diff --git a/arch/arm/mach-mxs/ocotp.c b/arch/arm/mach-mxs/ocotp.c
index 01db731..f230d9a 100644
--- a/arch/arm/mach-mxs/ocotp.c
+++ b/arch/arm/mach-mxs/ocotp.c
@@ -174,7 +174,6 @@
 
 static struct cdev_operations mxs_ocotp_ops = {
 	.read	= mxs_ocotp_cdev_read,
-	.lseek	= dev_lseek_default,
 };
 
 static int mxs_ocotp_probe(struct device_d *dev)
diff --git a/arch/sandbox/board/hostfile.c b/arch/sandbox/board/hostfile.c
index 3fc1503..745f078 100644
--- a/arch/sandbox/board/hostfile.c
+++ b/arch/sandbox/board/hostfile.c
@@ -67,7 +67,6 @@
 static struct cdev_operations hf_fops = {
 	.read  = hf_read,
 	.write = hf_write,
-	.lseek = dev_lseek_default,
 };
 
 static int hf_probe(struct device_d *dev)
diff --git a/commands/Kconfig b/commands/Kconfig
index 1de4b9d..c14332c 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -14,11 +14,6 @@
 	help
 	  Turns on compilation of digest.c
 
-config COMPILE_MEMORY
-	bool
-	help
-	  Turns on compilation of mem.c
-
 menu "Commands"
 
 
@@ -1493,7 +1488,7 @@
 config CMD_MD
 	tristate
 	default y
-	select COMPILE_MEMORY
+	select DEV_MEM
 	prompt "md"
 	help
 	  Memory display
@@ -1517,7 +1512,7 @@
 config CMD_MEMCMP
 	tristate
 	default y
-	select COMPILE_MEMORY
+	select DEV_MEM
 	prompt "memcmp"
 	help
 	  Memory compare
@@ -1539,7 +1534,7 @@
 config CMD_MEMCPY
 	tristate
 	default y
-	select COMPILE_MEMORY
+	select DEV_MEM
 	prompt "memcpy"
 	help
 	  Memory copy
@@ -1558,7 +1553,7 @@
 config CMD_MEMSET
 	tristate
 	default y
-	select COMPILE_MEMORY
+	select DEV_MEM
 	prompt "memset"
 	help
 	  Memory fill
@@ -1591,7 +1586,7 @@
 
 config CMD_MM
 	tristate
-	select COMPILE_MEMORY
+	select DEV_MEM
 	prompt "memory modify (mm)"
 	help
 	  Memory modify with mask
@@ -1609,7 +1604,7 @@
 config CMD_MW
 	tristate
 	default y
-	select COMPILE_MEMORY
+	select DEV_MEM
 	prompt "mw"
 	help
 	  Memory write
diff --git a/commands/Makefile b/commands/Makefile
index eb47963..358671b 100644
--- a/commands/Makefile
+++ b/commands/Makefile
@@ -1,7 +1,6 @@
 obj-$(CONFIG_STDDEV)		+= stddev.o
 obj-$(CONFIG_CMD_DIGEST)	+= digest.o
 obj-$(CONFIG_COMPILE_HASH)	+= hashsum.o
-obj-$(CONFIG_COMPILE_MEMORY)	+= mem.o
 obj-$(CONFIG_CMD_BOOTM)		+= bootm.o
 obj-$(CONFIG_CMD_UIMAGE)	+= uimage.o
 obj-$(CONFIG_CMD_LINUX16)	+= linux16.o
diff --git a/commands/md.c b/commands/md.c
index a495fc8..2389c12 100644
--- a/commands/md.c
+++ b/commands/md.c
@@ -34,8 +34,6 @@
 #include <linux/stat.h>
 #include <xfuncs.h>
 
-extern char *mem_rw_buf;
-
 static int do_mem_md(int argc, char *argv[])
 {
 	loff_t	start = 0, size = 0x100;
@@ -46,6 +44,7 @@
 	int mode = O_RWSIZE_4;
 	int swab = 0;
 	void *map;
+	void *buf = NULL;
 
 	if (argc < 2)
 		return COMMAND_ERROR_USAGE;
@@ -74,9 +73,11 @@
 		goto out;
 	}
 
+	buf = xmalloc(RW_BUF_SIZE);
+
 	do {
 		now = min(size, (loff_t)RW_BUF_SIZE);
-		r = read(fd, mem_rw_buf, now);
+		r = read(fd, buf, now);
 		if (r < 0) {
 			perror("read");
 			goto out;
@@ -84,8 +85,8 @@
 		if (!r)
 			goto out;
 
-		if ((ret = memory_display(mem_rw_buf, start, r,
-				mode >> O_RWSIZE_SHIFT, swab)))
+		if ((ret = memory_display(buf, start, r,
+					  mode >> O_RWSIZE_SHIFT, swab)))
 			goto out;
 
 		start += r;
@@ -93,6 +94,7 @@
 	} while (size);
 
 out:
+	free(buf);
 	close(fd);
 
 	return ret ? 1 : 0;
diff --git a/commands/mem.c b/commands/mem.c
deleted file mode 100644
index a9e12f3..0000000
--- a/commands/mem.c
+++ /dev/null
@@ -1,123 +0,0 @@
-/*
- * Copyright (c) 2011 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
- *
- * See file CREDITS for list of people who contributed to this
- * project.
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- */
-
-/*
- * Memory Functions
- *
- * Copied from FADS ROM, Dan Malek (dmalek@jlc.net)
- */
-
-#include <common.h>
-#include <command.h>
-#include <init.h>
-#include <driver.h>
-#include <malloc.h>
-#include <errno.h>
-#include <fs.h>
-#include <fcntl.h>
-#include <getopt.h>
-#include <linux/stat.h>
-#include <xfuncs.h>
-
-#ifdef	CMD_MEM_DEBUG
-#define	PRINTF(fmt,args...)	printf (fmt ,##args)
-#else
-#define PRINTF(fmt,args...)
-#endif
-
-char *mem_rw_buf;
-
-/*
- * Common function for parsing options for the 'md', 'mw', 'memcpy', 'memcmp'
- * commands.
- */
-int mem_parse_options(int argc, char *argv[], char *optstr, int *mode,
-		char **sourcefile, char **destfile, int *swab)
-{
-	int opt;
-
-	while((opt = getopt(argc, argv, optstr)) > 0) {
-		switch(opt) {
-		case 'b':
-			*mode = O_RWSIZE_1;
-			break;
-		case 'w':
-			*mode = O_RWSIZE_2;
-			break;
-		case 'l':
-			*mode = O_RWSIZE_4;
-			break;
-		case 'q':
-			*mode = O_RWSIZE_8;
-			break;
-		case 's':
-			*sourcefile = optarg;
-			break;
-		case 'd':
-			*destfile = optarg;
-			break;
-		case 'x':
-			*swab = 1;
-			break;
-		default:
-			return COMMAND_ERROR_USAGE;
-		}
-	}
-
-	return 0;
-}
-
-static struct cdev_operations memops = {
-	.read  = mem_read,
-	.write = mem_write,
-	.memmap = generic_memmap_rw,
-	.lseek = dev_lseek_default,
-};
-
-static int mem_probe(struct device_d *dev)
-{
-	struct cdev *cdev;
-
-	cdev = xzalloc(sizeof (*cdev));
-	dev->priv = cdev;
-
-	cdev->name = (char*)dev->resource[0].name;
-	cdev->size = min_t(unsigned long long, resource_size(&dev->resource[0]),
-			   S64_MAX);
-	cdev->ops = &memops;
-	cdev->dev = dev;
-
-	devfs_create(cdev);
-
-	return 0;
-}
-
-static struct driver_d mem_drv = {
-	.name  = "mem",
-	.probe = mem_probe,
-};
-
-static int mem_init(void)
-{
-	mem_rw_buf = malloc(RW_BUF_SIZE);
-	if(!mem_rw_buf)
-		return -ENOMEM;
-
-	add_mem_device("mem", 0, ~0, IORESOURCE_MEM_WRITEABLE);
-	return platform_driver_register(&mem_drv);
-}
-device_initcall(mem_init);
diff --git a/commands/memcmp.c b/commands/memcmp.c
index 981c8cb..48957b4 100644
--- a/commands/memcmp.c
+++ b/commands/memcmp.c
@@ -34,8 +34,6 @@
 #include <linux/stat.h>
 #include <xfuncs.h>
 
