Merge branch 'linux-2.6' into for-2.6.22

4 files changed, 509 insertions, 70 deletions

diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 440f6851da69..690c94236d7f 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -6,7 +6,7 @@ menu "Self-contained MTD device drivers"
 
 config MTD_PMC551
 	tristate "Ramix PMC551 PCI Mezzanine RAM card support"
-	depends on MTD && PCI
+	depends on PCI
 	---help---
 	  This provides a MTD device driver for the Ramix PMC551 RAM PCI card
 	  from Ramix Inc. <http://www.ramix.com/products/memory/pmc551.html>.
@@ -40,7 +40,7 @@ config MTD_PMC551_DEBUG
 
 config MTD_MS02NV
 	tristate "DEC MS02-NV NVRAM module support"
-	depends on MTD && MACH_DECSTATION
+	depends on MACH_DECSTATION
 	help
 	  This is an MTD driver for the DEC's MS02-NV (54-20948-01) battery
 	  backed-up NVRAM module.  The module was originally meant as an NFS
@@ -54,15 +54,23 @@ config MTD_MS02NV
 
 config MTD_DATAFLASH
 	tristate "Support for AT45xxx DataFlash"
-	depends on MTD && SPI_MASTER && EXPERIMENTAL
+	depends on SPI_MASTER && 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.
 
+config MTD_DATAFLASH26
+	tristate "AT91RM9200 DataFlash AT26xxx"
+	depends on MTD && ARCH_AT91RM9200 && AT91_SPI
+	help
+	  This enables access to the DataFlash chip (AT26xxx) on an
+	  AT91RM9200-based board.
+	  If you have such a board and such a DataFlash, say 'Y'.
+
 config MTD_M25P80
 	tristate "Support for M25 SPI Flash"
-	depends on MTD && SPI_MASTER && EXPERIMENTAL
+	depends on 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
@@ -70,7 +78,6 @@ config MTD_M25P80
 
 config MTD_SLRAM
 	tristate "Uncached system RAM"
-	depends on MTD
 	help
 	  If your CPU cannot cache all of the physical memory in your machine,
 	  you can still use it for storage or swap by using this driver to
@@ -78,7 +85,6 @@ config MTD_SLRAM
 
 config MTD_PHRAM
 	tristate "Physical system RAM"
-	depends on MTD
 	help
 	  This is a re-implementation of the slram driver above.
 
@@ -88,7 +94,7 @@ config MTD_PHRAM
 
 config MTD_LART
 	tristate "28F160xx flash driver for LART"
-	depends on SA1100_LART && MTD
+	depends on SA1100_LART
 	help
 	  This enables the flash driver for LART. Please note that you do
 	  not need any mapping/chip driver for LART. This one does it all
@@ -96,7 +102,6 @@ config MTD_LART
 
 config MTD_MTDRAM
 	tristate "Test driver using RAM"
-	depends on MTD
 	help
 	  This enables a test MTD device driver which uses vmalloc() to
 	  provide storage.  You probably want to say 'N' unless you're
@@ -136,7 +141,7 @@ config MTDRAM_ABS_POS
 
 config MTD_BLOCK2MTD
 	tristate "MTD using block device"
-	depends on MTD && BLOCK
+	depends on BLOCK
 	help
 	  This driver allows a block device to appear as an MTD. It would
 	  generally be used in the following cases:
@@ -150,7 +155,6 @@ comment "Disk-On-Chip Device Drivers"
 
 config MTD_DOC2000
 	tristate "M-Systems Disk-On-Chip 2000 and Millennium (DEPRECATED)"
-	depends on MTD
 	select MTD_DOCPROBE
 	select MTD_NAND_IDS
 	---help---
@@ -173,7 +177,6 @@ config MTD_DOC2000
 
 config MTD_DOC2001
 	tristate "M-Systems Disk-On-Chip Millennium-only alternative driver (DEPRECATED)"
-	depends on MTD
 	select MTD_DOCPROBE
 	select MTD_NAND_IDS
 	---help---
@@ -195,7 +198,6 @@ config MTD_DOC2001
 
