[PATCH v3 1/9] mtd: sharpslpart: add sharpslpart MTD partition parser

[Andrea Adami]

The Sharp SL Series (Zaurus) PXA handhelds have 16/64/128M of NAND flash
and share the same layout of the first 7M partition, managed by Sharp FTL.

The purpose of this self-contained patch is to add a common parser and
remove the hardcoded sizes in the board files (these devices are not yet
converted to devicetree).
Users will have benefits because the mtdparts= tag will not be necessary
anymore and they will be free to repartition the little sized flash.

The obsolete bootloader can not pass the partitioning info to modern
kernels anymore so it has to be read from flash at known logical addresses.
(see http://www.h5.dion.ne.jp/~rimemoon/zaurus/memo_006.htm )

In kernel, under arch/arm/mach-pxa we have already 8 machines:
MACH_POODLE, MACH_CORGI, MACH_SHEPERD, MACH_HUSKY, MACH_AKITA, MACH_SPITZ,
MACH_BORZOI, MACH_TOSA.
Lost after the 2.4 vendor kernel are MACH_BOXER and MACH_TERRIER.

Almost every model has different factory partitioning: add to this the
units can be repartitioned by users with userspace tools (nandlogical)
and installers for popular (back then) linux distributions.

The Parameter Area in the first (boot) partition extends from 0x00040000 to
0x0007bfff (176k) and contains two copies of the partition table:
...
0x00060000: Partition Info1     16k
0x00064000: Partition Info2     16k
0x00668000: Model               16k
...

The first 7M partition is managed by the Sharp FTL reserving 5% + 1 blocks
for wear-leveling: some blocks are remapped and one layer of translation
(logical to physical) is necessary.

There isn't much documentation about this FTL in the 2.4 sources, just the
MTD methods for reading and writing using logical addresses and the block
management (wear-leveling, use counter).
For the purpose of the MTD parser only the read part of the code was taken.

The NAND drivers that can use this parser are sharpsl.c and tmio_nand.c.

Signed-off-by: Andrea Adami <andrea.adami@xxxxxxxxx>
---
 drivers/mtd/Kconfig       |   8 ++
 drivers/mtd/Makefile      |   2 +
 drivers/mtd/sharpsl_ftl.c | 216 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/mtd/sharpsl_ftl.h |  34 ++++++++
 drivers/mtd/sharpslpart.c | 132 ++++++++++++++++++++++++++++
 5 files changed, 392 insertions(+)
 create mode 100644 drivers/mtd/sharpsl_ftl.c
 create mode 100644 drivers/mtd/sharpsl_ftl.h
 create mode 100644 drivers/mtd/sharpslpart.c

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index e83a279..5c96127 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -155,6 +155,14 @@ config MTD_BCM47XX_PARTS
 	  This provides partitions parser for devices based on BCM47xx
 	  boards.
 
+config MTD_SHARPSL_PARTS
+	tristate "Sharp SL Series NAND flash partition parser"
+	depends on MTD_NAND_SHARPSL || MTD_NAND_TMIO
+	help
+	  This provides the read-only FTL logic necessary to read the partition
+	  table from the NAND flash of Sharp SL Series (Zaurus) and the MTD
+	  partition parser using this code.
+
 comment "User Modules And Translation Layers"
 
 #
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 99bb9a1..89f707b 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -13,6 +13,8 @@ obj-$(CONFIG_MTD_AFS_PARTS)	+= afs.o
 obj-$(CONFIG_MTD_AR7_PARTS)	+= ar7part.o
 obj-$(CONFIG_MTD_BCM63XX_PARTS)	+= bcm63xxpart.o
 obj-$(CONFIG_MTD_BCM47XX_PARTS)	+= bcm47xxpart.o
+obj-$(CONFIG_MTD_SHARPSL_PARTS)	+= sharpsl-part.o
+sharpsl-part-objs := sharpsl_ftl.o sharpslpart.o
 
