openwrt/target/linux/generic/pending-6.6/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
Shiji Yang 007437c225 kernel: mtd: ubi: avoid attaching "linux,ubi" mtd again
"linux,ubi" compatible MTD device can be automatically attached early
since commit fc153aa8d94f. Therefore, there is no need to attach MTD
devices named "ubi" or "data" again.

Signed-off-by: Shiji Yang <yangshiji66@qq.com>
2024-06-28 20:55:11 +01:00

105 lines
2.6 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
@@ -1258,6 +1258,80 @@ static struct mtd_notifier ubi_mtd_notif
.remove = ubi_notify_remove,
};
+
+/*
+ * 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;
+ struct device_node *np;
+ 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;
+
+ /* skip "linux,ubi" mtd as it has already been attached */
+ np = mtd_get_of_node(mtd);
+ if (of_device_is_compatible(np, "linux,ubi"))
+ goto cleanup;
+
+ /* 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 if the read from flash was successful */
+ err = mtd_read(mtd, offset, 4, &len, (void *) magic);
+ if ((err && !mtd_is_bitflip(err)) || len != 4) {
+ pr_err("UBI error: unable to read from mtd%d\n", mtd->index);
+ goto cleanup;
+ }
+
+ /* check for a valid ubi magic */
+ if (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, false);
+ 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_attach(void)
{
int err, i, k;
@@ -1308,6 +1382,12 @@ static int __init ubi_init_attach(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();
+
return 0;
out_detach: