1 files changed, 425 insertions, 0 deletions
diff --git a/drivers/mtd/devices/sst25l.c b/drivers/mtd/devices/sst25l.c
new file mode 100644
index 000000000..10d24efb4
--- /dev/null
+++ b/drivers/mtd/devices/sst25l.c
@@ -0,0 +1,425 @@
+/*
+ * sst25l.c
+ *
+ * Driver for SST25L SPI Flash chips
+ *
+ * Copyright © 2009 Bluewater Systems Ltd
+ * Author: Andre Renaud <andre@bluewatersys.com>
+ * Author: Ryan Mallon
+ *
+ * Based on m25p80.c
+ *
+ * This code is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/flash.h>
+
+/* Erases can take up to 3 seconds! */
+#define MAX_READY_WAIT_JIFFIES	msecs_to_jiffies(3000)
+
+#define SST25L_CMD_WRSR		0x01	/* Write status register */
+#define SST25L_CMD_WRDI		0x04	/* Write disable */
+#define SST25L_CMD_RDSR		0x05	/* Read status register */
+#define SST25L_CMD_WREN		0x06	/* Write enable */
+#define SST25L_CMD_READ		0x03	/* High speed read */
+
+#define SST25L_CMD_EWSR		0x50	/* Enable write status register */
+#define SST25L_CMD_SECTOR_ERASE	0x20	/* Erase sector */
+#define SST25L_CMD_READ_ID	0x90	/* Read device ID */
+#define SST25L_CMD_AAI_PROGRAM	0xaf	/* Auto address increment */
+
+#define SST25L_STATUS_BUSY	(1 << 0)	/* Chip is busy */
+#define SST25L_STATUS_WREN	(1 << 1)	/* Write enabled */
+#define SST25L_STATUS_BP0	(1 << 2)	/* Block protection 0 */
+#define SST25L_STATUS_BP1	(1 << 3)	/* Block protection 1 */
+
+struct sst25l_flash {
+	struct spi_device	*spi;
+	struct mutex		lock;
+	struct mtd_info		mtd;
+};
+
+struct flash_info {
+	const char		*name;
+	uint16_t		device_id;
+	unsigned		page_size;
+	unsigned		nr_pages;
+	unsigned		erase_size;
+};
+
+#define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)
+
+static struct flash_info sst25l_flash_info[] = {
+	{"sst25lf020a", 0xbf43, 256, 1024, 4096},
+	{"sst25lf040a",	0xbf44,	256, 2048, 4096},
+};
+
+static int sst25l_status(struct sst25l_flash *flash, int *status)
+{
+	struct spi_message m;
+	struct spi_transfer t;
+	unsigned char cmd_resp[2];
+	int err;
+
+	spi_message_init(&m);
+	memset(&t, 0, sizeof(struct spi_transfer));
+
+	cmd_resp[0] = SST25L_CMD_RDSR;
+	cmd_resp[1] = 0xff;
+	t.tx_buf = cmd_resp;
+	t.rx_buf = cmd_resp;
+	t.len = sizeof(cmd_resp);
+	spi_message_add_tail(&t, &m);
+	err = spi_sync(flash->spi, &m);
+	if (err < 0)
+		return err;
+
+	*status = cmd_resp[1];
+	return 0;
+}
+
+static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
+{
+	unsigned char command[2];
+	int status, err;
+
+	command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
+	err = spi_write(flash->spi, command, 1);
+	if (err)
+		return err;
+
+	command[0] = SST25L_CMD_EWSR;
+	err = spi_write(flash->spi, command, 1);
+	if (err)
+		return err;
+
+	command[0] = SST25L_CMD_WRSR;
+	command[1] = enable ? 0 : SST25L_STATUS_BP0 | SST25L_STATUS_BP1;
+	err = spi_write(flash->spi, command, 2);
+	if (err)
+		return err;
+
+	if (enable) {
+		err = sst25l_status(flash, &status);
+		if (err)
+			return err;
+		if (!(status & SST25L_STATUS_WREN))
+			return -EROFS;
+	}
+
+	return 0;
+}
+
+static int sst25l_wait_till_ready(struct sst25l_flash *flash)
+{
+	unsigned long deadline;
+	int status, err;
+
+	deadline = jiffies + MAX_READY_WAIT_JIFFIES;
+	do {
+		err = sst25l_status(flash, &status);
+		if (err)
+			return err;
+		if (!(status & SST25L_STATUS_BUSY))
+			return 0;
+