-extern char *mem_rw_buf;
-
 static char *devmem = "/dev/mem";
 
 static int do_memcmp(int argc, char *argv[])
@@ -45,7 +43,7 @@
 	char   *sourcefile = devmem;
 	char   *destfile = devmem;
 	int     sourcefd, destfd;
-	char   *rw_buf1;
+	char   *buf, *source_data, *dest_data;
 	int     ret = 1;
 	int     offset = 0;
 	struct  stat statbuf;
@@ -84,20 +82,22 @@
 		return 1;
 	}
 
-	rw_buf1 = xmalloc(RW_BUF_SIZE);
+	buf = xmalloc(RW_BUF_SIZE + RW_BUF_SIZE);
+	source_data = buf;
+	dest_data   = buf + RW_BUF_SIZE;
 
 	while (count > 0) {
 		int now, r1, r2, i;
 
 		now = min((loff_t)RW_BUF_SIZE, count);
 
-		r1 = read_full(sourcefd, mem_rw_buf, now);
+		r1 = read_full(sourcefd, source_data, now);
 		if (r1 < 0) {
 			perror("read");
 			goto out;
 		}
 
-		r2 = read_full(destfd, rw_buf1, now);
+		r2 = read_full(destfd, dest_data, now);
 		if (r2 < 0) {
 			perror("read");
 			goto out;
@@ -109,7 +109,7 @@
 		}
 
 		for (i = 0; i < now; i++) {
-			if (mem_rw_buf[i] != rw_buf1[i]) {
+			if (source_data[i] != dest_data[i]) {
 				printf("files differ at offset %d\n", offset);
 				goto out;
 			}
@@ -124,7 +124,7 @@
 out:
 	close(sourcefd);
 	close(destfd);
-	free(rw_buf1);
+	free(buf);
 
 	return ret;
 }
diff --git a/commands/memcpy.c b/commands/memcpy.c
index 168ef3b..ddaf767 100644
--- a/commands/memcpy.c
+++ b/commands/memcpy.c
@@ -34,8 +34,6 @@
 #include <linux/stat.h>
 #include <xfuncs.h>
 
-extern char *mem_rw_buf;
-
 static char *devmem = "/dev/mem";
 
 static int do_memcpy(int argc, char *argv[])
@@ -47,6 +45,7 @@
 	int mode = 0;
 	struct stat statbuf;
 	int ret = 0;
+	char *buf;
 
 	if (mem_parse_options(argc, argv, "bwlqs:d:", &mode, &sourcefile,
 			&destfile, NULL) < 0)
@@ -82,12 +81,14 @@
 		return 1;
 	}
 
+	buf = xmalloc(RW_BUF_SIZE);
+
 	while (count > 0) {
 		int now, r, w, tmp;
 
 		now = min((loff_t)RW_BUF_SIZE, count);
 
-		r = read(sourcefd, mem_rw_buf, now);
+		r = read(sourcefd, buf, now);
 		if (r < 0) {
 			perror("read");
 			goto out;
@@ -99,7 +100,7 @@
 		tmp = 0;
 		now = r;
 		while (now) {
-			w = write(destfd, mem_rw_buf + tmp, now);
+			w = write(destfd, buf + tmp, now);
 			if (w < 0) {
 				perror("write");
 				goto out;
@@ -123,6 +124,7 @@
 	}
 
 out:
+	free(buf);
 	close(sourcefd);
 	close(destfd);
 
diff --git a/commands/memset.c b/commands/memset.c
index f99bf86..b077015 100644
--- a/commands/memset.c
+++ b/commands/memset.c
@@ -34,8 +34,6 @@
 #include <linux/stat.h>
 #include <xfuncs.h>
 
-extern char *mem_rw_buf;
-
 static int do_memset(int argc, char *argv[])
 {
 	loff_t	s, c, n;
diff --git a/commands/stddev.c b/commands/stddev.c
index 4d1b6f5..2b3d084 100644
--- a/commands/stddev.c
+++ b/commands/stddev.c
@@ -27,7 +27,6 @@
 
 static struct cdev_operations zeroops = {
 	.read  = zero_read,
-	.lseek = dev_lseek_default,
 };
 
 static int zero_init(void)
@@ -55,7 +54,6 @@
 
 static struct cdev_operations fullops = {
 	.read  = full_read,
-	.lseek = dev_lseek_default,
 };
 
 static int full_init(void)
@@ -82,7 +80,6 @@
 
 static struct cdev_operations nullops = {
 	.write = null_write,
-	.lseek = dev_lseek_default,
 };
 
 static int null_init(void)
@@ -110,7 +107,6 @@
 
 static struct cdev_operations prngops = {
 	.read  = prng_read,
-	.lseek = dev_lseek_default,
 };
 
 static int prng_init(void)
diff --git a/common/block.c b/common/block.c
index 8d0de42..d90c989 100644
--- a/common/block.c
+++ b/common/block.c
@@ -350,7 +350,6 @@
 #endif
 	.close	= block_op_close,
 	.flush	= block_op_flush,
-	.lseek	= dev_lseek_default,
 };
 
 int blockdevice_register(struct block_device *blk)
diff --git a/common/firmware.c b/common/firmware.c
index 250fef5..9d55d73 100644
--- a/common/firmware.c
+++ b/common/firmware.c
@@ -177,7 +177,7 @@
 	cdev = &mgr->cdev;
 
 	cdev->name = xstrdup(fh->id);
-	cdev->size = FILE_SIZE_STREAM;
+	cdev->flags = DEVFS_IS_CHARACTER_DEV;
 	cdev->ops = &firmware_ops;
 	cdev->priv = mgr;
 	cdev->dev = fh->dev;
diff --git a/common/ratp/md.c b/common/ratp/md.c
index ce343d7..a25cbf1 100644
--- a/common/ratp/md.c
+++ b/common/ratp/md.c
@@ -59,8 +59,6 @@
 	uint8_t  buffer[];
 } __packed;
 
