drivers/mtd/spi/spi_flash.c - platform/external/u-boot - Gitiles

 /*
  * SPI flash interface
  *
  * Copyright (C) 2008 Atmel Corporation
  * Copyright (C) 2010 Reinhard Meyer, EMK Elektronik
  *
  * Licensed under the GPL-2 or later.
  */

 #include <common.h>
 #include <fdtdec.h>
 #include <malloc.h>
 #include <spi.h>
 #include <spi_flash.h>
 #include <watchdog.h>

 #include "spi_flash_internal.h"

 DECLARE_GLOBAL_DATA_PTR;

 static void spi_flash_addr(u32 addr, u8 *cmd)
 {
 	/* cmd[0] is actual command */
 	cmd[1] = addr >> 16;
 	cmd[2] = addr >> 8;
 	cmd[3] = addr >> 0;
 }

 static int spi_flash_read_write(struct spi_slave *spi,
 				const u8 *cmd, size_t cmd_len,
 				const u8 *data_out, u8 *data_in,
 				size_t data_len)
 {
 	unsigned long flags = SPI_XFER_BEGIN;
 	int ret;

 	if (data_len == 0)
 		flags |= SPI_XFER_END;

 	ret = spi_xfer(spi, cmd_len * 8, cmd, NULL, flags);
 	if (ret) {
 		debug("SF: Failed to send command (%zu bytes): %d\n",
 				cmd_len, ret);
 	} else if (data_len != 0) {
 		ret = spi_xfer(spi, data_len * 8, data_out, data_in, SPI_XFER_END);
 		if (ret)
 			debug("SF: Failed to transfer %zu bytes of data: %d\n",
 					data_len, ret);
 	}

 	return ret;
 }

 int spi_flash_cmd(struct spi_slave *spi, u8 cmd, void *response, size_t len)
 {
 	return spi_flash_cmd_read(spi, &cmd, 1, response, len);
 }

 int spi_flash_cmd_read(struct spi_slave *spi, const u8 *cmd,
 		size_t cmd_len, void *data, size_t data_len)
 {
 	return spi_flash_read_write(spi, cmd, cmd_len, NULL, data, data_len);
 }

 int spi_flash_cmd_write(struct spi_slave *spi, const u8 *cmd, size_t cmd_len,
 		const void *data, size_t data_len)
 {
 	return spi_flash_read_write(spi, cmd, cmd_len, data, NULL, data_len);
 }

 int spi_flash_cmd_write_multi(struct spi_flash *flash, u32 offset,
 		size_t len, const void *buf)
 {
 	unsigned long page_addr, byte_addr, page_size;
 	size_t chunk_len, actual;
 	int ret;
 	u8 cmd[4];

 	page_size = flash->page_size;
 	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;
 	}

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

 		if (flash->spi->max_write_size)
 			chunk_len = min(chunk_len, flash->spi->max_write_size);

 		cmd[1] = page_addr >> 8;
 		cmd[2] = page_addr;
 		cmd[3] = byte_addr;

 		debug("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);

 		ret = spi_flash_cmd_write_enable(flash);
 		if (ret < 0) {
 			debug("SF: enabling write failed\n");
 			break;
 		}

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

 		ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
 		if (ret)
 			break;

 		byte_addr += chunk_len;
 		if (byte_addr == page_size) {
 			page_addr++;
 			byte_addr = 0;
 		}
 	}

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

 int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
 		size_t cmd_len, void *data, size_t data_len)
 {
 	struct spi_slave *spi = flash->spi;
 	int ret;

 	spi_claim_bus(spi);
 	ret = spi_flash_cmd_read(spi, cmd, cmd_len, data, data_len);
 	spi_release_bus(spi);

 	return ret;
 }

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

 	/* Handle memory-mapped SPI */
 	if (flash->memory_map) {
 		memcpy(data, flash->memory_map + offset, len);
 		return 0;
 	}

 	cmd[0] = CMD_READ_ARRAY_FAST;
 	spi_flash_addr(offset, cmd);
 	cmd[4] = 0x00;

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

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

 	ret = spi_xfer(spi, 8, &cmd, NULL, SPI_XFER_BEGIN);
 	if (ret) {
 		debug("SF: Failed to send command %02x: %d\n", cmd, ret);
 		return ret;
 	}

 	timebase = get_timer(0);
 	do {
 		WATCHDOG_RESET();

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

 		if ((status & poll_bit) == 0)
 			break;

