drivers/mtd/spi/sf_ops.c - github/trini/u-boot - Gitiles

 /*
  * SPI flash operations
  *
  * Copyright (C) 2008 Atmel Corporation
  * Copyright (C) 2010 Reinhard Meyer, EMK Elektronik
  * Copyright (C) 2013 Jagannadha Sutradharudu Teki, Xilinx Inc.
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */

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

 #include "sf_internal.h"

 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;
 }

 int spi_flash_cmd_read_status(struct spi_flash *flash, u8 *rs)
 {
 	int ret;
 	u8 cmd;

 	cmd = CMD_READ_STATUS;
 	ret = spi_flash_read_common(flash, &cmd, 1, rs, 1);
 	if (ret < 0) {
 		debug("SF: fail to read status register\n");
 		return ret;
 	}

 	return 0;
 }

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

 	cmd = CMD_WRITE_STATUS;
 	ret = spi_flash_write_common(flash, &cmd, 1, &ws, 1);
 	if (ret < 0) {
 		debug("SF: fail to write status register\n");
 		return ret;
 	}

 	return 0;
 }

 #if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
 int spi_flash_cmd_read_config(struct spi_flash *flash, u8 *rc)
 {
 	int ret;
 	u8 cmd;

 	cmd = CMD_READ_CONFIG;
 	ret = spi_flash_read_common(flash, &cmd, 1, rc, 1);
 	if (ret < 0) {
 		debug("SF: fail to read config register\n");
 		return ret;
 	}

 	return 0;
 }

 int spi_flash_cmd_write_config(struct spi_flash *flash, u8 wc)
 {
 	u8 data[2];
 	u8 cmd;
 	int ret;

 	ret = spi_flash_cmd_read_status(flash, &data[0]);
 	if (ret < 0)
 		return ret;

 	cmd = CMD_WRITE_STATUS;
 	data[1] = wc;
 	ret = spi_flash_write_common(flash, &cmd, 1, &data, 2);
 	if (ret) {
 		debug("SF: fail to write config register\n");
 		return ret;
 	}

 	return 0;
 }
 #endif

 #ifdef CONFIG_SPI_FLASH_BAR
 static int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel)
 {
 	u8 cmd;
 	int ret;

 	if (flash->bank_curr == bank_sel) {
 		debug("SF: not require to enable bank%d\n", bank_sel);
 		return 0;
 	}

 	cmd = flash->bank_write_cmd;
 	ret = spi_flash_write_common(flash, &cmd, 1, &bank_sel, 1);
 	if (ret < 0) {
 		debug("SF: fail to write bank register\n");
 		return ret;
 	}
 	flash->bank_curr = bank_sel;

 	return 0;
 }

 static int spi_flash_bank(struct spi_flash *flash, u32 offset)
 {
 	u8 bank_sel;
 	int ret;

 	bank_sel = offset / (SPI_FLASH_16MB_BOUN << flash->shift);

 	ret = spi_flash_cmd_bankaddr_write(flash, bank_sel);
 	if (ret) {
 		debug("SF: fail to set bank%d\n", bank_sel);
 		return ret;
 	}

 	return bank_sel;
 }
 #endif

 #ifdef CONFIG_SF_DUAL_FLASH
 static void spi_flash_dual_flash(struct spi_flash *flash, u32 *addr)
 {
 	switch (flash->dual_flash) {
 	case SF_DUAL_STACKED_FLASH:
 		if (*addr >= (flash->size >> 1)) {
 			*addr -= flash->size >> 1;
 			flash->spi->flags |= SPI_XFER_U_PAGE;
 		} else {
 			flash->spi->flags &= ~SPI_XFER_U_PAGE;
 		}
 		break;
 	case SF_DUAL_PARALLEL_FLASH:
 		*addr >>= flash->shift;
 		break;
 	default:
 		debug("SF: Unsupported dual_flash=%d\n", flash->dual_flash);
 		break;
 	}
 }
 #endif

 static int spi_flash_poll_status(struct spi_slave *spi, unsigned long timeout,
 				 u8 cmd, u8 poll_bit)
 {
 	unsigned long timebase;
 	unsigned long flags = SPI_XFER_BEGIN;
 	int ret;
 	u8 status;
 	u8 check_status = 0x0;

 	if (cmd == CMD_FLAG_STATUS)
 		check_status = poll_bit;

