[U-Boot] [PATCH 4/5 v2] sandbox: new SPI flash driver

Mike Frysinger vapier at gentoo.org
Tue Jan 31 20:53:33 CET 2012


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.

Signed-off-by: Mike Frysinger <vapier at gentoo.org>
---
 drivers/mtd/spi/Makefile  |    1 +
 drivers/mtd/spi/sandbox.c |  386 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/spi/sandbox_spi.c |    5 +
 3 files changed, 392 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/spi/sandbox.c

diff --git a/drivers/mtd/spi/Makefile b/drivers/mtd/spi/Makefile
index 90f8392..fb37807 100644
--- a/drivers/mtd/spi/Makefile
+++ b/drivers/mtd/spi/Makefile
@@ -33,6 +33,7 @@ COBJS-$(CONFIG_SPI_FLASH)	+= spi_flash.o
 COBJS-$(CONFIG_SPI_FLASH_ATMEL)	+= atmel.o
 COBJS-$(CONFIG_SPI_FLASH_EON)	+= eon.o
 COBJS-$(CONFIG_SPI_FLASH_MACRONIX)	+= macronix.o
+COBJS-$(CONFIG_SPI_FLASH_SANDBOX)	+= sandbox.o
 COBJS-$(CONFIG_SPI_FLASH_SPANSION)	+= spansion.o
 COBJS-$(CONFIG_SPI_FLASH_SST)	+= sst.o
 COBJS-$(CONFIG_SPI_FLASH_STMICRO)	+= stmicro.o
diff --git a/drivers/mtd/spi/sandbox.c b/drivers/mtd/spi/sandbox.c
new file mode 100644
index 0000000..4b8e384
--- /dev/null
+++ b/drivers/mtd/spi/sandbox.c
@@ -0,0 +1,386 @@
+/*
+ * Simulate a SPI flash
+ *
+ * Copyright (c) 2011-2012 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 "spi_flash_internal.h"
+
+#include <asm/spi.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.
+ */
+typedef enum {
+	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 */
+} sb_sf_state;
+
+static const char *sb_sf_state_name(sb_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 sb_spi_flash_erase_commands {
+	u8 cmd;
+	u32 size;
+};
+#define IDCODE_LEN 5
+#define MAX_ERASE_CMDS 2
+struct sb_spi_flash_data {
+	const char *name;
+	u8 idcode[IDCODE_LEN];
+	u32 size;
+	const struct sb_spi_flash_erase_commands erase_cmds[MAX_ERASE_CMDS];
+};
+
+/* Structure describing all the flashes we know how to emulate */
+static const struct sb_spi_flash_data sb_sf_flashes[] = {
+	{
+		"M25P16", { 0x20, 0x20, 0x15 }, (2 * 1024 * 1024),
+		{	/* erase commands */
+			{ 0xd8, (64 * 1024), }, /* sector */
+			{ 0xc7, (2 * 1024 * 1024), }, /* bulk */
+		},
+	},
+};
+
+/* Used to quickly bulk erase backing store */
+static u8 sb_sf_0xff[0x10000];
+
+/* Internal state data for each SPI flash */
+struct sb_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.
+	 */
+	sb_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) */
+	u8 status;
+	/* Data describing the flash we're emulating */
+	const struct sb_spi_flash_data *data;
+	/* The file on disk to serv up data from */
+	int fd;
+};
+
+static int sb_sf_setup(void **priv, const char *spec)
+{
+	/* spec = idcode:file */
+	struct sb_spi_flash *sbsf;
+	const char *file;
+	size_t i, len, idname_len;
+	const struct sb_spi_flash_data *data;
+
+	file = strchr(spec, ':');
+	if (!file)
+		goto error;
+	idname_len = file - spec;
+	++file;
+
+	for (i = 0; i < ARRAY_SIZE(sb_sf_flashes); ++i) {
+		data = &sb_sf_flashes[i];
+		len = strlen(data->name);
+		if (idname_len != len)
+			continue;
+		if (!memcmp(spec, data->name, len))
+			break;
+	}
+	if (i == ARRAY_SIZE(sb_sf_flashes)) {
+		printf("sb_sf: unknown flash '%*s'\n",
+			(int)idname_len, file);
+		goto error;
+	}
+
+	if (sb_sf_0xff[0] == 0x00)
+		memset(sb_sf_0xff, 0xff, sizeof(sb_sf_0xff));
+
+	sbsf = malloc(sizeof(*sbsf));
+	if (!sbsf)
+		goto error;
+
+	sbsf->fd = os_open(file, 02);
+	if (sbsf->fd == -1) {
+		free(sbsf);
+		goto error;
+	}
+
+	sbsf->data = data;
+
+	*priv = sbsf;