 # 'Users' - code which presents functionality to userspace.
 obj-$(CONFIG_MTD_BLKDEVS)	+= mtd_blkdevs.o
diff --git a/drivers/mtd/sharpsl_ftl.c b/drivers/mtd/sharpsl_ftl.c
new file mode 100644
index 0000000..1796d03
--- /dev/null
+++ b/drivers/mtd/sharpsl_ftl.c
@@ -0,0 +1,216 @@
+/*
+ * MTD method for NAND accessing via logical address (SHARP FTL)
+ *
+ * Copyright (C) 2017 Andrea Adami <andrea.adami@xxxxxxxxx>
+ *
+ * Based on 2.4 sources: drivers/mtd/nand/sharp_sl_logical.c
+ * Copyright (C) 2002  SHARP
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include "sharpsl_ftl.h"
+
+/* oob structure */
+#define NAND_NOOB_LOGADDR_00		8
+#define NAND_NOOB_LOGADDR_01		9
+#define NAND_NOOB_LOGADDR_10		10
+#define NAND_NOOB_LOGADDR_11		11
+#define NAND_NOOB_LOGADDR_20		12
+#define NAND_NOOB_LOGADDR_21		13
+
+/* Logical Table */
+struct mtd_logical {
+	u32 size;		/* size of the handled partition */
+	int index;		/* mtd->index */
+	u_int phymax;		/* physical blocks */
+	u_int logmax;		/* logical blocks */
+	u_int *log2phy;		/* the logical-to-physical table */
+};
+
+static struct mtd_logical *sharpsl_mtd_logical;
+
+static int sharpsl_nand_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
+				 uint8_t *buf)
+{
+	loff_t mask = mtd->writesize - 1;
+	struct mtd_oob_ops ops;
+	int ret;
+
+	ops.mode = MTD_OPS_PLACE_OOB;
+	ops.ooboffs = offs & mask;
+	ops.ooblen = len;
+	ops.oobbuf = buf;
+	ops.datbuf = NULL;
+
+	ret = mtd_read_oob(mtd, offs & ~mask, &ops);
+	if (ret != 0 || len != ops.oobretlen)
+		return -1;
+
+	return 0;
+}
+
+static u_int sharpsl_nand_get_logical_num(u_char *oob)
+{
+	u16 us;
+	int good0, good1;
+
+	if (oob[NAND_NOOB_LOGADDR_00] == oob[NAND_NOOB_LOGADDR_10] &&
+	    oob[NAND_NOOB_LOGADDR_01] == oob[NAND_NOOB_LOGADDR_11]) {
+		good0 = NAND_NOOB_LOGADDR_00;
+		good1 = NAND_NOOB_LOGADDR_01;
+	} else if (oob[NAND_NOOB_LOGADDR_10] == oob[NAND_NOOB_LOGADDR_20] &&
+		   oob[NAND_NOOB_LOGADDR_11] == oob[NAND_NOOB_LOGADDR_21]) {
+		good0 = NAND_NOOB_LOGADDR_10;
+		good1 = NAND_NOOB_LOGADDR_11;
+	} else if (oob[NAND_NOOB_LOGADDR_20] == oob[NAND_NOOB_LOGADDR_00] &&
+		   oob[NAND_NOOB_LOGADDR_21] == oob[NAND_NOOB_LOGADDR_01]) {
+		good0 = NAND_NOOB_LOGADDR_20;
+		good1 = NAND_NOOB_LOGADDR_21;
+	} else {
+		return UINT_MAX;
+	}
+
+	us = oob[good0] | oob[good1] << 8;
+
+	/* parity check */
+	if (hweight16(us) & 1)
+		return (UINT_MAX - 1);
+
+	/* reserved */
+	if (us == 0xffff)
+		return 0xffff;
+	else
+		return (us & 0x07fe) >> 1;
+}
+
+int sharpsl_nand_init_logical(struct mtd_info *mtd, u32 partition_size)
+{
+	struct mtd_logical *logical = NULL;
+	u_int block_num, log_num;
+	loff_t block_adr;
+	u_char *oob = NULL;
+	int i, readretry;
+
+	logical = kzalloc(sizeof(*logical), GFP_KERNEL);
+	if (!logical)
+		return -ENOMEM;
+
+	oob = kzalloc(mtd->oobsize, GFP_KERNEL);
+	if (!oob) {
+		kfree(logical);
+		return -ENOMEM;
+	}
+
+	/* initialize management structure */
+	logical->size = partition_size;
+	logical->index = mtd->index;
+	logical->phymax = (partition_size / mtd->erasesize);
+
+	/* FTL reserves 5% of the blocks + 1 spare  */
+	logical->logmax = ((logical->phymax * 95) / 100) - 1;
+
+	logical->log2phy = NULL;
+	logical->log2phy = kcalloc(logical->logmax, sizeof(u_int), GFP_KERNEL);
+	if (!logical->log2phy) {
+		kfree(logical);
+		kfree(oob);
+		return -ENOMEM;
+	}
+
