[PATCH 6/9] mtd: common module for smartmedia/xD support

Maxim Levitsky
2010-01-08T15:09:49Z

>From 7297f3c08c9cd19b5cca4073afc225e1e4e293fb Mon Sep 17 00:00:00 2001
From: Maxim Levitsky <maximlevitsky@gmail.com>
Date: Fri, 8 Jan 2010 16:00:56 +0200
Subject: [PATCH 6/9] mtd: common module for smartmedia/xD support
This small module implements few helpers that are usefull
for nand drivers for SmartMedia/xD card readers
and for SmartMedia translation layer.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
---
drivers/mtd/Kconfig | 9 ++
drivers/mtd/Makefile | 1 +
drivers/mtd/sm_common.c | 227 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/mtd/sm_common.h | 50 ++++++++++
4 files changed, 287 insertions(+), 0 deletions(-)
create mode 100644 drivers/mtd/sm_common.c
create mode 100644 drivers/mtd/sm_common.h

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index ecf90f5..ebeabd6 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -25,6 +25,15 @@ config MTD_DEBUG_VERBOSE
help
Determines the verbosity level of the MTD debugging messages.

+config MTD_NAND_SMARTMEDIA
+ boolean
+
+config MTD_SM_COMMON
+ depends on MTD_NAND
+ select MTD_NAND_SMARTMEDIA
+ tristate
+ default n
+
config MTD_TESTS
tristate "MTD tests support"
depends on m
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 82d1e4d..02c5b17 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_MTD) += mtd.o
mtd-y := mtdcore.o mtdsuper.o mtdbdi.o
mtd-$(CONFIG_MTD_PARTITIONS) += mtdpart.o

