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

 /*
  * Simulate a SPI flash
  *
  * Copyright (c) 2011-2013 The Chromium OS Authors.
  * See file CREDITS for list of people who contributed to this
  * project.
  *
  * Licensed under the GPL-2 or later.
  */

 #include <common.h>
 #include <malloc.h>
 #include <spi.h>
 #include <os.h>

 #include <spi_flash.h>
 #include "sf_internal.h"

 #include <asm/getopt.h>
 #include <asm/spi.h>
 #include <asm/state.h>

 /*
  * The different states that our SPI flash transitions between.
  * We need to keep track of this across multiple xfer calls since
  * the SPI bus could possibly call down into us multiple times.
  */
 enum sandbox_sf_state {
 	SF_CMD,   /* default state -- we're awaiting a command */
 	SF_ID,    /* read the flash's (jedec) ID code */
 	SF_ADDR,  /* processing the offset in the flash to read/etc... */
 	SF_READ,  /* reading data from the flash */
 	SF_WRITE, /* writing data to the flash, i.e. page programming */
 	SF_ERASE, /* erase the flash */
 	SF_READ_STATUS, /* read the flash's status register */
 	SF_READ_STATUS1, /* read the flash's status register upper 8 bits*/
 };

 static const char *sandbox_sf_state_name(enum sandbox_sf_state state)
 {
 	static const char * const states[] = {
 		"CMD", "ID", "ADDR", "READ", "WRITE", "ERASE", "READ_STATUS",
 	};
 	return states[state];
 }

 /* Bits for the status register */
 #define STAT_WIP	(1 << 0)
 #define STAT_WEL	(1 << 1)

 /* Assume all SPI flashes have 3 byte addresses since they do atm */
 #define SF_ADDR_LEN	3

 #define IDCODE_LEN 3

 /* Used to quickly bulk erase backing store */
 static u8 sandbox_sf_0xff[0x1000];

 /* Internal state data for each SPI flash */
 struct sandbox_spi_flash {
 	/*
 	 * As we receive data over the SPI bus, our flash transitions
 	 * between states.  For example, we start off in the SF_CMD
 	 * state where the first byte tells us what operation to perform
 	 * (such as read or write the flash).  But the operation itself
 	 * can go through a few states such as first reading in the
 	 * offset in the flash to perform the requested operation.
 	 * Thus "state" stores the exact state that our machine is in
 	 * while "cmd" stores the overall command we're processing.
 	 */
 	enum sandbox_sf_state state;
 	uint cmd;
 	/* Erase size of current erase command */
 	uint erase_size;
 	/* Current position in the flash; used when reading/writing/etc... */
 	uint off;
 	/* How many address bytes we've consumed */
 	uint addr_bytes, pad_addr_bytes;
 	/* The current flash status (see STAT_XXX defines above) */
 	u16 status;
 	/* Data describing the flash we're emulating */
 	const struct spi_flash_params *data;
 	/* The file on disk to serv up data from */
 	int fd;
 };

 static int sandbox_sf_setup(void **priv, const char *spec)
 {
 	/* spec = idcode:file */
 	struct sandbox_spi_flash *sbsf;
 	const char *file;
 	size_t len, idname_len;
 	const struct spi_flash_params *data;

 	file = strchr(spec, ':');
 	if (!file) {
 		printf("sandbox_sf: unable to parse file\n");
 		goto error;
 	}
 	idname_len = file - spec;
 	++file;

 	for (data = spi_flash_params_table; data->name; data++) {
 		len = strlen(data->name);
 		if (idname_len != len)
 			continue;
 		if (!memcmp(spec, data->name, len))
 			break;
 	}
 	if (!data->name) {
 		printf("sandbox_sf: unknown flash '%*s'\n", (int)idname_len,
 		       spec);
 		goto error;
 	}

 	if (sandbox_sf_0xff[0] == 0x00)
 		memset(sandbox_sf_0xff, 0xff, sizeof(sandbox_sf_0xff));

 	sbsf = calloc(sizeof(*sbsf), 1);
 	if (!sbsf) {
 		printf("sandbox_sf: out of memory\n");
 		goto error;
 	}

 	sbsf->fd = os_open(file, 02);
 	if (sbsf->fd == -1) {
 		free(sbsf);
 		printf("sandbox_sf: unable to open file '%s'\n", file);
 		goto error;
 	}

 	sbsf->data = data;

