mtd, spi: Add MTD layer driver

Add MTD layer driver for spi, original patch from:
http://git.denx.de/?p=u-boot/u-boot-mips.git;a=commitdiff;h=bb246819cdc90493dd7089eaa51b9e639765cced

Changes from Heiko Schocher against this patch:
- Remove compile error if not defining CONFIG_SPI_FLASH_MTD:

  LD      drivers/mtd/spi/built-in.o
drivers/mtd/spi/sf_probe.o: In function `spi_flash_mtd_unregister':
/home/hs/abb/imx6/u-boot/drivers/mtd/spi/sf_internal.h:168: multiple definition of `spi_flash_mtd_unregister'
drivers/mtd/spi/sf_params.o:/home/hs/abb/imx6/u-boot/drivers/mtd/spi/sf_internal.h:168: first defined here
drivers/mtd/spi/sf_ops.o: In function `spi_flash_mtd_unregister':
/home/hs/abb/imx6/u-boot/drivers/mtd/spi/sf_internal.h:168: multiple definition of `spi_flash_mtd_unregister'
drivers/mtd/spi/sf_params.o:/home/hs/abb/imx6/u-boot/drivers/mtd/spi/sf_internal.h:168: first defined here
make[1]: *** [drivers/mtd/spi/built-in.o] Fehler 1
make: *** [drivers/mtd/spi] Fehler 2

- Add a README entry.
- Add correct writebufsize, to fit with Linux v3.14
  MTD, UBI/UBIFS sync.

Note (From Jagan): For testing raw mtd parition erase/read/write operations
using cmd_sf, sf_mtd should be required to register the spi flash device to
MTD layer but the sf_mtd_info ops were not required until and unless if we
use any flash filesystem layer say for example UBI. Due to this the foot-print
got increased ~290bytes in non-UBI case here that should be acceptible.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
Tested-by: Jagannadh Teki <jteki@openedev.com>
Reviewed-by: Jagannadh Teki <jteki@openedev.com>

4 files changed, 116 insertions, 5 deletions

diff --git a/drivers/mtd/spi/Makefile b/drivers/mtd/spi/Makefile
index 87f20bc..ed46648 100644
--- a/drivers/mtd/spi/Makefile
+++ b/drivers/mtd/spi/Makefile
@@ -18,5 +18,6 @@ obj-$(CONFIG_SPI_FLASH) += sf_probe.o
 obj-$(CONFIG_SF_DATAFLASH) += sf_dataflash.o
 obj-$(CONFIG_CMD_SF) += sf.o
 obj-$(CONFIG_SPI_FLASH) += sf_ops.o sf_params.o
+obj-$(CONFIG_SPI_FLASH_MTD) += sf_mtd.o
 obj-$(CONFIG_SPI_FLASH_SANDBOX) += sandbox.o
 obj-$(CONFIG_SPI_M95XXX) += eeprom_m95xxx.o
diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index 4158e13..81eea8c 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -218,4 +218,9 @@ int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
 int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 		size_t len, void *data);
 
+#ifdef CONFIG_SPI_FLASH_MTD
+int spi_flash_mtd_register(struct spi_flash *flash);
+void spi_flash_mtd_unregister(void);
+#endif
+
 #endif /* _SF_INTERNAL_H_ */
diff --git a/drivers/mtd/spi/sf_mtd.c b/drivers/mtd/spi/sf_mtd.c
new file mode 100644
index 0000000..0b9cb62
--- /dev/null
+++ b/drivers/mtd/spi/sf_mtd.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2012-2014 Daniel Schwierzeck, daniel.schwierzeck@gmail.com
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <asm/errno.h>
+#include <linux/mtd/mtd.h>
+#include <spi_flash.h>
+
+static struct mtd_info sf_mtd_info;
+static char sf_mtd_name[8];
+
+static int spi_flash_mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+	struct spi_flash *flash = mtd->priv;
+	int err;
+
+	instr->state = MTD_ERASING;
+
+	err = spi_flash_erase(flash, instr->addr, instr->len);
+	if (err) {
+		instr->state = MTD_ERASE_FAILED;
+		instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
+		return -EIO;
+	}
+
+	instr->state = MTD_ERASE_DONE;
+	mtd_erase_callback(instr);
+
+	return 0;
+}
+
+static int spi_flash_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
+	size_t *retlen, u_char *buf)
+{
+	struct spi_flash *flash = mtd->priv;
+	int err;
+
+	err = spi_flash_read(flash, from, len, buf);
+	if (!err)
+		*retlen = len;
+
+	return err;
+}
+
+static int spi_flash_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
+	size_t *retlen, const u_char *buf)
+{
+	struct spi_flash *flash = mtd->priv;
+	int err;
+
+	err = spi_flash_write(flash, to, len, buf);
+	if (!err)
+		*retlen = len;
+
+	return err;
+}
+
+static void spi_flash_mtd_sync(struct mtd_info *mtd)
+{
+}
+
+static int spi_flash_mtd_number(void)
+{
+#ifdef CONFIG_SYS_MAX_FLASH_BANKS
+	return CONFIG_SYS_MAX_FLASH_BANKS;
+#else
+	return 0;
+#endif
+}
+
+int spi_flash_mtd_register(struct spi_flash *flash)
+{
+	memset(&sf_mtd_info, 0, sizeof(sf_mtd_info));
+	sprintf(sf_mtd_name, "nor%d", spi_flash_mtd_number());
+
+	sf_mtd_info.name = sf_mtd_name;
+	sf_mtd_info.type = MTD_NORFLASH;
+	sf_mtd_info.flags = MTD_CAP_NORFLASH;
+	sf_mtd_info.writesize = 1;
+	sf_mtd_info.writebufsize = flash->page_size;
+
+	sf_mtd_info._erase = spi_flash_mtd_erase;
+	sf_mtd_info._read = spi_flash_mtd_read;
+	sf_mtd_info._write = spi_flash_mtd_write;
+	sf_mtd_info._sync = spi_flash_mtd_sync;
+
+	sf_mtd_info.size = flash->size;
+	sf_mtd_info.priv = flash;
+
+	/* Only uniform flash devices for now */
+	sf_mtd_info.numeraseregions = 0;
+	sf_mtd_info.erasesize = flash->sector_size;
+
+	return add_mtd_device(&sf_mtd_info);
+}
+
+void spi_flash_mtd_unregister(void)
+{
+	del_mtd_device(&sf_mtd_info);
+}
diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
index 201471c..e0283dc 100644
--- a/drivers/mtd/spi/sf_probe.c
+++ b/drivers/mtd/spi/sf_probe.c
@@ -372,11 +372,9 @@ int spi_flash_probe_slave(struct spi_slave *spi, struct spi_flash *flash)
 		puts(" Full access #define CONFIG_SPI_FLASH_BAR\n");
 	}
 #endif
-
-	/* Release spi bus */
-	spi_release_bus(spi);
-
-	return 0;
+#ifdef CONFIG_SPI_FLASH_MTD
+	ret = spi_flash_mtd_register(flash);
+#endif
 
 err_read_id:
 	spi_release_bus(spi);
@@ -430,6 +428,9 @@ struct spi_flash *spi_flash_probe_fdt(const void *blob, int slave_node,
 
 void spi_flash_free(struct spi_flash *flash)
 {
+#ifdef CONFIG_SPI_FLASH_MTD
+	spi_flash_mtd_unregister();
+#endif
 	spi_free_slave(flash->spi);
 	free(flash);
 }