/*
 * Atmel SPI DataFlash support
 *
 * Copyright (C) 2008 Atmel Corporation
 */
#define DEBUG
#include <common.h>
#include <malloc.h>
#include <spi_flash.h>

#include "spi_flash_internal.h"

/* AT45-specific commands */
#define CMD_AT45_READ_STATUS            0xd7
#define CMD_AT45_ERASE_PAGE             0x81
#define CMD_AT45_LOAD_PROG_BUF1         0x82
#define CMD_AT45_LOAD_BUF1              0x84
#define CMD_AT45_LOAD_PROG_BUF2         0x85
#define CMD_AT45_LOAD_BUF2              0x87
#define CMD_AT45_PROG_BUF1              0x88
#define CMD_AT45_PROG_BUF2              0x89

/* AT45 status register bits */
#define AT45_STATUS_P2_PAGE_SIZE        (1 << 0)
#define AT45_STATUS_READY               (1 << 7)

/* DataFlash family IDs, as obtained from the second idcode byte */
#define DF_FAMILY_AT26F                 0
#define DF_FAMILY_AT45                  1
#define DF_FAMILY_AT26DF                2       /* AT25DF and AT26DF */

struct atmel_spi_flash_params {
        u8              idcode1;
        /* Log2 of page size in power-of-two mode */
        u8              l2_page_size;
        u8              pages_per_block;
        u8              blocks_per_sector;
        u8              nr_sectors;
        const char      *name;
};

/* spi_flash needs to be first so upper layers can free() it */
struct atmel_spi_flash {
        struct spi_flash flash;
        const struct atmel_spi_flash_params *params;
};

static inline struct atmel_spi_flash *
to_atmel_spi_flash(struct spi_flash *flash)
{
        return container_of(flash, struct atmel_spi_flash, flash);
}

static const struct atmel_spi_flash_params atmel_spi_flash_table[] = {
        {
                .idcode1                = 0x28,
                .l2_page_size           = 10,
                .pages_per_block        = 8,
                .blocks_per_sector      = 32,
                .nr_sectors             = 32,
                .name                   = "AT45DB642D",
        },
};

static int at45_wait_ready(struct spi_flash *flash, unsigned long timeout)
{
        struct spi_slave *spi = flash->spi;
        unsigned long timebase;
        int ret;
        u8 cmd = CMD_AT45_READ_STATUS;
        u8 status;

        timebase = get_timer(0);

        ret = spi_xfer(spi, 8, &cmd, NULL, SPI_XFER_BEGIN);
        if (ret)
                return -1;

        do {
                ret = spi_xfer(spi, 8, NULL, &status, 0);
                if (ret)
                        return -1;

                if (status & AT45_STATUS_READY)
                        break;
        } while (get_timer(timebase) < timeout);

        /* Deactivate CS */
        spi_xfer(spi, 0, NULL, NULL, SPI_XFER_END);

        if (status & AT45_STATUS_READY)
                return 0;

        /* Timed out */
        return -1;
}

/*
 * Assemble the address part of a command for AT45 devices in
 * non-power-of-two page size mode.
 */
static void at45_build_address(struct atmel_spi_flash *asf, u8 *cmd, u32 offset)
{
        unsigned long page_addr;
        unsigned long byte_addr;
        unsigned long page_size;
        unsigned int page_shift;

        /*
         * The "extra" space per page is the power-of-two page size
         * divided by 32.
         */
        page_shift = asf->params->l2_page_size;
        page_size = (1 << page_shift) + (1 << (page_shift - 5));
        page_shift++;
        page_addr = offset / page_size;
        byte_addr = offset % page_size;

        cmd[0] = page_addr >> (16 - page_shift);
        cmd[1] = page_addr << (page_shift - 8) | (byte_addr >> 8);
        cmd[2] = byte_addr;
}

static int dataflash_read_fast_p2(struct spi_flash *flash,
                u32 offset, size_t len, void *buf)
{
        u8 cmd[5];

        cmd[0] = CMD_READ_ARRAY_FAST;
        cmd[1] = offset >> 16;
        cmd[2] = offset >> 8;
        cmd[3] = offset;
        cmd[4] = 0x00;

        return spi_flash_read_common(flash, cmd, sizeof(cmd), buf, len);
}

static int dataflash_read_fast_at45(struct spi_flash *flash,
                u32 offset, size_t len, void *buf)
{
        struct atmel_spi_flash *asf = to_atmel_spi_flash(flash);
        u8 cmd[5];

        cmd[0] = CMD_READ_ARRAY_FAST;
        at45_build_address(asf, cmd + 1, offset);
        cmd[4] = 0x00;

        return spi_flash_read_common(flash, cmd, sizeof(cmd), buf, len);
}

static int dataflash_write_at45(struct spi_flash *flash,
                u32 offset, size_t len, const void *buf)
{
        struct atmel_spi_flash *asf = to_atmel_spi_flash(flash);
        unsigned long page_addr;
        unsigned long byte_addr;
        unsigned long page_size;
        unsigned int page_shift;
        size_t chunk_len;
        size_t actual;
        int ret;
        u8 cmd[4];

        page_shift = asf->params->l2_page_size;
        page_size = (1 << page_shift) + (1 << (page_shift - 5));
        page_shift++;
        page_addr = offset / page_size;
        byte_addr = offset % page_size;

        ret = spi_claim_bus(flash->spi);
        if (ret) {
                debug("SF: Unable to claim SPI bus\n");
                return ret;
        }

        for (actual = 0; actual < len; actual += chunk_len) {
                chunk_len = min(len - actual, page_size - byte_addr);

