/*
 * Copyright 2019 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include "amdgpu_ras_eeprom.h"
#include "amdgpu.h"
#include "amdgpu_ras.h"
#include <linux/bits.h>
#include "atom.h"

#define EEPROM_I2C_TARGET_ADDR_VEGA20           0xA0
#define EEPROM_I2C_TARGET_ADDR_ARCTURUS         0xA8
#define EEPROM_I2C_TARGET_ADDR_ARCTURUS_D342    0xA0

/*
 * The 2 macros bellow represent the actual size in bytes that
 * those entities occupy in the EEPROM memory.
 * EEPROM_TABLE_RECORD_SIZE is different than sizeof(eeprom_table_record) which
 * uses uint64 to store 6b fields such as retired_page.
 */
#define EEPROM_TABLE_HEADER_SIZE 20
#define EEPROM_TABLE_RECORD_SIZE 24

#define EEPROM_ADDRESS_SIZE 0x2

/* Table hdr is 'AMDR' */
#define EEPROM_TABLE_HDR_VAL 0x414d4452
#define EEPROM_TABLE_VER 0x00010000

/* Assume 2 Mbit size */
#define EEPROM_SIZE_BYTES 256000
#define EEPROM_PAGE__SIZE_BYTES 256
#define EEPROM_HDR_START 0
#define EEPROM_RECORD_START (EEPROM_HDR_START + EEPROM_TABLE_HEADER_SIZE)
#define EEPROM_MAX_RECORD_NUM ((EEPROM_SIZE_BYTES - EEPROM_TABLE_HEADER_SIZE) / EEPROM_TABLE_RECORD_SIZE)
#define EEPROM_ADDR_MSB_MASK GENMASK(17, 8)

#define to_amdgpu_device(x) (container_of(x, struct amdgpu_ras, eeprom_control))->adev

static bool __get_eeprom_i2c_addr_arct(struct amdgpu_device *adev,
                                       uint16_t *i2c_addr)
{
        struct atom_context *atom_ctx = adev->mode_info.atom_context;

        if (!i2c_addr || !atom_ctx)
                return false;

        if (strnstr(atom_ctx->vbios_version,
                    "D342",
                    sizeof(atom_ctx->vbios_version)))
                *i2c_addr = EEPROM_I2C_TARGET_ADDR_ARCTURUS_D342;
        else
                *i2c_addr = EEPROM_I2C_TARGET_ADDR_ARCTURUS;

        return true;
}

static bool __get_eeprom_i2c_addr(struct amdgpu_device *adev,
                                  uint16_t *i2c_addr)
{
        if (!i2c_addr)
                return false;

        switch (adev->asic_type) {
        case CHIP_VEGA20:
                *i2c_addr = EEPROM_I2C_TARGET_ADDR_VEGA20;
                break;

        case CHIP_ARCTURUS:
                return __get_eeprom_i2c_addr_arct(adev, i2c_addr);

        default:
                return false;
        }

        return true;
}

static void __encode_table_header_to_buff(struct amdgpu_ras_eeprom_table_header *hdr,
                                          unsigned char *buff)
{
        uint32_t *pp = (uint32_t *) buff;

        pp[0] = cpu_to_le32(hdr->header);
        pp[1] = cpu_to_le32(hdr->version);
        pp[2] = cpu_to_le32(hdr->first_rec_offset);
        pp[3] = cpu_to_le32(hdr->tbl_size);
        pp[4] = cpu_to_le32(hdr->checksum);
}

static void __decode_table_header_from_buff(struct amdgpu_ras_eeprom_table_header *hdr,
                                          unsigned char *buff)
{
        uint32_t *pp = (uint32_t *)buff;

        hdr->header           = le32_to_cpu(pp[0]);
        hdr->version          = le32_to_cpu(pp[1]);
        hdr->first_rec_offset = le32_to_cpu(pp[2]);
        hdr->tbl_size         = le32_to_cpu(pp[3]);
        hdr->checksum         = le32_to_cpu(pp[4]);
}

static int __update_table_header(struct amdgpu_ras_eeprom_control *control,
                                 unsigned char *buff)
{
        int ret = 0;
        struct amdgpu_device *adev = to_amdgpu_device(control);
        struct i2c_msg msg = {
                        .addr   = 0,
                        .flags  = 0,
                        .len    = EEPROM_ADDRESS_SIZE + EEPROM_TABLE_HEADER_SIZE,
                        .buf    = buff,
        };


        *(uint16_t *)buff = EEPROM_HDR_START;
        __encode_table_header_to_buff(&control->tbl_hdr, buff + EEPROM_ADDRESS_SIZE);

        msg.addr = control->i2c_address;

        ret = i2c_transfer(&adev->pm.smu_i2c, &msg, 1);
        if (ret < 1)
                DRM_ERROR("Failed to write EEPROM table header, ret:%d", ret);

        return ret;
}

static uint32_t  __calc_hdr_byte_sum(struct amdgpu_ras_eeprom_control *control)
{
        int i;
        uint32_t tbl_sum = 0;

