openwrtv3/target/linux/generic/pending-4.9/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
Mathias Kresin 0ac91d82ed kernel: handle bad blocks in ubi auto attach code
The first block(s) of the ubi mtd device might be bad. We need to take
care on our own to skip the bad block(s) and read the next one(s).

Don't treat recoverable read errors as fatal and check for the UBI magic
if the data of a block could be recovered using ECC or similar.

Signed-off-by: Mathias Kresin <dev@kresin.me>
2018-07-24 22:24:21 +02:00

92 lines
2.4 KiB
Diff

From: Daniel Golle <daniel@makrotopia.org>
Subject: ubi: auto-attach mtd device named "ubi" or "data" on boot
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
drivers/mtd/ubi/build.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -1226,6 +1226,68 @@ static struct mtd_info * __init open_mtd
return mtd;
}
+/*
+ * This function tries attaching mtd partitions named either "ubi" or "data"
+ * during boot.
+ */
+static void __init ubi_auto_attach(void)
+{
+ int err;
+ struct mtd_info *mtd;
+ loff_t offset = 0;
+ size_t len;
+ char magic[4];
+
+ /* try attaching mtd device named "ubi" or "data" */
+ mtd = open_mtd_device("ubi");
+ if (IS_ERR(mtd))
+ mtd = open_mtd_device("data");
+
+ if (IS_ERR(mtd))
+ return;
+
+ /* get the first not bad block */
+ if (mtd_can_have_bb(mtd))
+ while (mtd_block_isbad(mtd, offset)) {
+ offset += mtd->erasesize;
+
+ if (offset > mtd->size) {
+ pr_err("UBI error: Failed to find a non-bad "
+ "block on mtd%d\n", mtd->index);
+ goto cleanup;
+ }
+ }
+
+ /* check for a valid ubi magic if read from flash was successful */
+ err = mtd_read(mtd, offset, 4, &len, (void *) magic);
+ if ((!err || mtd_is_bitflip(err)) &&
+ len == 4 && strncmp(magic, "UBI#", 4)) {
+ pr_err("UBI error: no valid UBI magic found inside mtd%d\n", mtd->index);
+ goto cleanup;
+ }
+
+ /* don't auto-add media types where UBI doesn't makes sense */
+ if (mtd->type != MTD_NANDFLASH &&
+ mtd->type != MTD_NORFLASH &&
+ mtd->type != MTD_DATAFLASH &&
+ mtd->type != MTD_MLCNANDFLASH)
+ goto cleanup;
+
+ mutex_lock(&ubi_devices_mutex);
+ pr_notice("UBI: auto-attach mtd%d\n", mtd->index);
+ err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO, 0, 0);
+ mutex_unlock(&ubi_devices_mutex);
+ if (err < 0) {
+ pr_err("UBI error: cannot attach mtd%d\n", mtd->index);
+ goto cleanup;
+ }
+
+ return;
+
+cleanup:
+ put_mtd_device(mtd);
+}
+
static int __init ubi_init(void)
{
int err, i, k;
@@ -1309,6 +1371,12 @@ static int __init ubi_init(void)
}
}
+ /* auto-attach mtd devices only if built-in to the kernel and no ubi.mtd
+ * parameter was given */
+ if (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
+ !ubi_is_module() && !mtd_devs)
+ ubi_auto_attach();
+
err = ubiblock_init();
if (err) {
pr_err("UBI error: block: cannot initialize, error %d", err);