diff options
Diffstat (limited to 'linux_mtd.c')
-rw-r--r-- | linux_mtd.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/linux_mtd.c b/linux_mtd.c new file mode 100644 index 00000000..e65f093c --- /dev/null +++ b/linux_mtd.c @@ -0,0 +1,390 @@ +/* + * This file is part of the flashrom project. + * + * Copyright 2015 Google Inc. + * Copyright 2018-present Facebook, Inc. + * + * This program 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 of the License. + * + * This program 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. + */ + +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <mtd/mtd-user.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/stat.h> +#include <unistd.h> + +#include "flash.h" +#include "programmer.h" + +#define LINUX_DEV_ROOT "/dev" +#define LINUX_MTD_SYSFS_ROOT "/sys/class/mtd" + +static FILE *dev_fp = NULL; + +static int mtd_device_is_writeable; + +static int mtd_no_erase; + +/* Size info is presented in bytes in sysfs. */ +static unsigned long int mtd_total_size; +static unsigned long int mtd_numeraseregions; +static unsigned long int mtd_erasesize; /* only valid if numeraseregions is 0 */ + +/* read a string from a sysfs file and sanitize it */ +static int read_sysfs_string(const char *sysfs_path, const char *filename, char *buf, int len) +{ + int i; + size_t bytes_read; + FILE *fp; + char path[strlen(LINUX_MTD_SYSFS_ROOT) + 32]; + + snprintf(path, sizeof(path), "%s/%s", sysfs_path, filename); + + if ((fp = fopen(path, "r")) == NULL) { + msg_perr("Cannot open %s\n", path); + return 1; + } + + clearerr(fp); + bytes_read = fread(buf, 1, (size_t)len, fp); + if (!feof(fp) && ferror(fp)) { + msg_perr("Error occurred when reading %s\n", path); + fclose(fp); + return 1; + } + + buf[bytes_read] = '\0'; + + /* + * Files from sysfs sometimes contain a newline or other garbage that + * can confuse functions like strtoul() and ruin formatting in print + * statements. Replace the first non-printable character (space is + * considered printable) with a proper string terminator. + */ + for (i = 0; i < len; i++) { + if (!isprint(buf[i])) { + buf[i] = '\0'; + break; + } + } + + fclose(fp); + return 0; +} + +static int read_sysfs_int(const char *sysfs_path, const char *filename, unsigned long int *val) +{ + char buf[32]; + char *endptr; + + if (read_sysfs_string(sysfs_path, filename, buf, sizeof(buf))) + return 1; + + errno = 0; + *val = strtoul(buf, &endptr, 0); + if (*endptr != '\0') { + msg_perr("Error reading %s\n", filename); + return 1; + } + + if (errno) { + msg_perr("Error reading %s: %s\n", filename, strerror(errno)); + return 1; + } + + return 0; +} + +static int popcnt(unsigned int u) +{ + int count = 0; + + while (u) { + u &= u - 1; + count++; + } + + return count; +} + +/* returns 0 to indicate success, non-zero to indicate error */ +static int get_mtd_info(const char *sysfs_path) +{ + unsigned long int tmp; + char mtd_device_name[32]; + + /* Flags */ + if (read_sysfs_int(sysfs_path, "flags", &tmp)) + return 1; + if (tmp & MTD_WRITEABLE) { + /* cache for later use by write function */ + mtd_device_is_writeable = 1; + } + if (tmp & MTD_NO_ERASE) { + mtd_no_erase = 1; + } + + /* Device name */ + if (read_sysfs_string(sysfs_path, "name", mtd_device_name, sizeof(mtd_device_name))) + return 