4 files changed, 593 insertions, 0 deletions

diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 84f2eb1fae02..5038e90ceb12 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -55,6 +55,14 @@ config MTD_DATAFLASH
           Sometimes DataFlash chips are packaged inside MMC-format
           cards; at this writing, the MMC stack won't handle those.
 
+config MTD_M25P80
+        tristate "Support for M25 SPI Flash"
+        depends on MTD && SPI_MASTER && EXPERIMENTAL
+        help
+          This enables access to ST M25P80 and similar SPI flash chips,
+          used for program and data storage.  Set up your spi devices
+          with the right board-specific platform data.
+
 config MTD_SLRAM
         tristate "Uncached system RAM"
         depends on MTD
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index cd8d8074b5b6..7c5ed2178380 100644
--- a/drivers/mtd/devices/Makefile
+++ b/drivers/mtd/devices/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_MTD_LART)		+= lart.o
 obj-$(CONFIG_MTD_BLKMTD)        += blkmtd.o
 obj-$(CONFIG_MTD_BLOCK2MTD)     += block2mtd.o
 obj-$(CONFIG_MTD_DATAFLASH)     += mtd_dataflash.o
+obj-$(CONFIG_MTD_M25P80)        += m25p80.o
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
new file mode 100644
index 000000000000..71a072103a7f
--- /dev/null
+++ b/drivers/mtd/devices/m25p80.c
@@ -0,0 +1,580 @@
+/*
+ * MTD SPI driver for ST M25Pxx flash chips
+ *
+ * Author: Mike Lavender, mike@steroidmicros.com
+ *
+ * Copyright (c) 2005, Intec Automation Inc.
+ *
+ * Some parts are based on lart.c by Abraham Van Der Merwe
+ *
+ * Cleaned up and generalized based on mtd_dataflash.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/interrupt.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>
+
+#include <asm/semaphore.h>
+
+
+/* NOTE: AT 25F and SST 25LF series are very similar,
+ * but commands for sector erase and chip id differ...
+ */
+
+#define FLASH_PAGESIZE          256
+
+/* Flash opcodes. */
+#define OPCODE_WREN             6       /* Write enable */
+#define OPCODE_RDSR             5       /* Read status register */
+#define OPCODE_READ             3       /* Read data bytes */
+#define OPCODE_PP               2       /* Page program */
+#define OPCODE_SE               0xd8    /* Sector erase */
+#define OPCODE_RES              0xab    /* Read Electronic Signature */
+#define OPCODE_RDID             0x9f    /* Read JEDEC ID */
+
+/* Status Register bits. */
+#define SR_WIP                  1       /* Write in progress */
+#define SR_WEL                  2       /* Write enable latch */
+#define SR_BP0                  4       /* Block protect 0 */
+#define SR_BP1                  8       /* Block protect 1 */
+#define SR_BP2                  0x10    /* Block protect 2 */
+#define SR_SRWD                 0x80    /* SR write protect */
+
+/* Define max times to check status register before we give up. */
+#define MAX_READY_WAIT_COUNT    100000
+
+
+#ifdef CONFIG_MTD_PARTITIONS
+#define mtd_has_partitions()    (1)
+#else
+#define mtd_has_partitions()    (0)
+#endif
+
+/****************************************************************************/
+
+struct m25p {
+        struct spi_device       *spi;
+        struct semaphore        lock;
+        struct mtd_info         mtd;
+        unsigned                partitioned;
+        u8                      command[4];
+};
+
+static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
+{
+        return container_of(mtd, struct m25p, mtd);
+}
+
+/****************************************************************************/
+
+/*
+ * Internal helper functions
+ */
+
+/*
+ * Read the status register, returning its value in the location
+ * Return the status register value.
+ * Returns negative if error occurred.
