// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2020 SiFive, Inc.
 *
 * Based on board/freescale/common/sys_eeprom.c:
 * Copyright 2006, 2008-2009, 2011 Freescale Semiconductor
 * York Sun (yorksun@freescale.com)
 * Haiying Wang (haiying.wang@freescale.com)
 * Timur Tabi (timur@freescale.com)
 */

#include <common.h>
#include <command.h>
#include <env.h>
#include <i2c.h>
#include <init.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <u-boot/crc.h>

#ifndef CONFIG_SYS_EEPROM_BUS_NUM
#error Requires CONFIG_SYS_EEPROM_BUS_NUM to be defined
#endif

#define FORMAT_VERSION                          0x1

/* Options for the manuf_test_status field */
#define SIFIVE_MANUF_TEST_STATUS_UNKNOWN        0
#define SIFIVE_MANUF_TEST_STATUS_PASS           1
#define SIFIVE_MANUF_TEST_STATUS_FAIL           2

/*
 * BYTES_PER_EEPROM_PAGE: the AT24C02 datasheet says that data can
 * only be written in page mode, which means 8 bytes at a time
 */
#define BYTES_PER_EEPROM_PAGE                   8

/*
 * EEPROM_WRITE_DELAY_MS: the AT24C02 datasheet says it takes up to
 * 5ms to complete a given write
 */
#define EEPROM_WRITE_DELAY_MS                   5000

/*
 * MAGIC_NUMBER_BYTES: number of bytes used by the magic number
 */
#define MAGIC_NUMBER_BYTES                      4

/*
 * SERIAL_NUMBER_BYTES: number of bytes used by the board serial
 * number
 */
#define SERIAL_NUMBER_BYTES                     16

/*
 * MAC_ADDR_BYTES: number of bytes used by the Ethernet MAC address
 */
#define MAC_ADDR_BYTES                          6

/*
 * MAC_ADDR_STRLEN: length of mac address string
 */
#define MAC_ADDR_STRLEN                         17

/*
 * SiFive OUI. Registration Date is 2018-02-15
 */
#define SIFIVE_OUI_PREFIX                       "70:B3:D5:92:F"

/**
 * static eeprom: EEPROM layout for the SiFive platform I2C format
 */
static struct __attribute__ ((__packed__)) sifive_eeprom {
        u8 magic[MAGIC_NUMBER_BYTES];
        u8 format_ver;
        u16 product_id;
        u8 pcb_revision;
        u8 bom_revision;
        u8 bom_variant;
        u8 serial[SERIAL_NUMBER_BYTES];
        u8 manuf_test_status;
        u8 mac_addr[MAC_ADDR_BYTES];
        u32 crc;
} e;

struct sifive_product {
        u16 id;
        const char *name;
};

/* Set to 1 if we've read EEPROM into memory */
static int has_been_read;

/* Magic number at the first four bytes of EEPROM */
static const unsigned char magic[MAGIC_NUMBER_BYTES] = { 0xf1, 0x5e, 0x50, 0x45 };

/* Does the magic number match that of a SiFive EEPROM? */
static inline int is_match_magic(void)
{
        return (memcmp(&e.magic, &magic, MAGIC_NUMBER_BYTES) == 0);
}

/* Calculate the current CRC */
static inline u32 calculate_crc32(void)
{
        return crc32(0, (void *)&e, sizeof(struct sifive_eeprom) - sizeof(e.crc));
}

/* This function should be called after each update to the EEPROM structure */
static inline void update_crc(void)
{
        e.crc = calculate_crc32();
}

static struct sifive_product sifive_products[] = {
        { 0, "Unknown"},
        { 2, "HiFive Unmatched" },
};

/**
 * dump_raw_eeprom - display the raw contents of the EEPROM
 */
static void dump_raw_eeprom(void)
{
        unsigned int i;

        printf("EEPROM dump: (0x%lx bytes)\n", sizeof(e));
        for (i = 0; i < sizeof(e); i++) {
                if ((i % 16) == 0)
                        printf("%02X: ", i);
                printf("%02X ", ((u8 *)&e)[i]);
                if (((i % 16) == 15) || (i == sizeof(e) - 1))
                        printf("\n");
        }
}

