/* * fatfs.c - FATFS file system API implementation. * * Author Mohamed Lamine Karaoui (2014,2015) * Alain Greiner (2016,2017) * * Copyright (c) UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-MKH; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include #include #include #include #include #include #include #include #include #include ////////////////////////////////////////////////////////////////////////////////////////// // Extern variables ////////////////////////////////////////////////////////////////////////////////////////// extern vfs_ctx_t fs_context[FS_TYPES_NR]; // allocated in vfs.c file extern remote_barrier_t global_barrier; // allocated in kernel_init.c ////////////////////////////////////////////////////////////////////////////////////////// // FATFS private functions ////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////////////////////// // This function returns the LBA of the first sector of a FAT cluster. // This function can be called by any thread running in any cluster. ////////////////////////////////////////////////////////////////////////////////////////// // @ ctx : pointer on FATFS context. // @ cluster : cluster index in FATFS. // @ return the lba value. ////////////////////////////////////////////////////////////////////////////////////////// static inline uint32_t fatfs_lba_from_cluster( fatfs_ctx_t * ctx, uint32_t cluster ) { return (ctx->cluster_begin_lba + ((cluster - 2) << 3)); } ///////////////////////////////////////////// error_t fatfs_get_cluster( mapper_t * mapper, uint32_t first_cluster, uint32_t searched_page, uint32_t * cluster ) { page_t * current_page_desc; // pointer on current page descriptor uint32_t * current_page_buffer; // pointer on current page (array of uint32_t) uint32_t current_page_index; // index of current page in mapper uint32_t current_page_offset; // offset of slot in current page uint32_t page_count_in_file; // index of page in file (index in linked list) uint32_t current_cluster; // content of current FAT slot // compute number of FAT slots per PPM page uint32_t slots_per_page = CONFIG_PPM_PAGE_SIZE >> 2; // initialize loop variable current_page_index = first_cluster / slots_per_page; current_page_offset = first_cluster % slots_per_page; page_count_in_file = 0; // scan FAT (i.e. traverse FAT linked list) while( page_count_in_file <= searched_page ) { // get pointer on current page descriptor current_page_desc = mapper_get_page( mapper , current_page_index ); if( current_page_desc == NULL ) return EIO; // get pointer on buffer for current page current_page_buffer = (uint32_t *)ppm_page2vaddr( current_page_desc ); // get FAT slot content current_cluster = current_page_buffer[current_page_offset]; // update loop variables current_page_index = current_cluster / slots_per_page; current_page_offset = current_cluster % slots_per_page; page_count_in_file++; } // return success *cluster = current_cluster; return 0; } // end fatfs_get_cluster() /////////////////////////////////////////////////////////////////////////////////////// // This static function return an integer record value (one, two, or four bytes) // from a memory buffer, taking into account endianness. /////////////////////////////////////////////////////////////////////////////////////// // @ offset : first byte of record in buffer. // @ size : record length in bytes (1/2/4). // @ buffer : pointer on buffer base. // @ little endian : the most significant byte has the highest address when true. // @ return the integer value in a 32 bits word. /////////////////////////////////////////////////////////////////////////////////////// static uint32_t get_record_from_buffer( uint32_t offset, uint32_t size, uint8_t * buffer, uint32_t little_endian ) { uint32_t n; uint32_t res = 0; if ( little_endian) { for( n = size ; n > 0 ; n-- ) res = (res<<8) | buffer[offset+n-1]; } else { for( n = 0 ; n < size ; n++ ) res = (res<<8) | buffer[offset+n]; } return res; } // end get_record_from_buffer() //////////////////////////////////////////////////////////////////////////////////////// // This