// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for Intel client SoC with integrated memory controller using IBECC
 *
 * Copyright (C) 2020 Intel Corporation
 *
 * The In-Band ECC (IBECC) IP provides ECC protection to all or specific
 * regions of the physical memory space. It's used for memory controllers
 * that don't support the out-of-band ECC which often needs an additional
 * storage device to each channel for storing ECC data.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/irq_work.h>
#include <linux/llist.h>
#include <linux/genalloc.h>
#include <linux/edac.h>
#include <linux/bits.h>
#include <linux/io.h>
#include <asm/mach_traps.h>
#include <asm/nmi.h>
#include <asm/mce.h>

#include "edac_mc.h"
#include "edac_module.h"

#define IGEN6_REVISION  "v2.5"

#define EDAC_MOD_STR    "igen6_edac"
#define IGEN6_NMI_NAME  "igen6_ibecc"

/* Debug macros */
#define igen6_printk(level, fmt, arg...)                \
        edac_printk(level, "igen6", fmt, ##arg)

#define igen6_mc_printk(mci, level, fmt, arg...)        \
        edac_mc_chipset_printk(mci, level, "igen6", fmt, ##arg)

#define GET_BITFIELD(v, lo, hi) (((v) & GENMASK_ULL(hi, lo)) >> (lo))

#define NUM_IMC                         2 /* Max memory controllers */
#define NUM_CHANNELS                    2 /* Max channels */
#define NUM_DIMMS                       2 /* Max DIMMs per channel */

#define _4GB                            BIT_ULL(32)

/* Size of physical memory */
#define TOM_OFFSET                      0xa0
/* Top of low usable DRAM */
#define TOLUD_OFFSET                    0xbc
/* Capability register C */
#define CAPID_C_OFFSET                  0xec
#define CAPID_C_IBECC                   BIT(15)

/* Capability register E */
#define CAPID_E_OFFSET                  0xf0
#define CAPID_E_IBECC                   BIT(12)

/* Error Status */
#define ERRSTS_OFFSET                   0xc8
#define ERRSTS_CE                       BIT_ULL(6)
#define ERRSTS_UE                       BIT_ULL(7)

/* Error Command */
#define ERRCMD_OFFSET                   0xca
#define ERRCMD_CE                       BIT_ULL(6)
#define ERRCMD_UE                       BIT_ULL(7)

/* IBECC MMIO base address */
#define IBECC_BASE                      (res_cfg->ibecc_base)
#define IBECC_ACTIVATE_OFFSET           IBECC_BASE
#define IBECC_ACTIVATE_EN               BIT(0)

/* IBECC error log */
#define ECC_ERROR_LOG_OFFSET            (IBECC_BASE + res_cfg->ibecc_error_log_offset)
#define ECC_ERROR_LOG_CE                BIT_ULL(62)
#define ECC_ERROR_LOG_UE                BIT_ULL(63)
#define ECC_ERROR_LOG_ADDR_SHIFT        5
#define ECC_ERROR_LOG_ADDR(v)           GET_BITFIELD(v, 5, 38)
#define ECC_ERROR_LOG_SYND(v)           GET_BITFIELD(v, 46, 61)

/* Host MMIO base address */
#define MCHBAR_OFFSET                   0x48
#define MCHBAR_EN                       BIT_ULL(0)
#define MCHBAR_BASE(v)                  (GET_BITFIELD(v, 16, 38) << 16)
#define MCHBAR_SIZE                     0x10000

/* Parameters for the channel decode stage */
#define IMC_BASE                        (res_cfg->imc_base)
#define MAD_INTER_CHANNEL_OFFSET        IMC_BASE
#define MAD_INTER_CHANNEL_DDR_TYPE(v)   GET_BITFIELD(v, 0, 2)
#define MAD_INTER_CHANNEL_ECHM(v)       GET_BITFIELD(v, 3, 3)
#define MAD_INTER_CHANNEL_CH_L_MAP(v)   GET_BITFIELD(v, 4, 4)
#define MAD_INTER_CHANNEL_CH_S_SIZE(v)  ((u64)GET_BITFIELD(v, 12, 19) << 29)

/* Parameters for DRAM decode stage */
#define MAD_INTRA_CH0_OFFSET            (IMC_BASE + 4)
#define MAD_INTRA_CH_DIMM_L_MAP(v)      GET_BITFIELD(v, 0, 0)

/* DIMM characteristics */
#define MAD_DIMM_CH0_OFFSET             (IMC_BASE + 0xc)
#define MAD_DIMM_CH_DIMM_L_SIZE(v)      ((u64)GET_BITFIELD(v, 0, 6) << 29)
#define MAD_DIMM_CH_DLW(v)              GET_BITFIELD(v, 7, 8)
#define MAD_DIMM_CH_DIMM_S_SIZE(v)      ((u64)GET_BITFIELD(v, 16, 22) << 29)
#define MAD_DIMM_CH_DSW(v)              GET_BITFIELD(v, 24, 25)

/* Hash for memory controller selection */
#define MAD_MC_HASH_OFFSET              (IMC_BASE + 0x1b8)
#define MAC_MC_HASH_LSB(v)              GET_BITFIELD(v, 1, 3)

/* Hash for channel selection */
#define CHANNEL_HASH_OFFSET             (IMC_BASE + 0x24)
/* Hash for enhanced channel selection */
#define CHANNEL_EHASH_OFFSET            (IMC_BASE + 0x28)
#define CHANNEL_HASH_MASK(v)            (GET_BITFIELD(v, 6, 19) << 6)
#define CHANNEL_HASH_LSB_MASK_BIT(v)    GET_BITFIELD(v, 24, 26)
#define CHANNEL_HASH_MODE(v)            GET_BITFIELD(v, 28, 28)