 config MTD_DOC2001PLUS
 	tristate "M-Systems Disk-On-Chip Millennium Plus"
-	depends on MTD
 	select MTD_DOCPROBE
 	select MTD_NAND_IDS
 	---help---
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index 0f788d5c4bf8..8ab568b3f533 100644
--- a/drivers/mtd/devices/Makefile
+++ b/drivers/mtd/devices/Makefile
@@ -16,4 +16,5 @@ obj-$(CONFIG_MTD_MTDRAM)	+= mtdram.o
 obj-$(CONFIG_MTD_LART)		+= lart.o
 obj-$(CONFIG_MTD_BLOCK2MTD)	+= block2mtd.o
 obj-$(CONFIG_MTD_DATAFLASH)	+= mtd_dataflash.o
+obj-$(CONFIG_MTD_DATAFLASH26)	+= at91_dataflash26.o
 obj-$(CONFIG_MTD_M25P80)	+= m25p80.o
diff --git a/drivers/mtd/devices/at91_dataflash26.c b/drivers/mtd/devices/at91_dataflash26.c
new file mode 100644
index 000000000000..64ce37f986fc
--- /dev/null
+++ b/drivers/mtd/devices/at91_dataflash26.c
@@ -0,0 +1,485 @@
+/*
+ * Atmel DataFlash driver for Atmel AT91RM9200 (Thunder)
+ * This is a largely modified version of at91_dataflash.c that
+ * supports AT26xxx dataflash chips. The original driver supports
+ * AT45xxx chips.
+ *
+ * Note: This driver was only tested with an AT26F004. It should be
+ * easy to make it work with other AT26xxx dataflash devices, though.
+ *
+ * Copyright (C) 2007 Hans J. Koch <hjk@linutronix.de>
+ * original Copyright (C) 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
+ * version 2 as published by the Free Software Foundation.
+*/
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+
+#include <asm/arch/at91_spi.h>
+
+#define DATAFLASH_MAX_DEVICES	4	/* max number of dataflash devices */
+
+#define MANUFACTURER_ID_ATMEL		0x1F
+
+/* command codes */
+
+#define AT26_OP_READ_STATUS		0x05
+#define AT26_OP_READ_DEV_ID		0x9F
+#define AT26_OP_ERASE_PAGE_4K		0x20
+#define AT26_OP_READ_ARRAY_FAST		0x0B
+#define AT26_OP_SEQUENTIAL_WRITE	0xAF
+#define AT26_OP_WRITE_ENABLE		0x06
+#define AT26_OP_WRITE_DISABLE		0x04
+#define AT26_OP_SECTOR_PROTECT		0x36
+#define AT26_OP_SECTOR_UNPROTECT	0x39
+
+/* status register bits */
+
+#define AT26_STATUS_BUSY		0x01
+#define AT26_STATUS_WRITE_ENABLE	0x02
+
+struct dataflash_local
+{
+	int spi;			/* SPI chip-select number */
+	unsigned int page_size;		/* number of bytes per page */
+};
+
+
+/* Detected DataFlash devices */
+static struct mtd_info* mtd_devices[DATAFLASH_MAX_DEVICES];
+static int nr_devices = 0;
+
+/* Allocate a single SPI transfer descriptor.  We're assuming that if multiple
+   SPI transfers occur at the same time, spi_access_bus() will serialize them.
+   If this is not valid, then either (i) each dataflash 'priv' structure
+   needs it's own transfer descriptor, (ii) we lock this one, or (iii) use
+   another mechanism.   */
+static struct spi_transfer_list* spi_transfer_desc;
+
+/*
+ * Perform a SPI transfer to access the DataFlash device.
+ */
+static int do_spi_transfer(int nr, char* tx, int tx_len, char* rx, int rx_len,
+		char* txnext, int txnext_len, char* rxnext, int rxnext_len)
+{
+	struct spi_transfer_list* list = spi_transfer_desc;
+
+	list->tx[0] = tx;	list->txlen[0] = tx_len;
+	list->rx[0] = rx;	list->rxlen[0] = rx_len;
+
+	list->tx[1] = txnext; 	list->txlen[1] = txnext_len;
+	list->rx[1] = rxnext;	list->rxlen[1] = rxnext_len;
+
+	list->nr_transfers = nr;
+	/* Note: spi_transfer() always returns 0, there are no error checks */
+	return spi_transfer(list);
+}
+
+/*
+ * Return the status of the DataFlash device.
+ */
+static unsigned char at91_dataflash26_status(void)
+{
+	unsigned char command[2];
+
+	command[0] = AT26_OP_READ_STATUS;
+	command[1] = 0;
+
+	do_spi_transfer(1, command, 2, command, 2, NULL, 0, NULL, 0);
+
+	return command[1];
+}
+
+/*
+ * Poll the DataFlash device until it is READY.
+ */
+static unsigned char at91_dataflash26_waitready(void)
+{
+	unsigned char status;
+
+	while (1) {
+		status = at91_dataflash26_status();
+		if (!(status & AT26_STATUS_BUSY))
+			return status;
+	}
+}
+
+/*
+ * Enable/disable write access
+ */
+ static void at91_dataflash26_write_enable(int enable)
+{
+	unsigned char cmd[2];
+
+	DEBUG(MTD_DEBUG_LEVEL3, "write_enable: enable=%i\n", enable);
+
+	if (enable)
+		cmd[0] = AT26_OP_WRITE_ENABLE;
+	else
+		cmd[0] = AT26_OP_WRITE_DISABLE;
+	cmd[1] = 0;
+
+	do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
+}
+
+/*
+ * Protect/unprotect sector
+ */
+ static void at91_dataflash26_sector_protect(loff_t addr, int protect)
+{
+	unsigned char cmd[4];
+
+	DEBUG(MTD_DEBUG_LEVEL3, "sector_protect: addr=0x%06x prot=%d\n",
+	       addr, protect);
+
+	if (protect)
+		cmd[0] = AT26_OP_SECTOR_PROTECT;
+	else
+		cmd[0] = AT26_OP_SECTOR_UNPROTECT;
