From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta068a.interbusiness.it ([85.37.17.68]) by canuck.infradead.org with esmtp (Exim 4.62 #1 (Red Hat Linux)) id 1FsgET-0003HH-Pz for linux-mtd@lists.infradead.org; Tue, 20 Jun 2006 09:25:52 -0400 Message-ID: <4497F758.5090708@eptar.com> Date: Tue, 20 Jun 2006 15:25:44 +0200 From: Claudio Lanconelli MIME-Version: 1.0 To: David Woodhouse Subject: Re: FAT vs jFFS2 for NAND. References: <4497DCA6.2080006@eptar.com> <1150806658.17609.55.camel@hades.cambridge.redhat.com> In-Reply-To: <1150806658.17609.55.camel@hades.cambridge.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , David Woodhouse wrote: > Thanks. I think it makes a certain amount of sense to merge that -- > people can add write support to it later. Please could you re-send with > a Signed-off-by: line so that it can be merged Signed-off-by: Claudio Lanconelli /* * Linux driver for SSFDC Flash Translation Layer (Read only) * (c) 2005 Eptar srl * Author: Claudio Lanconelli * * 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. * * $Id: ssfdc_ro.c,v 1.5 2005/11/28 13:54:08 claudio Exp $ */ #include #include #include #include #include #include #include #include #include #undef ENABLE_GETGEO #undef DEBUG #define DEBUG(n, args...) \ do { \ if (n <= SSFDC_RO_DEBUG_VERBOSE) \ printk(KERN_INFO args); \ } while(0) #define SSFDC_RO_DEBUG_VERBOSE 0 struct ssfdcr_record { struct mtd_blktrans_dev mbd; int usecount; #ifdef ENABLE_GETGEO unsigned char heads; unsigned char sectors; unsigned short cylinders; #endif 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 }; static const struct nand_oobinfo ssfdc_oobinfo = { .useecc = MTD_NANDECC_PLACEONLY, .eccbytes = 6, .eccpos = {14, 13, 15, 9, 8, 10} }; #define SSFDCR_MAJOR 44 #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 ArraySize(x) ( sizeof(x) / sizeof((x)[0]) ) #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 **/ #ifdef ENABLE_GETGEO 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; } #endif static const unsigned char nibble_count_bits[16] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 }; //Counts bit 1 in a byte. Use look up table to speed up count static int byte_count_bits(unsigned char val) { return nibble_count_bits[val >> 4] + nibble_count_bits[val & 0x0f]; } static const unsigned char cis_numbers[] = { 0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20 }; #define OOB_BLOCKSTATUS_OFFSET 5 #define block_is_bad(x) ( byte_count_bits(x) < 7 ) #define block_is_good(x) ( !block_is_bad(x) ) //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; unsigned char sect_buf[SECTOR_SIZE]; unsigned char oob_buf[OOB_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) { ret = MTD_READOOB(mtd, offset, OOB_SIZE, &retlen, oob_buf); if ( ret < 0 || retlen != OOB_SIZE ) { DEBUG(MTD_DEBUG_LEVEL0, "SSFDC_RO: can't read OOB data on sector %d\n", (int)(offset >> SECTOR_SHIFT)); break; } if ( block_is_good( oob_buf[OOB_BLOCKSTATUS_OFFSET] ) ) { ret = MTD_READ(mtd, offset, SECTOR_SIZE, &retlen, sect_buf); if ( ret < 0 || retlen != SECTOR_SIZE ) { DEBUG(MTD_DEBUG_LEVEL0, "SSFDC_RO: can't read CIS/IDI sector\n"); } else if ( !memcmp(sect_buf, cis_numbers, sizeof(cis_numbers)) ) //CIS pattern matching on the sector buffer { cis_sector = (int)(offset >> SECTOR_SHIFT); //Found } 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 (just a wrapper to MTD_READ) static int read_physical_sector(struct mtd_info *mtd, unsigned char *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; } //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(unsigned char oob_buf[OOB_SIZE]) { int block_address, parity; int offset[2] = {6, 11}; //offset of the two address fields within OOB int j; int ok = 0; //First we check for good block if ( block_is_bad(oob_buf[OOB_BLOCKSTATUS_OFFSET]) ) { DEBUG(MTD_DEBUG_LEVEL0, "SSFDC_RO: get_logical_address() Bad block\n"); return -1; //Bad block } //Look for the first valid logical address //Valid address has fixed pattern on most significant bits and parity check for (j = 0; j < ArraySize(offset); j++) { block_address = ((int)oob_buf[offset[j]] << 8) | oob_buf[offset[j]+1]; //Check for the signature bits in the address field (most significant bits) 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; unsigned char oob_buf[OOB_SIZE]; int ret, block_address, phys_block; size_t retlen; DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: build_block_map() n.blocks = %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; ret = MTD_READOOB(ssfdc->mbd.mtd, offset, OOB_SIZE, &retlen, oob_buf); if ( ret < 0 || retlen != OOB_SIZE ) { DEBUG(MTD_DEBUG_LEVEL0, "SSFDC_RO: mtd read_oob() failed at %lu\n", offset); return -1; } block_address = get_logical_address(oob_buf); //Skip bad blocks and 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 NAND flash if (mtd->type != MTD_NANDFLASH) return; //Check for SSDFC format by reading CIS/IDI sector cis_sector = get_valid_cis_sector(mtd); if ( cis_sector == -1 ) return; ssfdc = kmalloc(sizeof(struct ssfdcr_record), GFP_KERNEL); if ( !ssfdc ) { printk(KERN_WARNING "SSFDC_RO: out of memory for data structures\n"); return; } memset(ssfdc, 0, sizeof(*ssfdc)); 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); #ifdef ENABLE_GETGEO // Set geometry 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; #else ssfdc->mbd.size = ssfdc->map_len * (ssfdc->erase_size >> SECTOR_SHIFT); #endif //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"); kfree(ssfdc); return; } 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 ) { if ( ssfdc->logic_block_map ) kfree(ssfdc->logic_block_map); kfree(ssfdc); return; } //Register device + partitions if (add_mtd_blktrans_dev(&ssfdc->mbd)) { if ( ssfdc->logic_block_map ) kfree(ssfdc->logic_block_map); kfree(ssfdc); return; } printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n", ssfdc->mbd.devnum + 'a', mtd->index, mtd->name); } 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); if (ssfdc->logic_block_map) 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; } #ifdef ENABLE_GETGEO 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; } #endif /**************************************************************************** * * Module stuff * ****************************************************************************/ static struct mtd_blktrans_ops ssfdcr_tr = { .name = "ssfdc", .major = SSFDCR_MAJOR, .part_bits = SSFDCR_PARTN_BITS, #ifdef ENABLE_GETGEO .getgeo = ssfdcr_getgeo, #endif .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 $Revision: 1.5 $\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 "); MODULE_DESCRIPTION("Flash Translation Layer for read-only SSDFC SmartMedia card");