/* Parameters for memory slice decode stage */
#define MEM_SLICE_HASH_MASK(v)          (GET_BITFIELD(v, 6, 19) << 6)
#define MEM_SLICE_HASH_LSB_MASK_BIT(v)  GET_BITFIELD(v, 24, 26)

static struct res_config {
        bool machine_check;
        int num_imc;
        u32 imc_base;
        u32 cmf_base;
        u32 cmf_size;
        u32 ms_hash_offset;
        u32 ibecc_base;
        u32 ibecc_error_log_offset;
        bool (*ibecc_available)(struct pci_dev *pdev);
        /* Convert error address logged in IBECC to system physical address */
        u64 (*err_addr_to_sys_addr)(u64 eaddr, int mc);
        /* Convert error address logged in IBECC to integrated memory controller address */
        u64 (*err_addr_to_imc_addr)(u64 eaddr, int mc);
} *res_cfg;

struct igen6_imc {
        int mc;
        struct mem_ctl_info *mci;
        struct pci_dev *pdev;
        struct device dev;
        void __iomem *window;
        u64 size;
        u64 ch_s_size;
        int ch_l_map;
        u64 dimm_s_size[NUM_CHANNELS];
        u64 dimm_l_size[NUM_CHANNELS];
        int dimm_l_map[NUM_CHANNELS];
};

static struct igen6_pvt {
        struct igen6_imc imc[NUM_IMC];
        u64 ms_hash;
        u64 ms_s_size;
        int ms_l_map;
} *igen6_pvt;

/* The top of low usable DRAM */
static u32 igen6_tolud;
/* The size of physical memory */
static u64 igen6_tom;

struct decoded_addr {
        int mc;
        u64 imc_addr;
        u64 sys_addr;
        int channel_idx;
        u64 channel_addr;
        int sub_channel_idx;
        u64 sub_channel_addr;
};

struct ecclog_node {
        struct llist_node llnode;
        int mc;
        u64 ecclog;
};

/*
 * In the NMI handler, the driver uses the lock-less memory allocator
 * to allocate memory to store the IBECC error logs and links the logs
 * to the lock-less list. Delay printk() and the work of error reporting
 * to EDAC core in a worker.
 */
#define ECCLOG_POOL_SIZE        PAGE_SIZE
static LLIST_HEAD(ecclog_llist);
static struct gen_pool *ecclog_pool;
static char ecclog_buf[ECCLOG_POOL_SIZE];
static struct irq_work ecclog_irq_work;
static struct work_struct ecclog_work;

/* Compute die IDs for Elkhart Lake with IBECC */
#define DID_EHL_SKU5    0x4514
#define DID_EHL_SKU6    0x4528
#define DID_EHL_SKU7    0x452a
#define DID_EHL_SKU8    0x4516
#define DID_EHL_SKU9    0x452c
#define DID_EHL_SKU10   0x452e
#define DID_EHL_SKU11   0x4532
#define DID_EHL_SKU12   0x4518
#define DID_EHL_SKU13   0x451a
#define DID_EHL_SKU14   0x4534
#define DID_EHL_SKU15   0x4536

/* Compute die IDs for ICL-NNPI with IBECC */
#define DID_ICL_SKU8    0x4581
#define DID_ICL_SKU10   0x4585
#define DID_ICL_SKU11   0x4589
#define DID_ICL_SKU12   0x458d

/* Compute die IDs for Tiger Lake with IBECC */
#define DID_TGL_SKU     0x9a14

/* Compute die IDs for Alder Lake with IBECC */
#define DID_ADL_SKU1    0x4601
#define DID_ADL_SKU2    0x4602
#define DID_ADL_SKU3    0x4621
#define DID_ADL_SKU4    0x4641

static bool ehl_ibecc_available(struct pci_dev *pdev)
{
        u32 v;

        if (pci_read_config_dword(pdev, CAPID_C_OFFSET, &v))
                return false;

        return !!(CAPID_C_IBECC & v);
}

static u64 ehl_err_addr_to_sys_addr(u64 eaddr, int mc)
{
        return eaddr;
}

static u64 ehl_err_addr_to_imc_addr(u64 eaddr, int mc)
{
        if (eaddr < igen6_tolud)
                return eaddr;

        if (igen6_tom <= _4GB)
                return eaddr + igen6_tolud - _4GB;

        if (eaddr < _4GB)
                return eaddr + igen6_tolud - igen6_tom;

        return eaddr;
}

static bool icl_ibecc_available(struct pci_dev *pdev)
{
        u32 v;

        if (pci_read_config_dword(pdev, CAPID_C_OFFSET, &v))
                return false;

        return !(CAPID_C_IBECC & v) &&
                (boot_cpu_data.x86_stepping >= 1);
}

static bool tgl_ibecc_available(struct pci_dev *pdev)
{
        u32 v;

        if (pci_read_config_dword(pdev, CAPID_E_OFFSET, &v))
                return false;

        return !(CAPID_E_IBECC & v);
}

static u64 mem_addr_to_sys_addr(u64 maddr)
{
        if (maddr < igen6_tolud)
                return maddr;

        if (igen6_tom <= _4GB)
                return maddr - igen6_tolud + _4GB;

        if (maddr < _4GB)
                return maddr - igen6_tolud + igen6_tom;

        return maddr;
}

static u64 mem_slice_hash(u64 addr, u64 mask, u64 hash_init, int intlv_bit)
{
        u64 hash_addr = addr & mask, hash = hash_init;
        u64 intlv = (addr >> intlv_bit) & 1;
        int i;

        for (i = 6; i < 20; i++)
                hash ^= (hash_addr >> i) & 1;

        return hash ^ intlv;
}

static u64 tgl_err_addr_to_mem_addr(u64 eaddr, int mc)
{
        u64 maddr, hash, mask, ms_s_size;
        int intlv_bit;
        u32 ms_hash;