        /* Header checksum, skip checksum field in the calculation */
        for (i = 0; i < sizeof(control->tbl_hdr) - sizeof(control->tbl_hdr.checksum); i++)
                tbl_sum += *(((unsigned char *)&control->tbl_hdr) + i);

        return tbl_sum;
}

static uint32_t  __calc_recs_byte_sum(struct eeprom_table_record *records,
                                      int num)
{
        int i, j;
        uint32_t tbl_sum = 0;

        /* Records checksum */
        for (i = 0; i < num; i++) {
                struct eeprom_table_record *record = &records[i];

                for (j = 0; j < sizeof(*record); j++) {
                        tbl_sum += *(((unsigned char *)record) + j);
                }
        }

        return tbl_sum;
}

static inline uint32_t  __calc_tbl_byte_sum(struct amdgpu_ras_eeprom_control *control,
                                  struct eeprom_table_record *records, int num)
{
        return __calc_hdr_byte_sum(control) + __calc_recs_byte_sum(records, num);
}

/* Checksum = 256 -((sum of all table entries) mod 256) */
static void __update_tbl_checksum(struct amdgpu_ras_eeprom_control *control,
                                  struct eeprom_table_record *records, int num,
                                  uint32_t old_hdr_byte_sum)
{
        /*
         * This will update the table sum with new records.
         *
         * TODO: What happens when the EEPROM table is to be wrapped around
         * and old records from start will get overridden.
         */

        /* need to recalculate updated header byte sum */
        control->tbl_byte_sum -= old_hdr_byte_sum;
        control->tbl_byte_sum += __calc_tbl_byte_sum(control, records, num);

        control->tbl_hdr.checksum = 256 - (control->tbl_byte_sum % 256);
}

/* table sum mod 256 + checksum must equals 256 */
static bool __validate_tbl_checksum(struct amdgpu_ras_eeprom_control *control,
                            struct eeprom_table_record *records, int num)
{
        control->tbl_byte_sum = __calc_tbl_byte_sum(control, records, num);

        if (control->tbl_hdr.checksum + (control->tbl_byte_sum % 256) != 256) {
                DRM_WARN("Checksum mismatch, checksum: %u ", control->tbl_hdr.checksum);
                return false;
        }

        return true;
}

int amdgpu_ras_eeprom_reset_table(struct amdgpu_ras_eeprom_control *control)
{
        unsigned char buff[EEPROM_ADDRESS_SIZE + EEPROM_TABLE_HEADER_SIZE] = { 0 };
        struct amdgpu_ras_eeprom_table_header *hdr = &control->tbl_hdr;
        int ret = 0;

        mutex_lock(&control->tbl_mutex);

        hdr->header = EEPROM_TABLE_HDR_VAL;
        hdr->version = EEPROM_TABLE_VER;
        hdr->first_rec_offset = EEPROM_RECORD_START;
        hdr->tbl_size = EEPROM_TABLE_HEADER_SIZE;

        control->tbl_byte_sum = 0;
        __update_tbl_checksum(control, NULL, 0, 0);
        control->next_addr = EEPROM_RECORD_START;

        ret = __update_table_header(control, buff);

        mutex_unlock(&control->tbl_mutex);

        return ret;

}

int amdgpu_ras_eeprom_init(struct amdgpu_ras_eeprom_control *control)
{
        int ret = 0;
        struct amdgpu_device *adev = to_amdgpu_device(control);
        unsigned char buff[EEPROM_ADDRESS_SIZE + EEPROM_TABLE_HEADER_SIZE] = { 0 };
        struct amdgpu_ras_eeprom_table_header *hdr = &control->tbl_hdr;
        struct i2c_msg msg = {
                        .addr   = 0,
                        .flags  = I2C_M_RD,
                        .len    = EEPROM_ADDRESS_SIZE + EEPROM_TABLE_HEADER_SIZE,
                        .buf    = buff,
        };

        /* Verify i2c adapter is initialized */
        if (!adev->pm.smu_i2c.algo)
                return -ENOENT;

        if (!__get_eeprom_i2c_addr(adev, &control->i2c_address))
                return -EINVAL;

        mutex_init(&control->tbl_mutex);

        msg.addr = control->i2c_address;
        /* Read/Create table header from EEPROM address 0 */
        ret = i2c_transfer(&adev->pm.smu_i2c, &msg, 1);
        if (ret < 1) {
                DRM_ERROR("Failed to read EEPROM table header, ret:%d", ret);
                return ret;
        }