+obj-$(CONFIG_MTD_SM_COMMON) += sm_common.o
obj-$(CONFIG_MTD_CONCAT) += mtdconcat.o
obj-$(CONFIG_MTD_REDBOOT_PARTS) += redboot.o
obj-$(CONFIG_MTD_CMDLINE_PARTS) += cmdlinepart.o
diff --git a/drivers/mtd/sm_common.c b/drivers/mtd/sm_common.c
new file mode 100644
index 0000000..45b577f
--- /dev/null
+++ b/drivers/mtd/sm_common.c
@@ -0,0 +1,227 @@
+/*
+ * 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/bitops.h>
+#include <linux/log2.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 = 4 , .length = 2}, /* data & block status */
+ {.offset = 6 , .length = 2}, /* LBA1 */
+ {.offset = 11, .length = 2} /* LBA2 */
+ }
+};
+
+static struct nand_ecclayout nand_oob_sm_smallpage = {
+ .eccbytes = 0,
+ .oobfree = {
+ {.offset = 0 , .length = 8},
+ }
+};
+
+static int sm_get_lba(u8 *lba)
+{
+ /* check fixed bits */
+ if ((lba[0] & 0xF8) != 0x10)
+ return -2;
+
+ /* check parity - endianess doesn't matter */
+ if (hweight16(*(u16 *)lba) & 1)
+ return -2;
+
+ return (lba[1] >> 1) | ((lba[0] & 0x07) << 7);
+}
+
+
+/*
+ * Read LBA asscociated with block
+ * returns -1, if block is erased
+ * returns -2 if error happens
+ */
+int sm_read_lba(struct sm_oob *oob)
+{
+ static const u32 erased_pattern[4] = {
+ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
+
+ u16 lba_test;
+ int lba;
+
+ /* First test for erased block */
+ if (!memcmp(oob, erased_pattern, sizeof(struct sm_oob)))
+ return -1;
+
+ /* Now check is both copies of the LBA differ too much */
+ lba_test = *(u16 *)oob->lba_copy1 ^ *(u16*)oob->lba_copy2;
+ if (lba_test && !is_power_of_2(lba_test))
+ return -2;
+
+ /* And read it */
+ lba = sm_get_lba(oob->lba_copy1);
+
+ if (lba == -2)
+ lba = sm_get_lba(oob->lba_copy2);
+
+ return lba;
+}
+EXPORT_SYMBOL_GPL(sm_read_lba);
+
+void sm_write_lba(struct sm_oob *oob, u16 lba)
+{
+ u8 tmp[2];
+
+ WARN_ON(lba > 1000);
+
+ tmp[0] = 0x10 | ((lba >> 7) & 0x07);
+ tmp[1] = (lba << 1) & 0xFF;
+
+ if (hweight16(*(u16 *)tmp) & 0x01)
+ tmp[1] |= 1;
+
+ oob->lba_copy1[0] = oob->lba_copy2[0] = tmp[0];
+ oob->lba_copy1[1] = oob->lba_copy2[1] = tmp[1];
+}
+EXPORT_SYMBOL_GPL(sm_write_lba);
+
+/* Test if whole block is valid, or at least is marked as such...*/
+int sm_block_valid(struct sm_oob *oob)
+{
+ /* test block status */
+ if (hweight16(oob->block_status) < 7)
+ return -EIO;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sm_block_valid);
+
+/* Test if sector is valid */
+int sm_sector_valid(struct sm_oob *oob)
+{
+ /* test data status */
+ if (hweight16(oob->data_status) < 5)
+ return -EIO;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sm_sector_valid);
+
+/* Nand interface helpers */
+static int sm_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip)
+{
+ struct nand_chip *chip = (struct nand_chip *)mtd->priv;
+ struct mtd_oob_ops ops;
+ struct sm_oob oob;
+ int ret;
+
+ ops.mode = MTD_OOB_AUTO;
+ ops.ooboffs = 0;
+ ops.ooblen = sizeof(struct sm_oob);
+ ops.oobbuf = (void *)&oob;
+ ops.datbuf = NULL;
+
+ /* TODO: This doesn't take controller lock,
+ but we know that all xD cards are single chip. */
+ if (getchip)
+ chip->select_chip(mtd, 0);
+
+ ret = nand_do_read_oob(mtd, ofs, &ops);
+ if (ret < 0 || ops.oobretlen != sizeof(struct sm_oob))
+ goto out;
+
+ ret = (sm_block_valid(&oob) || sm_sector_valid(&oob)) ? 1 : 0;
+out:
+ if (getchip)
+ chip->select_chip(mtd, -1);
+
+ if (ret)
+ printk(KERN_NOTICE "sm_common: bad sector at %i\n", (int)ofs);
+ return ret;
+}
+
+static int sm_block_markbad(struct mtd_info *mtd, loff_t ofs)
+{
+ struct mtd_oob_ops ops;
+ struct sm_oob oob;
+ int ret;
+
+ memset(&oob, -1, sizeof(oob));
+ oob.block_status = 0xF0;
+
+ ops.mode = MTD_OOB_AUTO;
+ ops.ooboffs = 0;
+ ops.ooblen = sizeof(struct sm_oob);
+ ops.oobbuf = (void *)&oob;
+ ops.datbuf = NULL;
+
+ ret = nand_do_write_oob(mtd, ofs, &ops);
+ if (ret < 0 || ops.oobretlen != sizeof(struct sm_oob)) {
+ printk(KERN_NOTICE "sm_common: can't mark sector at %i as bad\n",
+ (int)ofs);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int sm_block_bad_dummy(struct mtd_info *mtd, loff_t ofs, int getchip)
+{
+ return 0;
+}
+
+static int sm_block_markbad_dummy(struct mtd_info *mtd, loff_t ofs)
+{
+ return -EIO;
+}
+
+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_NO_AUTOINCR;
+
+ /* Scan for card properties */
+ ret = nand_scan_ident(mtd, 1);
+
+ if (ret)
+ return ret;
+
+ /* Set oob handling functions. */
+ if (mtd->writesize == SM_SECTOR_SIZE) {
+ chip->block_bad = sm_block_bad;
+ chip->block_markbad = sm_block_markbad;
+ chip->ecc.layout = &nand_oob_sm;
+
+ /* SmartMedia on small page nand has page depedent oob layout,
+ thus let FTL do that hard job */
+ } else if (mtd->writesize == SM_SMALL_PAGE) {
+ chip->block_bad = sm_block_bad_dummy;
+ chip->block_markbad = sm_block_markbad_dummy;
+ chip->ecc.layout = &nand_oob_sm_smallpage;
+ } else
+ return -ENODEV;
+
+ ret = nand_scan_tail(mtd);
+ if (ret)
+ return ret;
+
+ ret = add_mtd_device(mtd);
+
+ if (ret)
+ return ret;
+
+ return 0;
+}
+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/sm_common.h b/drivers/mtd/sm_common.h
new file mode 100644
index 0000000..42d94b2
--- /dev/null
+++ b/drivers/mtd/sm_common.h
@@ -0,0 +1,50 @@
+/*
+ * 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/mtd/nand.h>
+
+/* Full oob structure as written on the flash */
+struct sm_oob_raw {
+ u32 reserved;
+ u8 data_status;
+ u8 block_status;
+ u8 lba_copy1[2];
+ u8 ecc2[3];
+ u8 lba_copy2[2];
+ u8 ecc1[3];
+} __attribute__((packed));
+
+/* oob structure without ecc fields, used by external interfaces */
+struct sm_oob {
+ u32 reserved;
+ u8 data_status;
+ u8 block_status;
+ u8 lba_copy1[2];
+ u8 lba_copy2[2];
+} __attribute__((packed));
+
+
+/* one sector is always 512 bytes, but it can consist of two nand pages */
+#define SM_SECTOR_SIZE 512
+
+/* minumum size of the page */
+#define SM_SMALL_PAGE 256
+
+/* 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
+
+extern int sm_register_device(struct mtd_info *mtd);
+extern int sm_read_lba(struct sm_oob *oob);
+extern void sm_write_lba(struct sm_oob *oob, u16 lba);
+extern int sm_block_valid(struct sm_oob *oob);
+extern int sm_sector_valid(struct sm_oob *oob);
--
1.6.3.3