[PATCH 12/15] MTD: common module for smartmedia/xD support

Maxim Levitsky
2010-02-22T18:40:32Z

This small module implements few helpers that are usefull
for nand drivers for SmartMedia/xD card readers.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
---
drivers/mtd/nand/Kconfig | 9 ++++
drivers/mtd/nand/Makefile | 1 +
drivers/mtd/nand/sm_common.c | 107 ++++++++++++++++++++++++++++++++++++++++++
drivers/mtd/nand/sm_common.h | 61 ++++++++++++++++++++++++
4 files changed, 178 insertions(+), 0 deletions(-)
create mode 100644 drivers/mtd/nand/sm_common.c
create mode 100644 drivers/mtd/nand/sm_common.h

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 22cee48..31273c7 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -18,6 +18,10 @@ config MTD_NAND_VERIFY_WRITE
device thinks the write was successful, a bit could have been
flipped accidentally due to device wear or something else.

+config MTD_NAND_SMARTMEDIA
+ boolean
+ default n
+
config MTD_NAND_ECC_SMC
bool "NAND ECC Smart Media byte order"
default n
@@ -25,6 +29,11 @@ config MTD_NAND_ECC_SMC
Software ECC according to the Smart Media Specification.
The original Linux implementation had byte 0 and 1 swapped.

+config MTD_SM_COMMON
+ select MTD_NAND_SMARTMEDIA
+ tristate
+ default n
+
config MTD_NAND_MUSEUM_IDS
bool "Enable chip ids for obsolete ancient NAND devices"
depends on MTD_NAND
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index 39b4af2..e699bef 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -4,6 +4,7 @@

obj-$(CONFIG_MTD_NAND) += nand.o nand_ecc.o
obj-$(CONFIG_MTD_NAND_IDS) += nand_ids.o
+obj-$(CONFIG_MTD_SM_COMMON) += sm_common.o

obj-$(CONFIG_MTD_NAND_CAFE) += cafe_nand.o
obj-$(CONFIG_MTD_NAND_SPIA) += spia.o
diff --git a/drivers/mtd/nand/sm_common.c b/drivers/mtd/nand/sm_common.c
new file mode 100644
index 0000000..fc4ff71
--- /dev/null
+++ b/drivers/mtd/nand/sm_common.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2009 - Maxim Levitsky
+ * Common routines & support for xD format
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/mtd/nand.h>
+#include "sm_common.h"
+
+static struct nand_ecclayout nand_oob_sm = {
+ .eccbytes = 6,
+ .eccpos = {8, 9, 10, 13, 14, 15},
+ .oobfree = {
+ {.offset = 0 , .length = 4}, /* reserved */
+ {.offset = 6 , .length = 2}, /* LBA1 */
+ {.offset = 11, .length = 2} /* LBA2 */
+ }
+};
+
+/* NOTE: This layout is is not compatabable with SmartMedia, */
+/* because the 256 byte devices have page depenent oob layout */
+/* However it does preserve the bad block markers */
+/* If you use smftl, it will bypass this and work correctly */
+/* If you not, then you break SmartMedia compliance anyway */
+
+static struct nand_ecclayout nand_oob_sm_small = {
+ .eccbytes = 3,
+ .eccpos = {0, 1, 2},
+ .oobfree = {
+ {.offset = 3 , .length = 2}, /* reserved */
+ {.offset = 6 , .length = 2}, /* LBA1 */
+ }
+};
+
+
+static int sm_block_markbad(struct mtd_info *mtd, loff_t ofs)
+{
+ struct mtd_oob_ops ops;
+ struct sm_oob oob;
+ int ret, error = 0;
+
+ memset(&oob, -1, SM_OOB_SIZE);
+ oob.block_status = 0x0F;
+
+ /* As long as this function is called on erase block boundaries
+ it will work correctly for 256 byte nand */
+ ops.mode = MTD_OOB_PLACE;
+ ops.ooboffs = 0;
+ ops.ooblen = mtd->oobsize;
+ ops.oobbuf = (void *)&oob;
+ ops.datbuf = NULL;
+
+
+ ret = mtd->write_oob(mtd, ofs, &ops);
+ if (ret < 0 || ops.oobretlen != SM_OOB_SIZE) {
+ printk(KERN_NOTICE
+ "sm_common: can't mark sector at %i as bad\n",
+ (int)ofs);
+ error = -EIO;
+ } else
+ mtd->ecc_stats.badblocks++;
+
+ return error;
+}
+
+
+int sm_register_device(struct mtd_info *mtd)
+{
+ struct nand_chip *chip = (struct nand_chip *)mtd->priv;
+ int ret;
+
+ chip->options |= NAND_SKIP_BBTSCAN | NAND_SMARTMEDIA;
+
+ /* Scan for card properties */
+ ret = nand_scan_ident(mtd, 1);
+
+ if (ret)
+ return ret;
+
+ /* Bad block marker postion */
+ chip->badblockpos = 0x05;
+ chip->badblockbits = 7;
+ chip->block_markbad = sm_block_markbad;
+
+ /* ECC layout */
+ if (mtd->writesize == SM_SECTOR_SIZE)
+ chip->ecc.layout = &nand_oob_sm;
+ else if (mtd->writesize == SM_SMALL_PAGE)
+ chip->ecc.layout = &nand_oob_sm_small;
+ else
+ return -ENODEV;
+
+ ret = nand_scan_tail(mtd);
+
+ if (ret)
+ return ret;
+
+ return add_mtd_device(mtd);
+}
+EXPORT_SYMBOL_GPL(sm_register_device);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
+MODULE_DESCRIPTION("Common SmartMedia/xD functions");
diff --git a/drivers/mtd/nand/sm_common.h b/drivers/mtd/nand/sm_common.h
new file mode 100644
index 0000000..2e6b517
--- /dev/null
+++ b/drivers/mtd/nand/sm_common.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2009 - Maxim Levitsky
+ * Common routines & support for SmartMedia/xD format
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/bitops.h>
+#include <linux/mtd/mtd.h>
+
+/* Full oob structure as written on the flash */
+struct sm_oob {
+ u32 reserved;
+ u8 data_status;
+ u8 block_status;
+ u8 lba_copy1[2];
+ u8 ecc2[3];
+ u8 lba_copy2[2];
+ u8 ecc1[3];
+} __attribute__((packed));
+
+
+/* one sector is always 512 bytes, but it can consist of two nand pages */
+#define SM_SECTOR_SIZE 512
+
+/* oob area is also 16 bytes, but might be from two pages */
+#define SM_OOB_SIZE 16
+
+/* This is maximum zone size, and all devices that have more that one zone
+ have this size */
+#define SM_MAX_ZONE_SIZE 1024
+
+/* support for small page nand */
+#define SM_SMALL_PAGE 256
+#define SM_SMALL_OOB_SIZE 8
+
+
+extern int sm_register_device(struct mtd_info *mtd);
+
+
+inline int sm_sector_valid(struct sm_oob *oob)
+{
+ return hweight16(oob->data_status) >= 5;
+}
+
+inline int sm_block_valid(struct sm_oob *oob)
+{
+ return hweight16(oob->block_status) >= 7;
+}
+
+inline int sm_block_erased(struct sm_oob *oob)
+{
+ static const u32 erased_pattern[4] = {
+ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
+
+ /* First test for erased block */
+ if (!memcmp(oob, erased_pattern, sizeof(*oob)))
+ return 1;
+ return 0;
+}
--
1.6.3.3