/*
 * spiflash_n25q128.c
 * ------------------
 * Functions and defines for accessing SPI flash with part number n25q128.
 *
 * The Alpha board has two of these SPI flash memorys, the FPGA config memory
 * and the keystore memory.
 *
 * Copyright (c) 2016, NORDUnet A/S All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the NORDUnet nor the names of its contributors may
 *   be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "stm32f4xx_hal.h"
#include "stm-fpgacfg.h"
#include "stm-init.h"

#define _n25q128_select(ctx)	HAL_GPIO_WritePin(ctx->cs_n_port, ctx->cs_n_pin, GPIO_PIN_RESET);
#define _n25q128_deselect(ctx)	HAL_GPIO_WritePin(ctx->cs_n_port, ctx->cs_n_pin, GPIO_PIN_SET);


int _n25q128_get_wel_flag(struct spiflash_ctx *ctx);


int n25q128_check_id(struct spiflash_ctx *ctx)
{
    // tx, rx buffers
    uint8_t spi_tx[4];
    uint8_t spi_rx[4];

    // result
    HAL_StatusTypeDef ok;

    // send READ ID command
    spi_tx[0] = N25Q128_COMMAND_READ_ID;

    // select, send command & read response, deselect
    _n25q128_select(ctx);
    ok = HAL_SPI_TransmitReceive(ctx->hspi, spi_tx, spi_rx, 4, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return 0;

    // parse response (note, that the very first byte was received during the
    // transfer of the command byte, so it contains garbage and should
    // be ignored here)
    if (spi_rx[1] != N25Q128_ID_MANUFACTURER) return 0;
    if (spi_rx[2] != N25Q128_ID_DEVICE_TYPE) return 0;
    if (spi_rx[3] != N25Q128_ID_DEVICE_CAPACITY) return 0;

    // done
    return 1;
}


int n25q128_read_page(struct spiflash_ctx *ctx, uint32_t page_offset, uint8_t *page_buffer)
{
    // tx buffer
    uint8_t spi_tx[4];

    // result
    HAL_StatusTypeDef ok;

    // check offset
    if (page_offset >= N25Q128_NUM_PAGES) return 0;

    // calculate byte address
    page_offset *= N25Q128_PAGE_SIZE;

    // prepare READ command
    spi_tx[0] = N25Q128_COMMAND_READ_PAGE;
    spi_tx[1] = (uint8_t)(page_offset >> 16);
    spi_tx[2] = (uint8_t)(page_offset >>  8);
    spi_tx[3] = (uint8_t)(page_offset >>  0);

    // activate, send command
    _n25q128_select(ctx);
    ok = HAL_SPI_Transmit(ctx->hspi, spi_tx, 4, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);

    // check
    if (ok != HAL_OK) {
	_n25q128_deselect(ctx);
	return 0;
    }

    // read response, deselect
    ok = HAL_SPI_Receive(ctx->hspi, page_buffer, N25Q128_PAGE_SIZE, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return 0;

    // done
    return 1;
}


int n25q128_write_page(struct spiflash_ctx *ctx, uint32_t page_offset, const uint8_t *page_buffer)
{
    // tx buffer
    uint8_t spi_tx[4];

    // result
    HAL_StatusTypeDef ok;

    // check offset
    if (page_offset >= N25Q128_NUM_PAGES) return 0;

    // enable writing
    spi_tx[0] = N25Q128_COMMAND_WRITE_ENABLE;

    // activate, send command, deselect
    _n25q128_select(ctx);
    ok = HAL_SPI_Transmit(ctx->hspi, spi_tx, 1, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return 0;

    // make sure, that write enable did the job
    int wel = _n25q128_get_wel_flag(ctx);
    if (wel != 1) return 0;

    // calculate byte address
    page_offset *= N25Q128_PAGE_SIZE;

    // prepare PROGRAM PAGE command
    spi_tx[0] = N25Q128_COMMAND_PAGE_PROGRAM;
    spi_tx[1] = (uint8_t)(page_offset >> 16);
    spi_tx[2] = (uint8_t)(page_offset >>  8);
    spi_tx[3] = (uint8_t)(page_offset >>  0);

    // activate, send command
    _n25q128_select(ctx);
    ok = HAL_SPI_Transmit(ctx->hspi, spi_tx, 4, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);

    // check
    if (ok != HAL_OK) {
	_n25q128_deselect(ctx);
	return 0;
    }

    // send data, deselect
    ok = HAL_SPI_Transmit(ctx->hspi, (uint8_t *) page_buffer, N25Q128_PAGE_SIZE, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return 0;

    // done
    return 1;
}


int n25q128_get_wip_flag(struct spiflash_ctx *ctx)
{
    // tx, rx buffers
    uint8_t spi_tx[2];
    uint8_t spi_rx[2];

    // result
    HAL_StatusTypeDef ok;

