86", },
        { X86_VENDOR_TRANSMETA, "TransmetaCPU", },
        { X86_VENDOR_NSC,       "Geode by NSC", },
        { X86_VENDOR_SIS,       "SiS SiS SiS ", },
};

static void load_ds(u32 segment)
{
        asm volatile("movl %0, %%ds" : : "r" (segment * X86_GDT_ENTRY_SIZE));
}

static void load_es(u32 segment)
{
        asm volatile("movl %0, %%es" : : "r" (segment * X86_GDT_ENTRY_SIZE));
}

static void load_fs(u32 segment)
{
        asm volatile("movl %0, %%fs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
}

static void load_gs(u32 segment)
{
        asm volatile("movl %0, %%gs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
}

static void load_ss(u32 segment)
{
        asm volatile("movl %0, %%ss" : : "r" (segment * X86_GDT_ENTRY_SIZE));
}

static void load_gdt(const u64 *boot_gdt, u16 num_entries)
{
        struct gdt_ptr gdt;

        gdt.len = (num_entries * X86_GDT_ENTRY_SIZE) - 1;
        gdt.ptr = (ulong)boot_gdt;

        asm volatile("lgdtl %0\n" : : "m" (gdt));
}

void arch_setup_gd(gd_t *new_gd)
{
        u64 *gdt_addr;

        gdt_addr = new_gd->arch.gdt;

        /*
         * CS: code, read/execute, 4 GB, base 0
         *
         * Some OS (like VxWorks) requires GDT entry 1 to be the 32-bit CS
         */
        gdt_addr[X86_GDT_ENTRY_UNUSED] = GDT_ENTRY(0xc09b, 0, 0xfffff);
        gdt_addr[X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff);

        /* DS: data, read/write, 4 GB, base 0 */
        gdt_addr[X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff);

        /* FS: data, read/write, 4 GB, base (Global Data Pointer) */
        new_gd->arch.gd_addr = new_gd;
        gdt_addr[X86_GDT_ENTRY_32BIT_FS] = GDT_ENTRY(0xc093,
                     (ulong)&new_gd->arch.gd_addr, 0xfffff);

        /* 16-bit CS: code, read/execute, 64 kB, base 0 */
        gdt_addr[X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x009b, 0, 0x0ffff);

        /* 16-bit DS: data, read/write, 64 kB, base 0 */
        gdt_addr[X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x0093, 0, 0x0ffff);

        gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_CS] = GDT_ENTRY(0x809b, 0, 0xfffff);
        gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_DS] = GDT_ENTRY(0x8093, 0, 0xfffff);

        load_gdt(gdt_addr, X86_GDT_NUM_ENTRIES);
        load_ds(X86_GDT_ENTRY_32BIT_DS);
        load_es(X86_GDT_ENTRY_32BIT_DS);
        load_gs(X86_GDT_ENTRY_32BIT_DS);
        load_ss(X86_GDT_ENTRY_32BIT_DS);
        load_fs(X86_GDT_ENTRY_32BIT_FS);
}

#ifdef CONFIG_HAVE_FSP
/*
 * Setup FSP execution environment GDT
 *
 * Per Intel FSP external architecture specification, before calling any FSP
 * APIs, we need make sure the system is in flat 32-bit mode and both the code
 * and data selectors should have full 4GB access range. Here we reuse the one
 * we used in arch/x86/cpu/start16.S, and reload the segement registers.
 */
void setup_fsp_gdt(void)
{
        load_gdt((const u64 *)(gdt_rom + CONFIG_RESET_SEG_START), 4);
        load_ds(X86_GDT_ENTRY_32BIT_DS);
        load_ss(X86_GDT_ENTRY_32BIT_DS);
        load_es(X86_GDT_ENTRY_32BIT_DS);
        load_fs(X86_GDT_ENTRY_32BIT_DS);
        load_gs(X86_GDT_ENTRY_32BIT_DS);
}
#endif

/*
 * Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected
 * by the fact that they preserve the flags across the division of 5/2.
 * PII and PPro exhibit this behavior too, but they have cpuid available.
 */

/*
 * Perform the Cyrix 5/2 test. A Cyrix won't change
 * the flags, while other 486 chips will.
 */
static inline int test_cyrix_52div(void)
{
        unsigned int test;

