[PATCH 2.6-git] MTD/SPI dataflash driver

From: Vitaly Wool
Date: Thu Dec 01 2005 - 11:17:39 EST

Greetings,

this is a follow-up message on the one posted a few minutes ago containing the updated version of Pervushin/Wool's SPI core.
It took about fifteen minutes of mindwork to port the MTD dataflash driver posted by David Brownell 11/23 to our SPI core from David's, reducing both the size of the source code and the footprint of the object code.
I'd also like to mention that now it looks significatnly easier to understand due to no more use of complicated SPI message structures. The number of variables used was also decreased.
No other activity than porting the driver was performed.

Signed-off-by: Vitaly Wool <vwool@xxxxxxxxxxxxx>
Signed-off-by: dmitry pervushin <dpervushin@xxxxxxxxx>

drivers/mtd/devices/Kconfig | 8
drivers/mtd/devices/Makefile | 1
drivers/mtd/devices/mtd_dataflash.c | 568 ++++++++++++++++++++++++++++++++++++
include/linux/spi/flash.h | 27 +
4 files changed, 604 insertions(+)

Index: lsm-2.6/drivers/mtd/devices/Kconfig
===================================================================
--- lsm-2.6.orig/drivers/mtd/devices/Kconfig
+++ lsm-2.6/drivers/mtd/devices/Kconfig
@@ -255,5 +255,13 @@ config MTD_DOCPROBE_55AA
LinuxBIOS or if you need to recover a DiskOnChip Millennium on which
you have managed to wipe the first block.

+config MTD_DATAFLASH
+ tristate "Support for AT45xxx DataFlash"
+ depends on MTD && SPI && EXPERIMENTAL
+ help
+ This enables access to AT45xxx DataFlash chips, using SPI.
+ Sometimes DataFlash chips are packaged inside MMC-format
+ cards; at this writing, the MMC stack won't handle those.
+
endmenu

Index: lsm-2.6/include/linux/spi/flash.h
===================================================================
--- /dev/null
+++ lsm-2.6/include/linux/spi/flash.h
@@ -0,0 +1,27 @@
+#ifndef LINUX_SPI_FLASH_H
+#define LINUX_SPI_FLASH_H
+
+struct mtd_partition;
+
+/**
+ * struct flash_platform_data: board-specific flash data
+ * @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
+ *
+ * Board init code (in arch/.../mach-xxx/board-yyy.c files) can
+ * provide information about SPI flash parts (such as DataFlash) to
+ * help set up the device and its appropriate default partitioning.
+ *
+ * Note that for DataFlash, sizes for pages, blocks, and sectors are
+ * rarely powers of two; and partitions should be sector-aligned.
+ */
+struct flash_platform_data {
+ char *name;
+ struct mtd_partition *parts;
+ unsigned int nr_parts;
+
+ /* we'll likely add more ... use JEDEC IDs, etc */
+};
+
+#endif
Index: lsm-2.6/drivers/mtd/devices/Makefile
===================================================================
--- lsm-2.6.orig/drivers/mtd/devices/Makefile
+++ lsm-2.6/drivers/mtd/devices/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_MTD_MTDRAM) += mtdram.o
obj-$(CONFIG_MTD_LART) += lart.o
obj-$(CONFIG_MTD_BLKMTD) += blkmtd.o
obj-$(CONFIG_MTD_BLOCK2MTD) += block2mtd.o
+obj-$(CONFIG_MTD_DATAFLASH) += mtd_dataflash.o
Index: lsm-2.6/drivers/mtd/devices/mtd_dataflash.c
===================================================================
--- /dev/null
+++ lsm-2.6/drivers/mtd/devices/mtd_dataflash.c
@@ -0,0 +1,568 @@
+/*
+ * Atmel AT45xxx DataFlash MTD driver for lightweight SPI framework
+ *
+ * Largely derived from at91_dataflash.c:
+ * Copyright (C) 2003-2005 SAN People (Pty) Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+*/
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/spi.h>
+#include <linux/spi/flash.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+
+/*
+ * DataFlash is a kind of SPI flash. Most AT45 chips have two buffers in
+ * each chip, which may be used for double buffered I/O; but this driver
+ * doesn't (yet) use these for any kind of i/o overlap or prefetching.