 	*priv = sbsf;
 	return 0;

  error:
 	return 1;
 }

 static void sandbox_sf_free(void *priv)
 {
 	struct sandbox_spi_flash *sbsf = priv;

 	os_close(sbsf->fd);
 	free(sbsf);
 }

 static void sandbox_sf_cs_activate(void *priv)
 {
 	struct sandbox_spi_flash *sbsf = priv;

 	debug("sandbox_sf: CS activated; state is fresh!\n");

 	/* CS is asserted, so reset state */
 	sbsf->off = 0;
 	sbsf->addr_bytes = 0;
 	sbsf->pad_addr_bytes = 0;
 	sbsf->state = SF_CMD;
 	sbsf->cmd = SF_CMD;
 }

 static void sandbox_sf_cs_deactivate(void *priv)
 {
 	debug("sandbox_sf: CS deactivated; cmd done processing!\n");
 }

 /* Figure out what command this stream is telling us to do */
 static int sandbox_sf_process_cmd(struct sandbox_spi_flash *sbsf, const u8 *rx,
 				  u8 *tx)
 {
 	enum sandbox_sf_state oldstate = sbsf->state;

 	/* We need to output a byte for the cmd byte we just ate */
 	sandbox_spi_tristate(tx, 1);

 	sbsf->cmd = rx[0];
 	switch (sbsf->cmd) {
 	case CMD_READ_ID:
 		sbsf->state = SF_ID;
 		sbsf->cmd = SF_ID;
 		break;
 	case CMD_READ_ARRAY_FAST:
 		sbsf->pad_addr_bytes = 1;
 	case CMD_READ_ARRAY_SLOW:
 	case CMD_PAGE_PROGRAM:
 		sbsf->state = SF_ADDR;
 		break;
 	case CMD_WRITE_DISABLE:
 		debug(" write disabled\n");
 		sbsf->status &= ~STAT_WEL;
 		break;
 	case CMD_READ_STATUS:
 		sbsf->state = SF_READ_STATUS;
 		break;
 	case CMD_READ_STATUS1:
 		sbsf->state = SF_READ_STATUS1;
 		break;
 	case CMD_WRITE_ENABLE:
 		debug(" write enabled\n");
 		sbsf->status |= STAT_WEL;
 		break;
 	default: {
 		int flags = sbsf->data->flags;

 		/* we only support erase here */
 		if (sbsf->cmd == CMD_ERASE_CHIP) {
 			sbsf->erase_size = sbsf->data->sector_size *
 				sbsf->data->nr_sectors;
 		} else if (sbsf->cmd == CMD_ERASE_4K && (flags & SECT_4K)) {
 			sbsf->erase_size = 4 << 10;
 		} else if (sbsf->cmd == CMD_ERASE_32K && (flags & SECT_32K)) {
 			sbsf->erase_size = 32 << 10;
 		} else if (sbsf->cmd == CMD_ERASE_64K &&
 			   !(flags & (SECT_4K | SECT_32K))) {
 			sbsf->erase_size = 64 << 10;
 		} else {
 			debug(" cmd unknown: %#x\n", sbsf->cmd);
 			return 1;
 		}
 		sbsf->state = SF_ADDR;
 		break;
 	}
 	}

 	if (oldstate != sbsf->state)
 		debug(" cmd: transition to %s state\n",
 		      sandbox_sf_state_name(sbsf->state));

 	return 0;
 }

 int sandbox_erase_part(struct sandbox_spi_flash *sbsf, int size)
 {
 	int todo;
 	int ret;

 	while (size > 0) {
 		todo = min(size, sizeof(sandbox_sf_0xff));
 		ret = os_write(sbsf->fd, sandbox_sf_0xff, todo);
 		if (ret != todo)
 			return ret;
 		size -= todo;
 	}

 	return 0;
 }

 static int sandbox_sf_xfer(void *priv, const u8 *rx, u8 *tx,
 		uint bytes)
 {
 	struct sandbox_spi_flash *sbsf = priv;
 	uint cnt, pos = 0;
 	int ret;

 	debug("sandbox_sf: state:%x(%s) bytes:%u\n", sbsf->state,
 	      sandbox_sf_state_name(sbsf->state), bytes);

 	if (sbsf->state == SF_CMD) {
 		/* Figure out the initial state */
 		if (sandbox_sf_process_cmd(sbsf, rx, tx))
 			return 1;
 		++pos;
 	}