        __decode_table_header_from_buff(hdr, &buff[2]);

        if (hdr->header == EEPROM_TABLE_HDR_VAL) {
                control->num_recs = (hdr->tbl_size - EEPROM_TABLE_HEADER_SIZE) /
                                    EEPROM_TABLE_RECORD_SIZE;
                control->tbl_byte_sum = __calc_hdr_byte_sum(control);
                control->next_addr = EEPROM_RECORD_START;

                DRM_DEBUG_DRIVER("Found existing EEPROM table with %d records",
                                 control->num_recs);

        } else {
                DRM_INFO("Creating new EEPROM table");

                ret = amdgpu_ras_eeprom_reset_table(control);
        }

        return ret == 1 ? 0 : -EIO;
}

static void __encode_table_record_to_buff(struct amdgpu_ras_eeprom_control *control,
                                          struct eeprom_table_record *record,
                                          unsigned char *buff)
{
        __le64 tmp = 0;
        int i = 0;

        /* Next are all record fields according to EEPROM page spec in LE foramt */
        buff[i++] = record->err_type;

        buff[i++] = record->bank;

        tmp = cpu_to_le64(record->ts);
        memcpy(buff + i, &tmp, 8);
        i += 8;

        tmp = cpu_to_le64((record->offset & 0xffffffffffff));
        memcpy(buff + i, &tmp, 6);
        i += 6;

        buff[i++] = record->mem_channel;
        buff[i++] = record->mcumc_id;

        tmp = cpu_to_le64((record->retired_page & 0xffffffffffff));
        memcpy(buff + i, &tmp, 6);
}

static void __decode_table_record_from_buff(struct amdgpu_ras_eeprom_control *control,
                                            struct eeprom_table_record *record,
                                            unsigned char *buff)
{
        __le64 tmp = 0;
        int i =  0;

        /* Next are all record fields according to EEPROM page spec in LE foramt */
        record->err_type = buff[i++];

        record->bank = buff[i++];

        memcpy(&tmp, buff + i, 8);
        record->ts = le64_to_cpu(tmp);
        i += 8;

        memcpy(&tmp, buff + i, 6);
        record->offset = (le64_to_cpu(tmp) & 0xffffffffffff);
        i += 6;

        record->mem_channel = buff[i++];
        record->mcumc_id = buff[i++];

        memcpy(&tmp, buff + i,  6);
        record->retired_page = (le64_to_cpu(tmp) & 0xffffffffffff);
}

/*
 * When reaching end of EEPROM memory jump back to 0 record address
 * When next record access will go beyond EEPROM page boundary modify bits A17/A8
 * in I2C selector to go to next page
 */
static uint32_t __correct_eeprom_dest_address(uint32_t curr_address)
{
        uint32_t next_address = curr_address + EEPROM_TABLE_RECORD_SIZE;

        /* When all EEPROM memory used jump back to 0 address */
        if (next_address > EEPROM_SIZE_BYTES) {
                DRM_INFO("Reached end of EEPROM memory, jumping to 0 "
                         "and overriding old record");
                return EEPROM_RECORD_START;
        }

        /*
         * To check if we overflow page boundary  compare next address with
         * current and see if bits 17/8 of the EEPROM address will change
         * If they do start from the next 256b page
         *
         * https://www.st.com/resource/en/datasheet/m24m02-dr.pdf sec. 5.1.2
         */
        if ((curr_address & EEPROM_ADDR_MSB_MASK) != (next_address & EEPROM_ADDR_MSB_MASK)) {
                DRM_DEBUG_DRIVER("Reached end of EEPROM memory page, jumping to next: %lx",
                                (next_address & EEPROM_ADDR_MSB_MASK));

                return  (next_address & EEPROM_ADDR_MSB_MASK);
        }

        return curr_address;
}

int amdgpu_ras_eeprom_process_recods(struct amdgpu_ras_eeprom_control *control,
                                            struct eeprom_table_record *records,
                                            bool write,
                                            int num)
{
        int i, ret = 0;
        struct i2c_msg *msgs, *msg;
        unsigned char *buffs, *buff;
        struct eeprom_table_record *record;
        struct amdgpu_device *adev = to_amdgpu_device(control);

        if (adev->asic_type != CHIP_VEGA20 && adev->asic_type != CHIP_ARCTURUS)
                return 0;

        buffs = kcalloc(num, EEPROM_ADDRESS_SIZE + EEPROM_TABLE_RECORD_SIZE,
                         GFP_KERNEL);
        if (!buffs)
                return -ENOMEM;

        mutex_lock(&control->tbl_mutex);

        msgs = kcalloc(num, sizeof(*msgs), GFP_KERNEL);
        if (!msgs) {
                ret = -ENOMEM;
                goto free_buff;
        }