function returns the FATFS cluster index of a page identified by its page // index in the file, using the FAT mapper. It scans the FAT mapper, starting from the // FATFS cluster index allocated to the first page of the file, until it reaches the // searched page. The FAT mapper is automatically updated in case of miss. // This function can be called by any thread running in any cluster, as it uses the // RPC_FATFS_GET_CLUSTER to access the remote FAT mapper if required. // We use a RPC to scan the FAT because the RPC_FIFO will avoid contention // in the cluster containing the FAT mapper, and the RPC latency is not critical // compared to the device access latency. //////////////////////////////////////////////////////////////////////////////////////// // @ ctx : pointer on local FATFS context. // @ first_cluster : first cluster allocated to a file in FATFS. // @ page_index : index of searched page in file (one page occupies one cluster). // @ cluster_index : [out] pointer on buffer for FATFS cluster index. // @ return 0 if success / return EIO if a FAT cluster miss cannot be solved. //////////////////////////////////////////////////////////////////////////////////////// static error_t fatfs_cluster_from_index( fatfs_ctx_t * ctx, uint32_t first_cluster, uint32_t page_index, uint32_t * cluster_index ) { uint32_t searched_cluster; // searched FATFS cluster index error_t error; // get extended pointer on FAT mapper xptr_t fat_mapper_xp = ctx->fat_mapper_xp; // get cluster cxy and local pointer on FAT mapper cxy_t fat_mapper_cxy = GET_CXY( fat_mapper_xp ); mapper_t * fat_mapper_ptr = (mapper_t *)GET_PTR( fat_mapper_xp ); if( fat_mapper_cxy == local_cxy ) // FAT mapper is local { error = fatfs_get_cluster( fat_mapper_ptr, first_cluster, page_index, &searched_cluster ); } else // FAT mapper is remote { rpc_fatfs_get_cluster_client( fat_mapper_cxy, fat_mapper_ptr, first_cluster, page_index, &searched_cluster, &error ); } if( error ) { printk("\n[ERROR] in %s : cannot access FAT\n", __FUNCTION__ ); return error; } // return success *cluster_index = searched_cluster; return 0; } // end fatfs_cluster_from_index() /////////////////////////////////////////////////////////////////////////////////////// // Generic API : the following functions are called by the kernel // and must be defined by all supported file systems. /////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////// fatfs_ctx_t * fatfs_ctx_alloc() { kmem_req_t req; req.type = KMEM_FATFS_CTX; req.size = sizeof(fatfs_ctx_t); req.flags = AF_KERNEL | AF_ZERO; return (fatfs_ctx_t *)kmem_alloc( &req ); } ////////////////////////////////////////////// void fatfs_ctx_init( fatfs_ctx_t * fatfs_ctx ) { error_t error; kmem_req_t req; uint8_t * buffer; fatfs_dmsg("\n[INFO] %s : enters at cycle %d\n", __FUNCTION__ , hal_get_cycles() ); // allocate memory for FATFS context req.type = KMEM_FATFS_CTX; req.size = sizeof(fatfs_ctx_t); req.flags = AF_KERNEL | AF_ZERO; fatfs_ctx = (fatfs_ctx_t *)kmem_alloc( &req ); nolock_assert( (fatfs_ctx != NULL) , __FUNCTION__ , "cannot allocate memory for FATFS context\n" ); // allocate a 512 bytes buffer to store the boot record req.type = KMEM_512_BYTES; req.flags = AF_KERNEL | AF_ZERO; buffer = (uint8_t *)kmem_alloc( &req ); nolock_assert( (buffer != NULL) , __FUNCTION__ , "cannot allocate memory for 512 bytes buffer\n" ); // load the boot record from device // using a synchronous access to IOC device error = dev_ioc_sync_read( buffer , 0 , 1 ); nolock_assert( (error == 0) , __FUNCTION__ , "cannot access boot record\n" ); #if CONFIG_FATFS_DEBUG uint32_t line; uint32_t byte = 0; printk("\n*** boot record at cycle %d ***\n", hal_get_cycles() ); for ( line = 0 ; line < 32 ; line++ ) { printk(" %X | %x %x %x %x %x %x %x %x %x %x %x %x %x %x %x %x |\n", byte, buffer[byte+ 0],buffer[byte+ 1],buffer[byte+ 2],buffer[byte+ 3], buffer[byte+ 4],buffer[byte+ 5],buffer[byte+ 6],buffer[byte+ 7], buffer[byte+ 8],buffer[byte+ 9],buffer[byte+10],buffer[byte+11], buffer[byte+12],buffer[byte+13],buffer[byte+14],buffer[byte+15] ); byte += 16; } #endif // check sector size from boot record uint32_t sector_size = get_record_from_buffer( BPB_BYTSPERSEC , buffer , 1 ); nolock_assert( (sector_size == 512) , __FUNCTION__ , "sector size must be 512 bytes\n" ); // check cluster size from boot record uint32_t nb_sectors = get_record_from_buffer( BPB_SECPERCLUS , buffer , 1 ); nolock_assert( (nb_sectors == 8) , __FUNCTION__ , "cluster size must be 8 sectors\n" ); // check number of FAT copies from boot record uint32_t nb_fats = get_record_from_buffer( BPB_NUMFATS , buffer , 1 ); nolock_assert( (nb_fats == 1) , __FUNCTION__ , "number of FAT copies must be 1\n" ); // get & check number of sectors in FAT from boot record uint32_t fat_sectors = get_record_from_buffer( BPB_FAT32_FATSZ32 , buffer , 1 ); nolock_assert( ((fat_sectors & 0xF) == 0) , __FUNCTION__ , "FAT not multiple of 16 sectors\n"); // get and check root cluster from boot record uint32_t root_cluster = get_record_from_buffer( BPB_FAT32_ROOTCLUS , buffer , 1 ); nolock_assert( (root_cluster == 2) , __FUNCTION__ , "root cluster index must be 2\n"); // get FAT lba from boot record uint32_t fat_lba = get_record_from_buffer( BPB_RSVDSECCNT , buffer , 1 ); // release the 512 bytes buffer req.type = KMEM_512_BYTES; req.ptr = buffer; kmem_free( &req ); // allocate a mapper for the FAT itself mapper_t * fat_mapper = mapper_create(); assert( (fat_mapper != NULL) , __FUNCTION__ , "no memory for FAT mapper" ); // initialize the FATFS context fatfs_ctx->fat_begin_lba = fat_lba; fatfs_ctx->fat_sectors_count = fat_sectors; fatfs_ctx->bytes_per_sector = sector_size; fatfs_ctx->sectors_per_cluster = nb_sectors; fatfs_ctx->cluster_begin_lba = fat_lba + fat_sectors; fatfs_ctx->root_dir_cluster = 2; fatfs_ctx->last_allocated_sector = 0; // TODO ??? fatfs_ctx->last_allocated_index = 0; // TODO ??? fatfs_ctx->fat_mapper_xp = XPTR( local_cxy , fat_mapper ); fatfs_dmsg("\n*** FAT context ***\n" "- fat_sectors = %d\n" "- sector size = %d\n" "- cluster size = %d\n" "- fat_first_lba = %d\n" "- data_first_lba = %d\n" "- mapper = %l\n", fatfs_ctx->fat_sectors_count, fatfs_ctx->bytes_per_sector, fatfs_ctx->bytes_per_cluster, fatfs_ctx->fat_begin_lba, fatfs_ctx->cluster_begin_lba, fatfs_ctx->fat_mapper_xp ); } // end fatfs_ctx_init() ///////////////////////////////////////////////// void fatfs_ctx_destroy( fatfs_ctx_t * fatfs_ctx ) { kmem_req_t req; req.type = KMEM_FATFS_CTX; req.ptr = fatfs_ctx; kmem_free( &req ); } //////////////////////////////////////////////// static error_t fatfs_access_page( page_t * page, bool_t is_read ) { // get memory buffer base address uint8_t * buffer = (uint8_t *)ppm_page2vaddr( page ); // get pointer on source mapper and page index from page descriptor mapper_t * mapper = page->mapper; uint32_t page_index = page->index; // get VFS inode pointer from mapper vfs_inode_t * vfs_inode = mapper->inode; // get first cluster index from VFS inode uint32_t first_cluster = (uint32_t)(intptr_t)vfs_inode->extend; // get FATFS context pointer from VFS context fatfs_ctx_t * fatfs_ctx = (fatfs_ctx_t *)fs_context[FS_TYPE_FATFS].extend; // get number of sectors uint32_t count = fatfs_ctx->sectors_per_cluster; // compute FATFS_cluster index for the accessed page uint32_t cluster = 0; error_t error = fatfs_cluster_from_index( fatfs_ctx, first_cluster, page_index, &cluster ); if( error ) return EIO; // get lba from cluster uint32_t lba = fatfs_lba_from_cluster( fatfs_ctx , cluster ); // access device if( is_read ) error = dev_ioc_read ( buffer , lba , count ); else error = dev_ioc_write( buffer , lba , count ); if( error ) { printk("\n[ERROR] in %s : cannot access IOC device\n", __FUNCTION__ ); return error; } // successful access return 0; } //////////////////////////////////////////////// error_t fatfs_write_page( struct page_s * page ) { bool_t is_read = false; return fatfs_access_page( page , is_read ); } /////////////////////////////////////////////// error_t fatfs_read_page( struct page_s * page ) { bool_t is_read = true; return fatfs_access_page( page , is_read ); }