        ms_s_size = igen6_pvt->ms_s_size;
        if (eaddr >= ms_s_size)
                return eaddr + ms_s_size;

        ms_hash = igen6_pvt->ms_hash;

        mask = MEM_SLICE_HASH_MASK(ms_hash);
        intlv_bit = MEM_SLICE_HASH_LSB_MASK_BIT(ms_hash) + 6;

        maddr = GET_BITFIELD(eaddr, intlv_bit, 63) << (intlv_bit + 1) |
                GET_BITFIELD(eaddr, 0, intlv_bit - 1);

        hash = mem_slice_hash(maddr, mask, mc, intlv_bit);

        return maddr | (hash << intlv_bit);
}

static u64 tgl_err_addr_to_sys_addr(u64 eaddr, int mc)
{
        u64 maddr = tgl_err_addr_to_mem_addr(eaddr, mc);

        return mem_addr_to_sys_addr(maddr);
}

static u64 tgl_err_addr_to_imc_addr(u64 eaddr, int mc)
{
        return eaddr;
}

static u64 adl_err_addr_to_sys_addr(u64 eaddr, int mc)
{
        return mem_addr_to_sys_addr(eaddr);
}

static u64 adl_err_addr_to_imc_addr(u64 eaddr, int mc)
{
        u64 imc_addr, ms_s_size = igen6_pvt->ms_s_size;
        struct igen6_imc *imc = &igen6_pvt->imc[mc];
        int intlv_bit;
        u32 mc_hash;

        if (eaddr >= 2 * ms_s_size)
                return eaddr - ms_s_size;

        mc_hash = readl(imc->window + MAD_MC_HASH_OFFSET);

        intlv_bit = MAC_MC_HASH_LSB(mc_hash) + 6;

        imc_addr = GET_BITFIELD(eaddr, intlv_bit + 1, 63) << intlv_bit |
                   GET_BITFIELD(eaddr, 0, intlv_bit - 1);

        return imc_addr;
}

static struct res_config ehl_cfg = {
        .num_imc                = 1,
        .imc_base               = 0x5000,
        .ibecc_base             = 0xdc00,
        .ibecc_available        = ehl_ibecc_available,
        .ibecc_error_log_offset = 0x170,
        .err_addr_to_sys_addr   = ehl_err_addr_to_sys_addr,
        .err_addr_to_imc_addr   = ehl_err_addr_to_imc_addr,
};

static struct res_config icl_cfg = {
        .num_imc                = 1,
        .imc_base               = 0x5000,
        .ibecc_base             = 0xd800,
        .ibecc_error_log_offset = 0x170,
        .ibecc_available        = icl_ibecc_available,
        .err_addr_to_sys_addr   = ehl_err_addr_to_sys_addr,
        .err_addr_to_imc_addr   = ehl_err_addr_to_imc_addr,
};

static struct res_config tgl_cfg = {
        .machine_check          = true,
        .num_imc                = 2,
        .imc_base               = 0x5000,
        .cmf_base               = 0x11000,
        .cmf_size               = 0x800,
        .ms_hash_offset         = 0xac,
        .ibecc_base             = 0xd400,
        .ibecc_error_log_offset = 0x170,
        .ibecc_available        = tgl_ibecc_available,
        .err_addr_to_sys_addr   = tgl_err_addr_to_sys_addr,
        .err_addr_to_imc_addr   = tgl_err_addr_to_imc_addr,
};

static struct res_config adl_cfg = {
        .machine_check          = true,
        .num_imc                = 2,
        .imc_base               = 0xd800,
        .ibecc_base             = 0xd400,
        .ibecc_error_log_offset = 0x68,
        .ibecc_available        = tgl_ibecc_available,
        .err_addr_to_sys_addr   = adl_err_addr_to_sys_addr,
        .err_addr_to_imc_addr   = adl_err_addr_to_imc_addr,
};

static const struct pci_device_id igen6_pci_tbl[] = {
        { PCI_VDEVICE(INTEL, DID_EHL_SKU5), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU6), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU7), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU8), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU9), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU10), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU11), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU12), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU13), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU14), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_EHL_SKU15), (kernel_ulong_t)&ehl_cfg },
        { PCI_VDEVICE(INTEL, DID_ICL_SKU8), (kernel_ulong_t)&icl_cfg },
        { PCI_VDEVICE(INTEL, DID_ICL_SKU10), (kernel_ulong_t)&icl_cfg },
        { PCI_VDEVICE(INTEL, DID_ICL_SKU11), (kernel_ulong_t)&icl_cfg },
        { PCI_VDEVICE(INTEL, DID_ICL_SKU12), (kernel_ulong_t)&icl_cfg },
        { PCI_VDEVICE(INTEL, DID_TGL_SKU), (kernel_ulong_t)&tgl_cfg },
        { PCI_VDEVICE(INTEL, DID_ADL_SKU1), (kernel_ulong_t)&adl_cfg },
        { PCI_VDEVICE(INTEL, DID_ADL_SKU2), (kernel_ulong_t)&adl_cfg },
        { PCI_VDEVICE(INTEL, DID_ADL_SKU3), (kernel_ulong_t)&adl_cfg },
        { PCI_VDEVICE(INTEL, DID_ADL_SKU4), (kernel_ulong_t)&adl_cfg },
        { },
};
MODULE_DEVICE_TABLE(pci, igen6_pci_tbl);

static enum dev_type get_width(int dimm_l, u32 mad_dimm)
{
        u32 w = dimm_l ? MAD_DIMM_CH_DLW(mad_dimm) :
                         MAD_DIMM_CH_DSW(mad_dimm);