 	/* Process the remaining data */
 	while (pos < bytes) {
 		switch (sbsf->state) {
 		case SF_ID: {
 			u8 id;

 			debug(" id: off:%u tx:", sbsf->off);
 			if (sbsf->off < IDCODE_LEN) {
 				/* Extract correct byte from ID 0x00aabbcc */
 				id = sbsf->data->jedec >>
 					(8 * (IDCODE_LEN - 1 - sbsf->off));
 			} else {
 				id = 0;
 			}
 			debug("%d %02x\n", sbsf->off, id);
 			tx[pos++] = id;
 			++sbsf->off;
 			break;
 		}
 		case SF_ADDR:
 			debug(" addr: bytes:%u rx:%02x ", sbsf->addr_bytes,
 			      rx[pos]);

 			if (sbsf->addr_bytes++ < SF_ADDR_LEN)
 				sbsf->off = (sbsf->off << 8) | rx[pos];
 			debug("addr:%06x\n", sbsf->off);

 			sandbox_spi_tristate(&tx[pos++], 1);

 			/* See if we're done processing */
 			if (sbsf->addr_bytes <
 					SF_ADDR_LEN + sbsf->pad_addr_bytes)
 				break;

 			/* Next state! */
 			if (os_lseek(sbsf->fd, sbsf->off, OS_SEEK_SET) < 0) {
 				puts("sandbox_sf: os_lseek() failed");
 				return 1;
 			}
 			switch (sbsf->cmd) {
 			case CMD_READ_ARRAY_FAST:
 			case CMD_READ_ARRAY_SLOW:
 				sbsf->state = SF_READ;
 				break;
 			case CMD_PAGE_PROGRAM:
 				sbsf->state = SF_WRITE;
 				break;
 			default:
 				/* assume erase state ... */
 				sbsf->state = SF_ERASE;
 				goto case_sf_erase;
 			}
 			debug(" cmd: transition to %s state\n",
 			      sandbox_sf_state_name(sbsf->state));
 			break;
 		case SF_READ:
 			/*
 			 * XXX: need to handle exotic behavior:
 			 *      - reading past end of device
 			 */

 			cnt = bytes - pos;
 			debug(" tx: read(%u)\n", cnt);
 			ret = os_read(sbsf->fd, tx + pos, cnt);
 			if (ret < 0) {
 				puts("sandbox_spi: os_read() failed\n");
 				return 1;
 			}
 			pos += ret;
 			break;
 		case SF_READ_STATUS:
 			debug(" read status: %#x\n", sbsf->status);
 			cnt = bytes - pos;
 			memset(tx + pos, sbsf->status, cnt);
 			pos += cnt;
 			break;
 		case SF_READ_STATUS1:
 			debug(" read status: %#x\n", sbsf->status);
 			cnt = bytes - pos;
 			memset(tx + pos, sbsf->status >> 8, cnt);
 			pos += cnt;
 			break;
 		case SF_WRITE:
 			/*
 			 * XXX: need to handle exotic behavior:
 			 *      - unaligned addresses
 			 *      - more than a page (256) worth of data
 			 *      - reading past end of device
 			 */
 			if (!(sbsf->status & STAT_WEL)) {
 				puts("sandbox_sf: write enable not set before write\n");
 				goto done;
 			}

 			cnt = bytes - pos;
 			debug(" rx: write(%u)\n", cnt);
 			sandbox_spi_tristate(&tx[pos], cnt);
 			ret = os_write(sbsf->fd, rx + pos, cnt);
 			if (ret < 0) {
 				puts("sandbox_spi: os_write() failed\n");
 				return 1;
 			}
 			pos += ret;
 			sbsf->status &= ~STAT_WEL;
 			break;
 		case SF_ERASE:
  case_sf_erase: {
 			if (!(sbsf->status & STAT_WEL)) {
 				puts("sandbox_sf: write enable not set before erase\n");
 				goto done;
 			}

