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Diffstat (limited to 'drivers/mtd/chips/map_ram.c')
-rw-r--r--drivers/mtd/chips/map_ram.c159
1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/mtd/chips/map_ram.c b/drivers/mtd/chips/map_ram.c
new file mode 100644
index 0000000000..e8dd649692
--- /dev/null
+++ b/drivers/mtd/chips/map_ram.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common code to handle map devices which are simple RAM
+ * (C) 2000 Red Hat.
+ */
+
+#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>
+
+
+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 int mapram_point (struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, void **virt, resource_size_t *phys);
+static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len);
+
+
+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 = kzalloc(sizeof(*mtd), GFP_KERNEL);
+ if (!mtd)
+ return NULL;
+
+ 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->_panic_write = mapram_write;
+ mtd->_point = mapram_point;
+ mtd->_sync = mapram_nop;
+ mtd->_unpoint = mapram_unpoint;
+ mtd->flags = MTD_CAP_RAM;
+ mtd->writesize = 1;
+
+ mtd->erasesize = PAGE_SIZE;
+ while(mtd->size & (mtd->erasesize - 1))
+ mtd->erasesize >>= 1;
+
+ __module_get(THIS_MODULE);
+ return mtd;
+}
+
+static int mapram_point(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, void **virt, resource_size_t *phys)
+{
+ struct map_info *map = mtd->priv;
+
+ if (!map->virt)
+ return -EINVAL;
+ *virt = map->virt + from;
+ if (phys)
+ *phys = map->phys + from;
+ *retlen = len;
+ return 0;
+}
+
+static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
+{
+ return 0;
+}
+
+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);
+ 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");