/**
 * show_eeprom - display the contents of the EEPROM
 */
static void show_eeprom(void)
{
        unsigned int i;
        u32 crc;
        const char *product_name = "Unknown";
        char board_serial[SERIAL_NUMBER_BYTES + 1] = { 0 };

        if (!is_match_magic()) {
                printf("Not a SiFive HiFive EEPROM data format - magic bytes don't match\n");
                dump_raw_eeprom();
                return;
        };

        snprintf(board_serial, sizeof(board_serial), "%s", e.serial);

        for (i = 0; i < ARRAY_SIZE(sifive_products); i++) {
                if (sifive_products[i].id == e.product_id) {
                        product_name = sifive_products[i].name;
                        break;
                }
        };

        printf("SiFive PCB EEPROM format v%u\n", e.format_ver);
        printf("Product ID: %04hx (%s)\n", e.product_id, product_name);
        printf("PCB revision: %x\n", e.pcb_revision);
        printf("BOM revision: %c\n", e.bom_revision);
        printf("BOM variant: %x\n", e.bom_variant);
        printf("Serial number: %s\n", board_serial);
        printf("Ethernet MAC address: %02x:%02x:%02x:%02x:%02x:%02x\n",
               e.mac_addr[0], e.mac_addr[1], e.mac_addr[2],
               e.mac_addr[3], e.mac_addr[4], e.mac_addr[5]);

        crc = calculate_crc32();
        if (crc == e.crc) {
                printf("CRC: %08x\n", e.crc);
        } else {
                printf("CRC: %08x (should be %08x)\n", e.crc, crc);
                dump_raw_eeprom();
        }
}

/**
 * read_eeprom() - read the EEPROM into memory, if it hasn't been read already
 */
static int read_eeprom(void)
{
        int ret;
        struct udevice *dev;

        if (has_been_read)
                return 0;

        ret = i2c_get_chip_for_busnum(CONFIG_SYS_EEPROM_BUS_NUM,
                                      CONFIG_SYS_I2C_EEPROM_ADDR,
                                      1,
                                      &dev);
        if (!ret)
                dm_i2c_read(dev, 0, (void *)&e,
                            sizeof(struct sifive_eeprom));

        show_eeprom();

        has_been_read = (ret == 0) ? 1 : 0;

        return ret;
}

/**
 * prog_eeprom() - write the EEPROM from memory
 */
static int prog_eeprom(void)
{
        int ret = 0;
        unsigned int i;
        void *p;

        if (!is_match_magic()) {
                printf("Please read the EEPROM ('read_eeprom') and/or initialize the EEPROM ('initialize') first.\n");
                return 0;
        }

        for (i = 0, p = &e; i < sizeof(e);
             i += BYTES_PER_EEPROM_PAGE, p += BYTES_PER_EEPROM_PAGE) {
                struct udevice *dev;

                ret = i2c_get_chip_for_busnum(CONFIG_SYS_EEPROM_BUS_NUM,
                                              CONFIG_SYS_I2C_EEPROM_ADDR,
                                              CONFIG_SYS_I2C_EEPROM_ADDR_LEN,
                                              &dev);
                if (!ret)
                        ret = dm_i2c_write(dev, i, p,
                                           min((int)(sizeof(e) - i),
                                               BYTES_PER_EEPROM_PAGE));

                if (ret)
                        break;

                udelay(EEPROM_WRITE_DELAY_MS);
        }

        if (!ret) {
                /* Verify the write by reading back the EEPROM and comparing */
                struct sifive_eeprom e2;
                struct udevice *dev;

                ret = i2c_get_chip_for_busnum(CONFIG_SYS_EEPROM_BUS_NUM,
                                              CONFIG_SYS_I2C_EEPROM_ADDR,
                                              CONFIG_SYS_I2C_EEPROM_ADDR_LEN,
                                              &dev);
                if (!ret)
                        ret = dm_i2c_read(dev, 0, (void *)&e2, sizeof(e2));
                if (!ret && memcmp(&e, &e2, sizeof(e)))
                        ret = -1;
        }

        if (ret) {
                printf("Programming failed.\n");
                has_been_read = 0;
                return -1;
        }