 			/* verify address is aligned */
 			if (sbsf->off & (sbsf->erase_size - 1)) {
 				debug(" sector erase: cmd:%#x needs align:%#x, but we got %#x\n",
 				      sbsf->cmd, sbsf->erase_size,
 				      sbsf->off);
 				sbsf->status &= ~STAT_WEL;
 				goto done;
 			}

 			debug(" sector erase addr: %u, size: %u\n", sbsf->off,
 			      sbsf->erase_size);

 			cnt = bytes - pos;
 			sandbox_spi_tristate(&tx[pos], cnt);
 			pos += cnt;

 			/*
 			 * TODO(vapier@gentoo.org): latch WIP in status, and
 			 * delay before clearing it ?
 			 */
 			ret = sandbox_erase_part(sbsf, sbsf->erase_size);
 			sbsf->status &= ~STAT_WEL;
 			if (ret) {
 				debug("sandbox_sf: Erase failed\n");
 				goto done;
 			}
 			goto done;
 		}
 		default:
 			debug(" ??? no idea what to do ???\n");
 			goto done;
 		}
 	}

  done:
 	return pos == bytes ? 0 : 1;
 }

 static const struct sandbox_spi_emu_ops sandbox_sf_ops = {
 	.setup         = sandbox_sf_setup,
 	.free          = sandbox_sf_free,
 	.cs_activate   = sandbox_sf_cs_activate,
 	.cs_deactivate = sandbox_sf_cs_deactivate,
 	.xfer          = sandbox_sf_xfer,
 };

 static int sandbox_cmdline_cb_spi_sf(struct sandbox_state *state,
 				     const char *arg)
 {
 	unsigned long bus, cs;
 	const char *spec = sandbox_spi_parse_spec(arg, &bus, &cs);

 	if (!spec)
 		return 1;

 	/*
 	 * It is safe to not make a copy of 'spec' because it comes from the
 	 * command line.
 	 *
 	 * TODO(sjg@chromium.org): It would be nice if we could parse the
 	 * spec here, but the problem is that no U-Boot init has been done
 	 * yet. Perhaps we can figure something out.
 	 */
 	state->spi[bus][cs].ops = &sandbox_sf_ops;
 	state->spi[bus][cs].spec = spec;
 	return 0;
 }
 SANDBOX_CMDLINE_OPT(spi_sf, 1, "connect a SPI flash: <bus>:<cs>:<id>:<file>");
	/*
	* Simulate a SPI flash
	*
	* Copyright (c) 2011-2013 The Chromium OS Authors.
	* See file CREDITS for list of people who contributed to this
	* project.
	*
	* Licensed under the GPL-2 or later.
	*/

	#include <common.h>
	#include <malloc.h>
	#include <spi.h>
	#include <os.h>

	#include <spi_flash.h>
	#include "sf_internal.h"

	#include <asm/getopt.h>
	#include <asm/spi.h>
	#include <asm/state.h>

	/*
	* The different states that our SPI flash transitions between.
	* We need to keep track of this across multiple xfer calls since
	* the SPI bus could possibly call down into us multiple times.
	*/
	enum sandbox_sf_state {
	SF_CMD, /* default state -- we're awaiting a command */
	SF_ID, /* read the flash's (jedec) ID code */
	SF_ADDR, /* processing the offset in the flash to read/etc... */
	SF_READ, /* reading data from the flash */
	SF_WRITE, /* writing data to the flash, i.e. page programming */
	SF_ERASE, /* erase the flash */
	SF_READ_STATUS, /* read the flash's status register */
	SF_READ_STATUS1, /* read the flash's status register upper 8 bits*/
	};

	static const char *sandbox_sf_state_name(enum sandbox_sf_state state)
	{
	static const char * const states[] = {
	"CMD", "ID", "ADDR", "READ", "WRITE", "ERASE", "READ_STATUS",
	};
	return states[state];
	}

	/* Bits for the status register */
	#define STAT_WIP (1 << 0)
	#define STAT_WEL (1 << 1)

