X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fmtd%2Fchips%2Fmap_ram.c;fp=kernel%2Fdrivers%2Fmtd%2Fchips%2Fmap_ram.c;h=afb43d5e178269d33443a59a439245263cb263c0;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git

diff --git a/kernel/drivers/mtd/chips/map_ram.c b/kernel/drivers/mtd/chips/map_ram.c
new file mode 100644
index 000000000..afb43d5e1
--- /dev/null
+++ b/kernel/drivers/mtd/chips/map_ram.c
@@ -0,0 +1,154 @@
+/*
+ * Common code to handle map devices which are simple RAM
+ * (C) 2000 Red Hat. GPL'd.
+ */
+
+#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 unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long,
+					  unsigned long, unsigned long);
+
+
+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->_get_unmapped_area = mapram_unmapped_area;
+	mtd->_read = mapram_read;
+	mtd->_write = mapram_write;
+	mtd->_panic_write = mapram_write;
+	mtd->_sync = mapram_nop;
+	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;
+}
+
+
+/*
+ * Allow NOMMU mmap() to directly map the device (if not NULL)
+ * - return the address to which the offset maps
+ * - return -ENOSYS to indicate refusal to do the mapping
+ */
+static unsigned long mapram_unmapped_area(struct mtd_info *mtd,
+					  unsigned long len,
+					  unsigned long offset,
+					  unsigned long flags)
+{
+	struct map_info *map = mtd->priv;
+	return (unsigned long) map->virt + offset;
+}
+
+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");