sandbox: spi: Add new SPI flash driver

This adds a SPI flash driver which simulates SPI flash clients.
Currently supports the bare min that U-Boot requires: you can
probe, read, erase, and write.  Should be easy to extend to make
it behave more exactly like a real SPI flash, but this is good
enough to merge now.

sjg@chromium.org added a README and tidied up code a little.
Added a required map_sysmem() for sandbox.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

4 files changed, 487 insertions, 1 deletions

diff --git a/drivers/mtd/spi/Makefile b/drivers/mtd/spi/Makefile
index 1bbeb7d..26483a2 100644
--- a/drivers/mtd/spi/Makefile
+++ b/drivers/mtd/spi/Makefile
@@ -13,4 +13,5 @@ endif
 obj-$(CONFIG_CMD_SF)        += sf.o
 obj-$(CONFIG_SPI_FLASH) += sf_probe.o sf_ops.o
 obj-$(CONFIG_SPI_FRAM_RAMTRON) += ramtron.o
+obj-$(CONFIG_SPI_FLASH_SANDBOX) += sandbox.o
 obj-$(CONFIG_SPI_M95XXX) += eeprom_m95xxx.o
diff --git a/drivers/mtd/spi/sandbox.c b/drivers/mtd/spi/sandbox.c
new file mode 100644
index 0000000..a62ef4c
--- /dev/null
+++ b/drivers/mtd/spi/sandbox.c
@@ -0,0 +1,483 @@
+/*
+ * 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
+
+struct sandbox_spi_flash_erase_commands {
+	u8 cmd;
+	u32 size;
+};
+#define IDCODE_LEN 5
+#define MAX_ERASE_CMDS 3
+struct sandbox_spi_flash_data {
+	const char *name;
+	u8 idcode[IDCODE_LEN];
+	u32 size;
+	const struct sandbox_spi_flash_erase_commands
+						erase_cmds[MAX_ERASE_CMDS];
+};
+
+/* Structure describing all the flashes we know how to emulate */
+static const struct sandbox_spi_flash_data sandbox_sf_flashes[] = {
+	{
+		"M25P16", { 0x20, 0x20, 0x15 }, (2 << 20),
+		{	/* erase commands */
+			{ 0xd8, (64 << 10), }, /* sector */
+			{ 0xc7, (2 << 20), }, /* bulk */
+		},
+	},
+	{
+		"W25Q32", { 0xef, 0x40, 0x16 }, (4 << 20),
+		{	/* erase commands */
+			{ 0x20, (4 << 10), }, /* 4KB */
+			{ 0xd8, (64 << 10), }, /* sector */
+			{ 0xc7, (4 << 20), }, /* bulk */
+		},
+	},
+	{
+		"W25Q128", { 0xef, 0x40, 0x18 }, (16 << 20),
+		{	/* erase commands */
+			{ 0x20, (4 << 10), }, /* 4KB */
+			{ 0xd8, (64 << 10), }, /* sector */
+			{ 0xc7, (16 << 20), }, /* bulk */
+		},
+	},
+};
+
+/* 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;
+	const void *cmd_data;
+	/* 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 sandbox_spi_flash_data *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 i, len, idname_len;
+	const struct sandbox_spi_flash_data *data;
+
+	file = strchr(spec, ':');
+	if (!file) {
+		printf("sandbox_sf: unable to parse file\n");
+		goto error;
+	}
+	idname_len = file - spec;
+	++file;
+
+	for (i = 0; i < ARRAY_SIZE(sandbox_sf_flashes); ++i) {
+		data = &sandbox_sf_flashes[i];
+		len = strlen(data->name);
+		if (idname_len != len)
+			continue;
+		if (!memcmp(spec, data->name, len))
+			break;
+	}
+	if (i == ARRAY_SIZE(sandbox_sf_flashes)) {
+		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:
+ state_addr:
+		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: {
+		size_t i;
+
+		/* handle erase commands first */
+		for (i = 0; i < MAX_ERASE_CMDS; ++i) {
+			const struct sandbox_spi_flash_erase_commands *
+				erase_cmd = &sbsf->data->erase_cmds[i];
+
+			if (erase_cmd->cmd == 0x00)
+				continue;
+			if (sbsf->cmd != erase_cmd->cmd)
+				continue;
+
+			sbsf->cmd_data = erase_cmd;
+			goto state_addr;
+		}
+
+		debug(" cmd unknown: %#x\n", sbsf->cmd);
+		return 1;
+	}
+	}
+
+	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)
+				id = sbsf->data->idcode[sbsf->off];
+			else
+				id = 0;
+			debug("%02x\n", 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: {
+			const struct sandbox_spi_flash_erase_commands *
+						erase_cmd = sbsf->cmd_data;
+
+			if (!(sbsf->status & STAT_WEL)) {
+				puts("sandbox_sf: write enable not set before erase\n");
+				goto done;
+			}
+
+			/* verify address is aligned */
+			if (sbsf->off & (erase_cmd->size - 1)) {
+				debug(" sector erase: cmd:%#x needs align:%#x, but we got %#x\n",
+				      erase_cmd->cmd, erase_cmd->size,
+				      sbsf->off);
+				sbsf->status &= ~STAT_WEL;
+				goto done;
+			}
+
+			debug(" sector erase addr: %u\n", sbsf->off);
+
+			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, erase_cmd->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>");
diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index 732ddf8..d291746 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -28,6 +28,7 @@
 #define CMD_PAGE_PROGRAM		0x02
 #define CMD_WRITE_DISABLE		0x04
 #define CMD_READ_STATUS			0x05
+#define CMD_READ_STATUS1		0x35
 #define CMD_WRITE_ENABLE		0x06
 #define CMD_READ_CONFIG			0x35
 #define CMD_FLAG_STATUS			0x70
diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
index ca12715..c1eb754 100644
--- a/drivers/mtd/spi/sf_probe.c
+++ b/drivers/mtd/spi/sf_probe.c
@@ -13,6 +13,7 @@
 #include <malloc.h>
 #include <spi.h>
 #include <spi_flash.h>
+#include <asm/io.h>
 
 #include "sf_internal.h"
 
@@ -279,7 +280,7 @@ int spi_flash_decode_fdt(const void *blob, struct spi_flash *flash)
 		debug("%s: Memory map must cover entire device\n", __func__);
 		return -1;
 	}
-	flash->memory_map = (void *)addr;
+	flash->memory_map = map_sysmem(addr, size);
 
 	return 0;
 }