    // send READ STATUS command
    spi_tx[0] = N25Q128_COMMAND_READ_STATUS;

    // send command, read response, deselect
    _n25q128_select(ctx);
    ok = HAL_SPI_TransmitReceive(ctx->hspi, spi_tx, spi_rx, 2, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return -1;

    // done
    return (spi_rx[1] & 1);
}


int n25q128_erase_sector(struct spiflash_ctx *ctx, uint32_t sector_offset)
{
    // tx buffer
    uint8_t spi_tx[4];

    // result
    HAL_StatusTypeDef ok;

    // check offset
    if (sector_offset >= N25Q128_NUM_SECTORS) return 0;

    // enable writing
    spi_tx[0] = N25Q128_COMMAND_WRITE_ENABLE;

    // select, send command, deselect
    _n25q128_select(ctx);
    ok = HAL_SPI_Transmit(ctx->hspi, spi_tx, 1, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return 0;

    // make sure, that write enable did the job
    int wel = _n25q128_get_wel_flag(ctx);
    if (wel != 1) return 0;

    // calculate byte address
    sector_offset *= N25Q128_SECTOR_SIZE;

    // send ERASE SUBSECTOR command
    spi_tx[0] = N25Q128_COMMAND_ERASE_SECTOR;
    spi_tx[1] = (uint8_t)(sector_offset >> 16);
    spi_tx[2] = (uint8_t)(sector_offset >>  8);
    spi_tx[3] = (uint8_t)(sector_offset >>  0);

    // activate, send command, deselect
    _n25q128_select(ctx);
    ok = HAL_SPI_Transmit(ctx->hspi, spi_tx, 4, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return 0;

    // done
    return 1;
}


int _n25q128_get_wel_flag(struct spiflash_ctx *ctx)
{
    // tx, rx buffers
    uint8_t spi_tx[2];
    uint8_t spi_rx[2];

    // result
    HAL_StatusTypeDef ok;

    // send READ STATUS command
    spi_tx[0] = N25Q128_COMMAND_READ_STATUS;

    // send command, read response, deselect
    _n25q128_select(ctx);
    ok = HAL_SPI_TransmitReceive(ctx->hspi, spi_tx, spi_rx, 2, N25Q128_SPI_TIMEOUT);
    HAL_Delay(1);
    _n25q128_deselect(ctx);

    // check
    if (ok != HAL_OK) return -1;

    // done
    return ((spi_rx[1] >> 1) & 1);
}

/* Wait until the flash memory is done writing (wip = Write In Progress) */
inline int _wait_while_wip(struct spiflash_ctx *ctx, uint32_t timeout)
{
    int i;
    while (timeout--) {
	i = n25q128_get_wip_flag(ctx);
	if (i < 0) return 0;
	if (! i) break;
	HAL_Delay(10);
    }
    return 1;
}

/* This function performs erasure if needed, and then writing of a number of pages to the flash memory */
int n25q128_write_data(struct spiflash_ctx *ctx, uint32_t offset, const uint8_t *buf, const uint32_t len)
{
    uint32_t page;

    /* Ensure alignment */
    if ((offset % N25Q128_PAGE_SIZE) != 0) return -1;
    if ((len % N25Q128_PAGE_SIZE) != 0) return -2;

    if ((offset % N25Q128_SECTOR_SIZE) == 0) {
	/* first page in sector, need to erase sector */

	if (! _wait_while_wip(ctx, 1000)) return -3;

	if (! n25q128_erase_sector(ctx, offset / N25Q128_SECTOR_SIZE)) {
	    return -4;
	}
    }

    for (page = 0; page < len / N25Q128_PAGE_SIZE; page++) {
	if (! _wait_while_wip(ctx, 1000)) return -5;

	if (! n25q128_write_page(ctx, offset / N25Q128_PAGE_SIZE, buf)) {
	    return -6;
	}
	buf += N25Q128_PAGE_SIZE;
	offset += N25Q128_PAGE_SIZE;

	/* XXX read back data and verify it, or maybe just verify ability to write
	 * to memory by verifying the contents of one page after erase?
	 */
    }

    return 1;
}

/* This function reads zero or more pages from the SPI flash. */
int n25q128_read_data(struct spiflash_ctx *ctx, uint32_t offset, uint8_t *buf, const uint32_t len)
{
    uint32_t page;

    /* Ensure alignment */
    if ((offset % N25Q128_PAGE_SIZE) != 0) return -1;
    if ((len % N25Q128_PAGE_SIZE) != 0) return -2;

    for (page = 0; page < len / N25Q128_PAGE_SIZE; page++) {
	if (! n25q128_read_page(ctx, offset / N25Q128_PAGE_SIZE, buf)) {
	    return -3;
	}
	buf += N25Q128_PAGE_SIZE;
	offset += N25Q128_PAGE_SIZE;
    }

    return 1;
}