1 files changed, 143 insertions, 0 deletions

diff --git a/drivers/mtd/chips/map_ram.c b/drivers/mtd/chips/map_ram.c
new file mode 100644
index 000000000000..bd2e876a814b
--- /dev/null
+++ b/drivers/mtd/chips/map_ram.c
@@ -0,0 +1,143 @@
+/*
+ * Common code to handle map devices which are simple RAM
+ * (C) 2000 Red Hat. GPL'd.
+ * $Id: map_ram.c,v 1.22 2005/01/05 18:05:12 dwmw2 Exp $
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <asm/io.h>
+#include <asm/byteorder.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/compatmac.h>
+
+
+static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
+static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
+static int mapram_erase (struct mtd_info *, struct erase_info *);
+static void mapram_nop (struct mtd_info *);
+static struct mtd_info *map_ram_probe(struct map_info *map);
+
+
+static struct mtd_chip_driver mapram_chipdrv = {
+        .probe  = map_ram_probe,
+        .name   = "map_ram",
+        .module = THIS_MODULE
+};
+
+static struct mtd_info *map_ram_probe(struct map_info *map)
+{
+        struct mtd_info *mtd;
+
+        /* Check the first byte is RAM */
+#if 0
+        map_write8(map, 0x55, 0);
+        if (map_read8(map, 0) != 0x55)
+                return NULL;
+
+        map_write8(map, 0xAA, 0);
+        if (map_read8(map, 0) != 0xAA)
+                return NULL;
+
+        /* Check the last byte is RAM */
+        map_write8(map, 0x55, map->size-1);
+        if (map_read8(map, map->size-1) != 0x55)
+                return NULL;
+
+        map_write8(map, 0xAA, map->size-1);
+        if (map_read8(map, map->size-1) != 0xAA)
+                return NULL;
+#endif
+        /* OK. It seems to be RAM. */
+
+        mtd = kmalloc(sizeof(*mtd), GFP_KERNEL);
+        if (!mtd)
+                return NULL;
+
+        memset(mtd, 0, sizeof(*mtd));
+
+        map->fldrv = &mapram_chipdrv;
+        mtd->priv = map;
+        mtd->name = map->name;
+        mtd->type = MTD_RAM;
+        mtd->size = map->size;
+        mtd->erase = mapram_erase;
+        mtd->read = mapram_read;
+        mtd->write = mapram_write;
+        mtd->sync = mapram_nop;
+        mtd->flags = MTD_CAP_RAM | MTD_VOLATILE;
+
+        mtd->erasesize = PAGE_SIZE;
+        while(mtd->size & (mtd->erasesize - 1))
+                mtd->erasesize >>= 1;
+
+        __module_get(THIS_MODULE);
+        return mtd;
+}
+
+
+static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
+{
+        struct map_info *map = mtd->priv;
+
+        map_copy_from(map, buf, from, len);
+        *retlen = len;
+        return 0;
+}
+
+static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
+{
+        struct map_info *map = mtd->priv;
+
+        map_copy_to(map, to, buf, len);
+        *retlen = len;
+        return 0;
+}
+
+static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr)
+{
+        /* Yeah, it's inefficient. Who cares? It's faster than a _real_
+           flash erase. */
+        struct map_info *map = mtd->priv;
+        map_word allff;
+        unsigned long i;
+
+        allff = map_word_ff(map);
+
+        for (i=0; i<instr->len; i += map_bankwidth(map))
+                map_write(map, allff, instr->addr + i);
+
+        instr->state = MTD_ERASE_DONE;
+
+        mtd_erase_callback(instr);
+
+        return 0;
+}
+
+static void mapram_nop(struct mtd_info *mtd)
+{
+        /* Nothing to see here */
+}
+
+static int __init map_ram_init(void)
+{
+        register_mtd_chip_driver(&mapram_chipdrv);
+        return 0;
+}
+
+static void __exit map_ram_exit(void)
+{
+        unregister_mtd_chip_driver(&mapram_chipdrv);
+}
+
+module_init(map_ram_init);
+module_exit(map_ram_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
+MODULE_DESCRIPTION("MTD chip driver for RAM chips");