 	} while (get_timer(timebase) < timeout);

 	spi_xfer(spi, 0, NULL, NULL, SPI_XFER_END);

 	if ((status & poll_bit) == 0)
 		return 0;

 	/* Timed out */
 	debug("SF: time out!\n");
 	return -1;
 }

 int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
 {
 	return spi_flash_cmd_poll_bit(flash, timeout,
 		CMD_READ_STATUS, STATUS_WIP);
 }

 int spi_flash_cmd_erase(struct spi_flash *flash, u32 offset, size_t len)
 {
 	u32 end, erase_size;
 	int ret;
 	u8 cmd[4];

 	erase_size = flash->sector_size;
 	if (offset % erase_size || len % erase_size) {
 		debug("SF: Erase offset/length not multiple of erase size\n");
 		return -1;
 	}

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

 	if (erase_size == 4096)
 		cmd[0] = CMD_ERASE_4K;
 	else
 		cmd[0] = CMD_ERASE_64K;
 	end = offset + len;

 	while (offset < end) {
 		spi_flash_addr(offset, cmd);
 		offset += erase_size;

 		debug("SF: erase %2x %2x %2x %2x (%x)\n", cmd[0], cmd[1],
 		      cmd[2], cmd[3], offset);

 		ret = spi_flash_cmd_write_enable(flash);
 		if (ret)
 			goto out;

 		ret = spi_flash_cmd_write(flash->spi, cmd, sizeof(cmd), NULL, 0);
 		if (ret)
 			goto out;

 		ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PAGE_ERASE_TIMEOUT);
 		if (ret)
 			goto out;
 	}

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

 int spi_flash_cmd_write_status(struct spi_flash *flash, u8 sr)
 {
 	u8 cmd;
 	int ret;

 	ret = spi_flash_cmd_write_enable(flash);
 	if (ret < 0) {
 		debug("SF: enabling write failed\n");
 		return ret;
 	}

 	cmd = CMD_WRITE_STATUS;
 	ret = spi_flash_cmd_write(flash->spi, &cmd, 1, &sr, 1);
 	if (ret) {
 		debug("SF: fail to write status register\n");
 		return ret;
 	}

 	ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
 	if (ret < 0) {
 		debug("SF: write status register timed out\n");
 		return ret;
 	}

 	return 0;
 }

 #ifdef CONFIG_OF_CONTROL
 int spi_flash_decode_fdt(const void *blob, struct spi_flash *flash)
 {
 	fdt_addr_t addr;
 	fdt_size_t size;
 	int node;

 	/* If there is no node, do nothing */
 	node = fdtdec_next_compatible(blob, 0, COMPAT_GENERIC_SPI_FLASH);
 	if (node < 0)
 		return 0;

 	addr = fdtdec_get_addr_size(blob, node, "memory-map", &size);
 	if (addr == FDT_ADDR_T_NONE) {
 		debug("%s: Cannot decode address\n", __func__);
 		return 0;
 	}

 	if (flash->size != size) {
 		debug("%s: Memory map must cover entire device\n", __func__);
 		return -1;
 	}
 	flash->memory_map = (void *)addr;