        switch (w) {
        case 0:
                return DEV_X8;
        case 1:
                return DEV_X16;
        case 2:
                return DEV_X32;
        default:
                return DEV_UNKNOWN;
        }
}

static enum mem_type get_memory_type(u32 mad_inter)
{
        u32 t = MAD_INTER_CHANNEL_DDR_TYPE(mad_inter);

        switch (t) {
        case 0:
                return MEM_DDR4;
        case 1:
                return MEM_DDR3;
        case 2:
                return MEM_LPDDR3;
        case 3:
                return MEM_LPDDR4;
        case 4:
                return MEM_WIO2;
        default:
                return MEM_UNKNOWN;
        }
}

static int decode_chan_idx(u64 addr, u64 mask, int intlv_bit)
{
        u64 hash_addr = addr & mask, hash = 0;
        u64 intlv = (addr >> intlv_bit) & 1;
        int i;

        for (i = 6; i < 20; i++)
                hash ^= (hash_addr >> i) & 1;

        return (int)hash ^ intlv;
}

static u64 decode_channel_addr(u64 addr, int intlv_bit)
{
        u64 channel_addr;

        /* Remove the interleave bit and shift upper part down to fill gap */
        channel_addr  = GET_BITFIELD(addr, intlv_bit + 1, 63) << intlv_bit;
        channel_addr |= GET_BITFIELD(addr, 0, intlv_bit - 1);

        return channel_addr;
}

static void decode_addr(u64 addr, u32 hash, u64 s_size, int l_map,
                        int *idx, u64 *sub_addr)
{
        int intlv_bit = CHANNEL_HASH_LSB_MASK_BIT(hash) + 6;

        if (addr > 2 * s_size) {
                *sub_addr = addr - s_size;
                *idx = l_map;
                return;
        }

        if (CHANNEL_HASH_MODE(hash)) {
                *sub_addr = decode_channel_addr(addr, intlv_bit);
                *idx = decode_chan_idx(addr, CHANNEL_HASH_MASK(hash), intlv_bit);
        } else {
                *sub_addr = decode_channel_addr(addr, 6);
                *idx = GET_BITFIELD(addr, 6, 6);
        }
}

static int igen6_decode(struct decoded_addr *res)
{
        struct igen6_imc *imc = &igen6_pvt->imc[res->mc];
        u64 addr = res->imc_addr, sub_addr, s_size;
        int idx, l_map;
        u32 hash;

        if (addr >= igen6_tom) {
                edac_dbg(0, "Address 0x%llx out of range\n", addr);
                return -EINVAL;
        }

        /* Decode channel */
        hash   = readl(imc->window + CHANNEL_HASH_OFFSET);
        s_size = imc->ch_s_size;
        l_map  = imc->ch_l_map;
        decode_addr(addr, hash, s_size, l_map, &idx, &sub_addr);
        res->channel_idx  = idx;
        res->channel_addr = sub_addr;

        /* Decode sub-channel/DIMM */
        hash   = readl(imc->window + CHANNEL_EHASH_OFFSET);
        s_size = imc->dimm_s_size[idx];
        l_map  = imc->dimm_l_map[idx];
        decode_addr(res->channel_addr, hash, s_size, l_map, &idx, &sub_addr);
        res->sub_channel_idx  = idx;
        res->sub_channel_addr = sub_addr;

        return 0;
}

static void igen6_output_error(struct decoded_addr *res,
                               struct mem_ctl_info *mci, u64 ecclog)
{
        enum hw_event_mc_err_type type = ecclog & ECC_ERROR_LOG_UE ?
                                         HW_EVENT_ERR_UNCORRECTED :
                                         HW_EVENT_ERR_CORRECTED;

        edac_mc_handle_error(type, mci, 1,
                             res->sys_addr >> PAGE_SHIFT,
                             res->sys_addr & ~PAGE_MASK,
                             ECC_ERROR_LOG_SYND(ecclog),
                             res->channel_idx, res->sub_channel_idx,
                             -1, "", "");
}

static struct gen_pool *ecclog_gen_pool_create(void)
{
        struct gen_pool *pool;

        pool = gen_pool_create(ilog2(sizeof(struct ecclog_node)), -1);
        if (!pool)
                return NULL;

        if (gen_pool_add(pool, (unsigned long)ecclog_buf, ECCLOG_POOL_SIZE, -1)) {
                gen_pool_destroy(pool);
                return NULL;
        }

        return pool;
}

static int ecclog_gen_pool_add(int mc, u64 ecclog)
{
        struct ecclog_node *node;

        node = (void *)gen_pool_alloc(ecclog_pool, sizeof(*node));
        if (!node)
                return -ENOMEM;

        node->mc = mc;
        node->ecclog = ecclog;
        llist_add(&node->llnode, &ecclog_llist);

        return 0;
}

/*
 * Either the memory-mapped I/O status register ECC_ERROR_LOG or the PCI
 * configuration space status register ERRSTS can indicate whether a
 * correctable error or an uncorrectable error occurred. We only use the
 * ECC_ERROR_LOG register to check error type, but need to clear both
 * registers to enable future error events.
 */
static u64 ecclog_read_and_clear(struct igen6_imc *imc)
{
        u64 ecclog = readq(imc->window + ECC_ERROR_LOG_OFFSET);

        if (ecclog & (ECC_ERROR_LOG_CE | ECC_ERROR_LOG_UE)) {
                /* Clear CE/UE bits by writing 1s */
                writeq(ecclog, imc->window + ECC_ERROR_LOG_OFFSET);
                return ecclog;
        }

        return 0;
}

static void errsts_clear(struct igen6_imc *imc)
{
        u16 errsts;

        if (pci_read_config_word(imc->pdev, ERRSTS_OFFSET, &errsts)) {
                igen6_printk(KERN_ERR, "Failed to read ERRSTS\n");
                return;
        }

