/*
 * Copyright 2008, Network Appliance Inc.
 * Copyright 2014, Sage Electronic Engineering, LLC.
 *
 * Author: Jason McMullan <mcmullan <at> netapp.com>
 * Licensed under the GPL-2 or later.
 */

#include <stdlib.h>
#include <spi_flash.h>
#include "spi_flash_internal.h"

/* M25Pxx-specific commands */
#define CMD_AT25_WREN		0x06	/* Write Enable */
#define CMD_AT25_WRDI		0x04	/* Write Disable */
#define CMD_AT25_RDSR		0x05	/* Read Status Register */
#define CMD_AT25_WRSR		0x01	/* Write Status Register */
#define CMD_AT25_READ		0x03	/* Read Data Bytes */
#define CMD_AT25_FAST_READ	0x0b	/* Read Data Bytes at Higher Speed */
#define CMD_AT25_PP			0x02	/* Page Program */
#define CMD_AT25_SE			0x20	/* Sector (4K) Erase */
#define CMD_AT25_BE			0xd8	/* Block (64K) Erase */
#define CMD_AT25_CE			0xc7	/* Chip Erase */
#define CMD_AT25_DP			0xb9	/* Deep Power-down */
#define CMD_AT25_RES		0xab	/* Release from DP, and Read Signature */

struct atmel_spi_flash_params {
	uint16_t	id;
	/* Log2 of page size in power-of-two mode */
	uint8_t		l2_page_size;
	uint16_t	pages_per_sector;
	uint16_t	sectors_per_block;
	uint16_t	nr_blocks;
	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[] = {
	{
		.id			= 0x3015,
		.l2_page_size		= 8,
		.pages_per_sector	= 16,
		.sectors_per_block	= 16,
		.nr_blocks		= 32,
		.name			= "AT25X16",
	},
	{
		.id			= 0x47,
		.l2_page_size		= 8,
		.pages_per_sector	= 16,
		.sectors_per_block	= 16,
		.nr_blocks		= 64,
		.name			= "AT25DF32",
	},
	{
		.id			= 0x3017,
		.l2_page_size		= 8,
		.pages_per_sector	= 16,
		.sectors_per_block	= 16,
		.nr_blocks		= 128,
		.name			= "AT25X64",
	},
	{
		.id			= 0x4015,
		.l2_page_size		= 8,
		.pages_per_sector	= 16,
		.sectors_per_block	= 16,
		.nr_blocks		= 32,
		.name			= "AT25Q16",
	},
	{
		.id			= 0x4016,
		.l2_page_size		= 8,
		.pages_per_sector	= 16,
		.sectors_per_block	= 16,
		.nr_blocks		= 64,
		.name			= "AT25Q32",
	},
	{
		.id			= 0x4017,
		.l2_page_size		= 8,
		.pages_per_sector	= 16,
		.sectors_per_block	= 16,
		.nr_blocks		= 128,
		.name			= "AT25Q64",
	},
	{
		.id			= 0x4018,
		.l2_page_size		= 8,
		.pages_per_sector	= 16,
		.sectors_per_block	= 16,
		.nr_blocks		= 256,
		.name			= "AT25Q128",
	},
};

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

	page_size = 1 << stm->params->l2_page_size;
	byte_addr = offset % page_size;

	flash->spi->rw = SPI_WRITE_FLAG;
	ret = spi_claim_bus(flash->spi);
	if (ret) {
		printk(BIOS_WARNING, "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);
		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);

		cmd[0] = CMD_AT25_PP;
		cmd[1] = (offset >> 16) & 0xff;
		cmd[2] = (offset >> 8) & 0xff;
		cmd[3] = offset & 0xff;
#if CONFIG_DEBUG_SPI_FLASH
		printk(BIOS_SPEW, "PP: 0x%p => cmd = { 0x%02x 0x%02x%02x%02x }"
		        " chunk_len = %zu\n", buf + actual,
			cmd[0], cmd[1], cmd[2], cmd[3], chunk_len);
#endif

		ret = spi_flash_cmd(flash->spi, CMD_AT25_WREN, NULL, 0);
		if (ret < 0) {
			printk(BIOS_WARNING, "SF: Enabling Write failed\n");
			goto out;
		}

		ret = spi_flash_cmd_write(flash->spi, cmd, sizeof(cmd),
				buf + actual, chunk_len);
		if (ret < 0) {
			printk(BIOS_WARNING, "SF: Atmel Page Program failed\n");
			goto out;
		}

		ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
		if (ret)
			goto out;

		offset += chunk_len;
		byte_addr = 0;
	}

#if CONFIG_DEBUG_SPI_FLASH
	printk(BIOS_SPEW, "SF: Atmel: Successfully programmed %zu bytes @"
			" 0x%lx\n", len, (unsigned long)(offset - len));
#endif
	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 page_size;
	struct atmel_spi_flash *stm;
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(atmel_spi_flash_table); i++) {
		params = &atmel_spi_flash_table[i];
		if (params->id == ((idcode[1] << 8) | idcode[2]))
			break;
	}

	if (i == ARRAY_SIZE(atmel_spi_flash_table)) {
		printk(BIOS_WARNING, "SF: Unsupported Atmel ID %02x%02x\n",
				idcode[1], idcode[2]);
		return NULL;
	}

	stm = malloc(sizeof(struct atmel_spi_flash));
	if (!stm) {
		printk(BIOS_WARNING, "SF: Failed to allocate memory\n");
		return NULL;
	}

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

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

	stm->flash.write = atmel_write;
	stm->flash.erase = spi_flash_cmd_erase;
#if CONFIG_SPI_FLASH_NO_FAST_READ
	stm->flash.read = spi_flash_cmd_read_slow;
#else
	stm->flash.read = spi_flash_cmd_read_fast;
#endif
	stm->flash.sector_size = (1 << stm->params->l2_page_size) *
		stm->params->pages_per_sector;
	stm->flash.size = page_size * params->pages_per_sector
				* params->sectors_per_block
				* params->nr_blocks;
	stm->flash.erase_cmd = CMD_AT25_SE;

	return &stm->flash;
}