+	return 0;
+
+ error:
+	printf("sb_sf: unable to parse client spec\n");
+	return 1;
+}
+
+static void sb_sf_free(void *priv)
+{
+	struct sb_spi_flash *sbsf = priv;
+
+	os_close(sbsf->fd);
+	free(sbsf);
+}
+
+static void sb_sf_cs_activate(void *priv)
+{
+	struct sb_spi_flash *sbsf = priv;
+
+	debug("sb_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 = sbsf->cmd = SF_CMD;
+}
+
+static void sb_sf_cs_deactivate(void *priv)
+{
+	debug("sb_sf: CS deactivated; cmd done processing!\n");
+}
+
+/* Figure out what command this stream is telling us to do */
+static int sb_sf_process_cmd(struct sb_spi_flash *sbsf, const u8 *rx, u8 *tx)
+{
+	sb_sf_state oldstate = sbsf->state;
+
+	/* We need to output a byte for the cmd byte we just ate */
+	sb_spi_tristate(tx, 1);
+
+	sbsf->cmd = rx[0];
+	switch (sbsf->cmd) {
+	case CMD_READ_ID:
+		sbsf->state = 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_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 sb_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",
+			sb_sf_state_name(sbsf->state));
+
+	return 0;
+}
+
+static int sb_sf_xfer(void *priv, const u8 *rx, u8 *tx,
+		uint bytes)
+{
+	struct sb_spi_flash *sbsf = priv;
+	uint cnt, pos = 0;
+
+	debug("sb_sf: state:%x(%s) bytes:%u\n", sbsf->state,
+		sb_sf_state_name(sbsf->state), bytes);
+
+	if (sbsf->state == SF_CMD) {
+		/* Figure out the initial state */
+		if (sb_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);
+
+			sb_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! */
+			os_lseek(sbsf->fd, sbsf->off, OS_SEEK_SET);
+			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",
+				sb_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);
+			pos += os_read(sbsf->fd, tx + pos, cnt);
+			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_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("sb_sf: write enable not set before erase\n");
+				goto done;
+			}
+
+			cnt = bytes - pos;
+			debug(" rx: write(%u)\n", cnt);
+			sb_spi_tristate(&tx[pos], cnt);
+			pos += os_write(sbsf->fd, rx + pos, cnt);
+			sbsf->status &= ~STAT_WEL;
+			break;
+		case SF_ERASE:
+		case_SF_ERASE: {
+			const struct sb_spi_flash_erase_commands *erase_cmd =
+				sbsf->cmd_data;
+
+			if (!(sbsf->status & STAT_WEL)) {
+				puts("sb_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;
+			sb_spi_tristate(&tx[pos], cnt);
+			pos += cnt;
+
+			/* XXX: latch WIP in status, and delay before clearing it ? */
+			os_write(sbsf->fd, sb_sf_0xff, erase_cmd->size);
+			sbsf->status &= ~STAT_WEL;
+			goto done;
+		}
+		default:
+			debug(" ??? no idea what to do ???\n");
+			goto done;
+		}
+	}
+
+ done:
+	return pos == bytes ? 0 : 1;
+}
+
+const struct sb_spi_emu_ops sb_sf_ops = {
+	.setup         = sb_sf_setup,
+	.free          = sb_sf_free,
+	.cs_activate   = sb_sf_cs_activate,
+	.cs_deactivate = sb_sf_cs_deactivate,
+	.xfer          = sb_sf_xfer,
+};
diff --git a/drivers/spi/sandbox_spi.c b/drivers/spi/sandbox_spi.c
index d0cba76..88b51ab 100644
--- a/drivers/spi/sandbox_spi.c
+++ b/drivers/spi/sandbox_spi.c
@@ -35,10 +35,15 @@ static const char *sb_lookup_arg(unsigned int bus, unsigned int cs)
 	return os_getopt(sf_arg, 1);
 }
 
+extern const struct sb_spi_emu_ops sb_sf_ops;
+
 static const struct {
 	const char *spec;
 	const struct sb_spi_emu_ops *ops;
 } sb_emu_map[] = {
+#ifdef CONFIG_SPI_FLASH_SANDBOX
+	{ "sf", &sb_sf_ops, },
+#endif
 };
 
 static int sb_parse_type(struct sb_spi_slave *sss)
-- 
1.7.8.4



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