+		cond_resched();
+	} while (!time_after_eq(jiffies, deadline));
+
+	return -ETIMEDOUT;
+}
+
+static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
+{
+	unsigned char command[4];
+	int err;
+
+	err = sst25l_write_enable(flash, 1);
+	if (err)
+		return err;
+
+	command[0] = SST25L_CMD_SECTOR_ERASE;
+	command[1] = offset >> 16;
+	command[2] = offset >> 8;
+	command[3] = offset;
+	err = spi_write(flash->spi, command, 4);
+	if (err)
+		return err;
+
+	err = sst25l_wait_till_ready(flash);
+	if (err)
+		return err;
+
+	return sst25l_write_enable(flash, 0);
+}
+
+static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+	struct sst25l_flash *flash = to_sst25l_flash(mtd);
+	uint32_t addr, end;
+	int err;
+
+	/* Sanity checks */
+	if ((uint32_t)instr->len % mtd->erasesize)
+		return -EINVAL;
+
+	if ((uint32_t)instr->addr % mtd->erasesize)
+		return -EINVAL;
+
+	addr = instr->addr;
+	end = addr + instr->len;
+
+	mutex_lock(&flash->lock);
+
+	err = sst25l_wait_till_ready(flash);
+	if (err) {
+		mutex_unlock(&flash->lock);
+		return err;
+	}
+
+	while (addr < end) {
+		err = sst25l_erase_sector(flash, addr);
+		if (err) {
+			mutex_unlock(&flash->lock);
+			dev_err(&flash->spi->dev, "Erase failed\n");
+			return err;
+		}
+
+		addr += mtd->erasesize;
+	}
+
+	mutex_unlock(&flash->lock);
+
+	return 0;
+}
+
+static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
+		       size_t *retlen, unsigned char *buf)
+{
+	struct sst25l_flash *flash = to_sst25l_flash(mtd);
+	struct spi_transfer transfer[2];
+	struct spi_message message;
+	unsigned char command[4];
+	int ret;
+
+	spi_message_init(&message);
+	memset(&transfer, 0, sizeof(transfer));
+
+	command[0] = SST25L_CMD_READ;
+	command[1] = from >> 16;
+	command[2] = from >> 8;
+	command[3] = from;
+
+	transfer[0].tx_buf = command;
+	transfer[0].len = sizeof(command);
+	spi_message_add_tail(&transfer[0], &message);
+
+	transfer[1].rx_buf = buf;
+	transfer[1].len = len;
+	spi_message_add_tail(&transfer[1], &message);
+
+	mutex_lock(&flash->lock);
+
+	/* Wait for previous write/erase to complete */
+	ret = sst25l_wait_till_ready(flash);
+	if (ret) {
+		mutex_unlock(&flash->lock);
+		return ret;
+	}
+
+	spi_sync(flash->spi, &message);
+
+	if (retlen && message.actual_length > sizeof(command))
+		*retlen += message.actual_length - sizeof(command);
+
+	mutex_unlock(&flash->lock);
+	return 0;
+}
+
+static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
+			size_t *retlen, const unsigned char *buf)
+{
+	struct sst25l_flash *flash = to_sst25l_flash(mtd);
+	int i, j, ret, bytes, copied = 0;
+	unsigned char command[5];
+
+	if ((uint32_t)to % mtd->writesize)
+		return -EINVAL;
+
+	mutex_lock(&flash->lock);
+
+	ret = sst25l_write_enable(flash, 1);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < len; i += mtd->writesize) {
+		ret = sst25l_wait_till_ready(flash);
+		if (ret)
+			goto out;
+
+		/* Write the first byte of the page */
+		command[0] = SST25L_CMD_AAI_PROGRAM;
+		command[1] = (to + i) >> 16;
+		command[2] = (to + i) >> 8;
+		command[3] = (to + i);
+		command[4] = buf[i];
+		ret = spi_write(flash->spi, command, 5);
+		if (ret < 0)
+			goto out;
+		copied++;
+
+		/*
+		 * Write the remaining bytes using auto address
+		 * increment mode
+		 */
+		bytes = min_t(uint32_t, mtd->writesize, len - i);