 #ifdef CONFIG_SF_DUAL_FLASH
 	if (spi->flags & SPI_XFER_U_PAGE)
 		flags |= SPI_XFER_U_PAGE;
 #endif
 	ret = spi_xfer(spi, 8, &cmd, NULL, flags);
 	if (ret) {
 		debug("SF: fail to read %s status register\n",
 		      cmd == CMD_READ_STATUS ? "read" : "flag");
 		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) == check_status)
 			break;

 	} while (get_timer(timebase) < timeout);

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

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

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

 int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
 {
 	struct spi_slave *spi = flash->spi;
 	int ret;
 	u8 poll_bit = STATUS_WIP;
 	u8 cmd = CMD_READ_STATUS;

 	ret = spi_flash_poll_status(spi, timeout, cmd, poll_bit);
 	if (ret < 0)
 		return ret;

 	if (flash->poll_cmd == CMD_FLAG_STATUS) {
 		poll_bit = STATUS_PEC;
 		cmd = CMD_FLAG_STATUS;
 		ret = spi_flash_poll_status(spi, timeout, cmd, poll_bit);
 		if (ret < 0)
 			return ret;
 	}

 	return 0;
 }

 int spi_flash_write_common(struct spi_flash *flash, const u8 *cmd,
 		size_t cmd_len, const void *buf, size_t buf_len)
 {
 	struct spi_slave *spi = flash->spi;
 	unsigned long timeout = SPI_FLASH_PROG_TIMEOUT;
 	int ret;

 	if (buf == NULL)
 		timeout = SPI_FLASH_PAGE_ERASE_TIMEOUT;

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

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

 	ret = spi_flash_cmd_write(spi, cmd, cmd_len, buf, buf_len);
 	if (ret < 0) {
 		debug("SF: write cmd failed\n");
 		return ret;
 	}

 	ret = spi_flash_cmd_wait_ready(flash, timeout);
 	if (ret < 0) {
 		debug("SF: write %s timed out\n",
 		      timeout == SPI_FLASH_PROG_TIMEOUT ?
 			"program" : "page erase");
 		return ret;
 	}

 	spi_release_bus(spi);

 	return ret;
 }

 int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len)
 {
 	u32 erase_size, erase_addr;
 	u8 cmd[SPI_FLASH_CMD_LEN];
 	int ret = -1;

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

 	cmd[0] = flash->erase_cmd;
 	while (len) {
 		erase_addr = offset;

 #ifdef CONFIG_SF_DUAL_FLASH
 		if (flash->dual_flash > SF_SINGLE_FLASH)
 			spi_flash_dual_flash(flash, &erase_addr);
 #endif
 #ifdef CONFIG_SPI_FLASH_BAR
 		ret = spi_flash_bank(flash, erase_addr);
 		if (ret < 0)
 			return ret;
 #endif
 		spi_flash_addr(erase_addr, cmd);

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

 		ret = spi_flash_write_common(flash, cmd, sizeof(cmd), NULL, 0);
 		if (ret < 0) {
 			debug("SF: erase failed\n");
 			break;
 		}

 		offset += erase_size;
 		len -= erase_size;
 	}

 	return ret;
 }

 int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
 		size_t len, const void *buf)
 {
 	unsigned long byte_addr, page_size;
 	u32 write_addr;
 	size_t chunk_len, actual;
 	u8 cmd[SPI_FLASH_CMD_LEN];
 	int ret = -1;

 	page_size = flash->page_size;

 	cmd[0] = flash->write_cmd;
 	for (actual = 0; actual < len; actual += chunk_len) {
 		write_addr = offset;