+ */
+static int read_sr(struct m25p *flash)
+{
+        ssize_t retval;
+        u8 code = OPCODE_RDSR;
+        u8 val;
+
+        retval = spi_write_then_read(flash->spi, &code, 1, &val, 1);
+
+        if (retval < 0) {
+                dev_err(&flash->spi->dev, "error %d reading SR\n",
+                                (int) retval);
+                return retval;
+        }
+
+        return val;
+}
+
+
+/*
+ * Set write enable latch with Write Enable command.
+ * Returns negative if error occurred.
+ */
+static inline int write_enable(struct m25p *flash)
+{
+        u8      code = OPCODE_WREN;
+
+        return spi_write_then_read(flash->spi, &code, 1, NULL, 0);
+}
+
+
+/*
+ * Service routine to read status register until ready, or timeout occurs.
+ * Returns non-zero if error.
+ */
+static int wait_till_ready(struct m25p *flash)
+{
+        int count;
+        int sr;
+
+        /* one chip guarantees max 5 msec wait here after page writes,
+         * but potentially three seconds (!) after page erase.
+         */
+        for (count = 0; count < MAX_READY_WAIT_COUNT; count++) {
+                if ((sr = read_sr(flash)) < 0)
+                        break;
+                else if (!(sr & SR_WIP))
+                        return 0;
+
+                /* REVISIT sometimes sleeping would be best */
+        }
+
+        return 1;
+}
+
+
+/*
+ * Erase one sector of flash memory at offset ``offset'' which is any
+ * address within the sector which should be erased.
+ *
+ * Returns 0 if successful, non-zero otherwise.
+ */
+static int erase_sector(struct m25p *flash, u32 offset)
+{
+        DEBUG(MTD_DEBUG_LEVEL3, "%s: %s at 0x%08x\n", flash->spi->dev.bus_id,
+                        __FUNCTION__, offset);
+
+        /* Wait until finished previous write command. */
+        if (wait_till_ready(flash))
+                return 1;
+
+        /* Send write enable, then erase commands. */
+        write_enable(flash);
+
+        /* Set up command buffer. */
+        flash->command[0] = OPCODE_SE;
+        flash->command[1] = offset >> 16;
+        flash->command[2] = offset >> 8;
+        flash->command[3] = offset;
+
+        spi_write(flash->spi, flash->command, sizeof(flash->command));
+
+        return 0;
+}
+
+/****************************************************************************/
+
+/*
+ * MTD implementation
+ */
+
+/*
+ * Erase an address range on the flash chip.  The address range may extend
+ * one or more erase sectors.  Return an error is there is a problem erasing.
+ */
+static int m25p80_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+        struct m25p *flash = mtd_to_m25p(mtd);
+        u32 addr,len;
+
+        DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
+                        flash->spi->dev.bus_id, __FUNCTION__, "at",
+                        (u32)instr->addr, instr->len);
+
+        /* sanity checks */
+        if (instr->addr + instr->len > flash->mtd.size)
+                return -EINVAL;
+        if ((instr->addr % mtd->erasesize) != 0
+                        || (instr->len % mtd->erasesize) != 0) {
+                return -EINVAL;
+        }
+
+        addr = instr->addr;
+        len = instr->len;
+
+        down(&flash->lock);
+
+        /* now erase those sectors */
+        while (len) {
+                if (erase_sector(flash, addr)) {
+                        instr->state = MTD_ERASE_FAILED;
+                        up(&flash->lock);
+                        return -EIO;
+                }
+
+                addr += mtd->erasesize;
+                len -= mtd->erasesize;
+        }
+
+        up(&flash->lock);
+
+        instr->state = MTD_ERASE_DONE;
+        mtd_erase_callback(instr);
+
+        return 0;
+}
+
+/*
+ * Read an address range from the flash chip.  The address range
+ * may be any size provided it is within the physical boundaries.