+ *
+ * Sometimes DataFlash is packaged in MMC-format cards. This driver does
+ * not (yet) expect to be hotplugged through MMC or SPI. That's fair,
+ * since the MMC stack can't even use SPI (yet), much less distinguish
+ * between MMC and DataFlash protocols during enumeration.
+ */
+
+#define CONFIG_DATAFLASH_WRITE_VERIFY
+
+
+/* reads can bypass the buffers */
+#define OP_READ_CONTINUOUS 0xE8
+#define OP_READ_PAGE 0xD2
+
+/* group B requests can run even while status reports "busy" */
+#define OP_READ_STATUS 0xD7 /* group B */
+
+/* move data between host and buffer */
+#define OP_READ_BUFFER1 0xD4 /* group B */
+#define OP_READ_BUFFER2 0xD6 /* group B */
+#define OP_WRITE_BUFFER1 0x84 /* group B */
+#define OP_WRITE_BUFFER2 0x87 /* group B */
+
+/* erasing flash */
+#define OP_ERASE_PAGE 0x81
+#define OP_ERASE_BLOCK 0x50
+
+/* move data between buffer and flash */
+#define OP_TRANSFER_BUF1 0x53
+#define OP_TRANSFER_BUF2 0x55
+#define OP_MREAD_BUFFER1 0xD4
+#define OP_MREAD_BUFFER2 0xD6
+#define OP_MWERASE_BUFFER1 0x83
+#define OP_MWERASE_BUFFER2 0x86
+#define OP_MWRITE_BUFFER1 0x88 /* sector must be pre-erased */
+#define OP_MWRITE_BUFFER2 0x89 /* sector must be pre-erased */
+
+/* write to buffer, then write-erase to flash */
+#define OP_PROGRAM_VIA_BUF1 0x82
+#define OP_PROGRAM_VIA_BUF2 0x85
+
+/* compare buffer to flash */
+#define OP_COMPARE_BUF1 0x60
+#define OP_COMPARE_BUF2 0x61
+
+/* read flash to buffer, then write-erase to flash */
+#define OP_REWRITE_VIA_BUF1 0x58
+#define OP_REWRITE_VIA_BUF2 0x59
+
+/* newer chips report JEDEC manufacturer and device IDs; chip
+ * serial number and OTP bits; and per-sector writeprotect.
+ */
+#define OP_READ_ID 0x9F
+#define OP_READ_SECURITY 0x77
+#define OP_WRITE_SECURITY 0x9A /* OTP bits */
+
+
+struct dataflash {
+ u8 command[4];
+ char name[24];
+
+ unsigned short page_offset; /* offset in flash address */
+ unsigned int page_size; /* of bytes per page */
+
+ struct semaphore lock;
+ struct spi_device *spi;
+
+ struct mtd_info mtd;
+};
+
+/* ......................................................................... */
+
+/*
+ * Return the status of the DataFlash device.
+ */
+static inline int dataflash_status(struct spi_device *spi)
+{
+ /* NOTE: at45db321c over 25 MHz wants to write
+ * a dummy byte after the opcode...
+ */
+ return spi_w8r8(spi, OP_READ_STATUS);
+}
+
+/*
+ * Poll the DataFlash device until it is READY.
+ * This usually takes 5-20 msec or so; more for sector erase.
+ */
+static int dataflash_waitready(struct spi_device *spi)
+{
+ int status;
+
+ for (;;) {
+ status = dataflash_status(spi);
+ if (status < 0) {
+ DEBUG(MTD_DEBUG_LEVEL1, "%s: status %d?\n",
+ spi->dev.bus_id, status);
+ status = 0;
+ }
+
+ if (status & (1 << 7)) /* RDY/nBSY */
+ return status;
+
+ msleep(3);
+ }
+}
+
+/* ......................................................................... */
+
+/*
+ * Erase pages of flash.