 #ifdef CONFIG_SF_DUAL_FLASH
 		if (flash->dual_flash > SF_SINGLE_FLASH)
 			spi_flash_dual_flash(flash, &write_addr);
 #endif
 #ifdef CONFIG_SPI_FLASH_BAR
 		ret = spi_flash_bank(flash, write_addr);
 		if (ret < 0)
 			return ret;
 #endif
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, (size_t)(page_size - byte_addr));

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

 		spi_flash_addr(write_addr, cmd);

 		debug("SF: 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_write_common(flash, cmd, sizeof(cmd),
 					buf + actual, chunk_len);
 		if (ret < 0) {
 			debug("SF: write failed\n");
 			break;
 		}

 		offset += chunk_len;
 	}

 	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;

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

 	ret = spi_flash_cmd_read(spi, cmd, cmd_len, data, data_len);
 	if (ret < 0) {
 		debug("SF: read cmd failed\n");
 		return ret;
 	}

 	spi_release_bus(spi);

 	return ret;
 }

 int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 		size_t len, void *data)
 {
 	u8 *cmd, cmdsz;
 	u32 remain_len, read_len, read_addr;
 	int bank_sel = 0;
 	int ret = -1;

 	/* Handle memory-mapped SPI */
 	if (flash->memory_map) {
 		ret = spi_claim_bus(flash->spi);
 		if (ret) {
 			debug("SF: unable to claim SPI bus\n");
 			return ret;
 		}
 		spi_xfer(flash->spi, 0, NULL, NULL, SPI_XFER_MMAP);
 		memcpy(data, flash->memory_map + offset, len);
 		spi_xfer(flash->spi, 0, NULL, NULL, SPI_XFER_MMAP_END);
 		spi_release_bus(flash->spi);
 		return 0;
 	}

 	cmdsz = SPI_FLASH_CMD_LEN + flash->dummy_byte;
 	cmd = calloc(1, cmdsz);
 	if (!cmd) {
 		debug("SF: Failed to allocate cmd\n");
 		return -ENOMEM;
 	}

 	cmd[0] = flash->read_cmd;
 	while (len) {
 		read_addr = offset;

 #ifdef CONFIG_SF_DUAL_FLASH
 		if (flash->dual_flash > SF_SINGLE_FLASH)
 			spi_flash_dual_flash(flash, &read_addr);
 #endif
 #ifdef CONFIG_SPI_FLASH_BAR
 		bank_sel = spi_flash_bank(flash, read_addr);
 		if (bank_sel < 0)
 			return ret;
 #endif
 		remain_len = ((SPI_FLASH_16MB_BOUN << flash->shift) *
 				(bank_sel + 1)) - offset;
 		if (len < remain_len)
 			read_len = len;
 		else
 			read_len = remain_len;

 		spi_flash_addr(read_addr, cmd);

 		ret = spi_flash_read_common(flash, cmd, cmdsz, data, read_len);
 		if (ret < 0) {
 			debug("SF: read failed\n");
 			break;
 		}

 		offset += read_len;
 		len -= read_len;
 		data += read_len;
 	}

 	free(cmd);
 	return ret;
 }

 #ifdef CONFIG_SPI_FLASH_SST
 static int sst_byte_write(struct spi_flash *flash, u32 offset, const void *buf)
 {
 	int ret;
 	u8 cmd[4] = {
 		CMD_SST_BP,
 		offset >> 16,
 		offset >> 8,
 		offset,
 	};

 	debug("BP[%02x]: 0x%p => cmd = { 0x%02x 0x%06x }\n",
 	      spi_w8r8(flash->spi, CMD_READ_STATUS), buf, cmd[0], offset);

 	ret = spi_flash_cmd_write_enable(flash);
 	if (ret)
 		return ret;

 	ret = spi_flash_cmd_write(flash->spi, cmd, sizeof(cmd), buf, 1);
 	if (ret)
 		return ret;

 	return spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
 }

 int sst_write_wp(struct spi_flash *flash, u32 offset, size_t len,
 		const void *buf)
 {
 	size_t actual, cmd_len;
 	int ret;
 	u8 cmd[4];

