[][OpenWrt Dev][nmbm: add support to check the usability of a erased block]
[Description]
Add an option to specify the ability of the lower device which indicates
that whether the lower driver supports ECC correction on empty pages.
When this option is set, NMBM will read all pages of a just erased block.
If ECC error reported, the block is believed having too many bitflips and
should be marked bad.
[Release-log]
N/A
Change-Id: If837b97d4691ff6d41f11540ba1da295b2d45052
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/4649343
diff --git a/target/linux/generic/files-5.4/drivers/mtd/nmbm/nmbm-core.c b/target/linux/generic/files-5.4/drivers/mtd/nmbm/nmbm-core.c
index 16a2d01..d762d6a 100644
--- a/target/linux/generic/files-5.4/drivers/mtd/nmbm/nmbm-core.c
+++ b/target/linux/generic/files-5.4/drivers/mtd/nmbm/nmbm-core.c
@@ -618,6 +618,56 @@
}
/*
+ * nmbm_erase_block_and_check - Erase a block and check its usability
+ * @ni: NMBM instance structure
+ * @ba: block address to be erased
+ *
+ * Erase a block anc check its usability
+ *
+ * Return true if the block is usable, false if erasure failure or the block
+ * has too many bitflips.
+ */
+static bool nmbm_erase_block_and_check(struct nmbm_instance *ni, uint32_t ba)
+{
+ uint64_t addr, off;
+ bool success;
+ int ret;
+
+ success = nmbm_erase_phys_block(ni, ba2addr(ni, ba));
+ if (!success)
+ return false;
+
+ if (!(ni->lower.flags & NMBM_F_EMPTY_PAGE_ECC_OK))
+ return true;
+
+ /* Check every page to make sure there aren't too many bitflips */
+
+ addr = ba2addr(ni, ba);
+
+ for (off = 0; off < ni->lower.erasesize; off += ni->lower.writesize) {
+ WATCHDOG_RESET();
+
+ ret = nmbm_read_phys_page(ni, addr + off, ni->page_cache, NULL,
+ NMBM_MODE_PLACE_OOB);
+ if (ret == -EBADMSG) {
+ /*
+ * NMBM_F_EMPTY_PAGE_ECC_OK means the empty page is
+ * still protected by ECC. So reading pages with ECC
+ * enabled and -EBADMSG means there are too many
+ * bitflips that can't be recovered, and the block
+ * containing the page should be marked bad.
+ */
+ nlog_err(ni,
+ "Too many bitflips in empty page at 0x%llx\n",
+ addr + off);
+ return false;
+ }
+ }
+
+ return true;
+}
+
+/*
* nmbm_erase_range - Erase a range of blocks
* @ni: NMBM instance structure
* @ba: block address where the erasure will start
@@ -645,7 +695,7 @@
goto next_block;
}
- success = nmbm_erase_phys_block(ni, ba2addr(ni, ba));
+ success = nmbm_erase_block_and_check(ni, ba);
if (success)
goto next_block;
@@ -740,7 +790,7 @@
goto next_block;
}
- success = nmbm_erase_phys_block(ni, ba2addr(ni, ba));
+ success = nmbm_erase_block_and_check(ni, ba);
if (!success)
goto skip_bad_block;
@@ -905,7 +955,7 @@
goto next_block;
}
- success = nmbm_erase_phys_block(ni, ba2addr(ni, ba));
+ success = nmbm_erase_block_and_check(ni, ba);
if (!success)
goto skip_bad_block;
@@ -2348,7 +2398,7 @@
goto remap_logic_block;
}
- success = nmbm_erase_phys_block(ni, ba2addr(ni, pb));
+ success = nmbm_erase_block_and_check(ni, pb);
if (success)
return 0;