+ */
+static int dataflash_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+ struct dataflash *priv = (struct dataflash *)mtd->priv;
+ struct spi_device *spi = priv->spi;
+ u8 *command;
+
+ DEBUG(MTD_DEBUG_LEVEL2, "%s: erase addr=%x len %x\n",
+ spi->dev.bus_id,
+ instr->addr, instr->len);
+
+ /* Sanity checks */
+ if ((instr->addr + instr->len) > mtd->size
+ || (instr->len % priv->page_size) != 0
+ || (instr->addr % priv->page_size) != 0)
+ return -EINVAL;
+
+ command = priv->command;
+
+ down(&priv->lock);
+ while (instr->len > 0) {
+ unsigned int pageaddr;
+ int status;
+
+ /* Calculate flash page address */
+ // REVISIT: pageaddr == instr->addr, yes???
+ pageaddr = (instr->addr / priv->page_size) << priv->page_offset;
+
+ /* REVISIT block erase is faster, if this page is at a block
+ * boundary and the next eight pages must all be erased ...
+ */
+ command[0] = OP_ERASE_PAGE;
+ command[1] = (u8)(pageaddr >> 16);
+ command[2] = (u8)(pageaddr >> 8);
+ command[3] = 0;
+
+ DEBUG(MTD_DEBUG_LEVEL3, "ERASE: (%x) %x %x %x [%i]\n",
+ command[0], command[1], command[2], command[3],
+ pageaddr);
+
+ status = spi_write (spi, SPI_M_CS | SPI_M_CSREL, command, 4);
+ (void) dataflash_waitready(spi);
+
+ if (status < 0) {
+ printk(KERN_ERR "%s: erase %x, err %d\n",
+ spi->dev.bus_id, pageaddr, status);
+ continue;
+ }
+
+ instr->addr += priv->page_size; /* next page */
+ instr->len -= priv->page_size;
+ }
+ up(&priv->lock);
+
+ /* Inform MTD subsystem that erase is complete */
+ instr->state = MTD_ERASE_DONE;
+ mtd_erase_callback(instr);
+
+ return 0;
+}
+
+/*
+ * Read from the DataFlash device.
+ * from : Start offset in flash device
+ * len : Amount to read
+ * retlen : About of data actually read
+ * buf : Buffer containing the data
+ */
+static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct dataflash *priv = (struct dataflash *)mtd->priv;
+ unsigned int addr;
+ u8 *command;
+ int status;
+
+ DEBUG(MTD_DEBUG_LEVEL2, "%s: read %x..%x\n",
+ priv->spi->dev.bus_id, (unsigned)from, (unsigned)(from + len));
+
+ *retlen = 0;
+
+ /* Sanity checks */
+ if (!len)
+ return 0;
+ if (from + len > mtd->size)
+ return -EINVAL;
+
+ /* Calculate flash page/byte address */
+ addr = (((unsigned)from / priv->page_size) << priv->page_offset)
+ + ((unsigned)from % priv->page_size);
+
+ command = priv->command;
+
+ DEBUG(MTD_DEBUG_LEVEL3, "READ: (%x) %x %x %x\n",
+ command[0], command[1], command[2], command[3]);
+
+ down(&priv->lock);
+
+ /* Continuous read, max clock = f(car) which may be less than
+ * the peak rate available. Some chips support commands with
+ * fewer "don't care" bytes. Both buffers stay unchanged.
