/*
 *  AMD CPU Microcode Update Driver for Linux
 *  Copyright (C) 2008-2011 Advanced Micro Devices Inc.
 *
 *  Author: Peter Oruba <peter.oruba@amd.com>
 *
 *  Based on work by:
 *  Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
 *
 *  Maintainers:
 *  Andreas Herrmann <herrmann.der.user@googlemail.com>
 *  Borislav Petkov <bp@alien8.de>
 *
 *  This driver allows to upgrade microcode on F10h AMD
 *  CPUs and later.
 *
 *  Licensed under the terms of the GNU General Public
 *  License version 2. See file COPYING for details.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/firmware.h>
#include <linux/pci_ids.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>

#include <asm/microcode.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/microcode_amd.h>

MODULE_DESCRIPTION("AMD Microcode Update Driver");
MODULE_AUTHOR("Peter Oruba");
MODULE_LICENSE("GPL v2");

static struct equiv_cpu_entry *equiv_cpu_table;

struct ucode_patch {
        struct list_head plist;
        void *data;
        u32 patch_id;
        u16 equiv_cpu;
};

static LIST_HEAD(pcache);

static u16 __find_equiv_id(unsigned int cpu)
{
        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
        return find_equiv_id(equiv_cpu_table, uci->cpu_sig.sig);
}

static u32 find_cpu_family_by_equiv_cpu(u16 equiv_cpu)
{
        int i = 0;

        BUG_ON(!equiv_cpu_table);

        while (equiv_cpu_table[i].equiv_cpu != 0) {
                if (equiv_cpu == equiv_cpu_table[i].equiv_cpu)
                        return equiv_cpu_table[i].installed_cpu;
                i++;
        }
        return 0;
}

/*
 * a small, trivial cache of per-family ucode patches
 */
static struct ucode_patch *cache_find_patch(u16 equiv_cpu)
{
        struct ucode_patch *p;

        list_for_each_entry(p, &pcache, plist)
                if (p->equiv_cpu == equiv_cpu)
                        return p;
        return NULL;
}

static void update_cache(struct ucode_patch *new_patch)
{
        struct ucode_patch *p;

        list_for_each_entry(p, &pcache, plist) {
                if (p->equiv_cpu == new_patch->equiv_cpu) {
                        if (p->patch_id >= new_patch->patch_id)
                                /* we already have the latest patch */
                                return;

                        list_replace(&p->plist, &new_patch->plist);
                        kfree(p->data);
                        kfree(p);
                        return;
                }
        }
        /* no patch found, add it */
        list_add_tail(&new_patch->plist, &pcache);
}

static void free_cache(void)
{
        struct ucode_patch *p, *tmp;

        list_for_each_entry_safe(p, tmp, &pcache, plist) {
                __list_del(p->plist.prev, p->plist.next);
                kfree(p->data);
                kfree(p);
        }
}

static struct ucode_patch *find_patch(unsigned int cpu)
{
        u16 equiv_id;

        equiv_id = __find_equiv_id(cpu);
        if (!equiv_id)
                return NULL;

        return cache_find_patch(equiv_id);
}

static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
{
        struct cpuinfo_x86 *c = &cpu_data(cpu);
        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
        struct ucode_patch *p;

        csig->sig = cpuid_eax(0x00000001);
        csig->rev = c->microcode;

        /*
         * a patch could have been loaded early, set uci->mc so that
         * mc_bp_resume() can call apply_microcode()
         */
        p = find_patch(cpu);
        if (p && (p->patch_id == csig->rev))
                uci->mc = p->data;

        pr_info("CPU%d: patch_level=0x%08x\n", cpu, csig->rev);

        return 0;
}

static unsigned int verify_patch_size(u8 family, u32 patch_size,
                                      unsigned int size)
{
        u32 max_size;

#define F1XH_MPB_MAX_SIZE 2048
#define F14H_MPB_MAX_SIZE 1824
#define F15H_MPB_MAX_SIZE 4096
#define F16H_MPB_MAX_SIZE 3458

        switch (family) {
        case 0x14:
                max_size = F14H_MPB_MAX_SIZE;
                break;
        case 0x15:
                max_size = F15H_MPB_MAX_SIZE;
                break;
        case 0x16:
                max_size = F16H_MPB_MAX_SIZE;
                break;
        default:
                max_size = F1XH_MPB_MAX_SIZE;
                break;
        }

        if (patch_size > min_t(u32, size, max_size)) {
                pr_err("patch size mismatch\n");
                return 0;
        }

        return patch_size;
}

int __apply_microcode_amd(struct microcode_amd *mc_amd)
{
        u32 rev, dummy;

        native_wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code);