        __asm__ __volatile__(
             "sahf\n\t"         /* clear flags (%eax = 0x0005) */
             "div %b2\n\t"      /* divide 5 by 2 */
             "lahf"             /* store flags into %ah */
             : "=a" (test)
             : "0" (5), "q" (2)
             : "cc");

        /* AH is 0x02 on Cyrix after the divide.. */
        return (unsigned char) (test >> 8) == 0x02;
}

/*
 *      Detect a NexGen CPU running without BIOS hypercode new enough
 *      to have CPUID. (Thanks to Herbert Oppmann)
 */
static int deep_magic_nexgen_probe(void)
{
        int ret;

        __asm__ __volatile__ (
                "       movw    $0x5555, %%ax\n"
                "       xorw    %%dx,%%dx\n"
                "       movw    $2, %%cx\n"
                "       divw    %%cx\n"
                "       movl    $0, %%eax\n"
                "       jnz     1f\n"
                "       movl    $1, %%eax\n"
                "1:\n"
                : "=a" (ret) : : "cx", "dx");
        return  ret;
}

static bool has_cpuid(void)
{
        return flag_is_changeable_p(X86_EFLAGS_ID);
}

static bool has_mtrr(void)
{
        return cpuid_edx(0x00000001) & (1 << 12) ? true : false;
}

static int build_vendor_name(char *vendor_name)
{
        struct cpuid_result result;
        result = cpuid(0x00000000);
        unsigned int *name_as_ints = (unsigned int *)vendor_name;

        name_as_ints[0] = result.ebx;
        name_as_ints[1] = result.edx;
        name_as_ints[2] = result.ecx;

        return result.eax;
}

static void identify_cpu(struct cpu_device_id *cpu)
{
        char vendor_name[16];
        int i;

        vendor_name[0] = '\0'; /* Unset */
        cpu->device = 0; /* fix gcc 4.4.4 warning */

        /* Find the id and vendor_name */
        if (!has_cpuid()) {
                /* Its a 486 if we can modify the AC flag */
                if (flag_is_changeable_p(X86_EFLAGS_AC))
                        cpu->device = 0x00000400; /* 486 */
                else
                        cpu->device = 0x00000300; /* 386 */
                if ((cpu->device == 0x00000400) && test_cyrix_52div()) {
                        memcpy(vendor_name, "CyrixInstead", 13);
                        /* If we ever care we can enable cpuid here */
                }
                /* Detect NexGen with old hypercode */
                else if (deep_magic_nexgen_probe())
                        memcpy(vendor_name, "NexGenDriven", 13);
        }
        if (has_cpuid()) {
                int  cpuid_level;

                cpuid_level = build_vendor_name(vendor_name);
                vendor_name[12] = '\0';

                /* Intel-defined flags: level 0x00000001 */
                if (cpuid_level >= 0x00000001) {
                        cpu->device = cpuid_eax(0x00000001);
                } else {
                        /* Have CPUID level 0 only unheard of */
                        cpu->device = 0x00000400;
                }
        }
        cpu->vendor = X86_VENDOR_UNKNOWN;
        for (i = 0; i < ARRAY_SIZE(x86_vendors); i++) {
                if (memcmp(vendor_name, x86_vendors[i].name, 12) == 0) {
                        cpu->vendor = x86_vendors[i].vendor;
                        break;
                }
        }
}

static inline void get_fms(struct cpuinfo_x86 *c, uint32_t tfms)
{
        c->x86 = (tfms >> 8) & 0xf;
        c->x86_model = (tfms >> 4) & 0xf;
        c->x86_mask = tfms & 0xf;
        if (c->x86 == 0xf)
                c->x86 += (tfms >> 20) & 0xff;
        if (c->x86 >= 0x6)
                c->x86_model += ((tfms >> 16) & 0xF) << 4;
}

u32 cpu_get_family_model(void)
{
        return gd->arch.x86_device & 0x0fff0ff0;
}

u32 cpu_get_stepping(void)
{
        return gd->arch.x86_mask;
}

/* initialise FPU, reset EM, set MP and NE */
static void setup_cpu_features(void)
{
        const u32 em_rst = ~X86_CR0_EM;
        const u32 mp_ne_set = X86_CR0_MP | X86_CR0_NE;

        asm ("fninit\n" \
        "movl %%cr0, %%eax\n" \
        "andl %0, %%eax\n" \
        "orl  %1, %%eax\n" \
        "movl %%eax, %%cr0\n" \
        : : "i" (em_rst), "i" (mp_ne_set) : "eax");
}