        printf("Programming passed.\n");
        return 0;
}

/**
 * set_mac_address() - stores a MAC address into the local EEPROM copy
 *
 * This function takes a pointer to MAC address string
 * (i.e."XX:XX:XX:XX:XX:XX", where "XX" is a two-digit hex number),
 * stores it in the MAC address field of the EEPROM local copy, and
 * updates the local copy of the CRC.
 */
static void set_mac_address(char *string)
{
        unsigned int i;

        if (strncasecmp(SIFIVE_OUI_PREFIX, string, 13)) {
                printf("The MAC address doesn't match SiFive OUI %s\n",
                       SIFIVE_OUI_PREFIX);
                return;
        }

        for (i = 0; *string && (i < MAC_ADDR_BYTES); i++) {
                e.mac_addr[i] = hextoul(string, &string);
                if (*string == ':')
                        string++;
        }

        update_crc();
}

/**
 * set_manuf_test_status() - stores a test status byte into the in-memory copy
 *
 * Takes a pointer to a manufacturing test status string ("unknown",
 * "pass", "fail") and stores the corresponding numeric ID to the
 * manuf_test_status field of the EEPROM local copy, and updates the
 * CRC of the local copy.
 */
static void set_manuf_test_status(char *string)
{
        if (!strcasecmp(string, "unknown")) {
                e.manuf_test_status = SIFIVE_MANUF_TEST_STATUS_UNKNOWN;
        } else if (!strcasecmp(string, "pass")) {
                e.manuf_test_status = SIFIVE_MANUF_TEST_STATUS_PASS;
        } else if (!strcasecmp(string, "fail")) {
                e.manuf_test_status = SIFIVE_MANUF_TEST_STATUS_FAIL;
        } else {
                printf("Usage: mac manuf_test_status (unknown|pass|fail)\n");
                return;
        }

        update_crc();
}

/**
 * set_pcb_revision() - stores a SiFive PCB revision into the local EEPROM copy
 *
 * Takes a pointer to a string representing the numeric PCB revision in
 * decimal ("0" - "255"), stores it in the pcb_revision field of the
 * EEPROM local copy, and updates the CRC of the local copy.
 */
static void set_pcb_revision(char *string)
{
        unsigned long p;

        p = dectoul(string, &string);
        if (p > U8_MAX) {
                printf("%s must not be greater than %d\n", "PCB revision",
                       U8_MAX);
                return;
        }

        e.pcb_revision = p;

        update_crc();
}

/**
 * set_bom_revision() - stores a SiFive BOM revision into the local EEPROM copy
 *
 * Takes a pointer to a uppercase ASCII character representing the BOM
 * revision ("A" - "Z"), stores it in the bom_revision field of the
 * EEPROM local copy, and updates the CRC of the local copy.
 */
static void set_bom_revision(char *string)
{
        if (string[0] < 'A' || string[0] > 'Z') {
                printf("BOM revision must be an uppercase letter between A and Z\n");
                return;
        }

        e.bom_revision = string[0];

        update_crc();
}

/**
 * set_bom_variant() - stores a SiFive BOM variant into the local EEPROM copy
 *
 * Takes a pointer to a string representing the numeric BOM variant in
 * decimal ("0" - "255"), stores it in the bom_variant field of the
 * EEPROM local copy, and updates the CRC of the local copy.
 */
static void set_bom_variant(char *string)
{
        unsigned long p;

        p = dectoul(string, &string);
        if (p > U8_MAX) {
                printf("%s must not be greater than %d\n", "BOM variant",
                       U8_MAX);
                return;
        }

        e.bom_variant = p;

        update_crc();
}

/**
 * set_product_id() - stores a SiFive product ID into the local EEPROM copy
 *
 * Takes a pointer to a string representing the numeric product ID  in
 * decimal ("0" - "65535"), stores it in the product ID field of the
 * EEPROM local copy, and updates the CRC of the local copy.
 */
static void set_product_id(char *string)
{
        unsigned long p;

        p = dectoul(string, &string);
        if (p > U16_MAX) {
                printf("%s must not be greater than %d\n", "Product ID",
                       U16_MAX);
                return;
        }

        e.product_id = p;

        update_crc();
}

/**
 * init_local_copy() - initialize the in-memory EEPROM copy
 *
 * Initialize the in-memory EEPROM copy with the magic number.  Must
 * be done when preparing to initialize a blank EEPROM, or overwrite
 * one with a corrupted magic number.
 */
static void init_local_copy(void)
{
        memset(&e, 0, sizeof(e));
        memcpy(e.magic, magic, sizeof(e.magic));
        e.format_ver = FORMAT_VERSION;
        update_crc();
}

int do_mac(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
{
        char *cmd;

        if (argc == 1) {
                show_eeprom();
                return 0;
        }

        if (argc > 3)
                return cmd_usage(cmdtp);

        cmd = argv[1];