        /* Clear CE/UE bits by writing 1s */
        if (errsts & (ERRSTS_CE | ERRSTS_UE))
                pci_write_config_word(imc->pdev, ERRSTS_OFFSET, errsts);
}

static int errcmd_enable_error_reporting(bool enable)
{
        struct igen6_imc *imc = &igen6_pvt->imc[0];
        u16 errcmd;
        int rc;

        rc = pci_read_config_word(imc->pdev, ERRCMD_OFFSET, &errcmd);
        if (rc)
                return rc;

        if (enable)
                errcmd |= ERRCMD_CE | ERRSTS_UE;
        else
                errcmd &= ~(ERRCMD_CE | ERRSTS_UE);

        rc = pci_write_config_word(imc->pdev, ERRCMD_OFFSET, errcmd);
        if (rc)
                return rc;

        return 0;
}

static int ecclog_handler(void)
{
        struct igen6_imc *imc;
        int i, n = 0;
        u64 ecclog;

        for (i = 0; i < res_cfg->num_imc; i++) {
                imc = &igen6_pvt->imc[i];

                /* errsts_clear() isn't NMI-safe. Delay it in the IRQ context */

                ecclog = ecclog_read_and_clear(imc);
                if (!ecclog)
                        continue;

                if (!ecclog_gen_pool_add(i, ecclog))
                        irq_work_queue(&ecclog_irq_work);

                n++;
        }

        return n;
}

static void ecclog_work_cb(struct work_struct *work)
{
        struct ecclog_node *node, *tmp;
        struct mem_ctl_info *mci;
        struct llist_node *head;
        struct decoded_addr res;
        u64 eaddr;

        head = llist_del_all(&ecclog_llist);
        if (!head)
                return;

        llist_for_each_entry_safe(node, tmp, head, llnode) {
                memset(&res, 0, sizeof(res));
                eaddr = ECC_ERROR_LOG_ADDR(node->ecclog) <<
                        ECC_ERROR_LOG_ADDR_SHIFT;
                res.mc       = node->mc;
                res.sys_addr = res_cfg->err_addr_to_sys_addr(eaddr, res.mc);
                res.imc_addr = res_cfg->err_addr_to_imc_addr(eaddr, res.mc);

                mci = igen6_pvt->imc[res.mc].mci;

                edac_dbg(2, "MC %d, ecclog = 0x%llx\n", node->mc, node->ecclog);
                igen6_mc_printk(mci, KERN_DEBUG, "HANDLING IBECC MEMORY ERROR\n");
                igen6_mc_printk(mci, KERN_DEBUG, "ADDR 0x%llx ", res.sys_addr);

                if (!igen6_decode(&res))
                        igen6_output_error(&res, mci, node->ecclog);

                gen_pool_free(ecclog_pool, (unsigned long)node, sizeof(*node));
        }
}

static void ecclog_irq_work_cb(struct irq_work *irq_work)
{
        int i;

        for (i = 0; i < res_cfg->num_imc; i++)
                errsts_clear(&igen6_pvt->imc[i]);

        if (!llist_empty(&ecclog_llist))
                schedule_work(&ecclog_work);
}

static int ecclog_nmi_handler(unsigned int cmd, struct pt_regs *regs)
{
        unsigned char reason;

        if (!ecclog_handler())
                return NMI_DONE;

        /*
         * Both In-Band ECC correctable error and uncorrectable error are
         * reported by SERR# NMI. The NMI generic code (see pci_serr_error())
         * doesn't clear the bit NMI_REASON_CLEAR_SERR (in port 0x61) to
         * re-enable the SERR# NMI after NMI handling. So clear this bit here
         * to re-enable SERR# NMI for receiving future In-Band ECC errors.
         */
        reason  = x86_platform.get_nmi_reason() & NMI_REASON_CLEAR_MASK;
        reason |= NMI_REASON_CLEAR_SERR;
        outb(reason, NMI_REASON_PORT);
        reason &= ~NMI_REASON_CLEAR_SERR;
        outb(reason, NMI_REASON_PORT);

        return NMI_HANDLED;
}

static int ecclog_mce_handler(struct notifier_block *nb, unsigned long val,
                              void *data)
{
        struct mce *mce = (struct mce *)data;
        char *type;

        if (mce->kflags & MCE_HANDLED_CEC)
                return NOTIFY_DONE;

        /*
         * Ignore unless this is a memory related error.
         * We don't check the bit MCI_STATUS_ADDRV of MCi_STATUS here,
         * since this bit isn't set on some CPU (e.g., Tiger Lake UP3).
         */
        if ((mce->status & 0xefff) >> 7 != 1)
                return NOTIFY_DONE;

        if (mce->mcgstatus & MCG_STATUS_MCIP)
                type = "Exception";
        else
                type = "Event";

        edac_dbg(0, "CPU %d: Machine Check %s: 0x%llx Bank %d: 0x%llx\n",
                 mce->extcpu, type, mce->mcgstatus,
                 mce->bank, mce->status);
        edac_dbg(0, "TSC 0x%llx\n", mce->tsc);
        edac_dbg(0, "ADDR 0x%llx\n", mce->addr);
        edac_dbg(0, "MISC 0x%llx\n", mce->misc);
        edac_dbg(0, "PROCESSOR %u:0x%x TIME %llu SOCKET %u APIC 0x%x\n",
                 mce->cpuvendor, mce->cpuid, mce->time,
                 mce->socketid, mce->apicid);
        /*
         * We just use the Machine Check for the memory error notification.
         * Each memory controller is associated with an IBECC instance.
         * Directly read and clear the error information(error address and
         * error type) on all the IBECC instances so that we know on which
         * memory controller the memory error(s) occurred.
         */
        if (!ecclog_handler())
                return NOTIFY_DONE;

