--- /dev/null
+/*
+ * Linux driver for SSFDC Flash Translation Layer (Read only)
+ * (c) 2005 Eptar srl
+ * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>
+ *
+ * Based on NTFL and MTDBLOCK_RO drivers
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/hdreg.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/blktrans.h>
+
+struct ssfdcr_record {
+ struct mtd_blktrans_dev mbd;
+ int usecount;
+ unsigned char heads;
+ unsigned char sectors;
+ unsigned short cylinders;
+ int cis_block; /* block n. containing CIS/IDI */
+ int erase_size; /* phys_block_size */
+ unsigned short *logic_block_map; /* all zones (max 8192 phys blocks on
+ the 128MiB) */
+ int map_len; /* n. phys_blocks on the card */
+};
+
+#define SSFDCR_MAJOR 257
+#define SSFDCR_PARTN_BITS 3
+
+#define SECTOR_SIZE 512
+#define SECTOR_SHIFT 9
+#define OOB_SIZE 16
+
+#define MAX_LOGIC_BLK_PER_ZONE 1000
+#define MAX_PHYS_BLK_PER_ZONE 1024
+
+#define KiB(x) ( (x) * 1024L )
+#define MiB(x) ( KiB(x) * 1024L )
+
+/** CHS Table
+ 1MiB 2MiB 4MiB 8MiB 16MiB 32MiB 64MiB 128MiB
+NCylinder 125 125 250 250 500 500 500 500
+NHead 4 4 4 4 4 8 8 16
+NSector 4 8 8 16 16 16 32 32
+SumSector 2,000 4,000 8,000 16,000 32,000 64,000 128,000 256,000
+SectorSize 512 512 512 512 512 512 512 512
+**/
+
+typedef struct {
+ unsigned long size;
+ unsigned short cyl;
+ unsigned char head;
+ unsigned char sec;
+} chs_entry_t;
+
+/* Must be ordered by size */
+static const chs_entry_t chs_table[] = {
+ { MiB( 1), 125, 4, 4 },
+ { MiB( 2), 125, 4, 8 },
+ { MiB( 4), 250, 4, 8 },
+ { MiB( 8), 250, 4, 16 },
+ { MiB( 16), 500, 4, 16 },
+ { MiB( 32), 500, 8, 16 },
+ { MiB( 64), 500, 8, 32 },
+ { MiB(128), 500, 16, 32 },
+ { 0 },
+};
+
+static int get_chs(unsigned long size, unsigned short *cyl, unsigned char *head,
+ unsigned char *sec)
+{
+ int k;
+ int found = 0;
+
+ k = 0;
+ while (chs_table[k].size > 0 && size > chs_table[k].size)
+ k++;
+
+ if (chs_table[k].size > 0) {
+ if (cyl)
+ *cyl = chs_table[k].cyl;
+ if (head)
+ *head = chs_table[k].head;
+ if (sec)
+ *sec = chs_table[k].sec;
+ found = 1;
+ }
+
+ return found;
+}
+
+/* These bytes are the signature for the CIS/IDI sector */
+static const uint8_t cis_numbers[] = {
+ 0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
+};
+
+/* Read and check for a valid CIS sector */
+static int get_valid_cis_sector(struct mtd_info *mtd)
+{
+ int ret, k, cis_sector;
+ size_t retlen;
+ loff_t offset;
+ uint8_t *sect_buf;
+
+ cis_sector = -1;
+
+ sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL);
+ if (!sect_buf)
+ goto out;
+
+ /*
+ * Look for CIS/IDI sector on the first GOOD block (give up after 4 bad
+ * blocks). If the first good block doesn't contain CIS number the flash
+ * is not SSFDC formatted
+ */
+ for (k = 0, offset = 0; k < 4; k++, offset += mtd->erasesize) {
+ if (!mtd->block_isbad(mtd, offset)) {
+ ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen,
+ sect_buf);
+
+ /* CIS pattern match on the sector buffer */
+ if (ret < 0 || retlen != SECTOR_SIZE) {
+ printk(KERN_WARNING
+ "SSFDC_RO:can't read CIS/IDI sector\n");
+ } else if (!memcmp(sect_buf, cis_numbers,
+ sizeof(cis_numbers))) {
+ /* Found */
+ cis_sector = (int)(offset >> SECTOR_SHIFT);
+ } else {
+ DEBUG(MTD_DEBUG_LEVEL1,
+ "SSFDC_RO: CIS/IDI sector not found"
+ " on %s (mtd%d)\n", mtd->name,
+ mtd->index);
+ }
+ break;
+ }
+ }
+
+ kfree(sect_buf);
+ out:
+ return cis_sector;
+}
+
+/* Read physical sector (wrapper to MTD_READ) */
+static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf,
+ int sect_no)
+{
+ int ret;
+ size_t retlen;
+ loff_t offset = (loff_t)sect_no << SECTOR_SHIFT;
+
+ ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf);
+ if (ret < 0 || retlen != SECTOR_SIZE)
+ return -1;
+
+ return 0;
+}
+
+/* Read redundancy area (wrapper to MTD_READ_OOB */
+static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf)
+{
+ struct mtd_oob_ops ops;
+ int ret;
+
+ ops.mode = MTD_OOB_RAW;