+ */
+static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
+        size_t *retlen, u_char *buf)
+{
+        struct m25p *flash = mtd_to_m25p(mtd);
+        struct spi_transfer t[2];
+        struct spi_message m;
+
+        DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
+                        flash->spi->dev.bus_id, __FUNCTION__, "from",
+                        (u32)from, len);
+
+        /* sanity checks */
+        if (!len)
+                return 0;
+
+        if (from + len > flash->mtd.size)
+                return -EINVAL;
+
+        down(&flash->lock);
+
+        /* Wait till previous write/erase is done. */
+        if (wait_till_ready(flash)) {
+                /* REVISIT status return?? */
+                up(&flash->lock);
+                return 1;
+        }
+
+        memset(t, 0, (sizeof t));
+
+        /* NOTE:  OPCODE_FAST_READ (if available) is faster... */
+
+        /* Set up the write data buffer. */
+        flash->command[0] = OPCODE_READ;
+        flash->command[1] = from >> 16;
+        flash->command[2] = from >> 8;
+        flash->command[3] = from;
+
+        /* Byte count starts at zero. */
+        if (retlen)
+                *retlen = 0;
+
+        t[0].tx_buf = flash->command;
+        t[0].len = sizeof(flash->command);
+
+        t[1].rx_buf = buf;
+        t[1].len = len;
+
+        m.transfers = t;
+        m.n_transfer = 2;
+
+        spi_sync(flash->spi, &m);
+
+        *retlen = m.actual_length - sizeof(flash->command);
+
+        up(&flash->lock);
+
+        return 0;
+}
+
+/*
+ * Write an address range to the flash chip.  Data must be written in
+ * FLASH_PAGESIZE chunks.  The address range may be any size provided
+ * it is within the physical boundaries.
+ */
+static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,
+        size_t *retlen, const u_char *buf)
+{
+        struct m25p *flash = mtd_to_m25p(mtd);
+        u32 page_offset, page_size;
+        struct spi_transfer t[2];
+        struct spi_message m;
+
+        DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
+                        flash->spi->dev.bus_id, __FUNCTION__, "to",
+                        (u32)to, len);
+
+        if (retlen)
+                *retlen = 0;
+
+        /* sanity checks */
+        if (!len)
+                return(0);
+
+        if (to + len > flash->mtd.size)
+                return -EINVAL;
+
+        down(&flash->lock);
+
+        /* Wait until finished previous write command. */
+        if (wait_till_ready(flash))
+                return 1;
+
+        write_enable(flash);
+
+        memset(t, 0, (sizeof t));
+
+        /* Set up the opcode in the write buffer. */
+        flash->command[0] = OPCODE_PP;
+        flash->command[1] = to >> 16;
+        flash->command[2] = to >> 8;
+        flash->command[3] = to;
+
+        t[0].tx_buf = flash->command;
+        t[0].len = sizeof(flash->command);
+
+        m.transfers = t;
+        m.n_transfer = 2;
+
+        /* what page do we start with? */
+        page_offset = to % FLASH_PAGESIZE;
+
+        /* do all the bytes fit onto one page? */
+        if (page_offset + len <= FLASH_PAGESIZE) {
+                t[1].tx_buf = buf;
+                t[1].len = len;
+
+                spi_sync(flash->spi, &m);
+
+                *retlen = m.actual_length - sizeof(flash->command);
+        } else {
+                u32 i;
+
+                /* the size of data remaining on the first page */
+                page_size = FLASH_PAGESIZE - page_offset;
+
+                t[1].tx_buf = buf;
+                t[1].len = page_size;
+                spi_sync(flash->spi, &m);
+
+                *retlen = m.actual_length - sizeof(flash->command);
+
+                /* write everything in PAGESIZE chunks */
+                for (i = page_size; i < len; i += page_size) {
+                        page_size = len - i;
+                        if (page_size > FLASH_PAGESIZE)
+                                page_size = FLASH_PAGESIZE;
+
+                        /* write the next page to flash */
+                        flash->command[1] = (to + i) >> 16;
+                        flash->command[2] = (to + i) >> 8;
+                        flash->command[3] = (to + i);
+
+                        t[1].tx_buf = buf + i;
+                        t[1].len = page_size;
