// SPDX-License-Identifier: GPL-2.0-or-later

/*
 * Copyright (C) 2020 by Nuvoton Technology Corporation
 * Mulin Chao <mlchao@nuvoton.com>
 * Wealian Liao <WHLIAO@nuvoton.com>
 */

#include <stdint.h>
#include <string.h>
#include "npcx_flash.h"

/* flashloader parameter structure */
__attribute__ ((section(".buffers.g_cfg")))
static volatile struct npcx_flash_params g_cfg;
/* data buffer */
__attribute__ ((section(".buffers.g_buf")))
static uint8_t g_buf[NPCX_FLASH_LOADER_BUFFER_SIZE];

/*----------------------------------------------------------------------------
 *                             NPCX flash driver
 *----------------------------------------------------------------------------*/
static void flash_init(void)
{
	if (g_cfg.fiu_ver == NPCX_FIU_NPCK) {
		/* Set pinmux to SHD flash */
		NPCX_DEVCNT = 0x80;
		NPCX_DEVALT(0) = 0xC0;
		NPCX_DEVALT(4) = 0x00;
	} else {
		/* Avoid F_CS0 toggles while programming the internal flash. */
		NPCX_SET_BIT(NPCX_DEVALT(0), NPCX_DEVALT0_NO_F_SPI);
	}
}

static void flash_execute_cmd(uint8_t code, uint8_t cts)
{
	/* Set UMA code */
	NPCX_UMA_CODE = code;
	/* Execute UMA flash transaction by CTS setting */
	NPCX_UMA_CTS = cts;
	/* Wait for transaction completed */
	while (NPCX_IS_BIT_SET(NPCX_UMA_CTS, NPCX_UMA_CTS_EXEC_DONE))
		;
}

static void flash_cs_level(uint8_t level)
{
	int sw_cs = 0;

	if (g_cfg.fiu_ver == NPCX_FIU_NPCX) {
		sw_cs = 1;
	} else if (g_cfg.fiu_ver == NPCX_FIU_NPCX_V2) {
		sw_cs = 0;
	} else if (g_cfg.fiu_ver == NPCX_FIU_NPCK) {
		sw_cs = 1;
		/* Unlock UMA before pulling down CS in NPCK series */
		if (level)
			NPCX_CLEAR_BIT(NPCX_FIU_MSR_IE_CFG, NPCX_FIU_MSR_IE_CFG_UMA_BLOCK);
		else
			NPCX_SET_BIT(NPCX_FIU_MSR_IE_CFG, NPCX_FIU_MSR_IE_CFG_UMA_BLOCK);
	}

	/* Program chip select pin to high/low level */
	if (level)
		NPCX_SET_BIT(NPCX_UMA_ECTS, sw_cs);
	else
		NPCX_CLEAR_BIT(NPCX_UMA_ECTS, sw_cs);
}

static void flash_set_address(uint32_t dest_addr)
{
	uint8_t *addr = (uint8_t *)&dest_addr;

	/* Set target flash address */
	NPCX_UMA_DB0 = addr[2];
	NPCX_UMA_DB1 = addr[1];
	NPCX_UMA_DB2 = addr[0];
}

static void delay(uint32_t i)
{
	while (i--)
		__asm__ volatile ("nop");
}

static int flash_wait_ready(uint32_t timeout)
{
	/* Chip Select down. -- Burst mode */
	flash_cs_level(0);

	/* Command for Read status register */
	flash_execute_cmd(NPCX_CMD_READ_STATUS_REG, NPCX_MASK_CMD_ONLY);
	while (timeout > 0) {
		/* Read status register */
		NPCX_UMA_CTS = NPCX_MASK_RD_1BYTE;
		while (NPCX_IS_BIT_SET(NPCX_UMA_CTS, NPCX_UMA_CTS_EXEC_DONE))
			;

		if (!(NPCX_UMA_DB0 & NPCX_SPI_FLASH_SR1_BUSY))
			break;

		if (--timeout > 0)
			delay(100);

	}; /* Wait for Busy clear */

	/* Chip Select high. */
	flash_cs_level(1);

	if (timeout == 0)
		return NPCX_FLASH_STATUS_FAILED_TIMEOUT;

	return NPCX_FLASH_STATUS_OK;
}

static int flash_write_enable(void)
{
	/* Write enable command */
	flash_execute_cmd(NPCX_CMD_WRITE_EN, NPCX_MASK_CMD_ONLY);