+ ops.ooboffs = 0;
+ ops.ooblen = OOB_SIZE;
+ ops.oobbuf = buf;
+ ops.datbuf = NULL;
+
+ ret = mtd->read_oob(mtd, offs, &ops);
+ if (ret < 0 || ops.oobretlen != OOB_SIZE)
+ return -1;
+
+ return 0;
+}
+
+/* Parity calculator on a word of n bit size */
+static int get_parity(int number, int size)
+{
+ int k;
+ int parity;
+
+ parity = 1;
+ for (k = 0; k < size; k++) {
+ parity += (number >> k);
+ parity &= 1;
+ }
+ return parity;
+}
+
+/* Read and validate the logical block address field stored in the OOB */
+static int get_logical_address(uint8_t *oob_buf)
+{
+ int block_address, parity;
+ int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */
+ int j;
+ int ok = 0;
+
+ /*
+ * Look for the first valid logical address
+ * Valid address has fixed pattern on most significant bits and
+ * parity check
+ */
+ for (j = 0; j < ARRAY_SIZE(offset); j++) {
+ block_address = ((int)oob_buf[offset[j]] << 8) |
+ oob_buf[offset[j]+1];
+
+ /* Check for the signature bits in the address field (MSBits) */
+ if ((block_address & ~0x7FF) == 0x1000) {
+ parity = block_address & 0x01;
+ block_address &= 0x7FF;
+ block_address >>= 1;
+
+ if (get_parity(block_address, 10) != parity) {
+ DEBUG(MTD_DEBUG_LEVEL0,
+ "SSFDC_RO: logical address field%d"
+ "parity error(0x%04X)\n", j+1,
+ block_address);
+ } else {
+ ok = 1;
+ break;
+ }
+ }
+ }
+
+ if (!ok)
+ block_address = -2;
+
+ DEBUG(MTD_DEBUG_LEVEL3, "SSFDC_RO: get_logical_address() %d\n",
+ block_address);
+
+ return block_address;
+}
+
+/* Build the logic block map */
+static int build_logical_block_map(struct ssfdcr_record *ssfdc)
+{
+ unsigned long offset;
+ uint8_t oob_buf[OOB_SIZE];
+ int ret, block_address, phys_block;
+ struct mtd_info *mtd = ssfdc->mbd.mtd;
+
+ DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: build_block_map() nblks=%d (%luK)\n",
+ ssfdc->map_len,
+ (unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024);
+
+ /* Scan every physical block, skip CIS block */
+ for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len;
+ phys_block++) {
+ offset = (unsigned long)phys_block * ssfdc->erase_size;
+ if (mtd->block_isbad(mtd, offset))
+ continue; /* skip bad blocks */
+
+ ret = read_raw_oob(mtd, offset, oob_buf);
+ if (ret < 0) {
+ DEBUG(MTD_DEBUG_LEVEL0,
+ "SSFDC_RO: mtd read_oob() failed at %lu\n",
+ offset);
+ return -1;
+ }
+ block_address = get_logical_address(oob_buf);
+
+ /* Skip invalid addresses */
+ if (block_address >= 0 &&
+ block_address < MAX_LOGIC_BLK_PER_ZONE) {
+ int zone_index;
+
+ zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE;
+ block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE;
+ ssfdc->logic_block_map[block_address] =
+ (unsigned short)phys_block;
+
+ DEBUG(MTD_DEBUG_LEVEL2,
+ "SSFDC_RO: build_block_map() phys_block=%d,"
+ "logic_block_addr=%d, zone=%d\n",
+ phys_block, block_address, zone_index);
+ }
+ }
+ return 0;
+}
+
+static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
+{
+ struct ssfdcr_record *ssfdc;
+ int cis_sector;
+
+ /* Check for small page NAND flash */
+ if (mtd->type != MTD_NANDFLASH || mtd->oobsize != OOB_SIZE)
+ return;
+
+ /* Check for SSDFC format by reading CIS/IDI sector */
+ cis_sector = get_valid_cis_sector(mtd);
+ if (cis_sector == -1)
+ return;
+
+ ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL);
+ if (!ssfdc) {
+ printk(KERN_WARNING
+ "SSFDC_RO: out of memory for data structures\n");
+ return;
+ }
+
+ ssfdc->mbd.mtd = mtd;
+ ssfdc->mbd.devnum = -1;
+ ssfdc->mbd.tr = tr;
+ ssfdc->mbd.readonly = 1;
+
+ ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT);
+ ssfdc->erase_size = mtd->erasesize;
+ ssfdc->map_len = mtd->size / mtd->erasesize;
+
+ DEBUG(MTD_DEBUG_LEVEL1,
+ "SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n",
+ ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len,
+ (ssfdc->map_len + MAX_PHYS_BLK_PER_ZONE - 1) /
+ MAX_PHYS_BLK_PER_ZONE);
+
+ /* Set geometry */
+ ssfdc->heads = 16;
+ ssfdc->sectors = 32;