+		for (j = 1; j < bytes; j++, copied++) {
+			ret = sst25l_wait_till_ready(flash);
+			if (ret)
+				goto out;
+
+			command[1] = buf[i + j];
+			ret = spi_write(flash->spi, command, 2);
+			if (ret)
+				goto out;
+		}
+	}
+
+out:
+	ret = sst25l_write_enable(flash, 0);
+
+	if (retlen)
+		*retlen = copied;
+
+	mutex_unlock(&flash->lock);
+	return ret;
+}
+
+static struct flash_info *sst25l_match_device(struct spi_device *spi)
+{
+	struct flash_info *flash_info = NULL;
+	struct spi_message m;
+	struct spi_transfer t;
+	unsigned char cmd_resp[6];
+	int i, err;
+	uint16_t id;
+
+	spi_message_init(&m);
+	memset(&t, 0, sizeof(struct spi_transfer));
+
+	cmd_resp[0] = SST25L_CMD_READ_ID;
+	cmd_resp[1] = 0;
+	cmd_resp[2] = 0;
+	cmd_resp[3] = 0;
+	cmd_resp[4] = 0xff;
+	cmd_resp[5] = 0xff;
+	t.tx_buf = cmd_resp;
+	t.rx_buf = cmd_resp;
+	t.len = sizeof(cmd_resp);
+	spi_message_add_tail(&t, &m);
+	err = spi_sync(spi, &m);
+	if (err < 0) {
+		dev_err(&spi->dev, "error reading device id\n");
+		return NULL;
+	}
+
+	id = (cmd_resp[4] << 8) | cmd_resp[5];
+
+	for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
+		if (sst25l_flash_info[i].device_id == id)
+			flash_info = &sst25l_flash_info[i];
+
+	if (!flash_info)
+		dev_err(&spi->dev, "unknown id %.4x\n", id);
+
+	return flash_info;
+}
+
+static int sst25l_probe(struct spi_device *spi)
+{
+	struct flash_info *flash_info;
+	struct sst25l_flash *flash;
+	struct flash_platform_data *data;
+	int ret;
+
+	flash_info = sst25l_match_device(spi);
+	if (!flash_info)
+		return -ENODEV;
+
+	flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
+	if (!flash)
+		return -ENOMEM;
+
+	flash->spi = spi;
+	mutex_init(&flash->lock);
+	spi_set_drvdata(spi, flash);
+
+	data = dev_get_platdata(&spi->dev);
+	if (data && data->name)
+		flash->mtd.name = data->name;
+
+	flash->mtd.dev.parent   = &spi->dev;
+	flash->mtd.type		= MTD_NORFLASH;
+	flash->mtd.flags	= MTD_CAP_NORFLASH;
+	flash->mtd.erasesize	= flash_info->erase_size;
+	flash->mtd.writesize	= flash_info->page_size;
+	flash->mtd.writebufsize	= flash_info->page_size;
+	flash->mtd.size		= flash_info->page_size * flash_info->nr_pages;
+	flash->mtd._erase	= sst25l_erase;
+	flash->mtd._read		= sst25l_read;
+	flash->mtd._write 	= sst25l_write;
+
+	dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
+		 (long long)flash->mtd.size >> 10);
+
+	pr_debug("mtd .name = %s, .size = 0x%llx (%lldMiB) "
+	      ".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
+	      flash->mtd.name,
+	      (long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
+	      flash->mtd.erasesize, flash->mtd.erasesize / 1024,
+	      flash->mtd.numeraseregions);
+
+
+	ret = mtd_device_register(&flash->mtd, data ? data->parts : NULL,
+				  data ? data->nr_parts : 0);
+	if (ret)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int sst25l_remove(struct spi_device *spi)
+{
+	struct sst25l_flash *flash = spi_get_drvdata(spi);
+
+	return mtd_device_unregister(&flash->mtd);
+}
+
+static struct spi_driver sst25l_driver = {
+	.driver = {
+		.name	= "sst25l",
+	},
+	.probe		= sst25l_probe,
+	.remove		= sst25l_remove,
+};
+
+module_spi_driver(sst25l_driver);
+
+MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
+MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
+	      "Ryan Mallon");
+MODULE_LICENSE("GPL");