        /* Commands with no argument */
        if (!strcmp(cmd, "read_eeprom")) {
                read_eeprom();
                return 0;
        } else if (!strcmp(cmd, "initialize")) {
                init_local_copy();
                return 0;
        } else if (!strcmp(cmd, "write_eeprom")) {
                prog_eeprom();
                return 0;
        }

        if (argc != 3)
                return cmd_usage(cmdtp);

        if (!is_match_magic()) {
                printf("Please read the EEPROM ('read_eeprom') and/or initialize the EEPROM ('initialize') first.\n");
                return 0;
        }

        if (!strcmp(cmd, "manuf_test_status")) {
                set_manuf_test_status(argv[2]);
                return 0;
        } else if (!strcmp(cmd, "mac_address")) {
                set_mac_address(argv[2]);
                return 0;
        } else if (!strcmp(cmd, "pcb_revision")) {
                set_pcb_revision(argv[2]);
                return 0;
        } else if (!strcmp(cmd, "bom_variant")) {
                set_bom_variant(argv[2]);
                return 0;
        } else if (!strcmp(cmd, "bom_revision")) {
                set_bom_revision(argv[2]);
                return 0;
        } else if (!strcmp(cmd, "product_id")) {
                set_product_id(argv[2]);
                return 0;
        }

        return cmd_usage(cmdtp);
}

/**
 * mac_read_from_eeprom() - read the MAC address from EEPROM
 *
 * This function reads the MAC address from EEPROM and sets the
 * appropriate environment variables for each one read.
 *
 * The environment variables are only set if they haven't been set already.
 * This ensures that any user-saved variables are never overwritten.
 *
 * This function must be called after relocation.
 */
int mac_read_from_eeprom(void)
{
        u32 crc;
        char board_serial[SERIAL_NUMBER_BYTES + 1] = { 0 };

        puts("EEPROM: ");

        if (read_eeprom()) {
                printf("Read failed.\n");
                return 0;
        }

        if (!is_match_magic()) {
                printf("Invalid ID (%02x %02x %02x %02x)\n",
                       e.magic[0], e.magic[1], e.magic[2], e.magic[3]);
                dump_raw_eeprom();
                return 0;
        }

        crc = calculate_crc32();
        if (crc != e.crc) {
                printf("CRC mismatch (%08x != %08x)\n", crc, e.crc);
                dump_raw_eeprom();
                return 0;
        }

        eth_env_set_enetaddr("ethaddr", e.mac_addr);

        if (!env_get("serial#")) {
                snprintf(board_serial, sizeof(board_serial), "%s", e.serial);
                env_set("serial#", board_serial);
        }

        return 0;
}

/**
 * get_pcb_revision_from_eeprom - get the PCB revision
 *
 * Read the EEPROM to determine the board revision.
 *
 * This function is called before relocation, so we need to read a private
 * copy of the EEPROM into a local variable on the stack.
 */
u8 get_pcb_revision_from_eeprom(void)
{
        struct __attribute__ ((__packed__)) board_eeprom {
                u8 magic[MAGIC_NUMBER_BYTES];
                u8 format_ver;
                u16 product_id;
                u8 pcb_revision;
        } be;

        int ret;
        struct udevice *dev;

        ret = i2c_get_chip_for_busnum(CONFIG_SYS_EEPROM_BUS_NUM,
                                      CONFIG_SYS_I2C_EEPROM_ADDR,
                                      1,
                                      &dev);

        if (!ret)
                dm_i2c_read(dev, 0, (void *)&be,
                            sizeof(struct board_eeprom));

        return be.pcb_revision;
}