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

 	/* If the data is not word aligned, write out leading single byte */
 	actual = offset % 2;
 	if (actual) {
 		ret = sst_byte_write(flash, offset, buf);
 		if (ret)
 			goto done;
 	}
 	offset += actual;

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

 	cmd_len = 4;
 	cmd[0] = CMD_SST_AAI_WP;
 	cmd[1] = offset >> 16;
 	cmd[2] = offset >> 8;
 	cmd[3] = offset;

 	for (; actual < len - 1; actual += 2) {
 		debug("WP[%02x]: 0x%p => cmd = { 0x%02x 0x%06x }\n",
 		      spi_w8r8(flash->spi, CMD_READ_STATUS), buf + actual,
 		      cmd[0], offset);

 		ret = spi_flash_cmd_write(flash->spi, cmd, cmd_len,
 					buf + actual, 2);
 		if (ret) {
 			debug("SF: sst word program failed\n");
 			break;
 		}

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

 		cmd_len = 1;
 		offset += 2;
 	}

 	if (!ret)
 		ret = spi_flash_cmd_write_disable(flash);

 	/* If there is a single trailing byte, write it out */
 	if (!ret && actual != len)
 		ret = sst_byte_write(flash, offset, buf + actual);

  done:
 	debug("SF: sst: program %s %zu bytes @ 0x%zx\n",
 	      ret ? "failure" : "success", len, offset - actual);

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

 int sst_write_bp(struct spi_flash *flash, u32 offset, size_t len,
 		const void *buf)
 {
 	size_t actual;
 	int ret;

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

 	for (actual = 0; actual < len; actual++) {
 		ret = sst_byte_write(flash, offset, buf + actual);
 		if (ret) {
 			debug("SF: sst byte program failed\n");
 			break;
 		}
 		offset++;
 	}

 	if (!ret)
 		ret = spi_flash_cmd_write_disable(flash);

 	debug("SF: sst: program %s %zu bytes @ 0x%zx\n",
 	      ret ? "failure" : "success", len, offset - actual);

 	spi_release_bus(flash->spi);
 	return ret;
 }
 #endif
	/*
	* SPI flash operations
	*
	* Copyright (C) 2008 Atmel Corporation
	* Copyright (C) 2010 Reinhard Meyer, EMK Elektronik
	* Copyright (C) 2013 Jagannadha Sutradharudu Teki, Xilinx Inc.
	*
	* SPDX-License-Identifier: GPL-2.0+
	*/

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

	#include "sf_internal.h"

	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;
	}

	int spi_flash_cmd_read_status(struct spi_flash flash, u8 rs)
	{
	int ret;
	u8 cmd;

	cmd = CMD_READ_STATUS;
	ret = spi_flash_read_common(flash, &cmd, 1, rs, 1);
	if (ret < 0) {
	debug("SF: fail to read status register\n");
	return ret;
	}

	return 0;
	}

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

	cmd = CMD_WRITE_STATUS;
	ret = spi_flash_write_common(flash, &cmd, 1, &ws, 1);
	if (ret < 0) {
	debug("SF: fail to write status register\n");
	return ret;
	}

	return 0;
	}

	#if defined(CONFIG_SPI_FLASH_SPANSION) \|\| defined(CONFIG_SPI_FLASH_WINBOND)
	int spi_flash_cmd_read_config(struct spi_flash flash, u8 rc)
	{
	int ret;
	u8 cmd;

	cmd = CMD_READ_CONFIG;
	ret = spi_flash_read_common(flash, &cmd, 1, rc, 1);
	if (ret < 0) {
	debug("SF: fail to read config register\n");
	return ret;
	}

	return 0;
	}

	int spi_flash_cmd_write_config(struct spi_flash *flash, u8 wc)
	{
	u8 data[2];
	u8 cmd;
	int ret;

	ret = spi_flash_cmd_read_status(flash, &data[0]);
	if (ret < 0)
	return ret;

	cmd = CMD_WRITE_STATUS;
	data[1] = wc;
	ret = spi_flash_write_common(flash, &cmd, 1, &data, 2);
	if (ret) {
	debug("SF: fail to write config register\n");
	return ret;
	}

	return 0;
	}
	#endif

	#ifdef CONFIG_SPI_FLASH_BAR
	static int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel)
	{
	u8 cmd;
	int ret;

	if (flash->bank_curr == bank_sel) {
	debug("SF: not require to enable bank%d\n", bank_sel);
	return 0;
	}

	cmd = flash->bank_write_cmd;
	ret = spi_flash_write_common(flash, &cmd, 1, &bank_sel, 1);
	if (ret < 0) {
	debug("SF: fail to write bank register\n");
	return ret;
	}
	flash->bank_curr = bank_sel;

	return 0;
	}

	static int spi_flash_bank(struct spi_flash *flash, u32 offset)
	{
	u8 bank_sel;
	int ret;

	bank_sel = offset / (SPI_FLASH_16MB_BOUN << flash->shift);

	ret = spi_flash_cmd_bankaddr_write(flash, bank_sel);
	if (ret) {
	debug("SF: fail to set bank%d\n", bank_sel);
	return ret;
	}

	return bank_sel;
	}
	#endif

	#ifdef CONFIG_SF_DUAL_FLASH
	static void spi_flash_dual_flash(struct spi_flash flash, u32 addr)
	{
	switch (flash->dual_flash) {
	case SF_DUAL_STACKED_FLASH:
	if (*addr >= (flash->size >> 1)) {
	*addr -= flash->size >> 1;
	flash->spi->flags \|= SPI_XFER_U_PAGE;
	} else {
	flash->spi->flags &= ~SPI_XFER_U_PAGE;
	}
	break;
	case SF_DUAL_PARALLEL_FLASH:
	*addr >>= flash->shift;
	break;
	default:
	debug("SF: Unsupported dual_flash=%d\n", flash->dual_flash);
	break;
	}
	}
	#endif

	static int spi_flash_poll_status(struct spi_slave *spi, unsigned long timeout,
	u8 cmd, u8 poll_bit)
	{
	unsigned long timebase;
	unsigned long flags = SPI_XFER_BEGIN;
	int ret;
	u8 status;
	u8 check_status = 0x0;

	if (cmd == CMD_FLAG_STATUS)
	check_status = poll_bit;

	#ifdef CONFIG_SF_DUAL_FLASH
	if (spi->flags & SPI_XFER_U_PAGE)
	flags \|= SPI_XFER_U_PAGE;
	#endif
	ret = spi_xfer(spi, 8, &cmd, NULL, flags);
	if (ret) {
	debug("SF: fail to read %s status register\n",
	cmd == CMD_READ_STATUS ? "read" : "flag");
	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) == check_status)
	break;

	} while (get_timer(timebase) < timeout);

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

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

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

	int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
	{
	struct spi_slave *spi = flash->spi;
	int ret;
	u8 poll_bit = STATUS_WIP;
	u8 cmd = CMD_READ_STATUS;

	ret = spi_flash_poll_status(spi, timeout, cmd, poll_bit);
	if (ret < 0)
	return ret;

	if (flash->poll_cmd == CMD_FLAG_STATUS) {
	poll_bit = STATUS_PEC;
	cmd = CMD_FLAG_STATUS;
	ret = spi_flash_poll_status(spi, timeout, cmd, poll_bit);
	if (ret < 0)
	return ret;
	}

	return 0;
	}

	int spi_flash_write_common(struct spi_flash flash, const u8 cmd,
	size_t cmd_len, const void *buf, size_t buf_len)
	{
	struct spi_slave *spi = flash->spi;
	unsigned long timeout = SPI_FLASH_PROG_TIMEOUT;
	int ret;

	if (buf == NULL)
	timeout = SPI_FLASH_PAGE_ERASE_TIMEOUT;

