// SPDX-License-Identifier: GPL-2.0-only /* * Linux driver for SSFDC Flash Translation Layer (Read only) * © 2005 Eptar srl * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com> * * Based on NTFL and MTDBLOCK_RO drivers */ #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/rawnand.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 { pr_debug("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_OPS_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) { pr_debug("SSFDC_RO: logical address field%d" "parity error(0x%04X)\n", j+1, block_address); } else { ok = 1; break; } } } if (!ok) block_address = -2; pr_debug("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; pr_debug("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) { pr_debug("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; pr_debug("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_is_nand(mtd) || mtd->oobsize != OOB_SIZE || mtd->size > UINT_MAX) 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) 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 = (u32)mtd->size / mtd->erasesize; pr_debug("SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n", ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len, DIV_ROUND_UP(ssfdc->map_len, 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)(((u32)mtd->size >> SECTOR_SHIFT) / ((long)ssfdc->sectors * (long)ssfdc->heads)); pr_debug("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_array(ssfdc->map_len, sizeof(ssfdc->logic_block_map[0]), GFP_KERNEL); if (!ssfdc->logic_block_map) 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; pr_debug("SSFDC_RO: remove_dev (i=%d)\n", dev->devnum); del_mtd_blktrans_dev(dev); kfree(ssfdc->logic_block_map); } 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); pr_debug("SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d," " block_addr=%d\n", logic_sect_no, sectors_per_block, offset, block_address); BUG_ON(block_address >= ssfdc->map_len); block_address = ssfdc->logic_block_map[block_address]; pr_debug("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; pr_debug("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; pr_debug("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");