// SPDX-FileCopyrightText: 2020 Foundation Devices, Inc.  <hello@foundationdevices.com>
// SPDX-License-Identifier: GPL-3.0-or-later
//
// SPDX-FileCopyrightText: 2018 Coinkite, Inc.  <coldcardwallet.com>
// SPDX-License-Identifier: GPL-3.0-only
//
/*
 * (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
 * and is covered by GPLv3 license found in COPYING.
 *
 * sflash.c -- talk to the serial flash
 *
 */
#include <string.h>

#include "spiflash.h"

// Connections:
// - SPI4 port
// - all port E
//
// SF_CS   => PE11
// SF_SCLK => PE12
// SF_MISO => PE13
// SF_MOSI => PE14

#define SF_CS_PIN      GPIO_PIN_11  // port E
#define SF_SPI_SCK     GPIO_PIN_12  // port E
#define SF_SPI_MISO    GPIO_PIN_13  // port E
#define SF_SPI_MOSI    GPIO_PIN_14  // port E

#define CMD_WRSR        0x01
#define CMD_WRITE       0x02
#define CMD_READ        0x03
#define CMD_FAST_READ   0x0b
#define CMD_RDSR        0x05
#define CMD_WREN        0x06
#define CMD_SEC_ERASE   0x20
#define CMD_RDCR        0x35
#define CMD_RD_DEVID    0x9f
#define CMD_CHIP_ERASE  0xc7

// active-low chip-select line
#define CS_LOW()       HAL_GPIO_WritePin(GPIOE, SF_CS_PIN, 0)
#define CS_HIGH()      HAL_GPIO_WritePin(GPIOE, SF_CS_PIN, 1)

static SPI_HandleTypeDef   sf_spi_port;

static HAL_StatusTypeDef wait_wip_done()
{
    // read RDSR (status register) and busy-wait until 
    // the write operation is done
    while (1) {
        uint8_t pkt = CMD_RDSR, stat = 0;

        CS_LOW();

        HAL_StatusTypeDef rv = HAL_SPI_Transmit(&sf_spi_port, &pkt, 1, HAL_MAX_DELAY);

        if (rv == HAL_OK) {
            rv = HAL_SPI_Receive(&sf_spi_port, &stat, 1, HAL_MAX_DELAY);
        }

        CS_HIGH();

        if (rv != HAL_OK) return rv;

        if (stat & 0x01) continue;

        return HAL_OK;
    }
}

static HAL_StatusTypeDef write_enable(void)
{
    uint8_t pkt = CMD_WREN;

    CS_LOW();

    HAL_StatusTypeDef rv = HAL_SPI_Transmit(&sf_spi_port, &pkt, 1, HAL_MAX_DELAY);

    CS_HIGH();

    return rv;
}


HAL_StatusTypeDef spi_read(uint32_t addr, int len, uint8_t *buf)
{
    // send via SPI(1)
    uint8_t     pkt[5] = { CMD_FAST_READ,
                            (addr>>16) & 0xff, (addr >> 8) & 0xff, addr & 0xff,
                            0x0 };  // for fast-read case

    CS_LOW();

    HAL_StatusTypeDef rv = HAL_SPI_Transmit(&sf_spi_port, pkt, sizeof(pkt), HAL_MAX_DELAY);
    if (rv == HAL_OK) {
        rv = HAL_SPI_Receive(&sf_spi_port, (uint8_t *)buf, len, HAL_MAX_DELAY);
    }

    CS_HIGH();

    return rv;
}

HAL_StatusTypeDef spi_write(uint32_t addr, int len, const uint8_t *buf)
{
    // enable writing
    HAL_StatusTypeDef rv = write_enable();
    if (rv) return rv;

    // do a "PAGE Program" aka. write
    uint8_t     pkt[4] = { CMD_WRITE,
                            (addr>>16) & 0xff, (addr >> 8) & 0xff, addr & 0xff 
                        };

    CS_LOW();

    rv = HAL_SPI_Transmit(&sf_spi_port, pkt, sizeof(pkt), HAL_MAX_DELAY);
    if (rv == HAL_OK) {
        rv = HAL_SPI_Transmit(&sf_spi_port, (uint8_t *)buf, len, HAL_MAX_DELAY);
    }

    CS_HIGH();

    if (rv == HAL_OK) {
        rv = wait_wip_done();
    }

    return rv;
}

HAL_StatusTypeDef spi_setup(void)
{
    // enable some internal clocks
    __HAL_RCC_GPIOE_CLK_ENABLE();
    __HAL_RCC_SPI4_CLK_ENABLE();

    // simple pins
    GPIO_InitTypeDef setup = {
        .Pin = SF_CS_PIN,
        .Mode = GPIO_MODE_OUTPUT_PP,
        .Pull = GPIO_NOPULL,
        .Speed = GPIO_SPEED_FREQ_MEDIUM,
        .Alternate = 0,
    };
    HAL_GPIO_Init(GPIOE, &setup);

    // starting value: high
    HAL_GPIO_WritePin(GPIOE, SF_CS_PIN, 1);

    // SPI pins, on various ports
    setup.Pin = SF_SPI_SCK;
    setup.Mode = GPIO_MODE_AF_PP;
    setup.Alternate = GPIO_AF5_SPI4;
    HAL_GPIO_Init(GPIOE, &setup);

    setup.Pin = SF_SPI_MOSI | SF_SPI_MISO;
    HAL_GPIO_Init(GPIOE, &setup);

    memset(&sf_spi_port, 0, sizeof(sf_spi_port));

    sf_spi_port.Instance = SPI4;

    // see SPI_InitTypeDef
    sf_spi_port.Init.Mode = SPI_MODE_MASTER;
    sf_spi_port.Init.Direction = SPI_DIRECTION_2LINES;
    sf_spi_port.Init.DataSize = SPI_DATASIZE_8BIT;
    sf_spi_port.Init.CLKPolarity = SPI_POLARITY_LOW;
    sf_spi_port.Init.CLKPhase = SPI_PHASE_1EDGE;
    sf_spi_port.Init.NSS = SPI_NSS_SOFT;
    sf_spi_port.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_16;    // conservative
    sf_spi_port.Init.FirstBit = SPI_FIRSTBIT_MSB;
    sf_spi_port.Init.TIMode = SPI_TIMODE_DISABLED;
    sf_spi_port.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLED;

    return HAL_SPI_Init(&sf_spi_port);
}