+	/* initialize logical->log2phy */
+	for (i = 0; i < logical->logmax; i++)
+		logical->log2phy[i] = UINT_MAX;
+
+	/* create physical-logical table */
+	for (block_num = 0; block_num < logical->phymax; block_num++) {
+		block_adr = block_num * mtd->erasesize;
+
+		if (mtd_block_isbad(mtd, block_adr))
+			continue;
+
+		readretry = 3;
+read_retry:
+		if (sharpsl_nand_read_oob(mtd, block_adr, mtd->oobsize, oob))
+			continue;
+
+		/* get logical block */
+		log_num = sharpsl_nand_get_logical_num(oob);
+
+		/* skip out of range and not unique values */
+		if ((int)log_num >= 0  && (log_num < logical->logmax)) {
+			if (logical->log2phy[log_num] == UINT_MAX)
+				logical->log2phy[log_num] = block_num;
+		} else {
+			readretry--;
+			if (readretry)
+				goto read_retry;
+		}
+	}
+	kfree(oob);
+	sharpsl_mtd_logical = logical;
+
+	pr_info("Sharp SL FTL: %d blocks used (%d logical, %d reserved)\n",
+		logical->phymax, logical->logmax,
+		logical->phymax - logical->logmax);
+
+	return 0;
+}
+
+void sharpsl_nand_cleanup_logical(void)
+{
+	struct mtd_logical *logical = sharpsl_mtd_logical;
+
+	sharpsl_mtd_logical = NULL;
+
+	kfree(logical->log2phy);
+	logical->log2phy = NULL;
+	kfree(logical);
+	logical = NULL;
+}
+
+int sharpsl_nand_read_laddr(struct mtd_info *mtd,
+			    loff_t from,
+			    size_t len,
+			    u_char *buf)
+{
+	struct mtd_logical *logical;
+	u_int log_num, log_new;
+	u_int block_num;
+	loff_t block_adr;
+	loff_t block_ofs;
+	size_t retlen;
+	int ret;
+
+	logical = sharpsl_mtd_logical;
+	log_num = (u32)from / mtd->erasesize;
+	log_new = ((u32)from + len - 1) / mtd->erasesize;
+
+	if (len <= 0 || log_num >= logical->logmax || log_new > log_num)
+		return -EINVAL;
+
+	block_num = logical->log2phy[log_num];
+	block_adr = block_num * mtd->erasesize;
+	block_ofs = (u32)from % mtd->erasesize;
+
+	ret = mtd_read(mtd, block_adr + block_ofs, len, &retlen, buf);
+	if (ret != 0 || len != retlen)
+		return -EINVAL;
+
+	return 0;
+}
diff --git a/drivers/mtd/sharpsl_ftl.h b/drivers/mtd/sharpsl_ftl.h
new file mode 100644
index 0000000..2880cbe
--- /dev/null
+++ b/drivers/mtd/sharpsl_ftl.h
@@ -0,0 +1,34 @@
+/*
+ * Header file for NAND accessing via logical address (SHARP FTL)
+ *
+ * Copyright (C) 2017 Andrea Adami <andrea.adami@xxxxxxxxx>
+ *
+ * Based on 2.4 sources: linux/include/asm-arm/sharp_nand_logical.h
+ * Copyright (C) 2002  SHARP
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __SHARPSL_NAND_LOGICAL_H__
+#define __SHARPSL_NAND_LOGICAL_H__
+
+#include <linux/types.h>
+#include <linux/mtd/mtd.h>
+
+int sharpsl_nand_init_logical(struct mtd_info *mtd, u32 partition_size);
+
+void sharpsl_nand_cleanup_logical(void);
+
+int sharpsl_nand_read_laddr(struct mtd_info *mtd, loff_t from, size_t len,
+			    u_char *buf);
+
+#endif
diff --git a/drivers/mtd/sharpslpart.c b/drivers/mtd/sharpslpart.c
new file mode 100644
index 0000000..40aebe9
--- /dev/null
+++ b/drivers/mtd/sharpslpart.c
@@ -0,0 +1,132 @@
+/*
+ * MTD partition parser for NAND flash on Sharp SL Series
+ *
+ * Copyright (C) 2017 Andrea Adami <andrea.adami@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include "sharpsl_ftl.h"
+
+/* factory defaults */
+#define SHARPSL_NAND_PARTS		3
+#define SHARPSL_FTL_PARTITION_SIZE	(7 * 1024 * 1024)
+#define PARAM_BLOCK_PARTITIONINFO1	0x00060000
+#define PARAM_BLOCK_PARTITIONINFO2	0x00064000