        mce->kflags |= MCE_HANDLED_EDAC;

        return NOTIFY_DONE;
}

static struct notifier_block ecclog_mce_dec = {
        .notifier_call  = ecclog_mce_handler,
        .priority       = MCE_PRIO_EDAC,
};

static bool igen6_check_ecc(struct igen6_imc *imc)
{
        u32 activate = readl(imc->window + IBECC_ACTIVATE_OFFSET);

        return !!(activate & IBECC_ACTIVATE_EN);
}

static int igen6_get_dimm_config(struct mem_ctl_info *mci)
{
        struct igen6_imc *imc = mci->pvt_info;
        u32 mad_inter, mad_intra, mad_dimm;
        int i, j, ndimms, mc = imc->mc;
        struct dimm_info *dimm;
        enum mem_type mtype;
        enum dev_type dtype;
        u64 dsize;
        bool ecc;

        edac_dbg(2, "\n");

        mad_inter = readl(imc->window + MAD_INTER_CHANNEL_OFFSET);
        mtype = get_memory_type(mad_inter);
        ecc = igen6_check_ecc(imc);
        imc->ch_s_size = MAD_INTER_CHANNEL_CH_S_SIZE(mad_inter);
        imc->ch_l_map  = MAD_INTER_CHANNEL_CH_L_MAP(mad_inter);

        for (i = 0; i < NUM_CHANNELS; i++) {
                mad_intra = readl(imc->window + MAD_INTRA_CH0_OFFSET + i * 4);
                mad_dimm  = readl(imc->window + MAD_DIMM_CH0_OFFSET + i * 4);

                imc->dimm_l_size[i] = MAD_DIMM_CH_DIMM_L_SIZE(mad_dimm);
                imc->dimm_s_size[i] = MAD_DIMM_CH_DIMM_S_SIZE(mad_dimm);
                imc->dimm_l_map[i]  = MAD_INTRA_CH_DIMM_L_MAP(mad_intra);
                imc->size += imc->dimm_s_size[i];
                imc->size += imc->dimm_l_size[i];
                ndimms = 0;

                for (j = 0; j < NUM_DIMMS; j++) {
                        dimm = edac_get_dimm(mci, i, j, 0);

                        if (j ^ imc->dimm_l_map[i]) {
                                dtype = get_width(0, mad_dimm);
                                dsize = imc->dimm_s_size[i];
                        } else {
                                dtype = get_width(1, mad_dimm);
                                dsize = imc->dimm_l_size[i];
                        }

                        if (!dsize)
                                continue;

                        dimm->grain = 64;
                        dimm->mtype = mtype;
                        dimm->dtype = dtype;
                        dimm->nr_pages  = MiB_TO_PAGES(dsize >> 20);
                        dimm->edac_mode = EDAC_SECDED;
                        snprintf(dimm->label, sizeof(dimm->label),
                                 "MC#%d_Chan#%d_DIMM#%d", mc, i, j);
                        edac_dbg(0, "MC %d, Channel %d, DIMM %d, Size %llu MiB (%u pages)\n",
                                 mc, i, j, dsize >> 20, dimm->nr_pages);

                        ndimms++;
                }

                if (ndimms && !ecc) {
                        igen6_printk(KERN_ERR, "MC%d In-Band ECC is disabled\n", mc);
                        return -ENODEV;
                }
        }

        edac_dbg(0, "MC %d, total size %llu MiB\n", mc, imc->size >> 20);

        return 0;
}

#ifdef CONFIG_EDAC_DEBUG
/* Top of upper usable DRAM */
static u64 igen6_touud;
#define TOUUD_OFFSET    0xa8

static void igen6_reg_dump(struct igen6_imc *imc)
{
        int i;

        edac_dbg(2, "CHANNEL_HASH     : 0x%x\n",
                 readl(imc->window + CHANNEL_HASH_OFFSET));
        edac_dbg(2, "CHANNEL_EHASH    : 0x%x\n",
                 readl(imc->window + CHANNEL_EHASH_OFFSET));
        edac_dbg(2, "MAD_INTER_CHANNEL: 0x%x\n",
                 readl(imc->window + MAD_INTER_CHANNEL_OFFSET));
        edac_dbg(2, "ECC_ERROR_LOG    : 0x%llx\n",
                 readq(imc->window + ECC_ERROR_LOG_OFFSET));

        for (i = 0; i < NUM_CHANNELS; i++) {
                edac_dbg(2, "MAD_INTRA_CH%d    : 0x%x\n", i,
                         readl(imc->window + MAD_INTRA_CH0_OFFSET + i * 4));
                edac_dbg(2, "MAD_DIMM_CH%d     : 0x%x\n", i,
                         readl(imc->window + MAD_DIMM_CH0_OFFSET + i * 4));
        }
        edac_dbg(2, "TOLUD            : 0x%x", igen6_tolud);
        edac_dbg(2, "TOUUD            : 0x%llx", igen6_touud);
        edac_dbg(2, "TOM              : 0x%llx", igen6_tom);
}

static struct dentry *igen6_test;

static int debugfs_u64_set(void *data, u64 val)
{
        u64 ecclog;

        if ((val >= igen6_tolud && val < _4GB) || val >= igen6_touud) {
                edac_dbg(0, "Address 0x%llx out of range\n", val);
                return 0;
        }

        pr_warn_once("Fake error to 0x%llx injected via debugfs\n", val);

        val  >>= ECC_ERROR_LOG_ADDR_SHIFT;
        ecclog = (val << ECC_ERROR_LOG_ADDR_SHIFT) | ECC_ERROR_LOG_CE;

        if (!ecclog_gen_pool_add(0, ecclog))
                irq_work_queue(&ecclog_irq_work);