-extern char *mem_rw_buf;
-
 static int do_ratp_mem_md(const char *filename,
 			  loff_t start,
 			  loff_t size,
@@ -70,6 +68,7 @@
 	int ret = 0;
 	int fd;
 	void *map;
+	char *buf = NULL;
 
 	fd = open_and_lseek(filename, O_RWSIZE_1 | O_RDONLY, start);
 	if (fd < 0)
@@ -81,10 +80,11 @@
 		goto out;
 	}
 
+	buf = xmalloc(RW_BUF_SIZE);
 	t = 0;
 	do {
 		now = min(size, (loff_t)RW_BUF_SIZE);
-		r = read(fd, mem_rw_buf, now);
+		r = read(fd, buf, now);
 		if (r < 0) {
 			ret = -errno;
 			perror("read");
@@ -93,13 +93,14 @@
 		if (!r)
 			goto out;
 
-		memcpy(output + t, (uint8_t *)(mem_rw_buf), r);
+		memcpy(output + t, buf, r);
 
 		size  -= r;
 		t     += r;
 	} while (size);
 
 out:
+	free(buf);
 	close(fd);
 
 	return ret;
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 8bbc237..d2f8ec7 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -353,7 +353,6 @@
 }
 
 static struct cdev_operations regmap_fops = {
-	.lseek	= dev_lseek_default,
 	.read	= regmap_cdev_read,
 	.write	= regmap_cdev_write,
 };
diff --git a/drivers/eeprom/at24.c b/drivers/eeprom/at24.c
index e79031a..1fd4aea 100644
--- a/drivers/eeprom/at24.c
+++ b/drivers/eeprom/at24.c
@@ -447,7 +447,6 @@
 	at24->cdev.priv = at24;
 	at24->cdev.dev = dev;
 	at24->cdev.ops = &at24->fops;
-	at24->fops.lseek = dev_lseek_default;
 	at24->fops.read	= at24_cdev_read,
 	at24->fops.protect = at24_cdev_protect,
 	at24->cdev.size = chip.byte_len;
diff --git a/drivers/eeprom/at25.c b/drivers/eeprom/at25.c
index a9050d6..1c9ef12 100644
--- a/drivers/eeprom/at25.c
+++ b/drivers/eeprom/at25.c
@@ -235,7 +235,6 @@
 static struct cdev_operations at25_fops = {
 	.read	= at25_ee_read,
 	.write	= at25_ee_write,
-	.lseek	= dev_lseek_default,
 };
 
 static int at25_np_to_chip(struct device_d *dev,
diff --git a/drivers/hw_random/core.c b/drivers/hw_random/core.c
index 1c68a37..ee3d5a5 100644
--- a/drivers/hw_random/core.c
+++ b/drivers/hw_random/core.c
@@ -63,7 +63,6 @@
 
 static struct cdev_operations rng_chrdev_ops = {
 	.read  = rng_dev_read,
-	.lseek = dev_lseek_default,
 };
 
 static int hwrng_register_cdev(struct hwrng *rng)
diff --git a/drivers/mfd/act8846.c b/drivers/mfd/act8846.c
index 53ab70f..b7a64c7 100644
--- a/drivers/mfd/act8846.c
+++ b/drivers/mfd/act8846.c
@@ -117,7 +117,6 @@
 }
 
 static struct cdev_operations act8846_fops = {
-	.lseek	= dev_lseek_default,
 	.read	= act8846_read,
 	.write	= act8846_write,
 };
diff --git a/drivers/mfd/lp3972.c b/drivers/mfd/lp3972.c
index 42b2807..3ae9d1a 100644
--- a/drivers/mfd/lp3972.c
+++ b/drivers/mfd/lp3972.c
@@ -70,7 +70,6 @@
 }
 
 static struct cdev_operations lp_fops = {
-	.lseek	= dev_lseek_default,
 	.read	= lp_read,
 };
 
diff --git a/drivers/mfd/mc34704.c b/drivers/mfd/mc34704.c
index f15f37e..4aa02b7 100644
--- a/drivers/mfd/mc34704.c
+++ b/drivers/mfd/mc34704.c
@@ -100,7 +100,6 @@
 }
 
 static struct cdev_operations mc34704_fops = {
-	.lseek	= dev_lseek_default,
 	.read	= mc34704_read,
 	.write	= mc34704_write,
 };
diff --git a/drivers/mfd/mc9sdz60.c b/drivers/mfd/mc9sdz60.c
index 2cb38d9..408d746 100644
--- a/drivers/mfd/mc9sdz60.c
+++ b/drivers/mfd/mc9sdz60.c
@@ -112,7 +112,6 @@
 }
 
 static struct cdev_operations mc_fops = {
-	.lseek	= dev_lseek_default,
 	.read	= mc_read,
 	.write	= mc_write,
 };
diff --git a/drivers/mfd/stmpe-i2c.c b/drivers/mfd/stmpe-i2c.c
index 084e4b4..f140f1b 100644
--- a/drivers/mfd/stmpe-i2c.c
+++ b/drivers/mfd/stmpe-i2c.c
@@ -101,7 +101,6 @@
 }
 
 static struct cdev_operations stmpe_fops = {
-	.lseek	= dev_lseek_default,
 	.read	= stmpe_read,
 	.write	= stmpe_write,
 };
diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
index fb435f5..c3240b8 100644
--- a/drivers/mfd/twl-core.c
+++ b/drivers/mfd/twl-core.c
@@ -150,7 +150,6 @@
 }
 
 struct cdev_operations twl_fops = {
-	.lseek	= dev_lseek_default,
 	.read	= twl_read,
 	.write	= twl_write,
 };
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 6640a70..4c8a769 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -20,4 +20,7 @@
 	depends on OFDEVICE
 	depends on STATE
 