+	cmd[1] = (addr & 0x00FF0000) >> 16;
+	cmd[2] = (addr & 0x0000FF00) >> 8;
+	cmd[3] = (addr & 0x000000FF);
+
+	do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
+}
+
+/*
+ * Erase blocks of flash.
+ */
+static int at91_dataflash26_erase(struct mtd_info *mtd,
+				  struct erase_info *instr)
+{
+	struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
+	unsigned char cmd[4];
+
+	DEBUG(MTD_DEBUG_LEVEL1, "dataflash_erase: addr=0x%06x len=%i\n",
+	       instr->addr, instr->len);
+
+	/* Sanity checks */
+	if (priv->page_size != 4096)
+		return -EINVAL; /* Can't handle other sizes at the moment */
+
+	if (   ((instr->len % mtd->erasesize) != 0)
+	    || ((instr->len % priv->page_size) != 0)
+	    || ((instr->addr % priv->page_size) != 0)
+	    || ((instr->addr + instr->len) > mtd->size))
+		return -EINVAL;
+
+	spi_access_bus(priv->spi);
+
+	while (instr->len > 0) {
+		at91_dataflash26_write_enable(1);
+		at91_dataflash26_sector_protect(instr->addr, 0);
+		at91_dataflash26_write_enable(1);
+		cmd[0] = AT26_OP_ERASE_PAGE_4K;
+		cmd[1] = (instr->addr & 0x00FF0000) >> 16;
+		cmd[2] = (instr->addr & 0x0000FF00) >> 8;
+		cmd[3] = (instr->addr & 0x000000FF);
+
+		DEBUG(MTD_DEBUG_LEVEL3, "ERASE: (0x%02x) 0x%02x 0x%02x"
+					"0x%02x\n",
+			cmd[0], cmd[1], cmd[2], cmd[3]);
+
+		do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
+		at91_dataflash26_waitready();
+
+		instr->addr += priv->page_size;	 /* next page */
+		instr->len -= priv->page_size;
+	}
+
+	at91_dataflash26_write_enable(0);
+	spi_release_bus(priv->spi);
+
+	/* Inform MTD subsystem that erase is complete */
+	instr->state = MTD_ERASE_DONE;
+	if (instr->callback)
+		instr->callback(instr);
+
+	return 0;
+}
+
+/*
+ * Read from the DataFlash device.
+ *   from   : Start offset in flash device
+ *   len    : Number of bytes to read
+ *   retlen : Number of bytes actually read
+ *   buf    : Buffer that will receive data
+ */
+static int at91_dataflash26_read(struct mtd_info *mtd, loff_t from, size_t len,
+				 size_t *retlen, u_char *buf)
+{
+	struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
+	unsigned char cmd[5];
+
+	DEBUG(MTD_DEBUG_LEVEL1, "dataflash_read: %lli .. %lli\n",
+	      from, from+len);
+
+	*retlen = 0;
+
+	/* Sanity checks */
+	if (!len)
+		return 0;
+	if (from + len > mtd->size)
+		return -EINVAL;
+
+	cmd[0] = AT26_OP_READ_ARRAY_FAST;
+	cmd[1] = (from & 0x00FF0000) >> 16;
+	cmd[2] = (from & 0x0000FF00) >> 8;
+	cmd[3] = (from & 0x000000FF);
+	/* cmd[4] is a "Don't care" byte  */
+
+	DEBUG(MTD_DEBUG_LEVEL3, "READ: (0x%02x) 0x%02x 0x%02x 0x%02x\n",
+	       cmd[0], cmd[1], cmd[2], cmd[3]);
+
+	spi_access_bus(priv->spi);
+	do_spi_transfer(2, cmd, 5, cmd, 5, buf, len, buf, len);
+	spi_release_bus(priv->spi);
+
+	*retlen = len;
+	return 0;
+}
+
+/*
+ * Write to the DataFlash device.
+ *   to     : Start offset in flash device
+ *   len    : Number of bytes to write
+ *   retlen : Number of bytes actually written
+ *   buf    : Buffer containing the data
+ */
+static int at91_dataflash26_write(struct mtd_info *mtd, loff_t to, size_t len,
+				  size_t *retlen, const u_char *buf)
+{
+	struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
+	unsigned int addr, buf_index = 0;
+	int ret = -EIO, sector, last_sector;
+	unsigned char status, cmd[5];
+
+	DEBUG(MTD_DEBUG_LEVEL1, "dataflash_write: %lli .. %lli\n", to, to+len);
+
+	*retlen = 0;
+
+	/* Sanity checks */
+	if (!len)
+		return 0;
+	if (to + len > mtd->size)
+		return -EINVAL;
+
+	spi_access_bus(priv->spi);
+
+	addr = to;
+	last_sector = -1;
+
+	while (buf_index < len) {
+		sector = addr / priv->page_size;
+		/* Write first byte if a new sector begins */
+		if (sector != last_sector) {
+			at91_dataflash26_write_enable(1);
+			at91_dataflash26_sector_protect(addr, 0);
+			at91_dataflash26_write_enable(1);
+
+			/* Program first byte of a new sector */
+			cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
+			cmd[1] = (addr & 0x00FF0000) >> 16;
+			cmd[2] = (addr & 0x0000FF00) >> 8;
+			cmd[3] = (addr & 0x000000FF);
+			cmd[4] = buf[buf_index++];
+			do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
+			status = at91_dataflash26_waitready();
+			addr++;
+			/* On write errors, the chip resets the write enable
+			   flag. This also happens after the last byte of a
+			   sector is successfully programmed. */
+			if (   ( !(status & AT26_STATUS_WRITE_ENABLE))
+			    && ((addr % priv->page_size) != 0) ) {
+				DEBUG(MTD_DEBUG_LEVEL1,
+					"write error1: addr=0x%06x, "
