[openwrt/openwrt] uboot-mediatek: add support for UBI EOF marker

[LEDE Commits]

dangole pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/7659ee1e2786ccc78656362d7007e4c402c939b7

commit 7659ee1e2786ccc78656362d7007e4c402c939b7
Author: Daniel Golle <daniel at makrotopia.org>
AuthorDate: Wed Jul 13 04:30:00 2022 +0100

    uboot-mediatek: add support for UBI EOF marker
    
    Let U-Boot handle free space in UBI partitions by recognizing the EOF
    marker OpenWrt is using as well for that purpose.
    
    Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
 .../patches/600-ubi-detect-eof-marker.patch        | 51 ++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/package/boot/uboot-mediatek/patches/600-ubi-detect-eof-marker.patch b/package/boot/uboot-mediatek/patches/600-ubi-detect-eof-marker.patch
new file mode 100644
index 0000000000..ab5a5f1611
--- /dev/null
+++ b/package/boot/uboot-mediatek/patches/600-ubi-detect-eof-marker.patch
@@ -0,0 +1,51 @@
+--- a/drivers/mtd/ubi/attach.c	2022-07-11 14:42:58.000000000 +0100
++++ b/drivers/mtd/ubi/attach.c	2022-06-12 16:04:56.623658788 +0100
+@@ -802,6 +802,13 @@
+ 	return err;
+ }
+ 
++static bool ec_hdr_has_eof(struct ubi_ec_hdr *ech)
++{
++	return ech->padding1[0] == 'E' &&
++	       ech->padding1[1] == 'O' &&
++	       ech->padding1[2] == 'F';
++}
++
+ /**
+  * scan_peb - scan and process UBI headers of a PEB.
+  * @ubi: UBI device description object
+@@ -832,9 +839,21 @@
+ 		return 0;
+ 	}
+ 
+-	err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
+-	if (err < 0)
+-		return err;
++	if (!ai->eof_found) {
++		err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
++		if (err < 0)
++			return err;
++
++		if (ec_hdr_has_eof(ech)) {
++			pr_notice("UBI: EOF marker found, PEBs from %d will be erased\n",
++				pnum);
++			ai->eof_found = true;
++		}
++	}
++
++	if (ai->eof_found)
++		err = UBI_IO_FF_BITFLIPS;
++
+ 	switch (err) {
+ 	case 0:
+ 		break;
+--- a/drivers/mtd/ubi/ubi.h	2022-07-11 14:42:58.000000000 +0100
++++ b/drivers/mtd/ubi/ubi.h	2022-06-12 16:04:56.626992171 +0100
+@@ -745,6 +745,7 @@
+ 	int mean_ec;
+ 	uint64_t ec_sum;
+ 	int ec_count;
++	bool eof_found;
+ 	struct kmem_cache *aeb_slab_cache;
+ };
+