+config DEV_MEM
+        bool "Generic memory I/O device (/dev/mem)"
+
 endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 487e4b8..d4e616d 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -5,3 +5,4 @@
 obj-$(CONFIG_JTAG)		+= jtag.o
 obj-$(CONFIG_SRAM)		+= sram.o
 obj-$(CONFIG_STATE_DRV)		+= state.o
+obj-$(CONFIG_DEV_MEM)		+= mem.o
diff --git a/drivers/misc/mem.c b/drivers/misc/mem.c
new file mode 100644
index 0000000..6dd7f68
--- /dev/null
+++ b/drivers/misc/mem.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2011 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+
+static struct cdev_operations memops = {
+	.read  = mem_read,
+	.write = mem_write,
+	.memmap = generic_memmap_rw,
+};
+
+static int mem_probe(struct device_d *dev)
+{
+	struct cdev *cdev;
+
+	cdev = xzalloc(sizeof (*cdev));
+	dev->priv = cdev;
+
+	cdev->name = (char*)dev->resource[0].name;
+	if (dev->resource[0].start == 0 && dev->resource[0].end == ~0) {
+		/*
+		 * Special case for /dev/mem. We can't express it's size as it's
+		 * outside of our address range. Set DEVFS_IS_CHARACTER_DEV to
+		 * bypass size checks.
+		 */
+		cdev->size = 0;
+		cdev->flags = DEVFS_IS_CHARACTER_DEV;
+	} else {
+		cdev->size = resource_size(&dev->resource[0]);
+	}
+
+	cdev->ops = &memops;
+	cdev->dev = dev;
+
+	devfs_create(cdev);
+
+	return 0;
+}
+
+static struct driver_d mem_drv = {
+	.name  = "mem",
+	.probe = mem_probe,
+};
+
+static int mem_init(void)
+{
+	struct device_d *dev;
+	struct resource res = {
+		.start = 0,
+		.end = ~0,
+		.flags = IORESOURCE_MEM,
+		.name = "mem",
+	};
+	int ret;
+
+	dev = device_alloc("mem", DEVICE_ID_DYNAMIC);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->resource = xmemdup(&res, sizeof(res));
+	dev->num_resources = 1;
+
+	ret = platform_device_register(dev);
+	if (ret)
+		return ret;
+
+	return platform_driver_register(&mem_drv);
+}
+device_initcall(mem_init);
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
index 27b4c68..053b351 100644
--- a/drivers/misc/sram.c
+++ b/drivers/misc/sram.c
@@ -29,7 +29,6 @@
 	.read  = mem_read,
 	.write = mem_write,
 	.memmap = generic_memmap_rw,
-	.lseek = dev_lseek_default,
 };
 
 static int sram_probe(struct device_d *dev)
diff --git a/drivers/mtd/core.c b/drivers/mtd/core.c
index f44c6cf..881b5f4 100644
--- a/drivers/mtd/core.c
+++ b/drivers/mtd/core.c
@@ -462,7 +462,6 @@
 	.protect = mtd_op_protect,
 #endif
 	.ioctl  = mtd_ioctl,
-	.lseek  = dev_lseek_default,
 };
 
 static int mtd_partition_set(struct param_d *p, void *priv)
diff --git a/drivers/mtd/mtdoob.c b/drivers/mtd/mtdoob.c
index ffaf950..4aef844 100644
--- a/drivers/mtd/mtdoob.c
+++ b/drivers/mtd/mtdoob.c
@@ -66,7 +66,6 @@
 static struct cdev_operations mtd_ops_oob = {
 	.read   = mtd_op_read_oob,
 	.ioctl  = mtd_ioctl,
-	.lseek  = dev_lseek_default,
 };
 
 static int add_mtdoob_device(struct mtd_info *mtd, const char *devname, void **priv)
diff --git a/drivers/mtd/mtdraw.c b/drivers/mtd/mtdraw.c
index 6e36dc5..f63da7b 100644
--- a/drivers/mtd/mtdraw.c
+++ b/drivers/mtd/mtdraw.c
@@ -291,7 +291,6 @@
 	.read		= mtdraw_read,
 	.write		= mtdraw_write,
 	.erase		= mtdraw_erase,
-	.lseek		= dev_lseek_default,
 };
 
 static int add_mtdraw_device(struct mtd_info *mtd, const char *devname, void **priv)
diff --git a/drivers/mtd/nand/nand-bb.c b/drivers/mtd/nand/nand-bb.c
index 012163e..e578d72 100644
--- a/drivers/mtd/nand/nand-bb.c
+++ b/drivers/mtd/nand/nand-bb.c
@@ -236,17 +236,16 @@
 	return 0;
 }
 
-static loff_t nand_bb_lseek(struct cdev *cdev, loff_t __offset)
+static int nand_bb_lseek(struct cdev *cdev, loff_t offset)
 {
 	struct nand_bb *bb = cdev->priv;
 	loff_t raw_pos = 0;
-	uint32_t offset = __offset;
 
 	/* lseek only in readonly mode */
 	if (bb->flags & O_ACCMODE)
 		return -ENOSYS;
 	while (raw_pos < bb->mtd->size) {
-		off_t now = min(offset, bb->mtd->erasesize);
+		off_t now = min_t(loff_t, offset, bb->mtd->erasesize);
 
 		if (mtd_block_isbad(bb->mtd, raw_pos)) {
 			raw_pos += bb->mtd->erasesize;
@@ -257,7 +256,7 @@
 
 		if (!offset) {
 			bb->offset = raw_pos;
-			return __offset;
+			return 0;
 		}
 	}
 
diff --git a/drivers/mtd/ubi/barebox.c b/drivers/mtd/ubi/barebox.c
index 65f5456..781061d 100644
--- a/drivers/mtd/ubi/barebox.c
+++ b/drivers/mtd/ubi/barebox.c
@@ -151,7 +151,7 @@
 	return 0;
 }
 
-static loff_t ubi_volume_cdev_lseek(struct cdev *cdev, loff_t ofs)
+static int ubi_volume_cdev_lseek(struct cdev *cdev, loff_t ofs)
 {
 	struct ubi_volume_cdev_priv *priv = cdev->priv;
 
@@ -159,7 +159,7 @@
 	if (priv->written)
 		return -EINVAL;
 
-	return ofs;
+	return 0;
 }
 
 static int ubi_volume_cdev_truncate(struct cdev *cdev, size_t size)
diff --git a/drivers/net/e1000/eeprom.c b/drivers/net/e1000/eeprom.c
index 36d818b..5b34e9b 100644
--- a/drivers/net/e1000/eeprom.c
+++ b/drivers/net/e1000/eeprom.c
@@ -1326,7 +1326,6 @@
 static struct cdev_operations e1000_invm_ops = {
 	.read	= e1000_invm_cdev_read,
 	.write	= e1000_invm_cdev_write,
-	.lseek	= dev_lseek_default,
 };
 
 static ssize_t e1000_eeprom_cdev_read(struct cdev *cdev, void *buf,
@@ -1351,7 +1350,6 @@
 
 static struct cdev_operations e1000_eeprom_ops = {
 	.read = e1000_eeprom_cdev_read,
-	.lseek = dev_lseek_default,
 };
 
 static int e1000_mtd_read_or_write(bool read,
diff --git a/drivers/net/ksz8864rmn.c b/drivers/net/ksz8864rmn.c
index 4a19dd8..85063ff 100644
--- a/drivers/net/ksz8864rmn.c
+++ b/drivers/net/ksz8864rmn.c
@@ -113,7 +113,6 @@
 static struct cdev_operations micrel_switch_ops = {
 	.read  = micel_switch_read,
 	.write = micel_switch_write,
-	.lseek = dev_lseek_default,
 };
 
 static int micrel_switch_probe(struct device_d *dev)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index e1dd8f0..3480e2f 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -392,7 +392,6 @@
 static struct cdev_operations phydev_ops = {
 	.read  = phydev_read,
 	.write = phydev_write,
-	.lseek = dev_lseek_default,
 };
 
 static void of_set_phy_supported(struct phy_device *phydev)
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 63c0f99..6cf98f6 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -85,7 +85,6 @@
 static struct cdev_operations nvmem_chrdev_ops = {
 	.read  = nvmem_cdev_read,
 	.write  = nvmem_cdev_write,
-	.lseek = dev_lseek_default,
 };
 
 static int nvmem_register_cdev(struct nvmem_device *nvmem, const char *name)
@@ -96,7 +95,6 @@
 	alias = of_alias_get(dev->device_node);
 