+
+                        wait_till_ready(flash);
+
+                        write_enable(flash);
+
+                        spi_sync(flash->spi, &m);
+
+                        *retlen += m.actual_length - sizeof(flash->command);
+                }
+        }
+
+        up(&flash->lock);
+
+        return 0;
+}
+
+
+/****************************************************************************/
+
+/*
+ * SPI device driver setup and teardown
+ */
+
+struct flash_info {
+        char            *name;
+        u8              id;
+        u16             jedec_id;
+        unsigned        sector_size;
+        unsigned        n_sectors;
+};
+
+static struct flash_info __devinitdata m25p_data [] = {
+        /* REVISIT: fill in JEDEC ids, for parts that have them */
+        { "m25p05", 0x05, 0x0000, 32 * 1024, 2 },
+        { "m25p10", 0x10, 0x0000, 32 * 1024, 4 },
+        { "m25p20", 0x11, 0x0000, 64 * 1024, 4 },
+        { "m25p40", 0x12, 0x0000, 64 * 1024, 8 },
+        { "m25p80", 0x13, 0x0000, 64 * 1024, 16 },
+        { "m25p16", 0x14, 0x0000, 64 * 1024, 32 },
+        { "m25p32", 0x15, 0x0000, 64 * 1024, 64 },
+        { "m25p64", 0x16, 0x2017, 64 * 1024, 128 },
+};
+
+/*
+ * board specific setup should have ensured the SPI clock used here
+ * matches what the READ command supports, at least until this driver
+ * understands FAST_READ (for clocks over 25 MHz).
+ */
+static int __devinit m25p_probe(struct spi_device *spi)
+{
+        struct flash_platform_data      *data;
+        struct m25p                     *flash;
+        struct flash_info               *info;
+        unsigned                        i;
+
+        /* Platform data helps sort out which chip type we have, as
+         * well as how this board partitions it.
+         */
+        data = spi->dev.platform_data;
+        if (!data || !data->type) {
+                /* FIXME some chips can identify themselves with RES
+                 * or JEDEC get-id commands.  Try them ...
+                 */
+                DEBUG(MTD_DEBUG_LEVEL1, "%s: no chip id\n",
+                                flash->spi->dev.bus_id);
+                return -ENODEV;
+        }
+
+        for (i = 0, info = m25p_data; i < ARRAY_SIZE(m25p_data); i++, info++) {
+                if (strcmp(data->type, info->name) == 0)
+                        break;
+        }
+        if (i == ARRAY_SIZE(m25p_data)) {
+                DEBUG(MTD_DEBUG_LEVEL1, "%s: unrecognized id %s\n",
+                                flash->spi->dev.bus_id, data->type);
+                return -ENODEV;
+        }
+
+        flash = kzalloc(sizeof *flash, SLAB_KERNEL);
+        if (!flash)
+                return -ENOMEM;
+
+        flash->spi = spi;
+        init_MUTEX(&flash->lock);
+        dev_set_drvdata(&spi->dev, flash);
+
+        if (data->name)
+                flash->mtd.name = data->name;
+        else
+                flash->mtd.name = spi->dev.bus_id;
+
+        flash->mtd.type = MTD_NORFLASH;
+        flash->mtd.flags = MTD_CAP_NORFLASH;
+        flash->mtd.size = info->sector_size * info->n_sectors;
+        flash->mtd.erasesize = info->sector_size;
+        flash->mtd.erase = m25p80_erase;
+        flash->mtd.read = m25p80_read;
+        flash->mtd.write = m25p80_write;
+
+        dev_info(&spi->dev, "%s (%d Kbytes)\n", info->name,
+                        flash->mtd.size / 1024);
+
+        DEBUG(MTD_DEBUG_LEVEL2,
+                "mtd .name = %s, .size = 0x%.8x (%uM) "
+                        ".erasesize = 0x%.8x (%uK) .numeraseregions = %d\n",
+                flash->mtd.name,
+                flash->mtd.size, flash->mtd.size / (1024*1024),
+                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%.8x, "
+                                ".erasesize = 0x%.8x (%uK), "
+                                ".numblocks = %d }\n",
+                                i, flash->mtd.eraseregions[i].offset,
+                                flash->mtd.eraseregions[i].erasesize,
+                                flash->mtd.eraseregions[i].erasesize / 1024,
+                                flash->mtd.eraseregions[i].numblocks);
+
+
+        /* partitions should match sector boundaries; and it may be good to
+         * use readonly partitions for writeprotected sectors (BP2..BP0).
