mtd: SST25L (non JEDEC) SPI Flash driver

Add support for the non JEDEC SST25L SPI Flash devices.

[dwmw2: Some cleanups]

Signed-off-by: Andre Renaud <andre@bluewatersys.com>
Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: "H Hartley Sweeten" <hartleys@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

3 files changed, 521 insertions, 0 deletions

diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 325fab92a62c..c222514bb70d 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -104,6 +104,16 @@ config M25PXX_USE_FAST_READ
         help
           This option enables FAST_READ access supported by ST M25Pxx.
 
+config MTD_SST25L
+        tristate "Support SST25L (non JEDEC) SPI Flash chips"
+        depends on SPI_MASTER
+        help
+          This enables access to the non JEDEC SST25L SPI flash chips, used
+          for program and data storage.
+
+          Set up your spi devices with the right board-specific platform data,
+          if you want to specify device partitioning.
+
 config MTD_SLRAM
         tristate "Uncached system RAM"
         help
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index 0993d5cf3923..ab5c9b92ac82 100644
--- a/drivers/mtd/devices/Makefile
+++ b/drivers/mtd/devices/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_MTD_LART)		+= lart.o
 obj-$(CONFIG_MTD_BLOCK2MTD)     += block2mtd.o
 obj-$(CONFIG_MTD_DATAFLASH)     += mtd_dataflash.o
 obj-$(CONFIG_MTD_M25P80)        += m25p80.o
+obj-$(CONFIG_MTD_SST25L)        += sst25l.o
diff --git a/drivers/mtd/devices/sst25l.c b/drivers/mtd/devices/sst25l.c
new file mode 100644
index 000000000000..ac7d52b420cc
--- /dev/null
+++ b/drivers/mtd/devices/sst25l.c
@@ -0,0 +1,510 @@
+/*
+ * sst25l.c
+ *
+ * Driver for SST25L SPI Flash chips
+ *
+ * Copyright © 2009 Bluewater Systems Ltd
+ * Author: Andre Renaud <andre@bluewatersys.com>
+ * Author: Ryan Mallon <ryan@bluewatersys.com>
+ *
+ * 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/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.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;
+
+        int                     partitioned;
+};
+
+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 __initdata sst25l_flash_info[] = {
+        {"sst25lf020a", 0xbf43, 256, 1024, 4096},
+        {"sst25lf040a", 0xbf44, 256, 2048, 4096},
+};
+
+static int sst25l_status(struct sst25l_flash *flash, int *status)
+{
+        unsigned char command, response;
+        int err;
+
+        command = SST25L_CMD_RDSR;
+        err = spi_write_then_read(flash->spi, &command, 1, &response, 1);
+        if (err < 0)
+                return err;
+
+        *status = response;
+        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 (instr->addr + instr->len > flash->mtd.size)
+                return -EINVAL;
+
+        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)
+                return err;
+
+        while (addr < end) {
+                err = sst25l_erase_sector(flash, addr);
+                if (err) {
+                        mutex_unlock(&flash->lock);
+                        instr->state = MTD_ERASE_FAILED;
+                        dev_err(&flash->spi->dev, "Erase failed\n");
+                        return err;
+                }
+
+                addr += mtd->erasesize;
+        }
+
+        mutex_unlock(&flash->lock);
+
+        instr->state = MTD_ERASE_DONE;
+        mtd_erase_callback(instr);
+        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;
+
+        /* Sanity checking */
+        if (len == 0)
+                return 0;
+
+        if (from + len > flash->mtd.size)
+                return -EINVAL;
+
+        if (retlen)
+                *retlen = 0;
+
+        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];
+
+        /* Sanity checks */
+        if (!len)
+                return 0;
+
+        if (to + len > flash->mtd.size)
+                return -EINVAL;
+
+        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 *__init sst25l_match_device(struct spi_device *spi)
+{
+        struct flash_info *flash_info = NULL;
+        unsigned char command[4], response;
+        int i, err;
+        uint16_t id;
+
+        command[0] = SST25L_CMD_READ_ID;
+        command[1] = 0;
+        command[2] = 0;
+        command[3] = 0;
+        err = spi_write_then_read(spi, command, sizeof(command), &response, 1);
+        if (err < 0) {
+                dev_err(&spi->dev, "error reading device id msb\n");
+                return NULL;
+        }
+
+        id = response << 8;
+
+        command[0] = SST25L_CMD_READ_ID;
+        command[1] = 0;
+        command[2] = 0;
+        command[3] = 1;
+        err = spi_write_then_read(spi, command, sizeof(command), &response, 1);
+        if (err < 0) {