 	nvmem->cdev.name = xstrdup(alias ?: name);
-	nvmem->cdev.flags = DEVFS_IS_CHARACTER_DEV;
 	nvmem->cdev.ops = &nvmem_chrdev_ops;
 	nvmem->cdev.dev = &nvmem->dev;
 	nvmem->cdev.size = nvmem->size;
diff --git a/drivers/video/fb.c b/drivers/video/fb.c
index 72f33a6..2d82bc0 100644
--- a/drivers/video/fb.c
+++ b/drivers/video/fb.c
@@ -228,7 +228,6 @@
 	.read	= mem_read,
 	.write	= mem_write,
 	.memmap	= generic_memmap_rw,
-	.lseek	= dev_lseek_default,
 	.ioctl	= fb_ioctl,
 	.close  = fb_close,
 	.flush  = fb_op_flush,
diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c
index 13691d7..6446f4b 100644
--- a/drivers/w1/slaves/w1_ds2431.c
+++ b/drivers/w1/slaves/w1_ds2431.c
@@ -260,7 +260,6 @@
 static struct cdev_operations ds2431_ops = {
 	.read	= ds2431_cdev_read,
 	.write	= ds2431_cdev_write,
-	.lseek	= dev_lseek_default,
 };
 
 static int ds2431_probe(struct w1_device *dev)
diff --git a/drivers/w1/slaves/w1_ds2433.c b/drivers/w1/slaves/w1_ds2433.c
index f521a46..b24fb5b 100644
--- a/drivers/w1/slaves/w1_ds2433.c
+++ b/drivers/w1/slaves/w1_ds2433.c
@@ -159,7 +159,6 @@
 static struct cdev_operations ds2433_ops = {
 	.read	= ds2433_cdev_read,
 	.write	= ds2433_cdev_write,
-	.lseek	= dev_lseek_default,
 };
 
 static int ds2433_cdev_create(struct w1_device *dev, int size, int id)
diff --git a/fs/bpkfs.c b/fs/bpkfs.c
index f1db963..655cde0 100644
--- a/fs/bpkfs.c
+++ b/fs/bpkfs.c
@@ -192,7 +192,7 @@
 	}
 }
 
-static loff_t bpkfs_lseek(struct device_d *dev, FILE *file, loff_t pos)
+static int bpkfs_lseek(struct device_d *dev, FILE *file, loff_t pos)
 {
 	struct bpkfs_handle_data *d = file->priv;
 
@@ -201,7 +201,7 @@
 
 	d->pos = pos;
 
-	return pos;
+	return 0;
 }
 
 struct somfy_readdir {
diff --git a/fs/cramfs/cramfs.c b/fs/cramfs/cramfs.c
index a3ce354..3cc0fa7 100644
--- a/fs/cramfs/cramfs.c
+++ b/fs/cramfs/cramfs.c
@@ -166,12 +166,6 @@
 	return cramfs_read_file(f->f_inode, f->pos, buf, size);
 }
 
-static loff_t cramfs_lseek(struct device_d *dev, FILE *f, loff_t pos)
-{
-	f->pos = pos;
-	return f->pos;
-}
-
 #if 0
 static int cramfs_info (struct device_d *dev)
 {
@@ -491,7 +485,6 @@
 
 static struct fs_driver_d cramfs_driver = {
 	.read		= cramfs_read,
-	.lseek		= cramfs_lseek,
 	.drv = {
 		.probe = cramfs_probe,
 		.remove = cramfs_remove,
diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index f017e1c..2b93a95 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -459,7 +459,6 @@
 	.read = loop_read,
 	.write = loop_write,
 	.memmap = generic_memmap_rw,
-	.lseek = dev_lseek_default,
 };
 
 struct cdev *cdev_create_loop(const char *path, ulong flags, loff_t offset)
@@ -512,19 +511,29 @@
 	free(cdev);
 }
 
-static void memcpy_sz(void *dst, const void *src, size_t count, int rwsize)
+static ssize_t mem_copy(struct device_d *dev, void *dst, const void *src,
+			resource_size_t count, resource_size_t offset,
+			unsigned long flags)
 {
+	ssize_t size;
+	int rwsize = flags & O_RWSIZE_MASK;
+
+	if (!dev || dev->num_resources < 1)
+		return -1;
+
+	count = size = min(count, resource_size(&dev->resource[0]) - offset);
+
 	/* no rwsize specification given. Do whatever memcpy likes best */
 	if (!rwsize) {
 		memcpy(dst, src, count);
-		return;
+		goto out;
 	}
 
 	rwsize = rwsize >> O_RWSIZE_SHIFT;
 
-	count /= rwsize;
+	count = ALIGN_DOWN(count, rwsize);
 
-	while (count-- > 0) {
+	while (count) {
 		switch (rwsize) {
 		case 1:
 			*((u8 *)dst) = *((u8 *)src);
@@ -541,41 +550,34 @@
 		}
 		dst += rwsize;
 		src += rwsize;
+		count -= rwsize;
 	}
+out:
+	return size;
 }
 
 ssize_t mem_read(struct cdev *cdev, void *buf, size_t count, loff_t offset,
 		 unsigned long flags)
 {
-	unsigned long size;
-	struct device_d *dev;
+	struct device_d *dev = cdev->dev;
 
-	if (!cdev->dev || cdev->dev->num_resources < 1)
+	if (!dev)
 		return -1;
-	dev = cdev->dev;
 
-	size = min((resource_size_t)count,
-			resource_size(&dev->resource[0]) -
-			(resource_size_t)offset);
-	memcpy_sz(buf, dev_get_mem_region(dev, 0) + offset, size, flags & O_RWSIZE_MASK);
-	return size;
+	return mem_copy(dev, buf, dev_get_mem_region(dev, 0) + offset,
+			count, offset, flags);
 }
 EXPORT_SYMBOL(mem_read);
 
-ssize_t mem_write(struct cdev *cdev, const void *buf, size_t count, loff_t offset,
-		  unsigned long flags)
+ssize_t mem_write(struct cdev *cdev, const void *buf, size_t count,
+		  loff_t offset, unsigned long flags)
 {
-	unsigned long size;
-	struct device_d *dev;
+	struct device_d *dev = cdev->dev;
 
-	if (!cdev->dev || cdev->dev->num_resources < 1)
+	if (!dev)
 		return -1;
-	dev = cdev->dev;
 
-	size = min((resource_size_t)count,
-			resource_size(&dev->resource[0]) -
-			(resource_size_t)offset);
-	memcpy_sz(dev_get_mem_region(dev, 0) + offset, buf, size, flags & O_RWSIZE_MASK);
-	return size;
+	return mem_copy(dev, dev_get_mem_region(dev, 0) + offset, buf,
+			count, offset, flags);
 }
 EXPORT_SYMBOL(mem_write);
diff --git a/fs/devfs.c b/fs/devfs.c
index 81ae2c2..a7400df 100644
--- a/fs/devfs.c
+++ b/fs/devfs.c
@@ -57,18 +57,18 @@
 	return cdev_write(cdev, buf, size, f->pos, f->flags);
 }
 