                /* Use the same address bits for both commands */
                cmd[0] = CMD_AT45_LOAD_BUF1;
                cmd[1] = page_addr >> (16 - page_shift);
                cmd[2] = page_addr << (page_shift - 8) | (byte_addr >> 8);
                cmd[3] = byte_addr;

                ret = spi_flash_cmd_write(flash->spi, cmd, 4,
                                buf + actual, chunk_len);
                if (ret < 0) {
                        debug("SF: Loading AT45 buffer failed\n");
                        goto out;
                }

                cmd[0] = CMD_AT45_PROG_BUF1;
                ret = spi_flash_cmd_write(flash->spi, cmd, 4, NULL, 0);
                if (ret < 0) {
                        debug("SF: AT45 page programming failed\n");
                        goto out;
                }

                ret = at45_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
                if (ret < 0) {
                        debug("SF: AT45 page programming timed out\n");
                        goto out;
                }

                page_addr++;
                byte_addr = 0;
        }

        debug("SF: AT45: Successfully programmed %zu bytes @ 0x%x\n",
                        len, offset);
        ret = 0;

out:
        spi_release_bus(flash->spi);
        return ret;
}

int dataflash_erase_at45(struct spi_flash *flash, u32 offset, size_t len)
{
        struct atmel_spi_flash *asf = to_atmel_spi_flash(flash);
        unsigned long page_addr;
        unsigned long page_size;
        unsigned int page_shift;
        size_t actual;
        int ret;
        u8 cmd[4];

        /*
         * TODO: This function currently uses page erase only. We can
         * probably speed things up by using block and/or sector erase
         * when possible.
         */

        page_shift = asf->params->l2_page_size;
        page_size = (1 << page_shift) + (1 << (page_shift - 5));
        page_shift++;
        page_addr = offset / page_size;

        if (offset % page_size || len % page_size) {
                debug("SF: Erase offset/length not multiple of page size\n");
                return -1;
        }

        cmd[0] = CMD_AT45_ERASE_PAGE;
        cmd[3] = 0x00;

        ret = spi_claim_bus(flash->spi);
        if (ret) {
                debug("SF: Unable to claim SPI bus\n");
                return ret;
        }

        for (actual = 0; actual < len; actual += page_size) {
                cmd[1] = page_addr >> (16 - page_shift);
                cmd[2] = page_addr << (page_shift - 8);

                ret = spi_flash_cmd_write(flash->spi, cmd, 4, NULL, 0);
                if (ret < 0) {
                        debug("SF: AT45 page erase failed\n");
                        goto out;
                }

                ret = at45_wait_ready(flash, SPI_FLASH_PAGE_ERASE_TIMEOUT);
                if (ret < 0) {
                        debug("SF: AT45 page erase timed out\n");
                        goto out;
                }

                page_addr++;
        }

        debug("SF: AT45: Successfully erased %zu bytes @ 0x%x\n",
                        len, offset);
        ret = 0;

out:
        spi_release_bus(flash->spi);
        return ret;
}

struct spi_flash *spi_flash_probe_atmel(struct spi_slave *spi, u8 *idcode)
{
        const struct atmel_spi_flash_params *params;
        unsigned long page_size;
        unsigned int family;
        struct atmel_spi_flash *asf;
        unsigned int i;
        int ret;
        u8 status;

        for (i = 0; i < ARRAY_SIZE(atmel_spi_flash_table); i++) {
                params = &atmel_spi_flash_table[i];
                if (params->idcode1 == idcode[1])
                        break;
        }

        if (i == ARRAY_SIZE(atmel_spi_flash_table)) {
                debug("SF: Unsupported DataFlash ID %02x\n",
                                idcode[1]);
                return NULL;
        }

        asf = malloc(sizeof(struct atmel_spi_flash));
        if (!asf) {
                debug("SF: Failed to allocate memory\n");
                return NULL;
        }

        asf->params = params;
        asf->flash.spi = spi;
        asf->flash.name = params->name;

        /* Assuming power-of-two page size initially. */
        page_size = 1 << params->l2_page_size;

        family = idcode[1] >> 5;

        switch (family) {
        case DF_FAMILY_AT45:
                /*
                 * AT45 chips have configurable page size. The status
                 * register indicates which configuration is active.
                 */
                ret = spi_flash_cmd(spi, CMD_AT45_READ_STATUS, &status, 1);
                if (ret)
                        goto err;

                debug("SF: AT45 status register: %02x\n", status);

                if (!(status & AT45_STATUS_P2_PAGE_SIZE)) {
                        asf->flash.read = dataflash_read_fast_at45;
                        asf->flash.write = dataflash_write_at45;
                        asf->flash.erase = dataflash_erase_at45;
                        page_size += 1 << (params->l2_page_size - 5);
                } else {
                        asf->flash.read = dataflash_read_fast_p2;
                }

                break;

        case DF_FAMILY_AT26F:
        case DF_FAMILY_AT26DF:
                asf->flash.read = dataflash_read_fast_p2;
                break;

        default:
                debug("SF: Unsupported DataFlash family %u\n", family);
                goto err;
        }

        asf->flash.size = page_size * params->pages_per_block
                                * params->blocks_per_sector
                                * params->nr_sectors;

        debug("SF: Detected %s with page size %lu, total %u bytes\n",
                        params->name, page_size, asf->flash.size);

        return &asf->flash;

err:
        free(asf);
        return NULL;
}