+ */
+ command[0] = OP_READ_CONTINUOUS;
+ command[1] = (u8)(addr >> 16);
+ command[2] = (u8)(addr >> 8);
+ command[3] = (u8)(addr >> 0);
+ /* plus 4 "don't care" bytes */
+
+ spi_read (priv->spi, SPI_M_CS, command, 8);
+ status = spi_read (priv->spi, SPI_M_CSREL, buf, len);
+
+ up(&priv->lock);
+
+ if (status >= 0) {
+ *retlen = status;
+ status = 0;
+ } else
+ DEBUG(MTD_DEBUG_LEVEL1, "%s: read %x..%x --> %d\n",
+ priv->spi->dev.bus_id,
+ (unsigned)from, (unsigned)(from + len),
+ status);
+ return status;
+}
+
+/*
+ * Write to the DataFlash device.
+ * to : Start offset in flash device
+ * len : Amount to write
+ * retlen : Amount of data actually written
+ * buf : Buffer containing the data
+ */
+static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
+ size_t * retlen, const u_char * buf)
+{
+ struct dataflash *priv = (struct dataflash *)mtd->priv;
+ struct spi_device *spi = priv->spi;
+ unsigned int pageaddr, addr, offset, writelen;
+ size_t remaining = len;
+ u_char *writebuf = (u_char *) buf;
+ int status = -EINVAL;
+ u8 *command = priv->command;
+
+ DEBUG(MTD_DEBUG_LEVEL2, "%s: write %x..%x\n",
+ spi->dev.bus_id, (unsigned)to, (unsigned)(to + len));
+
+ *retlen = 0;
+
+ /* Sanity checks */
+ if (!len)
+ return 0;
+ if ((to + len) > mtd->size)
+ return -EINVAL;
+
+ pageaddr = ((unsigned)to / priv->page_size);
+ offset = ((unsigned)to % priv->page_size);
+ if (offset + len > priv->page_size)
+ writelen = priv->page_size - offset;
+ else
+ writelen = len;
+
+ down(&priv->lock);
+ while (remaining > 0) {
+ DEBUG(MTD_DEBUG_LEVEL3, "write @ %i:%i len=%i\n",
+ pageaddr, offset, writelen);
+
+ /* REVISIT:
+ * (a) each page in a sector must be rewritten at least
+ * once every 10K sibling erase/program operations.
+ * (b) for pages that are already erased, we could
+ * use WRITE+MWRITE not PROGRAM for ~30% speedup.
+ * (c) WRITE to buffer could be done while waiting for
+ * a previous MWRITE/MWERASE to complete ...
+ * (d) error handling here seems to be mostly missing.
+ *
+ * Two persistent bits per page, plus a per-sector counter,
+ * could support (a) and (b) ... we might consider using
+ * the second half of sector zero, which is just one block,
+ * to track that state. (On AT91, that sector should also
+ * support boot-from-DataFlash.)
+ */
+
+ addr = pageaddr << priv->page_offset;
+
+ /* (1) Maybe transfer partial page to Buffer1 */
+ if (writelen != priv->page_size) {
+ command[0] = OP_TRANSFER_BUF1;
+ command[1] = (addr & 0x00FF0000) >> 16;
+ command[2] = (addr & 0x0000FF00) >> 8;
+ command[3] = 0;
+
+ DEBUG(MTD_DEBUG_LEVEL3, "TRANSFER: (%x) %x %x %x\n",
+ command[0], command[1], command[2], command[3]);
+
+ spi_write (spi, SPI_M_CS | SPI_M_CSREL, command, 4);
+ if (status < 0)
+ DEBUG(MTD_DEBUG_LEVEL1, "%s: xfer %u -> %d \n",
+ spi->dev.bus_id, addr, status);
+
+ (void) dataflash_waitready(priv->spi);
+ }
+
+ /* (2) Program full page via Buffer1 */
+ addr += offset;
+ command[0] = OP_PROGRAM_VIA_BUF1;