+					"status=0x%02x\n", addr, status);
+				goto write_err;
+			}
+			(*retlen)++;
+			last_sector = sector;
+		}
+
+		/* Write subsequent bytes in the same sector */
+		cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
+		cmd[1] = buf[buf_index++];
+		do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
+		status = at91_dataflash26_waitready();
+		addr++;
+
+		if (   ( !(status & AT26_STATUS_WRITE_ENABLE))
+		    && ((addr % priv->page_size) != 0) ) {
+			DEBUG(MTD_DEBUG_LEVEL1, "write error2: addr=0x%06x, "
+				"status=0x%02x\n", addr, status);
+			goto write_err;
+		}
+
+		(*retlen)++;
+	}
+
+	ret = 0;
+	at91_dataflash26_write_enable(0);
+write_err:
+	spi_release_bus(priv->spi);
+	return ret;
+}
+
+/*
+ * Initialize and register DataFlash device with MTD subsystem.
+ */
+static int __init add_dataflash(int channel, char *name, int nr_pages,
+				int pagesize)
+{
+	struct mtd_info *device;
+	struct dataflash_local *priv;
+
+	if (nr_devices >= DATAFLASH_MAX_DEVICES) {
+		printk(KERN_ERR "at91_dataflash26: Too many devices "
+				"detected\n");
+		return 0;
+	}
+
+	device = kzalloc(sizeof(struct mtd_info) + strlen(name) + 8,
+			 GFP_KERNEL);
+	if (!device)
+		return -ENOMEM;
+
+	device->name = (char *)&device[1];
+	sprintf(device->name, "%s.spi%d", name, channel);
+	device->size = nr_pages * pagesize;
+	device->erasesize = pagesize;
+	device->owner = THIS_MODULE;
+	device->type = MTD_DATAFLASH;
+	device->flags = MTD_CAP_NORFLASH;
+	device->erase = at91_dataflash26_erase;
+	device->read = at91_dataflash26_read;
+	device->write = at91_dataflash26_write;
+
+	priv = (struct dataflash_local *)kzalloc(sizeof(struct dataflash_local),
+		GFP_KERNEL);
+	if (!priv) {
+		kfree(device);
+		return -ENOMEM;
+	}
+
+	priv->spi = channel;
+	priv->page_size = pagesize;
+	device->priv = priv;
+
+	mtd_devices[nr_devices] = device;
+	nr_devices++;
+	printk(KERN_INFO "at91_dataflash26: %s detected [spi%i] (%i bytes)\n",
+	       name, channel, device->size);
+
+	return add_mtd_device(device);
+}
+
+/*
+ * Detect and initialize DataFlash device connected to specified SPI channel.
+ *
+ */
+
+struct dataflash26_types {
+	unsigned char id0;
+	unsigned char id1;
+	char *name;
+	int pagesize;
+	int nr_pages;
+};
+
+struct dataflash26_types df26_types[] = {
+	{
+		.id0 = 0x04,
+		.id1 = 0x00,
+		.name = "AT26F004",
+		.pagesize = 4096,
+		.nr_pages = 128,
+	},
+	{
+		.id0 = 0x45,
+		.id1 = 0x01,
+		.name = "AT26DF081A", /* Not tested ! */
+		.pagesize = 4096,
+		.nr_pages = 256,
+	},
+};
+
+static int __init at91_dataflash26_detect(int channel)
+{
+	unsigned char status, cmd[5];
+	int i;
+
+	spi_access_bus(channel);
+	status = at91_dataflash26_status();
+
+	if (status == 0 || status == 0xff) {
+		printk(KERN_ERR "at91_dataflash26_detect: status error %d\n",
+			status);
+		spi_release_bus(channel);
+		return -ENODEV;
+	}
+
+	cmd[0] = AT26_OP_READ_DEV_ID;
+	do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
+	spi_release_bus(channel);
+
+	if (cmd[1] != MANUFACTURER_ID_ATMEL)
+		return -ENODEV;
+
+	for (i = 0; i < ARRAY_SIZE(df26_types); i++) {
+		if (   cmd[2] == df26_types[i].id0
+		    && cmd[3] == df26_types[i].id1)
+			return add_dataflash(channel,
+						df26_types[i].name,
+						df26_types[i].nr_pages,
+						df26_types[i].pagesize);
+	}
+
+	printk(KERN_ERR "at91_dataflash26_detect: Unsupported device "
+			"(0x%02x/0x%02x)\n", cmd[2], cmd[3]);
+	return -ENODEV;
+}
+
+static int __init at91_dataflash26_init(void)
+{
+	spi_transfer_desc = kmalloc(sizeof(struct spi_transfer_list),
+				    GFP_KERNEL);
+	if (!spi_transfer_desc)
+		return -ENOMEM;
+
+	/* DataFlash (SPI chip select 0) */
+	at91_dataflash26_detect(0);
+
+#ifdef CONFIG_MTD_AT91_DATAFLASH_CARD
+	/* DataFlash card (SPI chip select 3) */
+	at91_dataflash26_detect(3);
+#endif
+	return 0;
+}
+
+static void __exit at91_dataflash26_exit(void)
+{
+	int i;
+
+	for (i = 0; i < DATAFLASH_MAX_DEVICES; i++) {
+		if (mtd_devices[i]) {
+			del_mtd_device(mtd_devices[i]);
+			kfree(mtd_devices[i]->priv);
+			kfree(mtd_devices[i]);
+		}
+	}
+	nr_devices = 0;
+	kfree(spi_transfer_desc);
+}
+
+module_init(at91_dataflash26_init);
+module_exit(at91_dataflash26_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Hans J. Koch");
+MODULE_DESCRIPTION("DataFlash AT26xxx driver for Atmel AT91RM9200");
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index f9f2ce7806b0..ce47544dc120 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -40,56 +40,9 @@ struct block2mtd_dev {
 static LIST_HEAD(blkmtd_device_list);
 
