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@makrotopia.org>

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 (file)
index 0000000..ab5a5f1
--- /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;
+ };
+