target/linux/ath79/patches-5.4/471-mtd-cfi_cmdset_0002-AMD-chip-0x2201-write-words.patch

   1 From f1f811410af297c848e9ec17eaa280d190fdce10 Mon Sep 17 00:00:00 2001
   2 From: Mauri Sandberg <sandberg@mailfence.com>
   3 Date: Tue, 23 Feb 2021 18:09:31 +0200
   4 Subject: [PATCH] mtd: cfi_cmdset_0002: AMD chip 0x2201 - write words
   5
   6 Buffer writes do not work with AMD chip 0x2201. The chip in question
   7 is a AMD/Spansion/Cypress Semiconductor S29GL256N and datasheet [1]
   8 talks about writing buffers being possible. While waiting for a neater
   9 solution resort to writing word-sized chunks only.
  10
  11 Without the patch kernel logs will be flooded with entries like below:
  12
  13 jffs2_scan_eraseblock(): End of filesystem marker found at 0x0
  14 jffs2_build_filesystem(): unlocking the mtd device...
  15 done.
  16 jffs2_build_filesystem(): erasing all blocks after the end marker...
  17 MTD do_write_buffer_wait(): software timeout, address:0x01ec000a.
  18 jffs2: Write clean marker to block at 0x01920000 failed: -5
  19 MTD do_write_buffer_wait(): software timeout, address:0x01e2000a.
  20 jffs2: Write clean marker to block at 0x01880000 failed: -5
  21 MTD do_write_buffer_wait(): software timeout, address:0x01e0000a.
  22 jffs2: Write clean marker to block at 0x01860000 failed: -5
  23 MTD do_write_buffer_wait(): software timeout, address:0x01dc000a.
  24 jffs2: Write clean marker to block at 0x01820000 failed: -5
  25 MTD do_write_buffer_wait(): software timeout, address:0x01da000a.
  26 jffs2: Write clean marker to block at 0x01800000 failed: -5
  27 ...
  28
  29 Tested on a Buffalo wzr-hp-g300nh running kernel 5.10.16.
  30
  31 [1] https://www.cypress.com/file/219941/download
  32 or  https://datasheetspdf.com/pdf-file/565708/SPANSION/S29GL256N/1
  33
  34 Signed-off-by: Mauri Sandberg <sandberg@mailfence.com>
  35 ---
  36  drivers/mtd/chips/cfi_cmdset_0002.c | 4 ++++
  37  1 file changed, 4 insertions(+)
  38
  39 --- a/drivers/mtd/chips/cfi_cmdset_0002.c
  40 +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
  41 @@ -272,6 +272,10 @@ static void fixup_use_write_buffers(stru
  42  {
  43         struct map_info *map = mtd->priv;
  44         struct cfi_private *cfi = map->fldrv_priv;
  45 +
  46 +       if ((cfi->mfr == CFI_MFR_AMD) && (cfi->id == 0x2201))
  47 +               return;
  48 +
  49         if (cfi->cfiq->BufWriteTimeoutTyp) {
  50                 pr_debug("Using buffer write method\n");
  51                 mtd->_write = cfi_amdstd_write_buffers;