linux_mtd: move global state into programmer data field

BUG=b:161951062
BRANCH=none
TEST=builds, reading /dev/mtd0 on Oak succeeds

Change-Id: I5ce6900e4892ed5687cfddb245dfe5461a3e2e84
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/53947
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
diff --git a/linux_mtd.c b/linux_mtd.c
index 22702e9..7cdba6c 100644
--- a/linux_mtd.c
+++ b/linux_mtd.c
@@ -31,16 +31,16 @@
 #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 */
+struct linux_mtd_data {
+	FILE *dev_fp;
+	int mtd_device_is_writeable;
+	int mtd_no_erase;
+	/* Size info is presented in bytes in sysfs. */
+	unsigned long int mtd_total_size;
+	unsigned long int mtd_numeraseregions;
+	/* only valid if numeraseregions is 0 */
+	unsigned long int mtd_erasesize;
+};
 
 /* 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)
@@ -120,7 +120,7 @@
 }
 
 /* returns 0 to indicate success, non-zero to indicate error */
-static int get_mtd_info(const char *sysfs_path)
+static int get_mtd_info(const char *sysfs_path, struct linux_mtd_data *data)
 {
 	unsigned long int tmp;
 	char mtd_device_name[32];
@@ -130,10 +130,10 @@
 		return 1;
 	if (tmp & MTD_WRITEABLE) {
 		/* cache for later use by write function */
-		mtd_device_is_writeable = 1;
+		data->mtd_device_is_writeable = 1;
 	}
 	if (tmp & MTD_NO_ERASE) {
-		mtd_no_erase = 1;
+		data->mtd_no_erase = 1;
 	}
 
 	/* Device name */
@@ -141,55 +141,59 @@
 		return 1;
 
 	/* Total size */
-	if (read_sysfs_int(sysfs_path, "size", &mtd_total_size))
+	if (read_sysfs_int(sysfs_path, "size", &data->mtd_total_size))
 		return 1;
-	if (popcnt(mtd_total_size) != 1) {
+	if (popcnt(data->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))
+	if (read_sysfs_int(sysfs_path, "erasesize", &data->mtd_erasesize))
 		return 1;
-	if (popcnt(mtd_erasesize) != 1) {
+	if (popcnt(data->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))
+	if (read_sysfs_int(sysfs_path, "numeraseregions", &data->mtd_numeraseregions))
 		return 1;
-	if (mtd_numeraseregions != 0) {
+	if (data->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);
+		__func__, mtd_device_name, data->mtd_device_is_writeable,
+		data->mtd_numeraseregions, data->mtd_total_size, data->mtd_erasesize);
 
 	return 0;
 }
 
 static int linux_mtd_probe(struct flashctx *flash)
 {
-	if (mtd_no_erase)
+	struct linux_mtd_data *data = flash->mst->opaque.data;
+
+	if (data->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;
+	flash->chip->total_size = data->mtd_total_size / 1024;	/* bytes -> kB */
+	flash->chip->block_erasers[0].eraseblocks[0].size = data->mtd_erasesize;
+	flash->chip->block_erasers[0].eraseblocks[0].count =
+		data->mtd_total_size / data->mtd_erasesize;
 	return 1;
 }
 
 static int linux_mtd_read(struct flashctx *flash, uint8_t *buf,
 			  unsigned int start, unsigned int len)
 {
+	struct linux_mtd_data *data = flash->mst->opaque.data;
 	unsigned int eb_size = flash->chip->block_erasers[0].eraseblocks[0].size;
 	unsigned int i;
 
-	if (fseek(dev_fp, start, SEEK_SET) != 0) {
+	if (fseek(data->dev_fp, start, SEEK_SET) != 0) {
 		msg_perr("Cannot seek to 0x%06x: %s\n", start, strerror(errno));
 		return 1;
 	}
@@ -203,7 +207,7 @@
 		unsigned int step = eb_size - ((start + i) % eb_size);
 		step = min(step, len - i);
 
-		if (fread(buf + i, step, 1, dev_fp) != 1) {
+		if (fread(buf + i, step, 1, data->dev_fp) != 1) {
 			msg_perr("Cannot read 0x%06x bytes at 0x%06x: %s\n",
 					step, start + i, strerror(errno));
 			return 1;
@@ -219,13 +223,14 @@
 static int linux_mtd_write(struct flashctx *flash, const uint8_t *buf,
 				unsigned int start, unsigned int len)
 {
+	struct linux_mtd_data *data = flash->mst->opaque.data;
 	unsigned int chunksize = flash->chip->block_erasers[0].eraseblocks[0].size;
 	unsigned int i;
 