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

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

	ret = spi_flash_cmd_write(spi, cmd, cmd_len, buf, buf_len);
	if (ret < 0) {
	debug("SF: write cmd failed\n");
	return ret;
	}

	ret = spi_flash_cmd_wait_ready(flash, timeout);
	if (ret < 0) {
	debug("SF: write %s timed out\n",
	timeout == SPI_FLASH_PROG_TIMEOUT ?
	"program" : "page erase");
	return ret;
	}

	spi_release_bus(spi);

	return ret;
	}

	int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len)
	{
	u32 erase_size, erase_addr;
	u8 cmd[SPI_FLASH_CMD_LEN];
	int ret = -1;

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

	cmd[0] = flash->erase_cmd;
	while (len) {
	erase_addr = offset;

	#ifdef CONFIG_SF_DUAL_FLASH
	if (flash->dual_flash > SF_SINGLE_FLASH)
	spi_flash_dual_flash(flash, &erase_addr);
	#endif
	#ifdef CONFIG_SPI_FLASH_BAR
	ret = spi_flash_bank(flash, erase_addr);
	if (ret < 0)
	return ret;
	#endif
	spi_flash_addr(erase_addr, cmd);

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

	ret = spi_flash_write_common(flash, cmd, sizeof(cmd), NULL, 0);
	if (ret < 0) {
	debug("SF: erase failed\n");
	break;
	}

	offset += erase_size;
	len -= erase_size;
	}

	return ret;
	}

	int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
	size_t len, const void *buf)
	{
	unsigned long byte_addr, page_size;
	u32 write_addr;
	size_t chunk_len, actual;
	u8 cmd[SPI_FLASH_CMD_LEN];
	int ret = -1;

	page_size = flash->page_size;

	cmd[0] = flash->write_cmd;
	for (actual = 0; actual < len; actual += chunk_len) {
	write_addr = offset;

	#ifdef CONFIG_SF_DUAL_FLASH
	if (flash->dual_flash > SF_SINGLE_FLASH)
	spi_flash_dual_flash(flash, &write_addr);
	#endif
	#ifdef CONFIG_SPI_FLASH_BAR
	ret = spi_flash_bank(flash, write_addr);
	if (ret < 0)
	return ret;
	#endif
	byte_addr = offset % page_size;
	chunk_len = min(len - actual, (size_t)(page_size - byte_addr));

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

	spi_flash_addr(write_addr, cmd);

	debug("SF: 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_write_common(flash, cmd, sizeof(cmd),
	buf + actual, chunk_len);
	if (ret < 0) {
	debug("SF: write failed\n");
	break;
	}

	offset += chunk_len;
	}

	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;

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

	ret = spi_flash_cmd_read(spi, cmd, cmd_len, data, data_len);
	if (ret < 0) {
	debug("SF: read cmd failed\n");
	return ret;
	}

	spi_release_bus(spi);

	return ret;
	}

	int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
	size_t len, void *data)
	{
	u8 *cmd, cmdsz;
	u32 remain_len, read_len, read_addr;
	int bank_sel = 0;
	int ret = -1;

	/* Handle memory-mapped SPI */
	if (flash->memory_map) {
	ret = spi_claim_bus(flash->spi);
	if (ret) {
	debug("SF: unable to claim SPI bus\n");
	return ret;
	}
	spi_xfer(flash->spi, 0, NULL, NULL, SPI_XFER_MMAP);
	memcpy(data, flash->memory_map + offset, len);
	spi_xfer(flash->spi, 0, NULL, NULL, SPI_XFER_MMAP_END);
	spi_release_bus(flash->spi);
	return 0;
	}

	cmdsz = SPI_FLASH_CMD_LEN + flash->dummy_byte;
	cmd = calloc(1, cmdsz);
	if (!cmd) {
	debug("SF: Failed to allocate cmd\n");
	return -ENOMEM;
	}

	cmd[0] = flash->read_cmd;
	while (len) {
	read_addr = offset;