 	return 0;
 }
 #endif /* CONFIG_OF_CONTROL */

 /*
  * The following table holds all device probe functions
  *
  * shift:  number of continuation bytes before the ID
  * idcode: the expected IDCODE or 0xff for non JEDEC devices
  * probe:  the function to call
  *
  * Non JEDEC devices should be ordered in the table such that
  * the probe functions with best detection algorithms come first.
  *
  * Several matching entries are permitted, they will be tried
  * in sequence until a probe function returns non NULL.
  *
  * IDCODE_CONT_LEN may be redefined if a device needs to declare a
  * larger "shift" value.  IDCODE_PART_LEN generally shouldn't be
  * changed.  This is the max number of bytes probe functions may
  * examine when looking up part-specific identification info.
  *
  * Probe functions will be given the idcode buffer starting at their
  * manu id byte (the "idcode" in the table below).  In other words,
  * all of the continuation bytes will be skipped (the "shift" below).
  */
 #define IDCODE_CONT_LEN 0
 #define IDCODE_PART_LEN 5
 static const struct {
 	const u8 shift;
 	const u8 idcode;
 	struct spi_flash *(*probe) (struct spi_slave *spi, u8 *idcode);
 } flashes[] = {
 	/* Keep it sorted by define name */
 #ifdef CONFIG_SPI_FLASH_ATMEL
 	{ 0, 0x1f, spi_flash_probe_atmel, },
 #endif
 #ifdef CONFIG_SPI_FLASH_EON
 	{ 0, 0x1c, spi_flash_probe_eon, },
 #endif
 #ifdef CONFIG_SPI_FLASH_MACRONIX
 	{ 0, 0xc2, spi_flash_probe_macronix, },
 #endif
 #ifdef CONFIG_SPI_FLASH_SPANSION
 	{ 0, 0x01, spi_flash_probe_spansion, },
 #endif
 #ifdef CONFIG_SPI_FLASH_SST
 	{ 0, 0xbf, spi_flash_probe_sst, },
 #endif
 #ifdef CONFIG_SPI_FLASH_STMICRO
 	{ 0, 0x20, spi_flash_probe_stmicro, },
 #endif
 #ifdef CONFIG_SPI_FLASH_WINBOND
 	{ 0, 0xef, spi_flash_probe_winbond, },
 #endif
 #ifdef CONFIG_SPI_FRAM_RAMTRON
 	{ 6, 0xc2, spi_fram_probe_ramtron, },
 # undef IDCODE_CONT_LEN
 # define IDCODE_CONT_LEN 6
 #endif
 	/* Keep it sorted by best detection */
 #ifdef CONFIG_SPI_FLASH_STMICRO
 	{ 0, 0xff, spi_flash_probe_stmicro, },
 #endif
 #ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC
 	{ 0, 0xff, spi_fram_probe_ramtron, },
 #endif
 };
 #define IDCODE_LEN (IDCODE_CONT_LEN + IDCODE_PART_LEN)

 struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
 		unsigned int max_hz, unsigned int spi_mode)
 {
 	struct spi_slave *spi;
 	struct spi_flash *flash = NULL;
 	int ret, i, shift;
 	u8 idcode[IDCODE_LEN], *idp;

 	spi = spi_setup_slave(bus, cs, max_hz, spi_mode);
 	if (!spi) {
 		printf("SF: Failed to set up slave\n");
 		return NULL;
 	}

 	ret = spi_claim_bus(spi);
 	if (ret) {
 		debug("SF: Failed to claim SPI bus: %d\n", ret);
 		goto err_claim_bus;
 	}

 	/* Read the ID codes */
 	ret = spi_flash_cmd(spi, CMD_READ_ID, idcode, sizeof(idcode));
 	if (ret)
 		goto err_read_id;

 #ifdef DEBUG
 	printf("SF: Got idcodes\n");
 	print_buffer(0, idcode, 1, sizeof(idcode), 0);
 #endif

 	/* count the number of continuation bytes */
 	for (shift = 0, idp = idcode;
 	     shift < IDCODE_CONT_LEN && *idp == 0x7f;
 	     ++shift, ++idp)
 		continue;

 	/* search the table for matches in shift and id */
 	for (i = 0; i < ARRAY_SIZE(flashes); ++i)
 		if (flashes[i].shift == shift && flashes[i].idcode == *idp) {
 			/* we have a match, call probe */
 			flash = flashes[i].probe(spi, idp);
 			if (flash)
 				break;
 		}

 	if (!flash) {
 		printf("SF: Unsupported manufacturer %02x\n", *idp);
 		goto err_manufacturer_probe;
 	}

 #ifdef CONFIG_OF_CONTROL
 	if (spi_flash_decode_fdt(gd->fdt_blob, flash)) {
 		debug("SF: FDT decode error\n");
 		goto err_manufacturer_probe;
 	}
 #endif
 	printf("SF: Detected %s with page size ", flash->name);
 	print_size(flash->sector_size, ", total ");
 	print_size(flash->size, "");
 	if (flash->memory_map)
 		printf(", mapped at %p", flash->memory_map);
 	puts("\n");

 	spi_release_bus(spi);

 	return flash;

 err_manufacturer_probe:
 err_read_id:
 	spi_release_bus(spi);
 err_claim_bus:
 	spi_free_slave(spi);
 	return NULL;
 }

 void *spi_flash_do_alloc(int offset, int size, struct spi_slave *spi,
 			 const char *name)
 {
 	struct spi_flash *flash;
 	void *ptr;

 	ptr = malloc(size);
 	if (!ptr) {
 		debug("SF: Failed to allocate memory\n");
 		return NULL;
 	}
 	memset(ptr, '\0', size);
 	flash = (struct spi_flash *)(ptr + offset);