        /* verify patch application was successful */
        native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
        if (rev != mc_amd->hdr.patch_id)
                return -1;

        return 0;
}

int apply_microcode_amd(int cpu)
{
        struct cpuinfo_x86 *c = &cpu_data(cpu);
        struct microcode_amd *mc_amd;
        struct ucode_cpu_info *uci;
        struct ucode_patch *p;
        u32 rev, dummy;

        BUG_ON(raw_smp_processor_id() != cpu);

        uci = ucode_cpu_info + cpu;

        p = find_patch(cpu);
        if (!p)
                return 0;

        mc_amd  = p->data;
        uci->mc = p->data;

        rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);

        /* need to apply patch? */
        if (rev >= mc_amd->hdr.patch_id) {
                c->microcode = rev;
                uci->cpu_sig.rev = rev;
                return 0;
        }

        if (__apply_microcode_amd(mc_amd)) {
                pr_err("CPU%d: update failed for patch_level=0x%08x\n",
                        cpu, mc_amd->hdr.patch_id);
                return -1;
        }
        pr_info("CPU%d: new patch_level=0x%08x\n", cpu,
                mc_amd->hdr.patch_id);

        uci->cpu_sig.rev = mc_amd->hdr.patch_id;
        c->microcode = mc_amd->hdr.patch_id;

        return 0;
}

static int install_equiv_cpu_table(const u8 *buf)
{
        unsigned int *ibuf = (unsigned int *)buf;
        unsigned int type = ibuf[1];
        unsigned int size = ibuf[2];

        if (type != UCODE_EQUIV_CPU_TABLE_TYPE || !size) {
                pr_err("empty section/"
                       "invalid type field in container file section header\n");
                return -EINVAL;
        }

        equiv_cpu_table = vmalloc(size);
        if (!equiv_cpu_table) {
                pr_err("failed to allocate equivalent CPU table\n");
                return -ENOMEM;
        }

        memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, size);

        /* add header length */
        return size + CONTAINER_HDR_SZ;
}

static void free_equiv_cpu_table(void)
{
        vfree(equiv_cpu_table);
        equiv_cpu_table = NULL;
}

static void cleanup(void)
{
        free_equiv_cpu_table();
        free_cache();
}

/*
 * We return the current size even if some of the checks failed so that
 * we can skip over the next patch. If we return a negative value, we
 * signal a grave error like a memory allocation has failed and the
 * driver cannot continue functioning normally. In such cases, we tear
 * down everything we've used up so far and exit.
 */
static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
{
        struct microcode_header_amd *mc_hdr;
        struct ucode_patch *patch;
        unsigned int patch_size, crnt_size, ret;
        u32 proc_fam;
        u16 proc_id;

        patch_size  = *(u32 *)(fw + 4);
        crnt_size   = patch_size + SECTION_HDR_SIZE;
        mc_hdr      = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
        proc_id     = mc_hdr->processor_rev_id;

        proc_fam = find_cpu_family_by_equiv_cpu(proc_id);
        if (!proc_fam) {
                pr_err("No patch family for equiv ID: 0x%04x\n", proc_id);
                return crnt_size;
        }

        /* check if patch is for the current family */
        proc_fam = ((proc_fam >> 8) & 0xf) + ((proc_fam >> 20) & 0xff);
        if (proc_fam != family)
                return crnt_size;

        if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {
                pr_err("Patch-ID 0x%08x: chipset-specific code unsupported.\n",
                        mc_hdr->patch_id);
                return crnt_size;
        }

        ret = verify_patch_size(family, patch_size, leftover);
        if (!ret) {
                pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
                return crnt_size;
        }

        patch = kzalloc(sizeof(*patch), GFP_KERNEL);
        if (!patch) {
                pr_err("Patch allocation failure.\n");
                return -EINVAL;
        }

        patch->data = kzalloc(patch_size, GFP_KERNEL);
        if (!patch->data) {
                pr_err("Patch data allocation failure.\n");
                kfree(patch);
                return -EINVAL;
        }

        /* All looks ok, copy patch... */
        memcpy(patch->data, fw + SECTION_HDR_SIZE, patch_size);
        INIT_LIST_HEAD(&patch->plist);
        patch->patch_id  = mc_hdr->patch_id;
        patch->equiv_cpu = proc_id;

        pr_debug("%s: Added patch_id: 0x%08x, proc_id: 0x%04x\n",
                 __func__, patch->patch_id, proc_id);