	/* Wait for flash is not busy */
	int status = flash_wait_ready(NPCX_FLASH_ABORT_TIMEOUT);
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	if (NPCX_UMA_DB0 & NPCX_SPI_FLASH_SR1_WEL)
		return NPCX_FLASH_STATUS_OK;
	else
		return NPCX_FLASH_STATUS_FAILED;
}

static void flash_burst_write(uint32_t dest_addr, uint16_t bytes,
		const uint8_t *data)
{
	/* Chip Select down -- Burst mode */
	flash_cs_level(0);

	/* Set write address */
	flash_set_address(dest_addr);
	/* Start programming */
	flash_execute_cmd(NPCX_CMD_FLASH_PROGRAM, NPCX_MASK_CMD_WR_3BYTE);
	for (uint32_t i = 0; i < bytes; i++) {
		flash_execute_cmd(*data, NPCX_MASK_CMD_WR_ONLY);
		data++;
	}

	/* Chip Select up */
	flash_cs_level(1);
}

static void flash_get_stsreg(uint8_t *reg1, uint8_t *reg2)
{
	/* Read status register 1/2 for checking */
	flash_execute_cmd(NPCX_CMD_READ_STATUS_REG, NPCX_MASK_CMD_RD_1BYTE);
	*reg1 = NPCX_UMA_DB0;
	flash_execute_cmd(NPCX_CMD_READ_STATUS_REG2, NPCX_MASK_CMD_RD_1BYTE);
	*reg2 = NPCX_UMA_DB0;
}

/* The data to write cannot cross 256 Bytes boundary */
static int flash_program_write(uint32_t addr, uint32_t size,
		const uint8_t *data)
{
	int status = flash_write_enable();
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	flash_burst_write(addr, size, data);
	return flash_wait_ready(NPCX_FLASH_ABORT_TIMEOUT);
}

static int flash_physical_clear_stsreg(void)
{
	int status;
	uint8_t reg1, reg2;

	/* Read status register 1/2 for checking */
	flash_get_stsreg(&reg1, &reg2);
	if (reg1 == 0x00 && reg2 == 0x00)
		return NPCX_FLASH_STATUS_OK;

	/* Enable write */
	status = flash_write_enable();
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	NPCX_UMA_DB0 = 0x0;
	NPCX_UMA_DB1 = 0x0;

	/* Write status register 1/2 */
	flash_execute_cmd(NPCX_CMD_WRITE_STATUS_REG, NPCX_MASK_CMD_WR_2BYTE);

	/* Wait writing completed */
	status = flash_wait_ready(NPCX_FLASH_ABORT_TIMEOUT);
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	/* Read status register 1/2 for checking */
	flash_get_stsreg(&reg1, &reg2);
	if (reg1 != 0x00 || reg2 != 0x00)
		return NPCX_FLASH_STATUS_FAILED;

	return NPCX_FLASH_STATUS_OK;
}

static int flash_physical_write(uint32_t offset, uint32_t size, const uint8_t *data)
{
	int status;
	uint32_t trunk_start = (offset + 0xff) & ~0xff;

	/* write head */
	uint32_t dest_addr = offset;
	uint32_t write_len = ((trunk_start - offset) > size) ? size : (trunk_start - offset);

	/* Configure fiu and clear status registers if needed */
	flash_init();
	status = flash_physical_clear_stsreg();
	if (status != NPCX_FLASH_STATUS_OK)
		return status;


	if (write_len) {
		status = flash_program_write(dest_addr, write_len, data);
		if (status != NPCX_FLASH_STATUS_OK)
			return status;
		data += write_len;
	}

	dest_addr = trunk_start;
	size -= write_len;

	/* write remaining data*/
	while (size > 0) {
		write_len = (size > NPCX_FLASH_WRITE_SIZE) ?
					NPCX_FLASH_WRITE_SIZE : size;

		status = flash_program_write(dest_addr, write_len, data);
		if (status != NPCX_FLASH_STATUS_OK)
			return status;

		data      += write_len;
		dest_addr += write_len;
		size      -= write_len;
	}

	return NPCX_FLASH_STATUS_OK;
}

static int flash_physical_erase(uint32_t offset, uint32_t size)
{
	/* Configure fiu */
	flash_init();