static void setup_identity(void)
{
        /* identify CPU via cpuid and store the decoded info into gd->arch */
        if (has_cpuid()) {
                struct cpu_device_id cpu;
                struct cpuinfo_x86 c;

                identify_cpu(&cpu);
                get_fms(&c, cpu.device);
                gd->arch.x86 = c.x86;
                gd->arch.x86_vendor = cpu.vendor;
                gd->arch.x86_model = c.x86_model;
                gd->arch.x86_mask = c.x86_mask;
                gd->arch.x86_device = cpu.device;

                gd->arch.has_mtrr = has_mtrr();
        }
}

/* Don't allow PCI region 3 to use memory in the 2-4GB memory hole */
static void setup_pci_ram_top(void)
{
        gd->pci_ram_top = 0x80000000U;
}

static void setup_mtrr(void)
{
        u64 mtrr_cap;

        /* Configure fixed range MTRRs for some legacy regions */
        if (!gd->arch.has_mtrr)
                return;

        mtrr_cap = native_read_msr(MTRR_CAP_MSR);
        if (mtrr_cap & MTRR_CAP_FIX) {
                /* Mark the VGA RAM area as uncacheable */
                native_write_msr(MTRR_FIX_16K_A0000_MSR,
                                 MTRR_FIX_TYPE(MTRR_TYPE_UNCACHEABLE),
                                 MTRR_FIX_TYPE(MTRR_TYPE_UNCACHEABLE));

                /*
                 * Mark the PCI ROM area as cacheable to improve ROM
                 * execution performance.
                 */
                native_write_msr(MTRR_FIX_4K_C0000_MSR,
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
                native_write_msr(MTRR_FIX_4K_C8000_MSR,
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
                native_write_msr(MTRR_FIX_4K_D0000_MSR,
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
                native_write_msr(MTRR_FIX_4K_D8000_MSR,
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
                                 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));

                /* Enable the fixed range MTRRs */
                msr_setbits_64(MTRR_DEF_TYPE_MSR, MTRR_DEF_TYPE_FIX_EN);
        }
}

int x86_cpu_init_f(void)
{
        if (ll_boot_init())
                setup_cpu_features();
        setup_identity();
        setup_mtrr();
        setup_pci_ram_top();

        /* Set up the i8254 timer if required */
        if (IS_ENABLED(CONFIG_I8254_TIMER))
                i8254_init();

        return 0;
}

int x86_cpu_reinit_f(void)
{
        setup_identity();
        setup_pci_ram_top();

        return 0;
}

void x86_enable_caches(void)
{
        unsigned long cr0;

        cr0 = read_cr0();
        cr0 &= ~(X86_CR0_NW | X86_CR0_CD);
        write_cr0(cr0);
        wbinvd();
}
void enable_caches(void) __attribute__((weak, alias("x86_enable_caches")));

void x86_disable_caches(void)
{
        unsigned long cr0;

        cr0 = read_cr0();
        cr0 |= X86_CR0_NW | X86_CR0_CD;
        wbinvd();
        write_cr0(cr0);
        wbinvd();
}
void disable_caches(void) __attribute__((weak, alias("x86_disable_caches")));

int dcache_status(void)
{
        return !(read_cr0() & X86_CR0_CD);
}

void cpu_enable_paging_pae(ulong cr3)
{
        __asm__ __volatile__(
                /* Load the page table address */
                "movl   %0, %%cr3\n"
                /* Enable pae */
                "movl   %%cr4, %%eax\n"
                "orl    $0x00000020, %%eax\n"
                "movl   %%eax, %%cr4\n"
                /* Enable paging */
                "movl   %%cr0, %%eax\n"
                "orl    $0x80000000, %%eax\n"
                "movl   %%eax, %%cr0\n"
                :
                : "r" (cr3)
                : "eax");
}

void cpu_disable_paging_pae(void)
{
        /* Turn off paging */
        __asm__ __volatile__ (
                /* Disable paging */
                "movl   %%cr0, %%eax\n"
                "andl   $0x7fffffff, %%eax\n"
                "movl   %%eax, %%cr0\n"
                /* Disable pae */
                "movl   %%cr4, %%eax\n"
                "andl   $0xffffffdf, %%eax\n"
                "movl   %%eax, %%cr4\n"
                :
                :
                : "eax");
}

static bool can_detect_long_mode(void)
{
        return cpuid_eax(0x80000000) > 0x80000000UL;
}

static bool has_long_mode(void)
{
        return cpuid_edx(0x80000001) & (1 << 29) ? true : false;
}

int cpu_has_64bit(void)
{
        return has_cpuid() && can_detect_long_mode() &&
                has_long_mode();
}

