// SPDX-License-Identifier: GPL-2.0

#include <linux/sched.h>
#include <linux/sched/clock.h>

#include <asm/cpu.h>
#include <asm/cpufeature.h>
#include <asm/e820/api.h>
#include <asm/mtrr.h>
#include <asm/msr.h>

#include "cpu.h"

#define ACE_PRESENT     (1 << 6)
#define ACE_ENABLED     (1 << 7)
#define ACE_FCR         (1 << 28)       /* MSR_VIA_FCR */

#define RNG_PRESENT     (1 << 2)
#define RNG_ENABLED     (1 << 3)
#define RNG_ENABLE      (1 << 6)        /* MSR_VIA_RNG */

static void init_c3(struct cpuinfo_x86 *c)
{
        u32  lo, hi;

        /* Test for Centaur Extended Feature Flags presence */
        if (cpuid_eax(0xC0000000) >= 0xC0000001) {
                u32 tmp = cpuid_edx(0xC0000001);

                /* enable ACE unit, if present and disabled */
                if ((tmp & (ACE_PRESENT | ACE_ENABLED)) == ACE_PRESENT) {
                        rdmsr(MSR_VIA_FCR, lo, hi);
                        lo |= ACE_FCR;          /* enable ACE unit */
                        wrmsr(MSR_VIA_FCR, lo, hi);
                        pr_info("CPU: Enabled ACE h/w crypto\n");
                }

                /* enable RNG unit, if present and disabled */
                if ((tmp & (RNG_PRESENT | RNG_ENABLED)) == RNG_PRESENT) {
                        rdmsr(MSR_VIA_RNG, lo, hi);
                        lo |= RNG_ENABLE;       /* enable RNG unit */
                        wrmsr(MSR_VIA_RNG, lo, hi);
                        pr_info("CPU: Enabled h/w RNG\n");
                }

                /* store Centaur Extended Feature Flags as
                 * word 5 of the CPU capability bit array
                 */
                c->x86_capability[CPUID_C000_0001_EDX] = cpuid_edx(0xC0000001);
        }
#ifdef CONFIG_X86_32
        /* Cyrix III family needs CX8 & PGE explicitly enabled. */
        if (c->x86_model >= 6 && c->x86_model <= 13) {
                rdmsr(MSR_VIA_FCR, lo, hi);
                lo |= (1<<1 | 1<<7);
                wrmsr(MSR_VIA_FCR, lo, hi);
                set_cpu_cap(c, X86_FEATURE_CX8);
        }

        /* Before Nehemiah, the C3's had 3dNOW! */
        if (c->x86_model >= 6 && c->x86_model < 9)
                set_cpu_cap(c, X86_FEATURE_3DNOW);
#endif
        if (c->x86 == 0x6 && c->x86_model >= 0xf) {
                c->x86_cache_alignment = c->x86_clflush_size * 2;
                set_cpu_cap(c, X86_FEATURE_REP_GOOD);
        }

        if (c->x86 >= 7)
                set_cpu_cap(c, X86_FEATURE_REP_GOOD);
}

enum {
                ECX8            = 1<<1,
                EIERRINT        = 1<<2,
                DPM             = 1<<3,
                DMCE            = 1<<4,
                DSTPCLK         = 1<<5,
                ELINEAR         = 1<<6,
                DSMC            = 1<<7,
                DTLOCK          = 1<<8,
                EDCTLB          = 1<<8,
                EMMX            = 1<<9,
                DPDC            = 1<<11,
                EBRPRED         = 1<<12,
                DIC             = 1<<13,
                DDC             = 1<<14,
                DNA             = 1<<15,
                ERETSTK         = 1<<16,
                E2MMX           = 1<<19,
                EAMD3D          = 1<<20,
};

static void early_init_centaur(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
        /* Emulate MTRRs using Centaur's MCR. */
        if (c->x86 == 5)
                set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
#endif
        if ((c->x86 == 6 && c->x86_model >= 0xf) ||
            (c->x86 >= 7))
                set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);

        if (c->x86_power & (1 << 8)) {
                set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
                set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
        }
}

static void init_centaur(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
        char *name;
        u32  fcr_set = 0;
        u32  fcr_clr = 0;
        u32  lo, hi, newlo;
        u32  aa, bb, cc, dd;
#endif
        early_init_centaur(c);
        init_intel_cacheinfo(c);

        if (c->cpuid_level > 9) {
                unsigned int eax = cpuid_eax(10);

