474 lines
12 KiB
C
474 lines
12 KiB
C
/*
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* Linux driver for SSFDC Flash Translation Layer (Read only)
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* (c) 2005 Eptar srl
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* Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>
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*
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* Based on NTFL and MTDBLOCK_RO drivers
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/hdreg.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/nand.h>
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#include <linux/mtd/blktrans.h>
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struct ssfdcr_record {
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struct mtd_blktrans_dev mbd;
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int usecount;
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unsigned char heads;
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unsigned char sectors;
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unsigned short cylinders;
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int cis_block; /* block n. containing CIS/IDI */
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int erase_size; /* phys_block_size */
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unsigned short *logic_block_map; /* all zones (max 8192 phys blocks on
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the 128MiB) */
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int map_len; /* n. phys_blocks on the card */
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};
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#define SSFDCR_MAJOR 257
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#define SSFDCR_PARTN_BITS 3
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#define SECTOR_SIZE 512
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#define SECTOR_SHIFT 9
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#define OOB_SIZE 16
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#define MAX_LOGIC_BLK_PER_ZONE 1000
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#define MAX_PHYS_BLK_PER_ZONE 1024
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#define KiB(x) ( (x) * 1024L )
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#define MiB(x) ( KiB(x) * 1024L )
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/** CHS Table
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1MiB 2MiB 4MiB 8MiB 16MiB 32MiB 64MiB 128MiB
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NCylinder 125 125 250 250 500 500 500 500
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NHead 4 4 4 4 4 8 8 16
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NSector 4 8 8 16 16 16 32 32
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SumSector 2,000 4,000 8,000 16,000 32,000 64,000 128,000 256,000
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SectorSize 512 512 512 512 512 512 512 512
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**/
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typedef struct {
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unsigned long size;
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unsigned short cyl;
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unsigned char head;
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unsigned char sec;
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} chs_entry_t;
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/* Must be ordered by size */
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static const chs_entry_t chs_table[] = {
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{ MiB( 1), 125, 4, 4 },
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{ MiB( 2), 125, 4, 8 },
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{ MiB( 4), 250, 4, 8 },
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{ MiB( 8), 250, 4, 16 },
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{ MiB( 16), 500, 4, 16 },
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{ MiB( 32), 500, 8, 16 },
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{ MiB( 64), 500, 8, 32 },
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{ MiB(128), 500, 16, 32 },
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{ 0 },
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};
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static int get_chs(unsigned long size, unsigned short *cyl, unsigned char *head,
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unsigned char *sec)
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{
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int k;
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int found = 0;
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k = 0;
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while (chs_table[k].size > 0 && size > chs_table[k].size)
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k++;
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if (chs_table[k].size > 0) {
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if (cyl)
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*cyl = chs_table[k].cyl;
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if (head)
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*head = chs_table[k].head;
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if (sec)
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*sec = chs_table[k].sec;
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found = 1;
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}
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return found;
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}
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/* These bytes are the signature for the CIS/IDI sector */
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static const uint8_t cis_numbers[] = {
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0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
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};
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/* Read and check for a valid CIS sector */
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static int get_valid_cis_sector(struct mtd_info *mtd)
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{
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int ret, k, cis_sector;
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size_t retlen;
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loff_t offset;
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uint8_t *sect_buf;
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cis_sector = -1;
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sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL);
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if (!sect_buf)
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goto out;
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/*
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* Look for CIS/IDI sector on the first GOOD block (give up after 4 bad
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* blocks). If the first good block doesn't contain CIS number the flash
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* is not SSFDC formatted
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*/
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for (k = 0, offset = 0; k < 4; k++, offset += mtd->erasesize) {
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if (!mtd->block_isbad(mtd, offset)) {
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ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen,
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sect_buf);
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/* CIS pattern match on the sector buffer */
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if (ret < 0 || retlen != SECTOR_SIZE) {
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printk(KERN_WARNING
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"SSFDC_RO:can't read CIS/IDI sector\n");
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} else if (!memcmp(sect_buf, cis_numbers,
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sizeof(cis_numbers))) {
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/* Found */
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cis_sector = (int)(offset >> SECTOR_SHIFT);
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} else {
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DEBUG(MTD_DEBUG_LEVEL1,
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"SSFDC_RO: CIS/IDI sector not found"
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" on %s (mtd%d)\n", mtd->name,
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mtd->index);
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}
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break;
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}
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}
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kfree(sect_buf);
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out:
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return cis_sector;
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}
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/* Read physical sector (wrapper to MTD_READ) */
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static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf,
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int sect_no)
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{
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int ret;
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size_t retlen;
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loff_t offset = (loff_t)sect_no << SECTOR_SHIFT;
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ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf);
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if (ret < 0 || retlen != SECTOR_SIZE)
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return -1;
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return 0;