        /* In case of overflow just start from beginning to not lose newest records */
        if (write && (control->next_addr + EEPROM_TABLE_RECORD_SIZE * num > EEPROM_SIZE_BYTES))
                control->next_addr = EEPROM_RECORD_START;


        /*
         * TODO Currently makes EEPROM writes for each record, this creates
         * internal fragmentation. Optimized the code to do full page write of
         * 256b
         */
        for (i = 0; i < num; i++) {
                buff = &buffs[i * (EEPROM_ADDRESS_SIZE + EEPROM_TABLE_RECORD_SIZE)];
                record = &records[i];
                msg = &msgs[i];

                control->next_addr = __correct_eeprom_dest_address(control->next_addr);

                /*
                 * Update bits 16,17 of EEPROM address in I2C address by setting them
                 * to bits 1,2 of Device address byte
                 */
                msg->addr = control->i2c_address |
                                ((control->next_addr & EEPROM_ADDR_MSB_MASK) >> 15);
                msg->flags      = write ? 0 : I2C_M_RD;
                msg->len        = EEPROM_ADDRESS_SIZE + EEPROM_TABLE_RECORD_SIZE;
                msg->buf        = buff;

                /* Insert the EEPROM dest addess, bits 0-15 */
                buff[0] = ((control->next_addr >> 8) & 0xff);
                buff[1] = (control->next_addr & 0xff);

                /* EEPROM table content is stored in LE format */
                if (write)
                        __encode_table_record_to_buff(control, record, buff + EEPROM_ADDRESS_SIZE);

                /*
                 * The destination EEPROM address might need to be corrected to account
                 * for page or entire memory wrapping
                 */
                control->next_addr += EEPROM_TABLE_RECORD_SIZE;
        }

        ret = i2c_transfer(&adev->pm.smu_i2c, msgs, num);
        if (ret < 1) {
                DRM_ERROR("Failed to process EEPROM table records, ret:%d", ret);

                /* TODO Restore prev next EEPROM address ? */
                goto free_msgs;
        }


        if (!write) {
                for (i = 0; i < num; i++) {
                        buff = &buffs[i*(EEPROM_ADDRESS_SIZE + EEPROM_TABLE_RECORD_SIZE)];
                        record = &records[i];

                        __decode_table_record_from_buff(control, record, buff + EEPROM_ADDRESS_SIZE);
                }
        }

        if (write) {
                uint32_t old_hdr_byte_sum = __calc_hdr_byte_sum(control);

                /*
                 * Update table header with size and CRC and account for table
                 * wrap around where the assumption is that we treat it as empty
                 * table
                 *
                 * TODO - Check the assumption is correct
                 */
                control->num_recs += num;
                control->num_recs %= EEPROM_MAX_RECORD_NUM;
                control->tbl_hdr.tbl_size += EEPROM_TABLE_RECORD_SIZE * num;
                if (control->tbl_hdr.tbl_size > EEPROM_SIZE_BYTES)
                        control->tbl_hdr.tbl_size = EEPROM_TABLE_HEADER_SIZE +
                        control->num_recs * EEPROM_TABLE_RECORD_SIZE;

                __update_tbl_checksum(control, records, num, old_hdr_byte_sum);

                __update_table_header(control, buffs);
        } else if (!__validate_tbl_checksum(control, records, num)) {
                DRM_WARN("EEPROM Table checksum mismatch!");
                /* TODO Uncomment when EEPROM read/write is relliable */
                /* ret = -EIO; */
        }

free_msgs:
        kfree(msgs);

free_buff:
        kfree(buffs);

        mutex_unlock(&control->tbl_mutex);

        return ret == num ? 0 : -EIO;
}

/* Used for testing if bugs encountered */
#if 0
void amdgpu_ras_eeprom_test(struct amdgpu_ras_eeprom_control *control)
{
        int i;
        struct eeprom_table_record *recs = kcalloc(1, sizeof(*recs), GFP_KERNEL);

        if (!recs)
                return;

        for (i = 0; i < 1 ; i++) {
                recs[i].address = 0xdeadbeef;
                recs[i].retired_page = i;
        }

        if (!amdgpu_ras_eeprom_process_recods(control, recs, true, 1)) {

                memset(recs, 0, sizeof(*recs) * 1);

                control->next_addr = EEPROM_RECORD_START;

                if (!amdgpu_ras_eeprom_process_recods(control, recs, false, 1)) {
                        for (i = 0; i < 1; i++)
                                DRM_INFO("rec.address :0x%llx, rec.retired_page :%llu",
                                         recs[i].address, recs[i].retired_page);
                } else
                        DRM_ERROR("Failed in reading from table");

        } else
                DRM_ERROR("Failed in writing to table");
}
#endif