+ command[1] = (addr & 0x00FF0000) >> 16;
+ command[2] = (addr & 0x0000FF00) >> 8;
+ command[3] = (addr & 0x000000FF);
+
+ DEBUG(MTD_DEBUG_LEVEL3, "PROGRAM: (%x) %x %x %x\n",
+ command[0], command[1], command[2], command[3]);
+
+ spi_write (spi, SPI_M_CS, command, 4);
+ spi_write (spi, SPI_M_CSREL, writebuf, writelen);
+
+ if (status < 0)
+ DEBUG(MTD_DEBUG_LEVEL1, "%s: pgm %u/%u -> %d \n",
+ spi->dev.bus_id, addr, writelen, status);
+
+ (void) dataflash_waitready(priv->spi);
+
+#ifdef CONFIG_DATAFLASH_WRITE_VERIFY
+
+ /* (3) Compare to Buffer1 */
+ addr = pageaddr << priv->page_offset;
+ command[0] = OP_COMPARE_BUF1;
+ command[1] = (addr & 0x00FF0000) >> 16;
+ command[2] = (addr & 0x0000FF00) >> 8;
+ command[3] = 0;
+
+ DEBUG(MTD_DEBUG_LEVEL3, "COMPARE: (%x) %x %x %x\n",
+ command[0], command[1], command[2], command[3]);
+
+ status = spi_write (spi, SPI_M_CS | SPI_M_CSREL, command, 4);
+ if (status < 0)
+ DEBUG(MTD_DEBUG_LEVEL1, "%s: compare %u -> %d \n",
+ spi->dev.bus_id, addr, status);
+
+ status = dataflash_waitready(priv->spi);
+
+ /* Check result of the compare operation */
+ if ((status & (1 << 6)) == 1) {
+ printk(KERN_ERR "%s: compare page %u, err %d\n",
+ spi->dev.bus_id, pageaddr, status);
+ remaining = 0;
+ status = -EIO;
+ break;
+ } else
+ status = 0;
+
+#endif /* CONFIG_DATAFLASH_WRITE_VERIFY */
+
+ remaining = remaining - writelen;
+ pageaddr++;
+ offset = 0;
+ writebuf += writelen;
+ *retlen += writelen;
+
+ if (remaining > priv->page_size)
+ writelen = priv->page_size;
+ else
+ writelen = remaining;
+ }
+ up(&priv->lock);
+
+ return status;
+}
+
+/* ......................................................................... */
+
+/*
+ * Register DataFlash device with MTD subsystem.
+ */
+static int __init
+add_dataflash(struct spi_device *spi, char *name,
+ int nr_pages, int pagesize, int pageoffset)
+{
+ struct dataflash *priv;
+ struct mtd_info *device;
+ struct flash_platform_data *pdata = spi->dev.platform_data;
+
+ priv = (struct dataflash *) kzalloc(sizeof *priv, GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ init_MUTEX(&priv->lock);
+ priv->spi = spi;
+ priv->page_size = pagesize;
+ priv->page_offset = pageoffset;
+
+ /* name must be usable with cmdlinepart */
+ sprintf(priv->name, "mtd-%s",
+ spi->dev.parent->bus_id); /* mtd-spipnx0 */
+
+ device = &priv->mtd;
+ device->name = (pdata && pdata->name) ? pdata->name : priv->name;
+ device->size = nr_pages * pagesize;
+ device->erasesize = pagesize;
+ device->owner = THIS_MODULE;
+ device->type = MTD_DATAFLASH;
+ device->flags = MTD_CAP_NORFLASH;
+ device->erase = dataflash_erase;
+ device->read = dataflash_read;
+ device->write = dataflash_write;
+ device->priv = priv;
+
+ dev_info(&spi->dev, "%s (%d KBytes)\n", name, device->size/1024);
+ dev_set_drvdata(&spi->dev, priv);
+
+#ifdef CONFIG_MTD_PARTITIONS
+ {
+ struct mtd_partition *parts;
+ int nr_parts = 0;
+
+#ifdef CONFIG_MTD_CMDLINE_PARTS
+ static const char *part_probes[] = { "cmdlinepart", NULL, };