        return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");

static void igen6_debug_setup(void)
{
        igen6_test = edac_debugfs_create_dir("igen6_test");
        if (!igen6_test)
                return;

        if (!edac_debugfs_create_file("addr", 0200, igen6_test,
                                      NULL, &fops_u64_wo)) {
                debugfs_remove(igen6_test);
                igen6_test = NULL;
        }
}

static void igen6_debug_teardown(void)
{
        debugfs_remove_recursive(igen6_test);
}
#else
static void igen6_reg_dump(struct igen6_imc *imc) {}
static void igen6_debug_setup(void) {}
static void igen6_debug_teardown(void) {}
#endif

static int igen6_pci_setup(struct pci_dev *pdev, u64 *mchbar)
{
        union  {
                u64 v;
                struct {
                        u32 v_lo;
                        u32 v_hi;
                };
        } u;

        edac_dbg(2, "\n");

        if (!res_cfg->ibecc_available(pdev)) {
                edac_dbg(2, "No In-Band ECC IP\n");
                goto fail;
        }

        if (pci_read_config_dword(pdev, TOLUD_OFFSET, &igen6_tolud)) {
                igen6_printk(KERN_ERR, "Failed to read TOLUD\n");
                goto fail;
        }

        igen6_tolud &= GENMASK(31, 20);

        if (pci_read_config_dword(pdev, TOM_OFFSET, &u.v_lo)) {
                igen6_printk(KERN_ERR, "Failed to read lower TOM\n");
                goto fail;
        }

        if (pci_read_config_dword(pdev, TOM_OFFSET + 4, &u.v_hi)) {
                igen6_printk(KERN_ERR, "Failed to read upper TOM\n");
                goto fail;
        }

        igen6_tom = u.v & GENMASK_ULL(38, 20);

        if (pci_read_config_dword(pdev, MCHBAR_OFFSET, &u.v_lo)) {
                igen6_printk(KERN_ERR, "Failed to read lower MCHBAR\n");
                goto fail;
        }

        if (pci_read_config_dword(pdev, MCHBAR_OFFSET + 4, &u.v_hi)) {
                igen6_printk(KERN_ERR, "Failed to read upper MCHBAR\n");
                goto fail;
        }

        if (!(u.v & MCHBAR_EN)) {
                igen6_printk(KERN_ERR, "MCHBAR is disabled\n");
                goto fail;
        }

        *mchbar = MCHBAR_BASE(u.v);

#ifdef CONFIG_EDAC_DEBUG
        if (pci_read_config_dword(pdev, TOUUD_OFFSET, &u.v_lo))
                edac_dbg(2, "Failed to read lower TOUUD\n");
        else if (pci_read_config_dword(pdev, TOUUD_OFFSET + 4, &u.v_hi))
                edac_dbg(2, "Failed to read upper TOUUD\n");
        else
                igen6_touud = u.v & GENMASK_ULL(38, 20);
#endif

        return 0;
fail:
        return -ENODEV;

}

static int igen6_register_mci(int mc, u64 mchbar, struct pci_dev *pdev)
{
        struct edac_mc_layer layers[2];
        struct mem_ctl_info *mci;
        struct igen6_imc *imc;
        void __iomem *window;
        int rc;

        edac_dbg(2, "\n");

        mchbar += mc * MCHBAR_SIZE;
        window = ioremap(mchbar, MCHBAR_SIZE);
        if (!window) {
                igen6_printk(KERN_ERR, "Failed to ioremap 0x%llx\n", mchbar);
                return -ENODEV;
        }

        layers[0].type = EDAC_MC_LAYER_CHANNEL;
        layers[0].size = NUM_CHANNELS;
        layers[0].is_virt_csrow = false;
        layers[1].type = EDAC_MC_LAYER_SLOT;
        layers[1].size = NUM_DIMMS;
        layers[1].is_virt_csrow = true;

        mci = edac_mc_alloc(mc, ARRAY_SIZE(layers), layers, 0);
        if (!mci) {
                rc = -ENOMEM;
                goto fail;
        }

        mci->ctl_name = kasprintf(GFP_KERNEL, "Intel_client_SoC MC#%d", mc);
        if (!mci->ctl_name) {
                rc = -ENOMEM;
                goto fail2;
        }

        mci->mtype_cap = MEM_FLAG_LPDDR4 | MEM_FLAG_DDR4;
        mci->edac_ctl_cap = EDAC_FLAG_SECDED;
        mci->edac_cap = EDAC_FLAG_SECDED;
        mci->mod_name = EDAC_MOD_STR;
        mci->dev_name = pci_name(pdev);
        mci->pvt_info = &igen6_pvt->imc[mc];

        imc = mci->pvt_info;
        device_initialize(&imc->dev);
        /*
         * EDAC core uses mci->pdev(pointer of structure device) as
         * memory controller ID. The client SoCs attach one or more
         * memory controllers to single pci_dev (single pci_dev->dev
         * can be for multiple memory controllers).
         *
         * To make mci->pdev unique, assign pci_dev->dev to mci->pdev
         * for the first memory controller and assign a unique imc->dev
         * to mci->pdev for each non-first memory controller.
         */
        mci->pdev = mc ? &imc->dev : &pdev->dev;
        imc->mc = mc;
        imc->pdev = pdev;
        imc->window = window;

        igen6_reg_dump(imc);

        rc = igen6_get_dimm_config(mci);
        if (rc)
                goto fail3;

        rc = edac_mc_add_mc(mci);
        if (rc) {
                igen6_printk(KERN_ERR, "Failed to register mci#%d\n", mc);
                goto fail3;
        }

        imc->mci = mci;
        return 0;
fail3:
        kfree(mci->ctl_name);
fail2:
        edac_mc_free(mci);
fail:
        iounmap(window);
        return rc;
}

