[MTD] Add SSFDC (SmartMedia) read-only translation layer

Signed-off-by: Claudio Lanconelli <lanconelli.claudio@eptar.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 468 insertions, 0 deletions

diff --git a/drivers/mtd/ssfdc.c b/drivers/mtd/ssfdc.c
new file mode 100644
index 000000000000..ddbf015f4119
--- /dev/null
+++ b/drivers/mtd/ssfdc.c
@@ -0,0 +1,468 @@
+/*
+ * 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/config.h>
+#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 128MB) */
+        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 KB(x)   ( (x) * 1024L )
+#define MB(x)   ( KB(x) * 1024L )
+
+/** CHS Table
+                1MB     2MB     4MB     8MB     16MB    32MB    64MB    128MB
+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[] = {
+        { MB(  1), 125,  4,  4 },
+        { MB(  2), 125,  4,  8 },
+        { MB(  4), 250,  4,  8 },
+        { MB(  8), 250,  4, 16 },
+        { MB( 16), 500,  4, 16 },
+        { MB( 32), 500,  8, 16 },
+        { MB( 64), 500,  8, 32 },
+        { MB(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[SECTOR_SIZE];
+
+        /*
+         * 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
+         */
+        cis_sector = -1;
+        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;
+                }
+        }
+
+        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 = mtd->oobsize;
+        ops.len = OOB_SIZE;
+        ops.oobbuf = buf;
+        ops.datbuf = NULL;
+
+        ret = mtd->read_oob(mtd, offs, &ops);
+        if (ret < 0 || ops.retlen != 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.blksize = SECTOR_SIZE;
+        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,
+        .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");