	#ifdef CONFIG_SF_DUAL_FLASH
	if (flash->dual_flash > SF_SINGLE_FLASH)
	spi_flash_dual_flash(flash, &read_addr);
	#endif
	#ifdef CONFIG_SPI_FLASH_BAR
	bank_sel = spi_flash_bank(flash, read_addr);
	if (bank_sel < 0)
	return ret;
	#endif
	remain_len = ((SPI_FLASH_16MB_BOUN << flash->shift) *
	(bank_sel + 1)) - offset;
	if (len < remain_len)
	read_len = len;
	else
	read_len = remain_len;

	spi_flash_addr(read_addr, cmd);

	ret = spi_flash_read_common(flash, cmd, cmdsz, data, read_len);
	if (ret < 0) {
	debug("SF: read failed\n");
	break;
	}

	offset += read_len;
	len -= read_len;
	data += read_len;
	}

	free(cmd);
	return ret;
	}

	#ifdef CONFIG_SPI_FLASH_SST
	static int sst_byte_write(struct spi_flash flash, u32 offset, const void buf)
	{
	int ret;
	u8 cmd[4] = {
	CMD_SST_BP,
	offset >> 16,
	offset >> 8,
	offset,
	};

	debug("BP[%02x]: 0x%p => cmd = { 0x%02x 0x%06x }\n",
	spi_w8r8(flash->spi, CMD_READ_STATUS), buf, cmd[0], offset);

	ret = spi_flash_cmd_write_enable(flash);
	if (ret)
	return ret;

	ret = spi_flash_cmd_write(flash->spi, cmd, sizeof(cmd), buf, 1);
	if (ret)
	return ret;

	return spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
	}

	int sst_write_wp(struct spi_flash *flash, u32 offset, size_t len,
	const void *buf)
	{
	size_t actual, cmd_len;
	int ret;
	u8 cmd[4];

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

	/* If the data is not word aligned, write out leading single byte */
	actual = offset % 2;
	if (actual) {
	ret = sst_byte_write(flash, offset, buf);
	if (ret)
	goto done;
	}
	offset += actual;

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

	cmd_len = 4;
	cmd[0] = CMD_SST_AAI_WP;
	cmd[1] = offset >> 16;
	cmd[2] = offset >> 8;
	cmd[3] = offset;

	for (; actual < len - 1; actual += 2) {
	debug("WP[%02x]: 0x%p => cmd = { 0x%02x 0x%06x }\n",
	spi_w8r8(flash->spi, CMD_READ_STATUS), buf + actual,
	cmd[0], offset);

	ret = spi_flash_cmd_write(flash->spi, cmd, cmd_len,
	buf + actual, 2);
	if (ret) {
	debug("SF: sst word program failed\n");
	break;
	}

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

	cmd_len = 1;
	offset += 2;
	}

	if (!ret)
	ret = spi_flash_cmd_write_disable(flash);

	/* If there is a single trailing byte, write it out */
	if (!ret && actual != len)
	ret = sst_byte_write(flash, offset, buf + actual);

	done:
	debug("SF: sst: program %s %zu bytes @ 0x%zx\n",
	ret ? "failure" : "success", len, offset - actual);

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

	int sst_write_bp(struct spi_flash *flash, u32 offset, size_t len,
	const void *buf)
	{
	size_t actual;
	int ret;

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

	for (actual = 0; actual < len; actual++) {
	ret = sst_byte_write(flash, offset, buf + actual);
	if (ret) {
	debug("SF: sst byte program failed\n");
	break;
	}
	offset++;
	}

	if (!ret)
	ret = spi_flash_cmd_write_disable(flash);

	debug("SF: sst: program %s %zu bytes @ 0x%zx\n",
	ret ? "failure" : "success", len, offset - actual);

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