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[2nd,RESEND,v2,1/6] mtd: ubi: Do not zero out EC and VID on ECC-ed NOR flashes

Message ID 53a897774ae0b6357a867c0158cc68e01a578618.1727399650.git.Takahiro.Kuwano@infineon.com
State New
Delegated to: Jagannadha Sutradharudu Teki
Headers show
Series mtd: Make sure UBIFS does not do multi-pass page programming on flashes that don't support it | expand

Commit Message

Takahiro Kuwano Sept. 27, 2024, 1:18 a.m. UTC 
From: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>

For NOR flashes EC and VID are zeroed out before an erase is issued to
make sure UBI does not mistakenly treat the PEB as used and associate it
with an LEB.

But on some flashes, like the Infineon Semper NOR flash family,
multi-pass page programming is not allowed on the default ECC scheme.
This means zeroing out these magic numbers will result in the flash
throwing a page programming error.

Do not zero out EC and VID for such flashes. A writesize > 1 is an
indication of an ECC-ed flash.

This patch replicates the following upstream linux commit:
f669e74be820 ("ubi: Do not zero out EC and VID on ECC-ed NOR flashes")

Acked-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
---
 drivers/mtd/ubi/build.c | 4 +---
 drivers/mtd/ubi/io.c    | 9 ++++++++-
 2 files changed, 9 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index cf0d702421f..104537784ab 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -679,10 +679,8 @@  static int io_init(struct ubi_device *ubi, int max_beb_per1024)
 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
 	}
 
-	if (ubi->mtd->type == MTD_NORFLASH) {
-		ubi_assert(ubi->mtd->writesize == 1);
+	if (ubi->mtd->type == MTD_NORFLASH)
 		ubi->nor_flash = 1;
-	}
 
 	ubi->min_io_size = ubi->mtd->writesize;
 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 14be95b74bc..45699b4a477 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -563,7 +563,14 @@  int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 		return -EROFS;
 	}
 
-	if (ubi->nor_flash) {
+	/*
+	 * If the flash is ECC-ed then we have to erase the ECC block before we
+	 * can write to it. But the write is in preparation to an erase in the
+	 * first place. This means we cannot zero out EC and VID before the
+	 * erase and we just have to hope the flash starts erasing from the
+	 * start of the page.
+	 */
+	if (ubi->nor_flash && ubi->mtd->writesize == 1) {
 		err = nor_erase_prepare(ubi, pnum);
 		if (err)
 			return err;