	/* clear flash status registers */
	int status = flash_physical_clear_stsreg();
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	/* Alignment has been checked in upper layer */
	for (; size > 0; size -= NPCX_FLASH_ERASE_SIZE,
		offset += NPCX_FLASH_ERASE_SIZE) {
		/* Enable write */
		int status = flash_write_enable();
		if (status != NPCX_FLASH_STATUS_OK)
			return status;

		/* Set erase address */
		flash_set_address(offset);
		/* Start erase */
		flash_execute_cmd(NPCX_CMD_SECTOR_ERASE, NPCX_MASK_CMD_WR_3BYTE);
		/* Wait erase completed */
		status = flash_wait_ready(NPCX_FLASH_ABORT_TIMEOUT);
		if (status != NPCX_FLASH_STATUS_OK)
			return status;
	}

	return NPCX_FLASH_STATUS_OK;
}

static int flash_physical_erase_all(void)
{
	int status;

	/* Configure fiu and clear status register if needed */
	flash_init();
	status = flash_physical_clear_stsreg();
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	/* Enable write */
	status = flash_write_enable();
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	/* Start erase */
	flash_execute_cmd(NPCX_CMD_CHIP_ERASE, NPCX_MASK_CMD_ONLY);

	/* Wait erase completed */
	status = flash_wait_ready(NPCX_FLASH_ABORT_TIMEOUT);
	if (status != NPCX_FLASH_STATUS_OK)
		return status;

	return NPCX_FLASH_STATUS_OK;
}

static int flash_get_id(uint32_t *id)
{
	flash_init();

	flash_execute_cmd(NPCX_CMD_READ_ID, NPCX_MASK_CMD_RD_3BYTE);
	*id = NPCX_UMA_DB0 << 16 | NPCX_UMA_DB1 << 8 | NPCX_UMA_DB2;

	return NPCX_FLASH_STATUS_OK;
}

/*----------------------------------------------------------------------------
 *                             flash loader function
 *----------------------------------------------------------------------------*/
static uint32_t flashloader_init(struct npcx_flash_params *params)
{
	/* Initialize params buffers */
	memset(params, 0, sizeof(struct npcx_flash_params));

	return NPCX_FLASH_STATUS_OK;
}

/*----------------------------------------------------------------------------
 *                                      Functions
 *----------------------------------------------------------------------------*/
static int main(void)
{
	uint32_t id, status;

	/* set buffer */
	flashloader_init((struct npcx_flash_params *)&g_cfg);

	while (1) {
		/* wait command*/
		while (g_cfg.sync == NPCX_FLASH_LOADER_WAIT)
			;

		/* command handler */
		switch (g_cfg.cmd) {
		case NPCX_FLASH_CMD_GET_FLASH_ID:
			status = flash_get_id(&id);
			if (status == NPCX_FLASH_STATUS_OK) {
				g_buf[0] = id & 0xff;
				g_buf[1] = (id >> 8) & 0xff;
				g_buf[2] = (id >> 16) & 0xff;
				g_buf[3] = 0x00;
			}
			break;
		case NPCX_FLASH_CMD_ERASE_SECTORS:
			status = flash_physical_erase(g_cfg.addr, g_cfg.len);
			break;
		case NPCX_FLASH_CMD_ERASE_ALL:
			status = flash_physical_erase_all();
			break;
		case NPCX_FLASH_CMD_PROGRAM:
			status = flash_physical_write(g_cfg.addr,
							g_cfg.len,
							g_buf);
			break;
		default:
			status = NPCX_FLASH_STATUS_FAILED_UNKNOWN_COMMAND;
			break;
		}

		/* clear & set result for next command */
		if (status != NPCX_FLASH_STATUS_OK) {
			g_cfg.sync = status;
			while (1)
				;
		} else {
			g_cfg.sync = NPCX_FLASH_LOADER_WAIT;
		}
	}

	return 0;
}

__attribute__ ((section(".stack")))
__attribute__ ((used))
static uint32_t stack[NPCX_FLASH_LOADER_STACK_SIZE / 4];
extern uint32_t _estack;
extern uint32_t _bss;
extern uint32_t _ebss;

__attribute__ ((section(".entry")))
void entry(void)
{
	/* set sp from end of stack */
	__asm(" ldr sp, =_estack - 4");

	main();

	__asm(" bkpt #0x00");
}