-static loff_t devfs_lseek(struct device_d *_dev, FILE *f, loff_t pos)
+static int devfs_lseek(struct device_d *_dev, FILE *f, loff_t pos)
 {
 	struct cdev *cdev = f->priv;
-	loff_t ret = -1;
+	int ret;
 
-	if (cdev->ops->lseek)
+	if (cdev->ops->lseek) {
 		ret = cdev->ops->lseek(cdev, pos + cdev->offset);
+		if (ret < 0)
+			return ret;
+	}
 
-	if (ret != -1)
-		f->pos = pos;
-
-	return ret - cdev->offset;
+	return 0;
 }
 
 static int devfs_erase(struct device_d *_dev, FILE *f, loff_t count, loff_t offset)
@@ -168,18 +168,14 @@
 	return cdev_ioctl(cdev, request, buf);
 }
 
-static int devfs_truncate(struct device_d *dev, FILE *f, ulong size)
+static int devfs_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	struct cdev *cdev = f->priv;
 
 	if (cdev->ops->truncate)
 		return cdev->ops->truncate(cdev, size);
 
-	if (f->fsdev->dev.num_resources < 1)
-		return -ENOSPC;
-	if (size > resource_size(&f->fsdev->dev.resource[0]))
-		return -ENOSPC;
-	return 0;
+	return -EPERM;
 }
 
 static struct inode *devfs_alloc_inode(struct super_block *sb)
diff --git a/fs/efi.c b/fs/efi.c
index 692556b..81c1ffe 100644
--- a/fs/efi.c
+++ b/fs/efi.c
@@ -292,22 +292,20 @@
 	return bufsize;
 }
 
-static loff_t efifs_lseek(struct device_d *dev, FILE *f, loff_t pos)
+static int efifs_lseek(struct device_d *dev, FILE *f, loff_t pos)
 {
 	struct efifs_file *ufile = f->priv;
 	efi_status_t efiret;
 
-	f->pos = pos;
-
 	efiret = ufile->entry->set_position(ufile->entry, pos);
 	if (EFI_ERROR(efiret)) {
 		return -efi_errno(efiret);
 	}
 
-	return f->pos;
+	return 0;
 }
 
-static int efifs_truncate(struct device_d *dev, FILE *f, unsigned long size)
+static int efifs_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	struct efifs_file *ufile = f->priv;
 	efi_status_t efiret;
diff --git a/fs/efivarfs.c b/fs/efivarfs.c
index bf7351e..a911eac 100644
--- a/fs/efivarfs.c
+++ b/fs/efivarfs.c
@@ -288,7 +288,7 @@
 	return insize;
 }
 
-static int efivarfs_truncate(struct device_d *dev, FILE *f, ulong size)
+static int efivarfs_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	struct efivars_file *efile = f->priv;
 	efi_status_t efiret;
@@ -307,13 +307,6 @@
 	return 0;
 }
 
-static loff_t efivarfs_lseek(struct device_d *dev, FILE *f, loff_t pos)
-{
-	f->pos = pos;
-
-	return f->pos;
-}
-
 static DIR *efivarfs_opendir(struct device_d *dev, const char *pathname)
 {
 	struct efivarfs_priv *priv = dev->priv;
@@ -437,7 +430,6 @@
 	.read      = efivarfs_read,
 	.write     = efivarfs_write,
 	.truncate  = efivarfs_truncate,
-	.lseek     = efivarfs_lseek,
 	.opendir   = efivarfs_opendir,
 	.readdir   = efivarfs_readdir,
 	.closedir  = efivarfs_closedir,
diff --git a/fs/ext4/ext_barebox.c b/fs/ext4/ext_barebox.c
index 1e7da2a..82d4c58 100644
--- a/fs/ext4/ext_barebox.c
+++ b/fs/ext4/ext_barebox.c
@@ -59,13 +59,6 @@
 	return ext4fs_read_file(node, f->pos, insize, buf);
 }
 
-static loff_t ext_lseek(struct device_d *dev, FILE *f, loff_t pos)
-{
-	f->pos = pos;
-
-	return f->pos;
-}
-
 static struct inode *ext_alloc_inode(struct super_block *sb)
 {
 	struct fs_device_d *fsdev = container_of(sb, struct fs_device_d, sb);
@@ -304,7 +297,6 @@
 
 static struct fs_driver_d ext_driver = {
 	.read      = ext_read,
-	.lseek     = ext_lseek,
 	.type      = filetype_ext,
 	.flags     = 0,
 	.drv = {
diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 49cd78f..394c75f 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -177,7 +177,7 @@
 	return outsize;
 }
 
-static int fat_truncate(struct device_d *dev, FILE *f, ulong size)
+static int fat_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	FIL *f_file = f->priv;
 	unsigned long lastofs;
@@ -268,7 +268,7 @@
 	return outsize;
 }
 
-static loff_t fat_lseek(struct device_d *dev, FILE *f, loff_t pos)
+static int fat_lseek(struct device_d *dev, FILE *f, loff_t pos)
 {
 	FIL *f_file = f->priv;
 	int ret;
@@ -277,8 +277,7 @@
 	if (ret)
 		return ret;
 
-	f->pos = pos;
-	return pos;
+	return 0;
 }
 
 static DIR* fat_opendir(struct device_d *dev, const char *pathname)
diff --git a/fs/fs.c b/fs/fs.c
index a304bf1..1f6b3d3 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -213,11 +213,16 @@
 
 	f = &files[fd];
 
+	if (f->size == FILE_SIZE_STREAM)
+		return 0;
+
 	fsdrv = f->fsdev->driver;
 
 	ret = fsdrv->truncate(&f->fsdev->dev, f, length);
-	if (ret)
+	if (ret) {
+		errno = -ret;
 		return ret;
+	}
 
 	f->size = length;
 
@@ -413,41 +418,36 @@
 
 	f = &files[fildes];
 	fsdrv = f->fsdev->driver;
-	if (!fsdrv->lseek) {
-		ret = -ENOSYS;
-		goto out;
-	}
 
 	ret = -EINVAL;
 
 	switch (whence) {
 	case SEEK_SET:
-		if (f->size != FILE_SIZE_STREAM && offset > f->size)
-			goto out;
-		if (IS_ERR_VALUE(offset))
-			goto out;
-		pos = offset;
+		pos = 0;
 		break;
 	case SEEK_CUR:
-		if (f->size != FILE_SIZE_STREAM && offset + f->pos > f->size)
-			goto out;
-		pos = f->pos + offset;
+		pos = f->pos;
 		break;
 	case SEEK_END:
-		if (offset > 0)
-			goto out;
-		pos = f->size + offset;
+		pos = f->size;
 		break;
 	default:
 		goto out;
 	}
 
-	pos = fsdrv->lseek(&f->fsdev->dev, f, pos);
-	if (IS_ERR_VALUE(pos)) {
-		errno = -pos;
-		return -1;
+	pos += offset;
+
+	if (f->size != FILE_SIZE_STREAM && (pos < 0 || pos > f->size))
+		goto out;
+
+	if (fsdrv->lseek) {
+		ret = fsdrv->lseek(&f->fsdev->dev, f, pos);
+		if (ret < 0)
+			goto out;
 	}
 