#define PAGETABLE_BASE          0x80000
#define PAGETABLE_SIZE          (6 * 4096)

/**
 * build_pagetable() - build a flat 4GiB page table structure for 64-bti mode
 *
 * @pgtable: Pointer to a 24iKB block of memory
 */
static void build_pagetable(uint32_t *pgtable)
{
        uint i;

        memset(pgtable, '\0', PAGETABLE_SIZE);

        /* Level 4 needs a single entry */
        pgtable[0] = (ulong)&pgtable[1024] + 7;

        /* Level 3 has one 64-bit entry for each GiB of memory */
        for (i = 0; i < 4; i++)
                pgtable[1024 + i * 2] = (ulong)&pgtable[2048] + 0x1000 * i + 7;

        /* Level 2 has 2048 64-bit entries, each repesenting 2MiB */
        for (i = 0; i < 2048; i++)
                pgtable[2048 + i * 2] = 0x183 + (i << 21UL);
}

int cpu_jump_to_64bit(ulong setup_base, ulong target)
{
        uint32_t *pgtable;

        pgtable = memalign(4096, PAGETABLE_SIZE);
        if (!pgtable)
                return -ENOMEM;

        build_pagetable(pgtable);
        cpu_call64((ulong)pgtable, setup_base, target);
        free(pgtable);

        return -EFAULT;
}

/*
 * Jump from SPL to U-Boot
 *
 * This function is work-in-progress with many issues to resolve.
 *
 * It works by setting up several regions:
 *   ptr      - a place to put the code that jumps into 64-bit mode
 *   gdt      - a place to put the global descriptor table
 *   pgtable  - a place to put the page tables
 *
 * The cpu_call64() code is copied from ROM and then manually patched so that
 * it has the correct GDT address in RAM. U-Boot is copied from ROM into
 * its pre-relocation address. Then we jump to the cpu_call64() code in RAM,
 * which changes to 64-bit mode and starts U-Boot.
 */
int cpu_jump_to_64bit_uboot(ulong target)
{
        typedef void (*func_t)(ulong pgtable, ulong setup_base, ulong target);
        uint32_t *pgtable;
        func_t func;
        char *ptr;

        pgtable = (uint32_t *)PAGETABLE_BASE;

        build_pagetable(pgtable);

        extern long call64_stub_size;
        ptr = malloc(call64_stub_size);
        if (!ptr) {
                printf("Failed to allocate the cpu_call64 stub\n");
                return -ENOMEM;
        }
        memcpy(ptr, cpu_call64, call64_stub_size);

        func = (func_t)ptr;

        /*
         * Copy U-Boot from ROM
         * TODO(sjg@chromium.org): Figure out a way to get the text base
         * correctly here, and in the device-tree binman definition.
         *
         * Also consider using FIT so we get the correct image length and
         * parameters.
         */
        memcpy((char *)target, (char *)0xfff00000, 0x100000);

        /* Jump to U-Boot */
        func((ulong)pgtable, 0, (ulong)target);

        return -EFAULT;
}

#ifdef CONFIG_SMP
static int enable_smis(struct udevice *cpu, void *unused)
{
        return 0;
}

static struct mp_flight_record mp_steps[] = {
        MP_FR_BLOCK_APS(mp_init_cpu, NULL, mp_init_cpu, NULL),
        /* Wait for APs to finish initialization before proceeding */
        MP_FR_BLOCK_APS(NULL, NULL, enable_smis, NULL),
};

int x86_mp_init(void)
{
        struct mp_params mp_params;

        mp_params.parallel_microcode_load = 0,
        mp_params.flight_plan = &mp_steps[0];
        mp_params.num_records = ARRAY_SIZE(mp_steps);
        mp_params.microcode_pointer = 0;

        if (mp_init(&mp_params)) {
                printf("Warning: MP init failure\n");
                return -EIO;
        }

        return 0;
}
#endif