 	/* Set up some basic fields - caller will sort out sizes */
 	flash->spi = spi;
 	flash->name = name;

 	flash->read = spi_flash_cmd_read_fast;
 	flash->write = spi_flash_cmd_write_multi;
 	flash->erase = spi_flash_cmd_erase;

 	return flash;
 }

 void spi_flash_free(struct spi_flash *flash)
 {
 	spi_free_slave(flash->spi);
 	free(flash);
 }
	/*
	* SPI flash interface
	*
	* Copyright (C) 2008 Atmel Corporation
	* Copyright (C) 2010 Reinhard Meyer, EMK Elektronik
	*
	* Licensed under the GPL-2 or later.
	*/

	#include <common.h>
	#include <fdtdec.h>
	#include <malloc.h>
	#include <spi.h>
	#include <spi_flash.h>
	#include <watchdog.h>

	#include "spi_flash_internal.h"

	DECLARE_GLOBAL_DATA_PTR;

	static void spi_flash_addr(u32 addr, u8 *cmd)
	{
	/* cmd[0] is actual command */
	cmd[1] = addr >> 16;
	cmd[2] = addr >> 8;
	cmd[3] = addr >> 0;
	}

	static int spi_flash_read_write(struct spi_slave *spi,
	const u8 *cmd, size_t cmd_len,
	const u8 data_out, u8 data_in,
	size_t data_len)
	{
	unsigned long flags = SPI_XFER_BEGIN;
	int ret;

	if (data_len == 0)
	flags \|= SPI_XFER_END;

	ret = spi_xfer(spi, cmd_len * 8, cmd, NULL, flags);
	if (ret) {
	debug("SF: Failed to send command (%zu bytes): %d\n",
	cmd_len, ret);
	} else if (data_len != 0) {
	ret = spi_xfer(spi, data_len * 8, data_out, data_in, SPI_XFER_END);
	if (ret)
	debug("SF: Failed to transfer %zu bytes of data: %d\n",
	data_len, ret);
	}

	return ret;
	}

	int spi_flash_cmd(struct spi_slave spi, u8 cmd, void response, size_t len)
	{
	return spi_flash_cmd_read(spi, &cmd, 1, response, len);
	}

	int spi_flash_cmd_read(struct spi_slave spi, const u8 cmd,
	size_t cmd_len, void *data, size_t data_len)
	{
	return spi_flash_read_write(spi, cmd, cmd_len, NULL, data, data_len);
	}

	int spi_flash_cmd_write(struct spi_slave spi, const u8 cmd, size_t cmd_len,
	const void *data, size_t data_len)
	{
	return spi_flash_read_write(spi, cmd, cmd_len, data, NULL, data_len);
	}

	int spi_flash_cmd_write_multi(struct spi_flash *flash, u32 offset,
	size_t len, const void *buf)
	{
	unsigned long page_addr, byte_addr, page_size;
	size_t chunk_len, actual;
	int ret;
	u8 cmd[4];

	page_size = flash->page_size;
	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;
	}

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

	if (flash->spi->max_write_size)
	chunk_len = min(chunk_len, flash->spi->max_write_size);

	cmd[1] = page_addr >> 8;
	cmd[2] = page_addr;
	cmd[3] = byte_addr;

	debug("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);

	ret = spi_flash_cmd_write_enable(flash);
	if (ret < 0) {
	debug("SF: enabling write failed\n");
	break;
	}

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

	ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
	if (ret)
	break;

	byte_addr += chunk_len;
	if (byte_addr == page_size) {
	page_addr++;
	byte_addr = 0;
	}
	}

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

	int spi_flash_read_common(struct spi_flash flash, const u8 cmd,
	size_t cmd_len, void *data, size_t data_len)
	{
	struct spi_slave *spi = flash->spi;
	int ret;

	spi_claim_bus(spi);
	ret = spi_flash_cmd_read(spi, cmd, cmd_len, data, data_len);
	spi_release_bus(spi);

	return ret;
	}

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

	/* Handle memory-mapped SPI */
	if (flash->memory_map) {
	memcpy(data, flash->memory_map + offset, len);
	return 0;
	}

	cmd[0] = CMD_READ_ARRAY_FAST;
	spi_flash_addr(offset, cmd);
	cmd[4] = 0x00;

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

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

	ret = spi_xfer(spi, 8, &cmd, NULL, SPI_XFER_BEGIN);
	if (ret) {
	debug("SF: Failed to send command %02x: %d\n", cmd, ret);
	return ret;
	}

	timebase = get_timer(0);
	do {
	WATCHDOG_RESET();