+ get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors);
+ ssfdc->cylinders = (unsigned short)((mtd->size >> SECTOR_SHIFT) /
+ ((long)ssfdc->sectors * (long)ssfdc->heads));
+
+ DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n",
+ ssfdc->cylinders, ssfdc->heads , ssfdc->sectors,
+ (long)ssfdc->cylinders * (long)ssfdc->heads *
+ (long)ssfdc->sectors);
+
+ ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders *
+ (long)ssfdc->sectors;
+
+ /* Allocate logical block map */
+ ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) *
+ ssfdc->map_len, GFP_KERNEL);
+ if (!ssfdc->logic_block_map) {
+ printk(KERN_WARNING
+ "SSFDC_RO: out of memory for data structures\n");
+ goto out_err;
+ }
+ memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) *
+ ssfdc->map_len);
+
+ /* Build logical block map */
+ if (build_logical_block_map(ssfdc) < 0)
+ goto out_err;
+
+ /* Register device + partitions */
+ if (add_mtd_blktrans_dev(&ssfdc->mbd))
+ goto out_err;
+
+ printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n",
+ ssfdc->mbd.devnum + 'a', mtd->index, mtd->name);
+ return;
+
+out_err:
+ kfree(ssfdc->logic_block_map);
+ kfree(ssfdc);
+}
+
+static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev)
+{
+ struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
+
+ DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: remove_dev (i=%d)\n", dev->devnum);
+
+ del_mtd_blktrans_dev(dev);
+ kfree(ssfdc->logic_block_map);
+ kfree(ssfdc);
+}
+
+static int ssfdcr_readsect(struct mtd_blktrans_dev *dev,
+ unsigned long logic_sect_no, char *buf)
+{
+ struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
+ int sectors_per_block, offset, block_address;
+
+ sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT;
+ offset = (int)(logic_sect_no % sectors_per_block);
+ block_address = (int)(logic_sect_no / sectors_per_block);
+
+ DEBUG(MTD_DEBUG_LEVEL3,
+ "SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d,"
+ " block_addr=%d\n", logic_sect_no, sectors_per_block, offset,
+ block_address);
+
+ if (block_address >= ssfdc->map_len)
+ BUG();
+
+ block_address = ssfdc->logic_block_map[block_address];
+
+ DEBUG(MTD_DEBUG_LEVEL3,
+ "SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n",
+ block_address);
+
+ if (block_address < 0xffff) {
+ unsigned long sect_no;
+
+ sect_no = (unsigned long)block_address * sectors_per_block +
+ offset;
+
+ DEBUG(MTD_DEBUG_LEVEL3,
+ "SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n",
+ sect_no);
+
+ if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0)
+ return -EIO;
+ } else {
+ memset(buf, 0xff, SECTOR_SIZE);
+ }
+
+ return 0;
+}
+
+static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
+{
+ struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
+
+ DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n",
+ ssfdc->cylinders, ssfdc->heads, ssfdc->sectors);
+
+ geo->heads = ssfdc->heads;
+ geo->sectors = ssfdc->sectors;
+ geo->cylinders = ssfdc->cylinders;
+
+ return 0;
+}
+
+/****************************************************************************
+ *
+ * Module stuff
+ *
+ ****************************************************************************/
+
+static struct mtd_blktrans_ops ssfdcr_tr = {
+ .name = "ssfdc",
+ .major = SSFDCR_MAJOR,
+ .part_bits = SSFDCR_PARTN_BITS,
+ .blksize = SECTOR_SIZE,
+ .getgeo = ssfdcr_getgeo,
+ .readsect = ssfdcr_readsect,
+ .add_mtd = ssfdcr_add_mtd,
+ .remove_dev = ssfdcr_remove_dev,
+ .owner = THIS_MODULE,
+};
+
+static int __init init_ssfdcr(void)
+{
+ printk(KERN_INFO "SSFDC read-only Flash Translation layer\n");
+
+ return register_mtd_blktrans(&ssfdcr_tr);
+}
+
+static void __exit cleanup_ssfdcr(void)
+{
+ deregister_mtd_blktrans(&ssfdcr_tr);
+}
+
+module_init(init_ssfdcr);
+module_exit(cleanup_ssfdcr);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");
+MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card");
git://git.onelab.eu / linux-2.6.git / blobdiff