        /* ... and add to cache. */
        update_cache(patch);

        return crnt_size;
}

static enum ucode_state __load_microcode_amd(u8 family, const u8 *data,
                                             size_t size)
{
        enum ucode_state ret = UCODE_ERROR;
        unsigned int leftover;
        u8 *fw = (u8 *)data;
        int crnt_size = 0;
        int offset;

        offset = install_equiv_cpu_table(data);
        if (offset < 0) {
                pr_err("failed to create equivalent cpu table\n");
                return ret;
        }
        fw += offset;
        leftover = size - offset;

        if (*(u32 *)fw != UCODE_UCODE_TYPE) {
                pr_err("invalid type field in container file section header\n");
                free_equiv_cpu_table();
                return ret;
        }

        while (leftover) {
                crnt_size = verify_and_add_patch(family, fw, leftover);
                if (crnt_size < 0)
                        return ret;

                fw       += crnt_size;
                leftover -= crnt_size;
        }

        return UCODE_OK;
}

enum ucode_state load_microcode_amd(u8 family, const u8 *data, size_t size)
{
        enum ucode_state ret;

        /* free old equiv table */
        free_equiv_cpu_table();

        ret = __load_microcode_amd(family, data, size);

        if (ret != UCODE_OK)
                cleanup();

#if defined(CONFIG_MICROCODE_AMD_EARLY) && defined(CONFIG_X86_32)
        /* save BSP's matching patch for early load */
        if (cpu_data(smp_processor_id()).cpu_index == boot_cpu_data.cpu_index) {
                struct ucode_patch *p = find_patch(smp_processor_id());
                if (p) {
                        memset(amd_ucode_patch, 0, PATCH_MAX_SIZE);
                        memcpy(amd_ucode_patch, p->data, min_t(u32, ksize(p->data),
                                                               PATCH_MAX_SIZE));
                }
        }
#endif
        return ret;
}

/*
 * AMD microcode firmware naming convention, up to family 15h they are in
 * the legacy file:
 *
 *    amd-ucode/microcode_amd.bin
 *
 * This legacy file is always smaller than 2K in size.
 *
 * Beginning with family 15h, they are in family-specific firmware files:
 *
 *    amd-ucode/microcode_amd_fam15h.bin
 *    amd-ucode/microcode_amd_fam16h.bin
 *    ...
 *
 * These might be larger than 2K.
 */
static enum ucode_state request_microcode_amd(int cpu, struct device *device,
                                              bool refresh_fw)
{
        char fw_name[36] = "amd-ucode/microcode_amd.bin";
        struct cpuinfo_x86 *c = &cpu_data(cpu);
        enum ucode_state ret = UCODE_NFOUND;
        const struct firmware *fw;

        /* reload ucode container only on the boot cpu */
        if (!refresh_fw || c->cpu_index != boot_cpu_data.cpu_index)
                return UCODE_OK;

        if (c->x86 >= 0x15)
                snprintf(fw_name, sizeof(fw_name), "amd-ucode/microcode_amd_fam%.2xh.bin", c->x86);

        if (request_firmware_direct(&fw, (const char *)fw_name, device)) {
                pr_debug("failed to load file %s\n", fw_name);
                goto out;
        }

        ret = UCODE_ERROR;
        if (*(u32 *)fw->data != UCODE_MAGIC) {
                pr_err("invalid magic value (0x%08x)\n", *(u32 *)fw->data);
                goto fw_release;
        }

        ret = load_microcode_amd(c->x86, fw->data, fw->size);

 fw_release:
        release_firmware(fw);

 out:
        return ret;
}

static enum ucode_state
request_microcode_user(int cpu, const void __user *buf, size_t size)
{
        return UCODE_ERROR;
}

static void microcode_fini_cpu_amd(int cpu)
{
        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

        uci->mc = NULL;
}

static struct microcode_ops microcode_amd_ops = {
        .request_microcode_user           = request_microcode_user,
        .request_microcode_fw             = request_microcode_amd,
        .collect_cpu_info                 = collect_cpu_info_amd,
        .apply_microcode                  = apply_microcode_amd,
        .microcode_fini_cpu               = microcode_fini_cpu_amd,
};

struct microcode_ops * __init init_amd_microcode(void)
{
        struct cpuinfo_x86 *c = &cpu_data(0);

        if (c->x86_vendor != X86_VENDOR_AMD || c->x86 < 0x10) {
                pr_warning("AMD CPU family 0x%x not supported\n", c->x86);
                return NULL;
        }

        return &microcode_amd_ops;
}

void __exit exit_amd_microcode(void)
{
        cleanup();
}