mtd: common module for smartmedia/xD support

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>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

4 files changed, 178 insertions, 0 deletions

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 8a7ecfab4fe7..5010344f4bb2 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 1d19b7ab903a..d9257961a6ee 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 000000000000..07b6f725723f
--- /dev/null
+++ b/drivers/mtd/nand/sm_common.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright © 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 000000000000..7c03314bdac5
--- /dev/null
+++ b/drivers/mtd/nand/sm_common.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright © 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 {
+        uint32_t reserved;
+        uint8_t data_status;
+        uint8_t block_status;
+        uint8_t lba_copy1[2];
+        uint8_t ecc2[3];
+        uint8_t lba_copy2[2];
+        uint8_t 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 uint32_t erased_pattern[4] = {
+                0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
+
+        /* First test for erased block */
+        if (!memcmp(oob, erased_pattern, sizeof(*oob)))
+                return 1;
+        return 0;
+}