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}
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/* Read redundancy area (wrapper to MTD_READ_OOB */
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static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf)
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{
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struct mtd_oob_ops ops;
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int ret;
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ops.mode = MTD_OOB_RAW;
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ops.ooboffs = 0;
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ops.ooblen = OOB_SIZE;
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ops.oobbuf = buf;
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ops.datbuf = NULL;
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ret = mtd->read_oob(mtd, offs, &ops);
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if (ret < 0 || ops.oobretlen != OOB_SIZE)
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return -1;
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return 0;
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}
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/* Parity calculator on a word of n bit size */
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static int get_parity(int number, int size)
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{
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int k;
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int parity;
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parity = 1;
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for (k = 0; k < size; k++) {
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parity += (number >> k);
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parity &= 1;
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}
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return parity;
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}
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/* Read and validate the logical block address field stored in the OOB */
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static int get_logical_address(uint8_t *oob_buf)
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{
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int block_address, parity;
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int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */
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int j;
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int ok = 0;
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/*
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* Look for the first valid logical address
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* Valid address has fixed pattern on most significant bits and
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* parity check
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*/
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for (j = 0; j < ARRAY_SIZE(offset); j++) {
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block_address = ((int)oob_buf[offset[j]] << 8) |
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oob_buf[offset[j]+1];
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/* Check for the signature bits in the address field (MSBits) */
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if ((block_address & ~0x7FF) == 0x1000) {
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parity = block_address & 0x01;
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block_address &= 0x7FF;
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block_address >>= 1;
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if (get_parity(block_address, 10) != parity) {
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DEBUG(MTD_DEBUG_LEVEL0,
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"SSFDC_RO: logical address field%d"
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"parity error(0x%04X)\n", j+1,
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block_address);
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} else {
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ok = 1;
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break;
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}
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}
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}
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if (!ok)
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block_address = -2;
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DEBUG(MTD_DEBUG_LEVEL3, "SSFDC_RO: get_logical_address() %d\n",
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block_address);
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return block_address;
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}
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/* Build the logic block map */
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static int build_logical_block_map(struct ssfdcr_record *ssfdc)
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{
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unsigned long offset;
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uint8_t oob_buf[OOB_SIZE];
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int ret, block_address, phys_block;
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struct mtd_info *mtd = ssfdc->mbd.mtd;
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DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: build_block_map() nblks=%d (%luK)\n",
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ssfdc->map_len,
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(unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024);
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/* Scan every physical block, skip CIS block */
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for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len;
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phys_block++) {
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offset = (unsigned long)phys_block * ssfdc->erase_size;
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if (mtd->block_isbad(mtd, offset))
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continue; /* skip bad blocks */
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ret = read_raw_oob(mtd, offset, oob_buf);
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if (ret < 0) {
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DEBUG(MTD_DEBUG_LEVEL0,
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"SSFDC_RO: mtd read_oob() failed at %lu\n",
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offset);
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return -1;
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}
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block_address = get_logical_address(oob_buf);
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/* Skip invalid addresses */
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if (block_address >= 0 &&
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block_address < MAX_LOGIC_BLK_PER_ZONE) {
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int zone_index;
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zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE;
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block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE;
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ssfdc->logic_block_map[block_address] =
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(unsigned short)phys_block;
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DEBUG(MTD_DEBUG_LEVEL2,
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"SSFDC_RO: build_block_map() phys_block=%d,"
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"logic_block_addr=%d, zone=%d\n",
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phys_block, block_address, zone_index);
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}
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}
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return 0;
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}
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static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
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{
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struct ssfdcr_record *ssfdc;
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int cis_sector;
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/* Check for small page NAND flash */
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if (mtd->type != MTD_NANDFLASH || mtd->oobsize != OOB_SIZE ||
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mtd->size > UINT_MAX)
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return;
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/* Check for SSDFC format by reading CIS/IDI sector */
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cis_sector = get_valid_cis_sector(mtd);
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if (cis_sector == -1)
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return;
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ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL);
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if (!ssfdc) {
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printk(KERN_WARNING
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"SSFDC_RO: out of memory for data structures\n");
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return;
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}
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ssfdc->mbd.mtd = mtd;
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ssfdc->mbd.devnum = -1;
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ssfdc->mbd.tr = tr;
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ssfdc->mbd.readonly = 1;
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ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT);