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

	if ((status & poll_bit) == 0)
	break;

	} while (get_timer(timebase) < timeout);

	spi_xfer(spi, 0, NULL, NULL, SPI_XFER_END);

	if ((status & poll_bit) == 0)
	return 0;

	/* Timed out */
	debug("SF: time out!\n");
	return -1;
	}

	int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
	{
	return spi_flash_cmd_poll_bit(flash, timeout,
	CMD_READ_STATUS, STATUS_WIP);
	}

	int spi_flash_cmd_erase(struct spi_flash *flash, u32 offset, size_t len)
	{
	u32 end, erase_size;
	int ret;
	u8 cmd[4];

	erase_size = flash->sector_size;
	if (offset % erase_size \|\| len % erase_size) {
	debug("SF: Erase offset/length not multiple of erase size\n");
	return -1;
	}

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

	if (erase_size == 4096)
	cmd[0] = CMD_ERASE_4K;
	else
	cmd[0] = CMD_ERASE_64K;
	end = offset + len;

	while (offset < end) {
	spi_flash_addr(offset, cmd);
	offset += erase_size;

	debug("SF: erase %2x %2x %2x %2x (%x)\n", cmd[0], cmd[1],
	cmd[2], cmd[3], offset);

	ret = spi_flash_cmd_write_enable(flash);
	if (ret)
	goto out;

	ret = spi_flash_cmd_write(flash->spi, cmd, sizeof(cmd), NULL, 0);
	if (ret)
	goto out;

	ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PAGE_ERASE_TIMEOUT);
	if (ret)
	goto out;
	}

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

	int spi_flash_cmd_write_status(struct spi_flash *flash, u8 sr)
	{
	u8 cmd;
	int ret;

	ret = spi_flash_cmd_write_enable(flash);
	if (ret < 0) {
	debug("SF: enabling write failed\n");
	return ret;
	}

	cmd = CMD_WRITE_STATUS;
	ret = spi_flash_cmd_write(flash->spi, &cmd, 1, &sr, 1);
	if (ret) {
	debug("SF: fail to write status register\n");
	return ret;
	}

	ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
	if (ret < 0) {
	debug("SF: write status register timed out\n");
	return ret;
	}

	return 0;
	}

	#ifdef CONFIG_OF_CONTROL
	int spi_flash_decode_fdt(const void blob, struct spi_flash flash)
	{
	fdt_addr_t addr;
	fdt_size_t size;
	int node;

	/* If there is no node, do nothing */
	node = fdtdec_next_compatible(blob, 0, COMPAT_GENERIC_SPI_FLASH);
	if (node < 0)
	return 0;

	addr = fdtdec_get_addr_size(blob, node, "memory-map", &size);
	if (addr == FDT_ADDR_T_NONE) {
	debug("%s: Cannot decode address\n", __func__);
	return 0;
	}

	if (flash->size != size) {
	debug("%s: Memory map must cover entire device\n", __func__);
	return -1;
	}
	flash->memory_map = (void *)addr;