+                dev_err(&spi->dev, "error reading device id lsb\n");
+                return NULL;
+        }
+
+        id |= response;
+
+        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 __init sst25l_probe(struct spi_device *spi)
+{
+        struct flash_info *flash_info;
+        struct sst25l_flash *flash;
+        struct flash_platform_data *data;
+        int ret, i;
+
+        flash_info = sst25l_match_device(spi);
+        if (!flash_info)
+                return -ENODEV;
+
+        flash = kzalloc(sizeof(struct sst25l_flash), GFP_KERNEL);
+        if (!flash)
+                return -ENOMEM;
+
+        flash->spi = spi;
+        mutex_init(&flash->lock);
+        dev_set_drvdata(&spi->dev, flash);
+
+        data = spi->dev.platform_data;
+        if (data && data->name)
+                flash->mtd.name = data->name;
+        else
+                flash->mtd.name = dev_name(&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.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);
+
+        DEBUG(MTD_DEBUG_LEVEL2,
+              "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);
+
+        if (flash->mtd.numeraseregions)
+                for (i = 0; i < flash->mtd.numeraseregions; i++)
+                        DEBUG(MTD_DEBUG_LEVEL2,
+                              "mtd.eraseregions[%d] = { .offset = 0x%llx, "
+                              ".erasesize = 0x%.8x (%uKiB), "
+                              ".numblocks = %d }\n",
+                              i, (long long)flash->mtd.eraseregions[i].offset,
+                              flash->mtd.eraseregions[i].erasesize,
+                              flash->mtd.eraseregions[i].erasesize / 1024,
+                              flash->mtd.eraseregions[i].numblocks);
+
+        if (mtd_has_partitions()) {
+                struct mtd_partition *parts = NULL;
+                int nr_parts = 0;
+
+                if (mtd_has_cmdlinepart()) {
+                        static const char *part_probes[] =
+                                {"cmdlinepart", NULL};
+
+                        nr_parts = parse_mtd_partitions(&flash->mtd,
+                                                        part_probes,
+                                                        &parts, 0);
+                }
+
+                if (nr_parts <= 0 && data && data->parts) {
+                        parts = data->parts;
+                        nr_parts = data->nr_parts;
+                }
+
+                if (nr_parts > 0) {
+                        for (i = 0; i < nr_parts; i++) {
+                                DEBUG(MTD_DEBUG_LEVEL2, "partitions[%d] = "
+                                      "{.name = %s, .offset = 0x%llx, "
+                                      ".size = 0x%llx (%lldKiB) }\n",
+                                      i, parts[i].name,
+                                      (long long)parts[i].offset,
+                                      (long long)parts[i].size,
+                                      (long long)(parts[i].size >> 10));
+                        }
+
+                        flash->partitioned = 1;
+                        return add_mtd_partitions(&flash->mtd,
+                                                  parts, nr_parts);
+                }
+
+        } else if (data->nr_parts) {
+                dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
+                         data->nr_parts, data->name);
+        }
+
+        ret = add_mtd_device(&flash->mtd);
+        if (ret == 1) {
+                kfree(flash);
+                dev_set_drvdata(&spi->dev, NULL);
+                return -ENODEV;
+        }
+
+        return 0;
+}
+
+static int __exit sst25l_remove(struct spi_device *spi)
+{
+        struct sst25l_flash *flash = dev_get_drvdata(&spi->dev);
+        int ret;
+
+        if (mtd_has_partitions() && flash->partitioned)
+                ret = del_mtd_partitions(&flash->mtd);
+        else
+                ret = del_mtd_device(&flash->mtd);
+        if (ret == 0)
+                kfree(flash);
+        return ret;
+}
+
+static struct spi_driver sst25l_driver = {
+        .driver = {
+                .name   = "sst25l",
+                .bus    = &spi_bus_type,
+                .owner  = THIS_MODULE,
+        },
+        .probe          = sst25l_probe,
+        .remove         = __exit_p(sst25l_remove),
+};
+
+static int __init sst25l_init(void)
+{
+        return spi_register_driver(&sst25l_driver);
+}
+
+static void __exit sst25l_exit(void)
+{
+        spi_unregister_driver(&sst25l_driver);
+}
+
+module_init(sst25l_init);
+module_exit(sst25l_exit);
+
+MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
+MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
+              "Ryan Mallon <ryan@bluewatersys.com>");
+MODULE_LICENSE("GPL");