+         */
+        if (mtd_has_partitions()) {
+                struct mtd_partition    *parts = NULL;
+                int                     nr_parts = 0;
+
+#ifdef CONFIG_MTD_CMDLINE_PARTS
+                static const char *part_probes[] = { "cmdlinepart", NULL, };
+
+                nr_parts = parse_mtd_partitions(&flash->mtd,
+                                part_probes, &parts, 0);
+#endif
+
+                if (nr_parts <= 0 && data && data->parts) {
+                        parts = data->parts;
+                        nr_parts = data->nr_parts;
+                }
+
+                if (nr_parts > 0) {
+                        for (i = 0; i < data->nr_parts; i++) {
+                                DEBUG(MTD_DEBUG_LEVEL2, "partitions[%d] = "
+                                        "{.name = %s, .offset = 0x%.8x, "
+                                                ".size = 0x%.8x (%uK) }\n",
+                                        i, data->parts[i].name,
+                                        data->parts[i].offset,
+                                        data->parts[i].size,
+                                        data->parts[i].size / 1024);
+                        }
+                        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);
+
+        return add_mtd_device(&flash->mtd) == 1 ? -ENODEV : 0;
+}
+
+
+static int __devexit m25p_remove(struct spi_device *spi)
+{
+        struct m25p     *flash = dev_get_drvdata(&spi->dev);
+        int             status;
+
+        /* Clean up MTD stuff. */
+        if (mtd_has_partitions() && flash->partitioned)
+                status = del_mtd_partitions(&flash->mtd);
+        else
+                status = del_mtd_device(&flash->mtd);
+        if (status == 0)
+                kfree(flash);
+        return 0;
+}
+
+
+static struct spi_driver m25p80_driver = {
+        .driver = {
+                .name   = "m25p80",
+                .bus    = &spi_bus_type,
+                .owner  = THIS_MODULE,
+        },
+        .probe  = m25p_probe,
+        .remove = __devexit_p(m25p_remove),
+};
+
+
+static int m25p80_init(void)
+{
+        return spi_register_driver(&m25p80_driver);
+}
+
+
+static void m25p80_exit(void)
+{
+        spi_unregister_driver(&m25p80_driver);
+}
+
+
+module_init(m25p80_init);
+module_exit(m25p80_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mike Lavender");
+MODULE_DESCRIPTION("MTD SPI driver for ST M25Pxx flash chips");
diff --git a/include/linux/spi/flash.h b/include/linux/spi/flash.h
index 2ce6558bf3f8..3f22932e67a4 100644
--- a/include/linux/spi/flash.h
+++ b/include/linux/spi/flash.h
@@ -8,6 +8,8 @@ struct mtd_partition;
  * @name: optional flash device name (eg, as used with mtdparts=)
  * @parts: optional array of mtd_partitions for static partitioning
  * @nr_parts: number of mtd_partitions for static partitoning
+ * @type: optional flash device type (e.g. m25p80 vs m25p64), for use
+ *      with chips that can't be queried for JEDEC or other IDs
  *
  * Board init code (in arch/.../mach-xxx/board-yyy.c files) can
  * provide information about SPI flash parts (such as DataFlash) to
@@ -21,6 +23,8 @@ struct flash_platform_data {
         struct mtd_partition *parts;
         unsigned int    nr_parts;
 
+        char            *type;
+
         /* we'll likely add more ... use JEDEC IDs, etc */
 };