	return 0;
	}
	#endif /* CONFIG_OF_CONTROL */

	/*
	* The following table holds all device probe functions
	*
	* shift: number of continuation bytes before the ID
	* idcode: the expected IDCODE or 0xff for non JEDEC devices
	* probe: the function to call
	*
	* Non JEDEC devices should be ordered in the table such that
	* the probe functions with best detection algorithms come first.
	*
	* Several matching entries are permitted, they will be tried
	* in sequence until a probe function returns non NULL.
	*
	* IDCODE_CONT_LEN may be redefined if a device needs to declare a
	* larger "shift" value. IDCODE_PART_LEN generally shouldn't be
	* changed. This is the max number of bytes probe functions may
	* examine when looking up part-specific identification info.
	*
	* Probe functions will be given the idcode buffer starting at their
	* manu id byte (the "idcode" in the table below). In other words,
	* all of the continuation bytes will be skipped (the "shift" below).
	*/
	#define IDCODE_CONT_LEN 0
	#define IDCODE_PART_LEN 5
	static const struct {
	const u8 shift;
	const u8 idcode;
	struct spi_flash (probe) (struct spi_slave spi, u8 idcode);
	} flashes[] = {
	/* Keep it sorted by define name */
	#ifdef CONFIG_SPI_FLASH_ATMEL
	{ 0, 0x1f, spi_flash_probe_atmel, },
	#endif
	#ifdef CONFIG_SPI_FLASH_EON
	{ 0, 0x1c, spi_flash_probe_eon, },
	#endif
	#ifdef CONFIG_SPI_FLASH_MACRONIX
	{ 0, 0xc2, spi_flash_probe_macronix, },
	#endif
	#ifdef CONFIG_SPI_FLASH_SPANSION
	{ 0, 0x01, spi_flash_probe_spansion, },
	#endif
	#ifdef CONFIG_SPI_FLASH_SST
	{ 0, 0xbf, spi_flash_probe_sst, },
	#endif
	#ifdef CONFIG_SPI_FLASH_STMICRO
	{ 0, 0x20, spi_flash_probe_stmicro, },
	#endif
	#ifdef CONFIG_SPI_FLASH_WINBOND
	{ 0, 0xef, spi_flash_probe_winbond, },
	#endif
	#ifdef CONFIG_SPI_FRAM_RAMTRON
	{ 6, 0xc2, spi_fram_probe_ramtron, },
	# undef IDCODE_CONT_LEN
	# define IDCODE_CONT_LEN 6
	#endif
	/* Keep it sorted by best detection */
	#ifdef CONFIG_SPI_FLASH_STMICRO
	{ 0, 0xff, spi_flash_probe_stmicro, },
	#endif
	#ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC
	{ 0, 0xff, spi_fram_probe_ramtron, },
	#endif
	};
	#define IDCODE_LEN (IDCODE_CONT_LEN + IDCODE_PART_LEN)

	struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
	unsigned int max_hz, unsigned int spi_mode)
	{
	struct spi_slave *spi;
	struct spi_flash *flash = NULL;
	int ret, i, shift;
	u8 idcode[IDCODE_LEN], *idp;

	spi = spi_setup_slave(bus, cs, max_hz, spi_mode);
	if (!spi) {
	printf("SF: Failed to set up slave\n");
	return NULL;
	}

	ret = spi_claim_bus(spi);
	if (ret) {
	debug("SF: Failed to claim SPI bus: %d\n", ret);
	goto err_claim_bus;
	}

	/* Read the ID codes */
	ret = spi_flash_cmd(spi, CMD_READ_ID, idcode, sizeof(idcode));
	if (ret)
	goto err_read_id;

	#ifdef DEBUG
	printf("SF: Got idcodes\n");
	print_buffer(0, idcode, 1, sizeof(idcode), 0);
	#endif

	/* count the number of continuation bytes */
	for (shift = 0, idp = idcode;
	shift < IDCODE_CONT_LEN && *idp == 0x7f;
	++shift, ++idp)
	continue;

	/* search the table for matches in shift and id */
	for (i = 0; i < ARRAY_SIZE(flashes); ++i)
	if (flashes[i].shift == shift && flashes[i].idcode == *idp) {
	/* we have a match, call probe */
	flash = flashes[i].probe(spi, idp);
	if (flash)
	break;
	}

	if (!flash) {
	printf("SF: Unsupported manufacturer %02x\n", *idp);
	goto err_manufacturer_probe;
	}

	#ifdef CONFIG_OF_CONTROL
	if (spi_flash_decode_fdt(gd->fdt_blob, flash)) {
	debug("SF: FDT decode error\n");
	goto err_manufacturer_probe;
	}
	#endif
	printf("SF: Detected %s with page size ", flash->name);
	print_size(flash->sector_size, ", total ");
	print_size(flash->size, "");
	if (flash->memory_map)
	printf(", mapped at %p", flash->memory_map);
	puts("\n");

	spi_release_bus(spi);

	return flash;

	err_manufacturer_probe:
	err_read_id:
	spi_release_bus(spi);
	err_claim_bus:
	spi_free_slave(spi);
	return NULL;
	}

	void spi_flash_do_alloc(int offset, int size, struct spi_slave spi,
	const char *name)
	{
	struct spi_flash *flash;
	void *ptr;

	ptr = malloc(size);
	if (!ptr) {
	debug("SF: Failed to allocate memory\n");
	return NULL;
	}
	memset(ptr, '\0', size);
	flash = (struct spi_flash *)(ptr + offset);

	/* Set up some basic fields - caller will sort out sizes */
	flash->spi = spi;
	flash->name = name;

	flash->read = spi_flash_cmd_read_fast;
	flash->write = spi_flash_cmd_write_multi;
	flash->erase = spi_flash_cmd_erase;

	return flash;
	}

	void spi_flash_free(struct spi_flash *flash)
	{
	spi_free_slave(flash->spi);
	free(flash);
	}