+	f->pos = pos;
+
 	return pos;
 
 out:
diff --git a/fs/nfs.c b/fs/nfs.c
index d7f1566..43476d1 100644
--- a/fs/nfs.c
+++ b/fs/nfs.c
@@ -928,7 +928,7 @@
 	nfs_len = len;
 }
 
-static int nfs_truncate(struct device_d *dev, FILE *f, ulong size)
+static int nfs_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	return -ENOSYS;
 }
@@ -1060,14 +1060,13 @@
 	return kfifo_get(priv->fifo, buf, insize);
 }
 
-static loff_t nfs_lseek(struct device_d *dev, FILE *file, loff_t pos)
+static int nfs_lseek(struct device_d *dev, FILE *file, loff_t pos)
 {
 	struct file_priv *priv = file->priv;
 
-	file->pos = pos;
 	kfifo_reset(priv->fifo);
 
-	return file->pos;
+	return 0;
 }
 
 static int nfs_iterate(struct file *file, struct dir_context *ctx)
diff --git a/fs/omap4_usbbootfs.c b/fs/omap4_usbbootfs.c
index b35f411..169cde7 100644
--- a/fs/omap4_usbbootfs.c
+++ b/fs/omap4_usbbootfs.c
@@ -57,7 +57,7 @@
 	return -ENOSYS;
 }
 
-static int omap4_usbbootfs_truncate(struct device_d *dev, FILE *f, ulong size)
+static int omap4_usbbootfs_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	return -ENOSYS;
 }
@@ -149,12 +149,6 @@
 	return size;
 }
 
-static loff_t omap4_usbbootfs_lseek(struct device_d *dev, FILE *f, loff_t pos)
-{
-	f->pos = pos;
-	return pos;
-}
-
 static DIR *omap4_usbbootfs_opendir(struct device_d *dev, const char *pathname)
 {
 	return NULL;
@@ -191,7 +185,6 @@
 	.open    = omap4_usbbootfs_open,
 	.close   = omap4_usbbootfs_close,
 	.read    = omap4_usbbootfs_read,
-	.lseek   = omap4_usbbootfs_lseek,
 	.opendir = omap4_usbbootfs_opendir,
 	.stat    = omap4_usbbootfs_stat,
 /*
diff --git a/fs/pstore/fs.c b/fs/pstore/fs.c
index a879a68..9a7e0b5 100644
--- a/fs/pstore/fs.c
+++ b/fs/pstore/fs.c
@@ -172,13 +172,13 @@
 	return insize;
 }
 
-static loff_t pstore_lseek(struct device_d *dev, FILE *file, loff_t pos)
+static int pstore_lseek(struct device_d *dev, FILE *file, loff_t pos)
 {
 	struct pstore_private *d = file->priv;
 
 	d->pos = pos;
 
-	return pos;
+	return 0;
 }
 
 static DIR *pstore_opendir(struct device_d *dev, const char *pathname)
diff --git a/fs/ramfs.c b/fs/ramfs.c
index 84ecfa0..4fba40d 100644
--- a/fs/ramfs.c
+++ b/fs/ramfs.c
@@ -347,13 +347,7 @@
 	return insize;
 }
 
-static loff_t ramfs_lseek(struct device_d *dev, FILE *f, loff_t pos)
-{
-	f->pos = pos;
-	return f->pos;
-}
-
-static int ramfs_truncate(struct device_d *dev, FILE *f, ulong size)
+static int ramfs_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	struct inode *inode = f->f_inode;
 	struct ramfs_inode *node = to_ramfs_inode(inode);
@@ -448,7 +442,6 @@
 static struct fs_driver_d ramfs_driver = {
 	.read      = ramfs_read,
 	.write     = ramfs_write,
-	.lseek     = ramfs_lseek,
 	.truncate  = ramfs_truncate,
 	.flags     = FS_DRIVER_NO_DEV,
 	.drv = {
diff --git a/fs/ratpfs.c b/fs/ratpfs.c
index 902289b..b6857c6 100644
--- a/fs/ratpfs.c
+++ b/fs/ratpfs.c
@@ -77,7 +77,7 @@
 }
 
 static int ratpfs_truncate(struct device_d __always_unused *dev,
-			  FILE *f, ulong size)
+			  FILE *f, loff_t size)
 {
 	int len_tx = 1 /* type */
 		+ 4 /* handle */
@@ -284,14 +284,6 @@
 	return ret;
 }
 
-static loff_t ratpfs_lseek(struct device_d __always_unused *dev,
-			  FILE *f, loff_t pos)
-{
-	pr_debug("%s\n", __func__);
-	f->pos = pos;
-	return f->pos;
-}
-
 static DIR* ratpfs_opendir(struct device_d __always_unused *dev,
 			  const char *pathname)
 {
@@ -450,7 +442,6 @@
 	.open      = ratpfs_open,
 	.close     = ratpfs_close,
 	.read      = ratpfs_read,
-	.lseek     = ratpfs_lseek,
 	.opendir   = ratpfs_opendir,
 	.readdir   = ratpfs_readdir,
 	.closedir  = ratpfs_closedir,
diff --git a/fs/smhfs.c b/fs/smhfs.c
index f1b6d6b..2e99b05 100644
--- a/fs/smhfs.c
+++ b/fs/smhfs.c
@@ -56,7 +56,7 @@
 
 static int smhfs_truncate(struct device_d __always_unused *dev,
 			  FILE __always_unused *f,
-			  ulong __always_unused size)
+			  loff_t __always_unused size)
 {
 	return 0;
 }
@@ -109,15 +109,13 @@
 		return -semihosting_errno();
 }
 
-static loff_t smhfs_lseek(struct device_d __always_unused *dev,
+static int smhfs_lseek(struct device_d __always_unused *dev,
 			  FILE *f, loff_t pos)
 {
-	if (semihosting_seek(file_to_fd(f), pos)) {
+	if (semihosting_seek(file_to_fd(f), pos))
 		return -semihosting_errno();
-	} else {
-		f->pos = pos;
-		return f->pos;
-	}
+
+	return 0;
 }
 
 static DIR* smhfs_opendir(struct device_d __always_unused *dev,
diff --git a/fs/squashfs/squashfs.c b/fs/squashfs/squashfs.c
index d9049b7..38aff6d 100644
--- a/fs/squashfs/squashfs.c
+++ b/fs/squashfs/squashfs.c
@@ -231,13 +231,6 @@
 	return insize;
 }
 
-static loff_t squashfs_lseek(struct device_d *dev, FILE *f, loff_t pos)
-{
-	f->pos = pos;
-
-	return pos;
-}
-
 struct squashfs_dir {
 	struct file file;
 	struct dentry dentry;
@@ -253,7 +246,6 @@
 	.open		= squashfs_open,
 	.close		= squashfs_close,
 	.read		= squashfs_read,
-	.lseek		= squashfs_lseek,
 	.type		= filetype_squashfs,
 	.drv = {
 		.probe = squashfs_probe,
diff --git a/fs/tftp.c b/fs/tftp.c
index 1b50ba8..4329327 100644
--- a/fs/tftp.c
+++ b/fs/tftp.c
@@ -93,7 +93,7 @@
 	IPaddr_t server;
 };
 