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ssfdc->erase_size = mtd->erasesize;
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ssfdc->map_len = (u32)mtd->size / mtd->erasesize;
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DEBUG(MTD_DEBUG_LEVEL1,
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"SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n",
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ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len,
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DIV_ROUND_UP(ssfdc->map_len, MAX_PHYS_BLK_PER_ZONE));
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/* Set geometry */
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ssfdc->heads = 16;
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ssfdc->sectors = 32;
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get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors);
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ssfdc->cylinders = (unsigned short)(((u32)mtd->size >> SECTOR_SHIFT) /
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((long)ssfdc->sectors * (long)ssfdc->heads));
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DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n",
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ssfdc->cylinders, ssfdc->heads , ssfdc->sectors,
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(long)ssfdc->cylinders * (long)ssfdc->heads *
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(long)ssfdc->sectors);
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ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders *
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(long)ssfdc->sectors;
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/* Allocate logical block map */
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ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) *
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ssfdc->map_len, GFP_KERNEL);
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if (!ssfdc->logic_block_map) {
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printk(KERN_WARNING
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"SSFDC_RO: out of memory for data structures\n");
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goto out_err;
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}
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memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) *
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ssfdc->map_len);
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/* Build logical block map */
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if (build_logical_block_map(ssfdc) < 0)
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goto out_err;
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/* Register device + partitions */
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if (add_mtd_blktrans_dev(&ssfdc->mbd))
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goto out_err;
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printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n",
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ssfdc->mbd.devnum + 'a', mtd->index, mtd->name);
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return;
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out_err:
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kfree(ssfdc->logic_block_map);
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kfree(ssfdc);
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}
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static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev)
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{
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struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
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DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: remove_dev (i=%d)\n", dev->devnum);
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del_mtd_blktrans_dev(dev);
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kfree(ssfdc->logic_block_map);
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kfree(ssfdc);
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}
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static int ssfdcr_readsect(struct mtd_blktrans_dev *dev,
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unsigned long logic_sect_no, char *buf)
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{
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struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
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int sectors_per_block, offset, block_address;
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sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT;
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offset = (int)(logic_sect_no % sectors_per_block);
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block_address = (int)(logic_sect_no / sectors_per_block);
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DEBUG(MTD_DEBUG_LEVEL3,
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"SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d,"
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" block_addr=%d\n", logic_sect_no, sectors_per_block, offset,
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block_address);
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if (block_address >= ssfdc->map_len)
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BUG();
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block_address = ssfdc->logic_block_map[block_address];
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DEBUG(MTD_DEBUG_LEVEL3,
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"SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n",
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block_address);
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if (block_address < 0xffff) {
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unsigned long sect_no;
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sect_no = (unsigned long)block_address * sectors_per_block +
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offset;
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DEBUG(MTD_DEBUG_LEVEL3,
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"SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n",
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sect_no);
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if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0)
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return -EIO;
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} else {
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memset(buf, 0xff, SECTOR_SIZE);
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}
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return 0;
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}
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static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
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{
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struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
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DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n",
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ssfdc->cylinders, ssfdc->heads, ssfdc->sectors);
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geo->heads = ssfdc->heads;
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geo->sectors = ssfdc->sectors;
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geo->cylinders = ssfdc->cylinders;
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return 0;
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}
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/****************************************************************************
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*
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* Module stuff
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*
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****************************************************************************/
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static struct mtd_blktrans_ops ssfdcr_tr = {
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.name = "ssfdc",
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.major = SSFDCR_MAJOR,
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.part_bits = SSFDCR_PARTN_BITS,
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.blksize = SECTOR_SIZE,
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.getgeo = ssfdcr_getgeo,
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.readsect = ssfdcr_readsect,
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.add_mtd = ssfdcr_add_mtd,
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.remove_dev = ssfdcr_remove_dev,
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.owner = THIS_MODULE,
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};
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static int __init init_ssfdcr(void)
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{
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printk(KERN_INFO "SSFDC read-only Flash Translation layer\n");
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return register_mtd_blktrans(&ssfdcr_tr);
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}
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static void __exit cleanup_ssfdcr(void)
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{
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deregister_mtd_blktrans(&ssfdcr_tr);
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}
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module_init(init_ssfdcr);
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module_exit(cleanup_ssfdcr);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");
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MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card");
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