 
-#define PAGE_READAHEAD 64
-static void cache_readahead(struct address_space *mapping, int index)
+static struct page* page_read(struct address_space *mapping, int index)
 {
 	filler_t *filler = (filler_t*)mapping->a_ops->readpage;
-	int i, pagei;
-	unsigned ret = 0;
-	unsigned long end_index;
-	struct page *page;
-	LIST_HEAD(page_pool);
-	struct inode *inode = mapping->host;
-	loff_t isize = i_size_read(inode);
-
-	if (!isize) {
-		INFO("iSize=0 in cache_readahead\n");
-		return;
-	}
-
-	end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
-
-	read_lock_irq(&mapping->tree_lock);
-	for (i = 0; i < PAGE_READAHEAD; i++) {
-		pagei = index + i;
-		if (pagei > end_index) {
-			INFO("Overrun end of disk in cache readahead\n");
-			break;
-		}
-		page = radix_tree_lookup(&mapping->page_tree, pagei);
-		if (page && (!i))
-			break;
-		if (page)
-			continue;
-		read_unlock_irq(&mapping->tree_lock);
-		page = page_cache_alloc_cold(mapping);
-		read_lock_irq(&mapping->tree_lock);
-		if (!page)
-			break;
-		page->index = pagei;
-		list_add(&page->lru, &page_pool);
-		ret++;
-	}
-	read_unlock_irq(&mapping->tree_lock);
-	if (ret)
-		read_cache_pages(mapping, &page_pool, filler, NULL);
-}
-
-
-static struct page* page_readahead(struct address_space *mapping, int index)
-{
-	filler_t *filler = (filler_t*)mapping->a_ops->readpage;
-	cache_readahead(mapping, index);
 	return read_cache_page(mapping, index, filler, NULL);
 }
 
