[PATCH] UCLinux generic memory mapped MTD driver

drivers/mtd/maps/Kconfig

@@ -346,5 +346,11 @@ config MTD_PCMCIA
 	  cards are usually around 4-16MiB in size. This does not include
 	  Compact Flash cards which are treated as IDE devices.
 
+config MTD_UCLINUX
+	tristate "Generic uClinux RAM/ROM filesystem support"
+	depends on MTD_PARTITIONS
+	help
+	  Map driver to support image based filesystems for uClinux.
+
 endmenu
 

drivers/mtd/maps/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_MTD_VMAX)		+= vmax301.o
 obj-$(CONFIG_MTD_SCx200_DOCFLASH)+= scx200_docflash.o
 obj-$(CONFIG_MTD_DBOX2)		+= dbox2-flash.o
 obj-$(CONFIG_MTD_OCELOT)	+= ocelot.o
+obj-$(CONFIG_MTD_UCLINUX)	+= uclinux.o
 obj-$(CONFIG_MTD_SOLUTIONENGINE)+= solutionengine.o
 obj-$(CONFIG_MTD_PCI)		+= pci.o
 obj-$(CONFIG_MTD_AUTCPU12)	+= autcpu12-nvram.o

drivers/mtd/maps/uclinux.c

+/****************************************************************************/
+
+/*
+ *	uclinux.c -- generic memory mapped MTD driver for uclinux
+ *
+ *	(C) Copyright 2002, Greg Ungerer (gerg@snapgear.com)
+ */
+
+/****************************************************************************/
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/major.h>
+#include <linux/root_dev.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/partitions.h>
+#include <asm/io.h>
+
+/****************************************************************************/
+
+__u8 uclinux_read8(struct map_info *map, unsigned long ofs)
+{
+	return(*((__u8 *) (map->map_priv_1 + ofs)));
+}
+
+__u16 uclinux_read16(struct map_info *map, unsigned long ofs)
+{
+	return(*((__u16 *) (map->map_priv_1 + ofs)));
+}
+
+__u32 uclinux_read32(struct map_info *map, unsigned long ofs)
+{
+	return(*((__u32 *) (map->map_priv_1 + ofs)));
+}
+
+void uclinux_copy_from(struct map_info *map, void *to, unsigned long from, ssize_t len)
+{
+	memcpy(to, (void *)(map->map_priv_1 + from), len);
+}
+
+void uclinux_write8(struct map_info *map, __u8 d, unsigned long adr)
+{
+	*((__u8 *) (map->map_priv_1 + adr)) = d;
+}
+
+void uclinux_write16(struct map_info *map, __u16 d, unsigned long adr)
+{
+	*((__u16 *) (map->map_priv_1 + adr)) = d;
+}
+
+void uclinux_write32(struct map_info *map, __u32 d, unsigned long adr)
+{
+	*((__u32 *) (map->map_priv_1 + adr)) = d;
+}
+
+void uclinux_copy_to(struct map_info *map, unsigned long to, const void *from, ssize_t len)
+{
+	memcpy((void *) (map->map_priv_1 + to), from, len);
+}
+
+/****************************************************************************/
+
+struct map_info uclinux_ram_map = {
+	name:		"RAM",
+	read8:		uclinux_read8,
+	read16:		uclinux_read16,
+	read32:		uclinux_read32,
+	copy_from:	uclinux_copy_from,
+	write8:		uclinux_write8,
+	write16:	uclinux_write16,
+	write32:	uclinux_write32,
+	copy_to:	uclinux_copy_to,
+};
+
+struct mtd_info *uclinux_ram_mtdinfo;
+
+/****************************************************************************/
+
+struct mtd_partition uclinux_romfs[] = {
+	{ name: "ROMfs", offset: 0 }
+};
+
+#define	NUM_PARTITIONS	(sizeof(uclinux_romfs) / sizeof(uclinux_romfs[0]))
+
+/****************************************************************************/
+
+int uclinux_point(struct mtd_info *mtd, loff_t from, size_t len,
+	size_t *retlen, u_char **mtdbuf)
+{
+	struct map_info *map = (struct map_info *) mtd->priv;
+	*mtdbuf = (u_char *) (map->map_priv_1 + ((int) from));
+	*retlen = len;
+	return(0);
+}
+
+/****************************************************************************/
+
+int __init uclinux_mtd_init(void)
+{
+	struct mtd_info *mtd;
+	struct map_info *mapp;
+	extern char _ebss;
+
+	mapp = &uclinux_ram_map;
+	mapp->map_priv_2 = (unsigned long) &_ebss;
+	mapp->size = PAGE_ALIGN(*((unsigned long *)((&_ebss) + 8)));
+	mapp->buswidth = 4;
+
+	printk("uclinux[mtd]: RAM probe address=0x%x size=0x%x\n",
+	       	(int) mapp->map_priv_2, (int) mapp->size);
+
+	mapp->map_priv_1 = (unsigned long)
+		ioremap_nocache(mapp->map_priv_2, mapp->size);
+
+	if (mapp->map_priv_1 == 0) {
+		printk("uclinux[mtd]: ioremap_nocache() failed\n");
+		return(-EIO);
+	}
+
+	mtd = do_map_probe("map_ram", mapp);
+	if (!mtd) {
+		printk("uclinux[mtd]: failed to find a mapping?\n");
+		iounmap((void *) mapp->map_priv_1);
+		return(-ENXIO);
+	}
+		
+	mtd->module = THIS_MODULE;
+	mtd->point = uclinux_point;
+	mtd->priv = mapp;
+
+	uclinux_ram_mtdinfo = mtd;
+	add_mtd_partitions(mtd, uclinux_romfs, NUM_PARTITIONS);
+
+	printk("uclinux[mtd]: set %s to be root filesystem\n",
+		uclinux_romfs[0].name);
+	ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, 0);
+	put_mtd_device(mtd);
+
+	return(0);
+}
+
+/****************************************************************************/
+
+void __exit uclinux_mtd_cleanup(void)
+{
+	if (uclinux_ram_mtdinfo) {
+		del_mtd_partitions(uclinux_ram_mtdinfo);
+		map_destroy(uclinux_ram_mtdinfo);
+		uclinux_ram_mtdinfo = NULL;
+	}
+	if (uclinux_ram_map.map_priv_1) {
+		iounmap((void *) uclinux_ram_map.map_priv_1);
+		uclinux_ram_map.map_priv_1 = 0;
+	}
+}
+
+/****************************************************************************/
+
+module_init(uclinux_mtd_init);
+module_exit(uclinux_mtd_cleanup);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>");
+MODULE_DESCRIPTION("Generic RAM based MTD for uClinux");
+
+/****************************************************************************/