	/* Assume all SPI flashes have 3 byte addresses since they do atm */
	#define SF_ADDR_LEN 3

	#define IDCODE_LEN 3

	/* Used to quickly bulk erase backing store */
	static u8 sandbox_sf_0xff[0x1000];

	/* Internal state data for each SPI flash */
	struct sandbox_spi_flash {
	/*
	* As we receive data over the SPI bus, our flash transitions
	* between states. For example, we start off in the SF_CMD
	* state where the first byte tells us what operation to perform
	* (such as read or write the flash). But the operation itself
	* can go through a few states such as first reading in the
	* offset in the flash to perform the requested operation.
	* Thus "state" stores the exact state that our machine is in
	* while "cmd" stores the overall command we're processing.
	*/
	enum sandbox_sf_state state;
	uint cmd;
	/* Erase size of current erase command */
	uint erase_size;
	/* Current position in the flash; used when reading/writing/etc... */
	uint off;
	/* How many address bytes we've consumed */
	uint addr_bytes, pad_addr_bytes;
	/* The current flash status (see STAT_XXX defines above) */
	u16 status;
	/* Data describing the flash we're emulating */
	const struct spi_flash_params *data;
	/* The file on disk to serv up data from */
	int fd;
	};

	static int sandbox_sf_setup(void *priv, const char spec)
	{
	/* spec = idcode:file */
	struct sandbox_spi_flash *sbsf;
	const char *file;
	size_t len, idname_len;
	const struct spi_flash_params *data;

	file = strchr(spec, ':');
	if (!file) {
	printf("sandbox_sf: unable to parse file\n");
	goto error;
	}
	idname_len = file - spec;
	++file;

	for (data = spi_flash_params_table; data->name; data++) {
	len = strlen(data->name);
	if (idname_len != len)
	continue;
	if (!memcmp(spec, data->name, len))
	break;
	}
	if (!data->name) {
	printf("sandbox_sf: unknown flash '%*s'\n", (int)idname_len,
	spec);
	goto error;
	}

	if (sandbox_sf_0xff[0] == 0x00)
	memset(sandbox_sf_0xff, 0xff, sizeof(sandbox_sf_0xff));

	sbsf = calloc(sizeof(*sbsf), 1);
	if (!sbsf) {
	printf("sandbox_sf: out of memory\n");
	goto error;
	}

	sbsf->fd = os_open(file, 02);
	if (sbsf->fd == -1) {
	free(sbsf);
	printf("sandbox_sf: unable to open file '%s'\n", file);
	goto error;
	}

	sbsf->data = data;

	*priv = sbsf;
	return 0;

	error:
	return 1;
	}

	static void sandbox_sf_free(void *priv)
	{
	struct sandbox_spi_flash *sbsf = priv;

	os_close(sbsf->fd);
	free(sbsf);
	}

	static void sandbox_sf_cs_activate(void *priv)
	{
	struct sandbox_spi_flash *sbsf = priv;

	debug("sandbox_sf: CS activated; state is fresh!\n");

	/* CS is asserted, so reset state */
	sbsf->off = 0;
	sbsf->addr_bytes = 0;
	sbsf->pad_addr_bytes = 0;
	sbsf->state = SF_CMD;
	sbsf->cmd = SF_CMD;
	}

	static void sandbox_sf_cs_deactivate(void *priv)
	{
	debug("sandbox_sf: CS deactivated; cmd done processing!\n");
	}

	/* Figure out what command this stream is telling us to do */
	static int sandbox_sf_process_cmd(struct sandbox_spi_flash sbsf, const u8 rx,
	u8 *tx)
	{
	enum sandbox_sf_state oldstate = sbsf->state;

	/* We need to output a byte for the cmd byte we just ate */
	sandbox_spi_tristate(tx, 1);

	sbsf->cmd = rx[0];
	switch (sbsf->cmd) {
	case CMD_READ_ID:
	sbsf->state = SF_ID;
	sbsf->cmd = SF_ID;
	break;
	case CMD_READ_ARRAY_FAST:
	sbsf->pad_addr_bytes = 1;
	case CMD_READ_ARRAY_SLOW:
	case CMD_PAGE_PROGRAM:
	sbsf->state = SF_ADDR;
	break;
	case CMD_WRITE_DISABLE:
	debug(" write disabled\n");
	sbsf->status &= ~STAT_WEL;
	break;
	case CMD_READ_STATUS:
	sbsf->state = SF_READ_STATUS;
	break;
	case CMD_READ_STATUS1:
	sbsf->state = SF_READ_STATUS1;
	break;
	case CMD_WRITE_ENABLE:
	debug(" write enabled\n");
	sbsf->status \|= STAT_WEL;
	break;
	default: {
	int flags = sbsf->data->flags;