+
+#define BOOT_MAGIC			be32_to_cpu(0x424f4f54)   /* BOOT */
+#define FSRO_MAGIC			be32_to_cpu(0x4653524f)   /* FSRO */
+#define FSRW_MAGIC			be32_to_cpu(0x46535257)   /* FSRW */
+
+/*
+ * Sample values read from SL-C860
+ *
+ * # cat /proc/mtd
+ * dev:    size   erasesize  name
+ * mtd0: 006d0000 00020000 "Filesystem"
+ * mtd1: 00700000 00004000 "smf"
+ * mtd2: 03500000 00004000 "root"
+ * mtd3: 04400000 00004000 "home"
+ *
+ * PARTITIONINFO1
+ * 0x00060000: 00 00 00 00 00 00 70 00 42 4f 4f 54 00 00 00 00  ......p.BOOT....
+ * 0x00060010: 00 00 70 00 00 00 c0 03 46 53 52 4f 00 00 00 00  ..p.....FSRO....
+ * 0x00060020: 00 00 c0 03 00 00 00 04 46 53 52 57 00 00 00 00  ........FSRW....
+ * 0x00060030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff  ................
+ *
+ */
+
+struct sharpsl_nand_partitioninfo {
+	u32 start;
+	u32 end;
+	u32 magic;
+	u32 reserved;
+};
+
+static int sharpsl_parse_mtd_partitions(struct mtd_info *master,
+					const struct mtd_partition **pparts,
+					struct mtd_part_parser_data *data)
+{
+	struct sharpsl_nand_partitioninfo buf1[SHARPSL_NAND_PARTS];
+	struct sharpsl_nand_partitioninfo buf2[SHARPSL_NAND_PARTS];
+	struct mtd_partition *sharpsl_nand_parts;
+
+	/* init logical mgmt (FTL) */
+	if (sharpsl_nand_init_logical(master, SHARPSL_FTL_PARTITION_SIZE))
+		return -EINVAL;
+
+	/* read the two partition tables */
+	if (sharpsl_nand_read_laddr(master,
+				    PARAM_BLOCK_PARTITIONINFO1,
+				    sizeof(buf1), (u_char *)&buf1) ||
+	    sharpsl_nand_read_laddr(master,
+				    PARAM_BLOCK_PARTITIONINFO2,
+				    sizeof(buf2), (u_char *)&buf2))
+		return -EINVAL;
+
+	/* cleanup logical mgmt (FTL) */
+	sharpsl_nand_cleanup_logical();
+
+	/* compare the two buffers */
+	if (memcmp(&buf1, &buf2, sizeof(buf1))) {
+		pr_err("sharpslpart: PARTITIONINFO 1,2 differ. Quit parser.\n");
+		return -EINVAL;
+	}
+
+	/* check for magics (just in the first) */
+	if (buf1[0].magic != BOOT_MAGIC ||
+	    buf1[1].magic != FSRO_MAGIC ||
+	    buf1[2].magic != FSRW_MAGIC) {
+		pr_err("sharpslpart: magic values mismatch. Quit parser.\n");
+		return -EINVAL;
+	}
+
+	sharpsl_nand_parts = kzalloc(sizeof(*sharpsl_nand_parts) *
+				     SHARPSL_NAND_PARTS, GFP_KERNEL);
+	if (!sharpsl_nand_parts)
+		return -ENOMEM;
+
+	/* original names */
+	sharpsl_nand_parts[0].name = "smf";
+	sharpsl_nand_parts[0].offset = buf1[0].start;
+	sharpsl_nand_parts[0].size = buf1[0].end - buf1[0].start;
+	sharpsl_nand_parts[0].mask_flags = 0;
+
+	sharpsl_nand_parts[1].name = "root";
+	sharpsl_nand_parts[1].offset = buf1[1].start;
+	sharpsl_nand_parts[1].size = buf1[1].end - buf1[1].start;
+	sharpsl_nand_parts[1].mask_flags = 0;
+
+	sharpsl_nand_parts[2].name = "home";
+	sharpsl_nand_parts[2].offset = buf1[2].start;
+	/* discard buf1[2].end, was for older models with 64M flash */
+	sharpsl_nand_parts[2].size = master->size - buf1[2].start;
+	sharpsl_nand_parts[2].mask_flags = 0;
+
+	*pparts = sharpsl_nand_parts;
+	return SHARPSL_NAND_PARTS;
+}
+
+static struct mtd_part_parser sharpsl_mtd_parser = {
+	.parse_fn = sharpsl_parse_mtd_partitions,
+	.name = "sharpslpart",
+};
+module_mtd_part_parser(sharpsl_mtd_parser);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrea Adami <andrea.adami@xxxxxxxxx>");
+MODULE_DESCRIPTION("MTD partitioning for NAND flash on Sharp SL Series");
-- 
2.7.4