                /*
                 * Check for version and the number of counters
                 * Version(eax[7:0]) can't be 0;
                 * Counters(eax[15:8]) should be greater than 1;
                 */
                if ((eax & 0xff) && (((eax >> 8) & 0xff) > 1))
                        set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
        }

#ifdef CONFIG_X86_32
        if (c->x86 == 5) {
                switch (c->x86_model) {
                case 4:
                        name = "C6";
                        fcr_set = ECX8|DSMC|EDCTLB|EMMX|ERETSTK;
                        fcr_clr = DPDC;
                        pr_notice("Disabling bugged TSC.\n");
                        clear_cpu_cap(c, X86_FEATURE_TSC);
                        break;
                case 8:
                        switch (c->x86_stepping) {
                        default:
                        name = "2";
                                break;
                        case 7 ... 9:
                                name = "2A";
                                break;
                        case 10 ... 15:
                                name = "2B";
                                break;
                        }
                        fcr_set = ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|
                                  E2MMX|EAMD3D;
                        fcr_clr = DPDC;
                        break;
                case 9:
                        name = "3";
                        fcr_set = ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|
                                  E2MMX|EAMD3D;
                        fcr_clr = DPDC;
                        break;
                default:
                        name = "??";
                }

                rdmsr(MSR_IDT_FCR1, lo, hi);
                newlo = (lo|fcr_set) & (~fcr_clr);

                if (newlo != lo) {
                        pr_info("Centaur FCR was 0x%X now 0x%X\n",
                                lo, newlo);
                        wrmsr(MSR_IDT_FCR1, newlo, hi);
                } else {
                        pr_info("Centaur FCR is 0x%X\n", lo);
                }
                /* Emulate MTRRs using Centaur's MCR. */
                set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
                /* Report CX8 */
                set_cpu_cap(c, X86_FEATURE_CX8);
                /* Set 3DNow! on Winchip 2 and above. */
                if (c->x86_model >= 8)
                        set_cpu_cap(c, X86_FEATURE_3DNOW);
                /* See if we can find out some more. */
                if (cpuid_eax(0x80000000) >= 0x80000005) {
                        /* Yes, we can. */
                        cpuid(0x80000005, &aa, &bb, &cc, &dd);
                        /* Add L1 data and code cache sizes. */
                        c->x86_cache_size = (cc>>24)+(dd>>24);
                }
                sprintf(c->x86_model_id, "WinChip %s", name);
        }
#endif
        if (c->x86 == 6 || c->x86 >= 7)
                init_c3(c);
#ifdef CONFIG_X86_64
        set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
#endif

        init_ia32_feat_ctl(c);
}

#ifdef CONFIG_X86_32
static unsigned int
centaur_size_cache(struct cpuinfo_x86 *c, unsigned int size)
{
        /* VIA C3 CPUs (670-68F) need further shifting. */
        if ((c->x86 == 6) && ((c->x86_model == 7) || (c->x86_model == 8)))
                size >>= 8;

        /*
         * There's also an erratum in Nehemiah stepping 1, which
         * returns '65KB' instead of '64KB'
         *  - Note, it seems this may only be in engineering samples.
         */
        if ((c->x86 == 6) && (c->x86_model == 9) &&
                                (c->x86_stepping == 1) && (size == 65))
                size -= 1;
        return size;
}
#endif

static const struct cpu_dev centaur_cpu_dev = {
        .c_vendor       = "Centaur",
        .c_ident        = { "CentaurHauls" },
        .c_early_init   = early_init_centaur,
        .c_init         = init_centaur,
#ifdef CONFIG_X86_32
        .legacy_cache_size = centaur_size_cache,
#endif
        .c_x86_vendor   = X86_VENDOR_CENTAUR,
};

cpu_dev_register(centaur_cpu_dev);