static void igen6_unregister_mcis(void)
{
        struct mem_ctl_info *mci;
        struct igen6_imc *imc;
        int i;

        edac_dbg(2, "\n");

        for (i = 0; i < res_cfg->num_imc; i++) {
                imc = &igen6_pvt->imc[i];
                mci = imc->mci;
                if (!mci)
                        continue;

                edac_mc_del_mc(mci->pdev);
                kfree(mci->ctl_name);
                edac_mc_free(mci);
                iounmap(imc->window);
        }
}

static int igen6_mem_slice_setup(u64 mchbar)
{
        struct igen6_imc *imc = &igen6_pvt->imc[0];
        u64 base = mchbar + res_cfg->cmf_base;
        u32 offset = res_cfg->ms_hash_offset;
        u32 size = res_cfg->cmf_size;
        u64 ms_s_size, ms_hash;
        void __iomem *cmf;
        int ms_l_map;

        edac_dbg(2, "\n");

        if (imc[0].size < imc[1].size) {
                ms_s_size = imc[0].size;
                ms_l_map  = 1;
        } else {
                ms_s_size = imc[1].size;
                ms_l_map  = 0;
        }

        igen6_pvt->ms_s_size = ms_s_size;
        igen6_pvt->ms_l_map  = ms_l_map;

        edac_dbg(0, "ms_s_size: %llu MiB, ms_l_map %d\n",
                 ms_s_size >> 20, ms_l_map);

        if (!size)
                return 0;

        cmf = ioremap(base, size);
        if (!cmf) {
                igen6_printk(KERN_ERR, "Failed to ioremap cmf 0x%llx\n", base);
                return -ENODEV;
        }

        ms_hash = readq(cmf + offset);
        igen6_pvt->ms_hash = ms_hash;

        edac_dbg(0, "MEM_SLICE_HASH: 0x%llx\n", ms_hash);

        iounmap(cmf);

        return 0;
}

static int register_err_handler(void)
{
        int rc;

        if (res_cfg->machine_check) {
                mce_register_decode_chain(&ecclog_mce_dec);
                return 0;
        }

        rc = register_nmi_handler(NMI_SERR, ecclog_nmi_handler,
                                  0, IGEN6_NMI_NAME);
        if (rc) {
                igen6_printk(KERN_ERR, "Failed to register NMI handler\n");
                return rc;
        }

        return 0;
}

static void unregister_err_handler(void)
{
        if (res_cfg->machine_check) {
                mce_unregister_decode_chain(&ecclog_mce_dec);
                return;
        }

        unregister_nmi_handler(NMI_SERR, IGEN6_NMI_NAME);
}

static int igen6_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        u64 mchbar;
        int i, rc;

        edac_dbg(2, "\n");

        igen6_pvt = kzalloc(sizeof(*igen6_pvt), GFP_KERNEL);
        if (!igen6_pvt)
                return -ENOMEM;

        res_cfg = (struct res_config *)ent->driver_data;

        rc = igen6_pci_setup(pdev, &mchbar);
        if (rc)
                goto fail;

        for (i = 0; i < res_cfg->num_imc; i++) {
                rc = igen6_register_mci(i, mchbar, pdev);
                if (rc)
                        goto fail2;
        }

        if (res_cfg->num_imc > 1) {
                rc = igen6_mem_slice_setup(mchbar);
                if (rc)
                        goto fail2;
        }

        ecclog_pool = ecclog_gen_pool_create();
        if (!ecclog_pool) {
                rc = -ENOMEM;
                goto fail2;
        }

        INIT_WORK(&ecclog_work, ecclog_work_cb);
        init_irq_work(&ecclog_irq_work, ecclog_irq_work_cb);

        /* Check if any pending errors before registering the NMI handler */
        ecclog_handler();

        rc = register_err_handler();
        if (rc)
                goto fail3;

        /* Enable error reporting */
        rc = errcmd_enable_error_reporting(true);
        if (rc) {
                igen6_printk(KERN_ERR, "Failed to enable error reporting\n");
                goto fail4;
        }

        igen6_debug_setup();
        return 0;
fail4:
        unregister_nmi_handler(NMI_SERR, IGEN6_NMI_NAME);
fail3:
        gen_pool_destroy(ecclog_pool);
fail2:
        igen6_unregister_mcis();
fail:
        kfree(igen6_pvt);
        return rc;
}

static void igen6_remove(struct pci_dev *pdev)
{
        edac_dbg(2, "\n");

        igen6_debug_teardown();
        errcmd_enable_error_reporting(false);
        unregister_err_handler();
        irq_work_sync(&ecclog_irq_work);
        flush_work(&ecclog_work);
        gen_pool_destroy(ecclog_pool);
        igen6_unregister_mcis();
        kfree(igen6_pvt);
}

static struct pci_driver igen6_driver = {
        .name     = EDAC_MOD_STR,
        .probe    = igen6_probe,
        .remove   = igen6_remove,
        .id_table = igen6_pci_tbl,
};

static int __init igen6_init(void)
{
        const char *owner;
        int rc;

        edac_dbg(2, "\n");

        owner = edac_get_owner();
        if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
                return -ENODEV;

        edac_op_state = EDAC_OPSTATE_NMI;

        rc = pci_register_driver(&igen6_driver);
        if (rc)
                return rc;

        igen6_printk(KERN_INFO, "%s\n", IGEN6_REVISION);

        return 0;
}

static void __exit igen6_exit(void)
{
        edac_dbg(2, "\n");

        pci_unregister_driver(&igen6_driver);
}

module_init(igen6_init);
module_exit(igen6_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Qiuxu Zhuo");
MODULE_DESCRIPTION("MC Driver for Intel client SoC using In-Band ECC");