	/* we only support erase here */
	if (sbsf->cmd == CMD_ERASE_CHIP) {
	sbsf->erase_size = sbsf->data->sector_size *
	sbsf->data->nr_sectors;
	} else if (sbsf->cmd == CMD_ERASE_4K && (flags & SECT_4K)) {
	sbsf->erase_size = 4 << 10;
	} else if (sbsf->cmd == CMD_ERASE_32K && (flags & SECT_32K)) {
	sbsf->erase_size = 32 << 10;
	} else if (sbsf->cmd == CMD_ERASE_64K &&
	!(flags & (SECT_4K \| SECT_32K))) {
	sbsf->erase_size = 64 << 10;
	} else {
	debug(" cmd unknown: %#x\n", sbsf->cmd);
	return 1;
	}
	sbsf->state = SF_ADDR;
	break;
	}
	}

	if (oldstate != sbsf->state)
	debug(" cmd: transition to %s state\n",
	sandbox_sf_state_name(sbsf->state));

	return 0;
	}

	int sandbox_erase_part(struct sandbox_spi_flash *sbsf, int size)
	{
	int todo;
	int ret;

	while (size > 0) {
	todo = min(size, sizeof(sandbox_sf_0xff));
	ret = os_write(sbsf->fd, sandbox_sf_0xff, todo);
	if (ret != todo)
	return ret;
	size -= todo;
	}

	return 0;
	}

	static int sandbox_sf_xfer(void priv, const u8 rx, u8 *tx,
	uint bytes)
	{
	struct sandbox_spi_flash *sbsf = priv;
	uint cnt, pos = 0;
	int ret;

	debug("sandbox_sf: state:%x(%s) bytes:%u\n", sbsf->state,
	sandbox_sf_state_name(sbsf->state), bytes);

	if (sbsf->state == SF_CMD) {
	/* Figure out the initial state */
	if (sandbox_sf_process_cmd(sbsf, rx, tx))
	return 1;
	++pos;
	}

	/* Process the remaining data */
	while (pos < bytes) {
	switch (sbsf->state) {
	case SF_ID: {
	u8 id;

	debug(" id: off:%u tx:", sbsf->off);
	if (sbsf->off < IDCODE_LEN) {
	/* Extract correct byte from ID 0x00aabbcc */
	id = sbsf->data->jedec >>
	(8 * (IDCODE_LEN - 1 - sbsf->off));
	} else {
	id = 0;
	}
	debug("%d %02x\n", sbsf->off, id);
	tx[pos++] = id;
	++sbsf->off;
	break;
	}
	case SF_ADDR:
	debug(" addr: bytes:%u rx:%02x ", sbsf->addr_bytes,
	rx[pos]);

	if (sbsf->addr_bytes++ < SF_ADDR_LEN)
	sbsf->off = (sbsf->off << 8) \| rx[pos];
	debug("addr:%06x\n", sbsf->off);

	sandbox_spi_tristate(&tx[pos++], 1);

	/* See if we're done processing */
	if (sbsf->addr_bytes <
	SF_ADDR_LEN + sbsf->pad_addr_bytes)
	break;

