--- /dev/null
+/*
+ * 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 %d\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;
+
+ spi_message_init(&m);
+ memset(t, 0, (sizeof t));
+
+ t[0].tx_buf = flash->command;
+ t[0].len = sizeof(flash->command);
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].rx_buf = buf;
+ t[1].len = len;
+ spi_message_add_tail(&t[1], &m);
+
+ /* Byte count starts at zero. */
+ if (retlen)
+ *retlen = 0;
+
+ down(&flash->lock);
+
+ /* Wait till previous write/erase is done. */
+ if (wait_till_ready(flash)) {
+ /* REVISIT status return?? */
+ up(&flash->lock);
+ return 1;
+ }
+
+ /* 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;
+
+ 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;
+
+ spi_message_init(&m);
+ memset(t, 0, (sizeof t));
+
+ t[0].tx_buf = flash->command;
+ t[0].len = sizeof(flash->command);
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].tx_buf = buf;
+ spi_message_add_tail(&t[1], &m);
+
+ down(&flash->lock);
+
+ /* Wait until finished previous write command. */
+ if (wait_till_ready(flash))
+ return 1;
+
+ write_enable(flash);
+
+ /* 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;
+
+ /* 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].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].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);
+
+ if (retlen)
+ *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");
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