libmtd: support MEMERASE64

This patch is base on Kevin Cernekee's patch posted to the MTD mailing
list. It adds MEMERASE64 support to the 'mtd_erase()' call. Now it
first tries to use MEMERASE64, and if that is not supported, falls
back to the old MEMERASE ioctl.

This patch also introduces an 'offs64_ioctl' flag to the libmtd
descriptor. However, we cannot initialize it in 'libmtd_open()',
because we need an MTD device node, which we do not have in
'libmtd_open()'. Thus, we firs mark this flag as "uninitialized",
and at the first invocation of 'mtd_erase()' we initialize it.

This also means that we have to pass the limbtd descriptor to
'mtd_erase()', to save the flag value. This, in turn, requires
tweaking 'mtd_erase()' users.

This is not very nice, but good enough so far.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

2 files changed, 70 insertions, 6 deletions

diff --git a/lib/libmtd.c b/lib/libmtd.c
index 3ff031c..a976679 100644
--- a/lib/libmtd.c
+++ b/lib/libmtd.c
@@ -560,6 +560,8 @@ libmtd_t libmtd_open(void)
 	if (!lib)
 		return NULL;
 
+	lib->offs64_ioctls = OFFS64_IOCTLS_UNKNOWN;
+
 	lib->sysfs_mtd = mkpath("/sys", SYSFS_MTD);
 	if (!lib->sysfs_mtd)
 		goto out_error;
@@ -789,13 +791,57 @@ int mtd_get_dev_info(libmtd_t desc, const char *node, struct mtd_dev_info *mtd)
 	return mtd_get_dev_info1(desc, mtd_num, mtd);
 }
 
-int mtd_erase(const struct mtd_dev_info *mtd, int fd, int eb)
+int mtd_erase(libmtd_t desc, const struct mtd_dev_info *mtd, int fd, int eb)
 {
+	int ret;
+	struct libmtd *lib = (struct libmtd *)desc;
+	struct erase_info_user64 ei64;
 	struct erase_info_user ei;
 
-	ei.start = eb * mtd->eb_size;;
-	ei.length = mtd->eb_size;
-	return ioctl(fd, MEMERASE, &ei);
+	if (eb < 0 || eb >= mtd->eb_cnt) {
+		errmsg("bad eraseblock number %d, mtd%d has %d eraseblocks",
+		       eb, mtd->mtd_num, mtd->eb_cnt);
+		errno = EINVAL;
+		return -1;
+	}
+
+	ei64.start = (__u64)eb * mtd->eb_size;
+	ei64.length = mtd->eb_size;
+
+	if (lib->offs64_ioctls == OFFS64_IOCTLS_SUPPORTED ||
+	    lib->offs64_ioctls == OFFS64_IOCTLS_UNKNOWN) {
+		ret = ioctl(fd, MEMERASE64, &ei64);
+		if (ret == 0)
+			return ret;
+
+		if (errno != ENOTTY ||
+		    lib->offs64_ioctls != OFFS64_IOCTLS_UNKNOWN)
+			return sys_errmsg("MEMERASE64 ioctl failed for "
+					  "eraseblock %d (mtd%d)",
+					  eb, mtd->mtd_num);
+
+		/*
+		 * MEMERASE64 support was added in kernel version 2.6.31, so
+		 * probably we are working with older kernel and this ioctl is
+		 * not supported.
+		 */
+		lib->offs64_ioctls = OFFS64_IOCTLS_NOT_SUPPORTED;
+	}
+
+	if (ei64.start + ei64.length > 0xFFFFFFFF) {
+		errmsg("this system can address only %u eraseblocks",
+		       0xFFFFFFFFU / mtd->eb_size);
+		errno = EINVAL;
+		return -1;
+	}
+
+	ei.start = ei64.start;
+	ei.length = ei64.length;
+	ret = ioctl(fd, MEMERASE, &ei);
+	if (ret < 0)
+		return sys_errmsg("MEMERASE ioctl failed for eraseblock %d "
+				  "(mtd%d)", eb, mtd->mtd_num);
+	return 0;
 }
 
 /* Patterns to write to a physical eraseblock when torturing it */
@@ -820,7 +866,7 @@ static int check_pattern(const void *buf, uint8_t patt, int size)
 	return 1;
 }
 
-int mtd_torture(const struct mtd_dev_info *mtd, int fd, int eb)
+int mtd_torture(libmtd_t desc, const struct mtd_dev_info *mtd, int fd, int eb)
 {
 	int err, i, patt_count;
 	void *buf;
@@ -835,7 +881,7 @@ int mtd_torture(const struct mtd_dev_info *mtd, int fd, int eb)
 	}
 
 	for (i = 0; i < patt_count; i++) {
-		err = mtd_erase(mtd, fd, eb);
+		err = mtd_erase(desc, mtd, fd, eb);
 		if (err)
 			goto out;
 
diff --git a/lib/libmtd_int.h b/lib/libmtd_int.h
index 7de4b42..bb48d35 100644
--- a/lib/libmtd_int.h
+++ b/lib/libmtd_int.h
@@ -43,6 +43,10 @@ extern "C" {
 #define MTD_REGION_CNT   "numeraseregions"
 #define MTD_FLAGS        "flags"
 
+#define OFFS64_IOCTLS_UNKNOWN       0
+#define OFFS64_IOCTLS_NOT_SUPPORTED 1
+#define OFFS64_IOCTLS_SUPPORTED     2
+
 /**
  * libmtd - MTD library description data structure.
  * @sysfs_mtd: MTD directory in sysfs
@@ -58,6 +62,19 @@ extern "C" {
  * @mtd_region_cnt: count of additional erase regions file pattern
  * @mtd_flags: MTD device flags file pattern
  * @sysfs_supported: non-zero if sysfs is supported by MTD
+ * @offs64_ioctls: %OFFS64_IOCTLS_SUPPORTED if 64-bit %MEMERASE64,
+ *                 %MEMREADOOB64, %MEMWRITEOOB64 MTD device ioctls are
+ *                 supported, %OFFS64_IOCTLS_NOT_SUPPORTED if not, and
+ *                 %OFFS64_IOCTLS_UNKNOWN if it is not known yet;
+ *
+ *  Note, we cannot find out whether 64-bit ioctls are supported by MTD when we
+ *  are initializing the library, because this requires an MTD device node.
+ *  Indeed, we have to actually call the ioctl and check for %ENOTTY to find
+ *  out whether it is supported or not.
+ *
+ *  Thus, we leave %offs64_ioctls uninitialized in 'libmtd_open()', and
+ *  initialize it later, when corresponding libmtd function is used, and when
+ *  we actually have a device node and can invoke an ioctl command on it.
  */
 struct libmtd
 {
@@ -74,6 +91,7 @@ struct libmtd
 	char *mtd_region_cnt;
 	char *mtd_flags;
 	unsigned int sysfs_supported:1;
+	unsigned int offs64_ioctls:2;
 };
 
 int legacy_libmtd_open(void);