-	if (!mtd_device_is_writeable)
+	if (!data->mtd_device_is_writeable)
 		return 1;
 
-	if (fseek(dev_fp, start, SEEK_SET) != 0) {
+	if (fseek(data->dev_fp, start, SEEK_SET) != 0) {
 		msg_perr("Cannot seek to 0x%06x: %s\n", start, strerror(errno));
 		return 1;
 	}
@@ -240,12 +245,12 @@
 		unsigned int step = chunksize - ((start + i) % chunksize);
 		step = min(step, len - i);
 
-		if (fwrite(buf + i, step, 1, dev_fp) != 1) {
+		if (fwrite(buf + i, step, 1, data->dev_fp) != 1) {
 			msg_perr("Cannot write 0x%06x bytes at 0x%06x\n", step, start + i);
 			return 1;
 		}
 
-		if (fflush(dev_fp) == EOF) {
+		if (fflush(data->dev_fp) == EOF) {
 			msg_perr("Failed to flush buffer: %s\n", strerror(errno));
 			return 1;
 		}
@@ -259,28 +264,29 @@
 static int linux_mtd_erase(struct flashctx *flash,
 			unsigned int start, unsigned int len)
 {
+	struct linux_mtd_data *data = flash->mst->opaque.data;
 	uint32_t u;
 
-	if (mtd_no_erase) {
+	if (data->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) {
+	if (data->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) {
+	for (u = 0; u < len; u += data->mtd_erasesize) {
 		struct erase_info_user erase_info = {
 			.start = start + u,
-			.length = mtd_erasesize,
+			.length = data->mtd_erasesize,
 		};
 
-		if (ioctl(fileno(dev_fp), MEMERASE, &erase_info) == -1) {
+		if (ioctl(fileno(data->dev_fp), MEMERASE, &erase_info) == -1) {
 			msg_perr("%s: ioctl: %s\n", __func__, strerror(errno));
 			return 1;
 		}
@@ -300,7 +306,7 @@
 };
 
 /* Returns 0 if setup is successful, non-zero to indicate error */
-static int linux_mtd_setup(int dev_num)
+static int linux_mtd_setup(int dev_num, struct linux_mtd_data *data)
 {
 	char sysfs_path[32];
 	int ret = 1;
@@ -332,15 +338,15 @@
 	/* 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))
+	if (get_mtd_info(sysfs_path, data))
 		goto linux_mtd_setup_exit;
 
 	/* open file stream and go! */
-	if ((dev_fp = fopen(dev_path, "r+")) == NULL) {
+	if ((data->dev_fp = fopen(dev_path, "r+")) == NULL) {
 		msg_perr("Cannot open file stream for %s\n", dev_path);
 		goto linux_mtd_setup_exit;
 	}
-	ret = setvbuf(dev_fp, NULL, _IONBF, 0);
+	ret = setvbuf(data->dev_fp, NULL, _IONBF, 0);
 	if (ret)
 		msg_pwarn("Failed to set MTD device to unbuffered: %d\n", ret);
 
@@ -353,10 +359,11 @@
 
 static int linux_mtd_shutdown(void *data)
 {
-	if (dev_fp != NULL) {
-		fclose(dev_fp);
-		dev_fp = NULL;
+	struct linux_mtd_data *mtd_data = data;
+	if (mtd_data->dev_fp != NULL) {
+		fclose(mtd_data->dev_fp);
 	}
+	free(data);
 
 	return 0;
 }
@@ -366,6 +373,7 @@
 	char *param;
 	int dev_num = 0;
 	int ret = 1;
+	struct linux_mtd_data *data = NULL;
 
 	param = extract_programmer_param("dev");
 	if (param) {
@@ -398,11 +406,23 @@
 		goto linux_mtd_init_exit;
 	}
 
-	if (linux_mtd_setup(dev_num))
+	data = calloc(1, sizeof(*data));
+	if (!data) {
+		msg_perr("Unable to allocate memory for linux_mtd_data\n");
 		goto linux_mtd_init_exit;
+	}
 
-	if (register_shutdown(linux_mtd_shutdown, NULL))
+	/* Get MTD info and store it in `data` */
+	if (linux_mtd_setup(dev_num, data)) {
+		free(data);
 		goto linux_mtd_init_exit;
+	}
+
+	programmer_linux_mtd.data = data;
+	if (register_shutdown(linux_mtd_shutdown, (void *)data)) {
+		free(data);
+		goto linux_mtd_init_exit;
+	}
 
 	register_opaque_master(&programmer_linux_mtd);