-static int tftp_truncate(struct device_d *dev, FILE *f, ulong size)
+static int tftp_truncate(struct device_d *dev, FILE *f, loff_t size)
 {
 	return 0;
 }
@@ -573,15 +573,17 @@
 	return outsize;
 }
 
-static loff_t tftp_lseek(struct device_d *dev, FILE *f, loff_t pos)
+static int tftp_lseek(struct device_d *dev, FILE *f, loff_t pos)
 {
 	/* We cannot seek backwards without reloading or caching the file */
-	if (pos >= f->pos) {
-		loff_t ret;
+	loff_t f_pos = f->pos;
+
+	if (pos >= f_pos) {
+		int ret = 0;
 		char *buf = xmalloc(1024);
 
-		while (pos > f->pos) {
-			size_t len = min_t(size_t, 1024, pos - f->pos);
+		while (pos > f_pos) {
+			size_t len = min_t(size_t, 1024, pos - f_pos);
 
 			ret = tftp_read(dev, f, buf, len);
 
@@ -591,14 +593,21 @@
 			if (ret < 0)
 				goto out_free;
 
-			f->pos += ret;
+			f_pos += ret;
 		}
 
-		ret = pos;
-
 out_free:
 		free(buf);
-		return ret;
+		if (ret < 0) {
+			/*
+			 * Update f->pos even if the overall request
+			 * failed since we can't move backwards
+			 */
+			f->pos = f_pos;
+			return ret;
+		}
+
+		return 0;
 	}
 
 	return -ENOSYS;
diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
index 7545dd4..494b1f2 100644
--- a/fs/ubifs/ubifs.c
+++ b/fs/ubifs/ubifs.c
@@ -394,13 +394,6 @@
 	return insize;
 }
 
-static loff_t ubifs_lseek(struct device_d *dev, FILE *f, loff_t pos)
-{
-	f->pos = pos;
-
-	return pos;
-}
-
 static void ubifs_set_rootarg(struct ubifs_priv *priv, struct fs_device_d *fsdev)
 {
 	struct ubi_volume_info vi = {};
@@ -477,7 +470,6 @@
 	.open      = ubifs_open,
 	.close     = ubifs_close,
 	.read      = ubifs_read,
-	.lseek     = ubifs_lseek,
 	.type = filetype_ubifs,
 	.flags     = 0,
 	.drv = {
diff --git a/fs/uimagefs.c b/fs/uimagefs.c
index c120944..e5ada82 100644
--- a/fs/uimagefs.c
+++ b/fs/uimagefs.c
@@ -116,7 +116,7 @@
 	}
 }
 
-static loff_t uimagefs_lseek(struct device_d *dev, FILE *file, loff_t pos)
+static int uimagefs_lseek(struct device_d *dev, FILE *file, loff_t pos)
 {
 	struct uimagefs_handle_data *d = file->priv;
 
@@ -125,7 +125,7 @@
 
 	d->pos = pos;
 
-	return pos;
+	return 0;
 }
 
 static DIR *uimagefs_opendir(struct device_d *dev, const char *pathname)
diff --git a/include/driver.h b/include/driver.h
index 7da184d..a8e046e 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -360,11 +360,6 @@
 int generic_memmap_ro(struct cdev *dev, void **map, int flags);
 int generic_memmap_rw(struct cdev *dev, void **map, int flags);
 
-static inline loff_t dev_lseek_default(struct cdev *cdev, loff_t ofs)
-{
-	return ofs;
-}
-
 static inline int dev_open_default(struct device_d *dev, struct filep *f)
 {
 	return 0;
@@ -439,7 +434,7 @@
 	ssize_t (*write)(struct cdev*, const void* buf, size_t count, loff_t offset, ulong flags);
 
 	int (*ioctl)(struct cdev*, int, void *);
-	loff_t (*lseek)(struct cdev*, loff_t);
+	int (*lseek)(struct cdev*, loff_t);
 	int (*open)(struct cdev*, unsigned long flags);
 	int (*close)(struct cdev*);
 	int (*flush)(struct cdev*);
diff --git a/include/fs.h b/include/fs.h
index f1514af..38debfc 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -46,14 +46,14 @@
 	int (*unlink)(struct device_d *dev, const char *pathname);
 
 	/* Truncate a file to given size */
-	int (*truncate)(struct device_d *dev, FILE *f, ulong size);
+	int (*truncate)(struct device_d *dev, FILE *f, loff_t size);
 
 	int (*open)(struct device_d *dev, FILE *f, const char *pathname);
 	int (*close)(struct device_d *dev, FILE *f);
 	int (*read)(struct device_d *dev, FILE *f, void *buf, size_t size);
 	int (*write)(struct device_d *dev, FILE *f, const void *buf, size_t size);
 	int (*flush)(struct device_d *dev, FILE *f);
-	loff_t (*lseek)(struct device_d *dev, FILE *f, loff_t pos);
+	int (*lseek)(struct device_d *dev, FILE *f, loff_t pos);
 
 	int (*ioctl)(struct device_d *dev, FILE *f, int request, void *buf);
 	int (*erase)(struct device_d *dev, FILE *f, loff_t count,
diff --git a/lib/libfile.c b/lib/libfile.c
index 8f2aed2..9a223d2 100644
--- a/lib/libfile.c
+++ b/lib/libfile.c
@@ -556,8 +556,7 @@
 		}
 	}
 
-	ret = lseek(fd, pos, SEEK_SET);
-	if (ret == -1) {
+	if (lseek(fd, pos, SEEK_SET) != pos) {
 		perror("lseek");
 		close(fd);
 		return -errno;
diff --git a/lib/misc.c b/lib/misc.c
index 1d20e1b..cd420a5 100644
--- a/lib/misc.c
+++ b/lib/misc.c
@@ -23,6 +23,7 @@
 #include <fs.h>
 #include <string.h>
 #include <linux/ctype.h>
+#include <getopt.h>
 
 /*
  * Like simple_strtoull() but handles an optional G, M, K or k
@@ -129,3 +130,44 @@
 	return 0;
 }
 EXPORT_SYMBOL(parse_area_spec);
+
+/*
+ * Common function for parsing options for the 'md', 'mw', 'memcpy', 'memcmp'
+ * commands.
+ */
+int mem_parse_options(int argc, char *argv[], char *optstr, int *mode,
+		      char **sourcefile, char **destfile, int *swab)
+{
+	int opt;
+
+	while((opt = getopt(argc, argv, optstr)) > 0) {
+		switch(opt) {
+		case 'b':
+			*mode = O_RWSIZE_1;
+			break;
+		case 'w':
+			*mode = O_RWSIZE_2;
+			break;
+		case 'l':
+			*mode = O_RWSIZE_4;
+			break;
+		case 'q':
+			*mode = O_RWSIZE_8;
+			break;
+		case 's':
+			*sourcefile = optarg;
+			break;
+		case 'd':
+			*destfile = optarg;
+			break;
+		case 'x':
+			*swab = 1;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+