1; + + /* Total size */ + if (read_sysfs_int(sysfs_path, "size", &mtd_total_size)) + return 1; + if (popcnt(mtd_total_size) != 1) { + msg_perr("MTD size is not a power of 2\n"); + return 1; + } + + /* Erase size */ + if (read_sysfs_int(sysfs_path, "erasesize", &mtd_erasesize)) + return 1; + if (popcnt(mtd_erasesize) != 1) { + msg_perr("MTD erase size is not a power of 2\n"); + return 1; + } + + /* Erase regions */ + if (read_sysfs_int(sysfs_path, "numeraseregions", &mtd_numeraseregions)) + return 1; + if (mtd_numeraseregions != 0) { + msg_perr("Non-uniform eraseblock size is unsupported.\n"); + return 1; + } + + msg_pdbg("%s: device_name: \"%s\", is_writeable: %d, " + "numeraseregions: %lu, total_size: %lu, erasesize: %lu\n", + __func__, mtd_device_name, mtd_device_is_writeable, + mtd_numeraseregions, mtd_total_size, mtd_erasesize); + + return 0; +} + +static int linux_mtd_probe(struct flashctx *flash) +{ + if (mtd_no_erase) + flash->chip->feature_bits |= FEATURE_NO_ERASE; + flash->chip->tested = TEST_OK_PREW; + flash->chip->total_size = mtd_total_size / 1024; /* bytes -> kB */ + flash->chip->block_erasers[0].eraseblocks[0].size = mtd_erasesize; + flash->chip->block_erasers[0].eraseblocks[0].count = mtd_total_size / mtd_erasesize; + return 1; +} + +static int linux_mtd_read(struct flashctx *flash, uint8_t *buf, + unsigned int start, unsigned int len) +{ + unsigned int eb_size = flash->chip->block_erasers[0].eraseblocks[0].size; + unsigned int i; + + if (fseek(dev_fp, start, SEEK_SET) != 0) { + msg_perr("Cannot seek to 0x%06x: %s\n", start, strerror(errno)); + return 1; + } + + for (i = 0; i < len; ) { + /* + * Try to align reads to eraseblock size. + * FIXME: Shouldn't actually be necessary, but not all MTD + * drivers handle arbitrary large reads well. + */ + unsigned int step = eb_size - ((start + i) % eb_size); + step = min(step, len - i); + + if (fread(buf + i, step, 1, dev_fp) != 1) { + msg_perr("Cannot read 0x%06x bytes at 0x%06x: %s\n", + step, start + i, strerror(errno)); + return 1; + } + + i += step; + } + + return 0; +} + +/* this version assumes we must divide the write request into chunks ourselves */ +static int linux_mtd_write(struct flashctx *flash, const uint8_t *buf, + unsigned int start, unsigned int len) +{ + unsigned int chunksize = flash->chip->block_erasers[0].eraseblocks[0].size; + unsigned int i; + + if (!mtd_device_is_writeable) + return 1; + + if (fseek(dev_fp, start, SEEK_SET) != 0) { + msg_perr("Cannot seek to 0x%06x: %s\n", start, strerror(errno)); + return 1; + } + + /* + * Try to align writes to eraseblock size. We want these large enough + * to give MTD room for optimizing performance. + * FIXME: Shouldn't need to divide this up at all, but not all MTD + * drivers handle arbitrary large writes well. + */ + for (i = 0; i < len; ) { + unsigned int step = chunksize - ((start + i) % chunksize); + step = min(step, len - i); + + if (fwrite(buf + i, step, 1, dev_fp) != 1) { + msg_perr("Cannot write 0x%06x bytes at 0x%06x\n", step, start + i); + return 1; + } + + if (fflush(dev_fp) == EOF) { + msg_perr("Failed to flush buffer: %s\n", strerror(errno)); + return 1; + } + + i += step; + } + + return 0; +} + +static int linux_mtd_erase(struct flashctx *flash, + unsigned int start, unsigned int len) +{ + uint32_t u; + + if (mtd_no_erase) { + msg_perr("%s: device does not support erasing. Please file a " + "bug report at flashrom@flashrom.org\n", __func__); + return 1; + } + + if (mtd_numeraseregions != 0) { + /* TODO: Support non-uniform eraseblock size using + use MEMGETREGIONCOUNT/MEMGETREGIONINFO ioctls */ + msg_perr("%s: mtd_numeraseregions must be 0\n", __func__); + return 1; + } + + for (u = 0; u < len; u += mtd_erasesize) { + struct erase_info_user erase_info = { + .start = start + u, + .length = mtd_erasesize, + }; + + if (ioctl(fileno(dev_fp), MEMERASE, &erase_info) == -1) { + msg_perr("%s: ioctl: %s\n", __func__, strerror(errno)); + return 1; + } + } + + return 0; +} + +static struct opaque_master programmer_linux_mtd = { + /* max_data_{read,write} don't have any effect for this programmer */ + .max_data_read = MAX_DATA_UNSPECIFIED, + .max_data_write = MAX_DATA_UNSPECIFIED, + .probe = linux_mtd_probe, + .read = linux_mtd_read, + .write = linux_mtd_write, + .erase = linux_mtd_erase, +}; + +/* Returns 0 if setup is successful, non-zero to indicate error */ +static int linux_mtd_setup(int dev_num) +{ + char sysfs_path[32]; + int ret = 1; + + /* Start by checking /sys/class/mtd/mtdN/type which should be "nor" for NOR flash */ + if (snprintf(sysfs_path, sizeof(sysfs_path), "%s/mtd%d/", LINUX_MTD_SYSFS_ROOT, dev_num) < 0) + goto linux_mtd_setup_exit; + + char buf[4]; + memset(buf, 0, sizeof(buf)); + if (read_sysfs_string(sysfs_path, "type", buf, sizeof(buf))) + return 1; + + if (strcmp(buf, "nor")) { + msg_perr("MTD device %d type is not \"nor\"\n", dev_num); + goto linux_mtd_setup_exit; + } + + /* sysfs shows the correct device type, see if corresponding device node exists */ + char dev_path[32]; + struct stat s; + snprintf(dev_path, sizeof(dev_path), "%s/mtd%d", LINUX_DEV_ROOT, dev_num); + errno = 0; + if (stat(dev_path, &s) < 0) { + msg_pdbg("Cannot stat \"%s\": %s\n", dev_path, strerror(errno)); + goto linux_mtd_setup_exit; + } + + /* so far so good, get more info from other files in this dir */ + if (snprintf(sysfs_path, sizeof(sysfs_path), "%s/mtd%d/", LINUX_MTD_SYSFS_ROOT, dev_num) < 0) + goto linux_mtd_setup_exit; + if (get_mtd_info(sysfs_path)) + goto linux_mtd_setup_exit; + + /* open file stream and go! */ + if ((dev_fp = fopen(dev_path, "r+")) == NULL) { + msg_perr("Cannot open file stream for %s\n", dev_path); + goto linux_mtd_setup_exit; + } + msg_pinfo("Opened %s successfully\n", dev_path); + + ret = 0; +linux_mtd_setup_exit: + return ret; +} + +static int linux_mtd_shutdown(void *data) +{ + if (dev_fp != NULL) { + fclose(dev_fp); + dev_fp = NULL; + } + + return 0; +} + +int linux_mtd_init(void) +{ + char *param; + int dev_num = 0; + int ret = 1; + + param = extract_programmer_param("dev"); + if (param) { + char *endptr; + + dev_num = strtol(param, &endptr, 0); + if ((*endptr != '\0') || (dev_num < 0)) { + msg_perr("Invalid device number %s. Use flashrom -p " + "linux_mtd:dev=N where N is a valid MTD\n" + "device number.\n", param); + goto linux_mtd_init_exit; + } + } + + if (linux_mtd_setup(dev_num)) + goto linux_mtd_init_exit; + + if (register_shutdown(linux_mtd_shutdown, NULL)) + goto linux_mtd_init_exit; + + register_opaque_master(&programmer_linux_mtd); + + ret = 0; +linux_mtd_init_exit: + return ret; +} |