	/* Next state! */
	if (os_lseek(sbsf->fd, sbsf->off, OS_SEEK_SET) < 0) {
	puts("sandbox_sf: os_lseek() failed");
	return 1;
	}
	switch (sbsf->cmd) {
	case CMD_READ_ARRAY_FAST:
	case CMD_READ_ARRAY_SLOW:
	sbsf->state = SF_READ;
	break;
	case CMD_PAGE_PROGRAM:
	sbsf->state = SF_WRITE;
	break;
	default:
	/* assume erase state ... */
	sbsf->state = SF_ERASE;
	goto case_sf_erase;
	}
	debug(" cmd: transition to %s state\n",
	sandbox_sf_state_name(sbsf->state));
	break;
	case SF_READ:
	/*
	* XXX: need to handle exotic behavior:
	* - reading past end of device
	*/

	cnt = bytes - pos;
	debug(" tx: read(%u)\n", cnt);
	ret = os_read(sbsf->fd, tx + pos, cnt);
	if (ret < 0) {
	puts("sandbox_spi: os_read() failed\n");
	return 1;
	}
	pos += ret;
	break;
	case SF_READ_STATUS:
	debug(" read status: %#x\n", sbsf->status);
	cnt = bytes - pos;
	memset(tx + pos, sbsf->status, cnt);
	pos += cnt;
	break;
	case SF_READ_STATUS1:
	debug(" read status: %#x\n", sbsf->status);
	cnt = bytes - pos;
	memset(tx + pos, sbsf->status >> 8, cnt);
	pos += cnt;
	break;
	case SF_WRITE:
	/*
	* XXX: need to handle exotic behavior:
	* - unaligned addresses
	* - more than a page (256) worth of data
	* - reading past end of device
	*/
	if (!(sbsf->status & STAT_WEL)) {
	puts("sandbox_sf: write enable not set before write\n");
	goto done;
	}

	cnt = bytes - pos;
	debug(" rx: write(%u)\n", cnt);
	sandbox_spi_tristate(&tx[pos], cnt);
	ret = os_write(sbsf->fd, rx + pos, cnt);
	if (ret < 0) {
	puts("sandbox_spi: os_write() failed\n");
	return 1;
	}
	pos += ret;
	sbsf->status &= ~STAT_WEL;
	break;
	case SF_ERASE:
	case_sf_erase: {
	if (!(sbsf->status & STAT_WEL)) {
	puts("sandbox_sf: write enable not set before erase\n");
	goto done;
	}

	/* verify address is aligned */
	if (sbsf->off & (sbsf->erase_size - 1)) {
	debug(" sector erase: cmd:%#x needs align:%#x, but we got %#x\n",
	sbsf->cmd, sbsf->erase_size,
	sbsf->off);
	sbsf->status &= ~STAT_WEL;
	goto done;
	}

	debug(" sector erase addr: %u, size: %u\n", sbsf->off,
	sbsf->erase_size);

	cnt = bytes - pos;
	sandbox_spi_tristate(&tx[pos], cnt);
	pos += cnt;

	/*
	* TODO(vapier@gentoo.org): latch WIP in status, and
	* delay before clearing it ?
	*/
	ret = sandbox_erase_part(sbsf, sbsf->erase_size);
	sbsf->status &= ~STAT_WEL;
	if (ret) {
	debug("sandbox_sf: Erase failed\n");
	goto done;
	}
	goto done;
	}
	default:
	debug(" ??? no idea what to do ???\n");
	goto done;
	}
	}

	done:
	return pos == bytes ? 0 : 1;
	}

	static const struct sandbox_spi_emu_ops sandbox_sf_ops = {
	.setup = sandbox_sf_setup,
	.free = sandbox_sf_free,
	.cs_activate = sandbox_sf_cs_activate,
	.cs_deactivate = sandbox_sf_cs_deactivate,
	.xfer = sandbox_sf_xfer,
	};

	static int sandbox_cmdline_cb_spi_sf(struct sandbox_state *state,
	const char *arg)
	{
	unsigned long bus, cs;
	const char *spec = sandbox_spi_parse_spec(arg, &bus, &cs);

	if (!spec)
	return 1;

	/*
	* It is safe to not make a copy of 'spec' because it comes from the
	* command line.
	*
	* TODO(sjg@chromium.org): It would be nice if we could parse the
	* spec here, but the problem is that no U-Boot init has been done
	* yet. Perhaps we can figure something out.
	*/
	state->spi[bus][cs].ops = &sandbox_sf_ops;
	state->spi[bus][cs].spec = spec;
	return 0;
	}
	SANDBOX_CMDLINE_OPT(spi_sf, 1, "connect a SPI flash: <bus>:<cs>:<id>:<file>");