@@ -105,14 +58,14 @@ static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
 	u_long *max;
 
 	while (pages) {
-		page = page_readahead(mapping, index);
+		page = page_read(mapping, index);
 		if (!page)
 			return -ENOMEM;
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
-		max = (u_long*)page_address(page) + PAGE_SIZE;
-		for (p=(u_long*)page_address(page); p<max; p++)
+		max = page_address(page) + PAGE_SIZE;
+		for (p=page_address(page); p<max; p++)
 			if (*p != -1UL) {
 				lock_page(page);
 				memset(page_address(page), 0xff, PAGE_SIZE);
@@ -174,8 +127,7 @@ static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
 			cpylen = len;	// this page
 		len = len - cpylen;
 
-		//      Get page
-		page = page_readahead(dev->blkdev->bd_inode->i_mapping, index);
+		page = page_read(dev->blkdev->bd_inode->i_mapping, index);
 		if (!page)
 			return -ENOMEM;
 		if (IS_ERR(page))
@@ -213,8 +165,7 @@ static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf,
 			cpylen = len;			// this page
 		len = len - cpylen;
 
-		//	Get page
-		page = page_readahead(mapping, index);
+		page = page_read(mapping, index);
 		if (!page)
 			return -ENOMEM;
 		if (IS_ERR(page))
@@ -308,9 +259,9 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
 		/* We might not have rootfs mounted at this point. Try
 		   to resolve the device name by other means. */
 
-		dev_t dev = name_to_dev_t(devname);
-		if (dev != 0) {
-			bdev = open_by_devnum(dev, FMODE_WRITE | FMODE_READ);
+		dev_t devt = name_to_dev_t(devname);
+		if (devt) {
+			bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
 		}
 	}
 #endif