1 files changed, 390 insertions, 0 deletions
diff --git a/linux_mtd.c b/linux_mtd.c
new file mode 100644
index 000000000..e65f093c0
--- /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;
+}