+
+ nr_parts = parse_mtd_partitions(device, part_probes, &parts, 0);
+#endif
+
+ if (nr_parts <= 0 && pdata && pdata->parts) {
+ parts = pdata->parts;
+ nr_parts = pdata->nr_parts;
+ }
+
+ if (nr_parts > 0)
+ return add_mtd_partitions(device, parts, nr_parts);
+ }
+#endif
+ return add_mtd_device(device);
+}
+
+/*
+ * Detect and initialize DataFlash device:
+ *
+ * Device Density ID code #Pages PageSize Offset
+ * AT45DB011B 1Mbit (128K) xx0011xx (0x0c) 512 264 9
+ * AT45DB021B 2Mbit (256K) xx0101xx (0x14) 1025 264 9
+ * AT45DB041B 4Mbit (512K) xx0111xx (0x1c) 2048 264 9
+ * AT45DB081B 8Mbit (1M) xx1001xx (0x24) 4096 264 9
+ * AT45DB0161B 16Mbit (2M) xx1011xx (0x2c) 4096 528 10
+ * AT45DB0321B 32Mbit (4M) xx1101xx (0x34) 8192 528 10
+ * AT45DB0642 64Mbit (8M) xx111xxx (0x3c) 8192 1056 11
+ * AT45DB1282 128Mbit (16M) xx0100xx (0x10) 16384 1056 11
+ */
+static int __init dataflash_probe(struct spi_device *spi)
+{
+ int status;
+
+ /* if there's a device there, assume it's dataflash.
+ * board setup should have set spi->max_speed_max to
+ * match f(car) for continuous reads, mode 0 or 3.
+ */
+ status = dataflash_status(spi);
+ if (status > 0 && status != 0xff) {
+ switch (status & 0x3c) {
+ case 0x0c: /* 0 0 1 1 x x */
+ status = add_dataflash(spi, "AT45DB011B",
+ 512, 264, 9);
+ break;
+ case 0x14: /* 0 1 0 1 x x */
+ status = add_dataflash(spi, "AT45DB021B",
+ 1025, 264, 9);
+ break;
+ case 0x1c: /* 0 1 1 1 x x */
+ status = add_dataflash(spi, "AT45DB041B",
+ 2048, 264, 9);
+ break;
+ case 0x24: /* 1 0 0 1 x x */
+ status = add_dataflash(spi, "AT45DB081B",
+ 4096, 264, 9);
+ break;
+ case 0x2c: /* 1 0 1 1 x x */
+ status = add_dataflash(spi, "AT45DB161x",
+ 4096, 528, 10);
+ break;
+ case 0x34: /* 1 1 0 1 x x */
+ status = add_dataflash(spi, "AT45DB321x",
+ 8192, 528, 10);
+ break;
+ case 0x38: /* 1 1 1 x x x */
+ case 0x3c:
+ status = add_dataflash(spi, "AT45DB642x",
+ 8192, 1056, 11);
+ break;
+ /* obsolete AT45DB1282 not (yet?) supported */
+ default:
+ printk(KERN_WARNING "%s: unsupported device (%x)\n",
+ spi->dev.bus_id, status & 0x3c);
+ status = -EINVAL;
+ }
+ }
+
+ return status;
+}
+
+static int __exit dataflash_remove(struct spi_device *spi)
+{
+ // struct dataflash *flash = dev_get_drvdata(dev);
+
+ dev_warn(&spi->dev, "implement remove!\n");
+ return -EINVAL;
+}
+
+static struct spi_driver dataflash_driver = {
+ .name = "mtd_dataflash",
+
+ .probe = dataflash_probe,
+ .remove = __exit_p(dataflash_remove),
+
+ /* FIXME: investigate suspend and resume... */
+};
+
+static int __init dataflash_init(void)
+{
+ return spi_driver_add(&dataflash_driver);
+}
+module_init(dataflash_init);
+
+#if 0
+static void __exit dataflash_exit(void)
+{
+ driver_unregister(&dataflash_driver);
+}
+module_exit(dataflash_exit);
+#endif
+
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrew Victor, David Brownell");
+MODULE_DESCRIPTION("MTD DataFlash driver");
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