generic: spi-nor: fix 4-byte opcode support for w25q256

There are 2 different chips (w25q256fv and w25q256jv) that share
the same JEDEC ID. Only w25q256jv fully supports 4-byte opcodes.
Use SFDP header version to differentiate between them.

Fixes broken reboot on 8devices Habanero since f0f35fdac

Signed-off-by: Mantas Pucka <mantas@8devices.com>

diff --git a/target/linux/generic/pending-5.4/482-mtd-spi-nor-fix-4-byte-opcode-support-for-w25q256.patch b/target/linux/generic/pending-5.4/482-mtd-spi-nor-fix-4-byte-opcode-support-for-w25q256.patch
new file mode 100644 (file)
index 0000000..d63aa76
--- /dev/null
+++ b/target/linux/generic/pending-5.4/482-mtd-spi-nor-fix-4-byte-opcode-support-for-w25q256.patch
@@ -0,0 +1,60 @@
+From: Mantas Pucka <mantas@8devices.com>
+To: linux-mtd@lists.infradead.org
+Subject: [PATCH] mtd: spi-nor: fix 4-byte opcode support for w25q256
+Date: Wed, 15 Apr 2020 16:48:30 +0300
+Message-ID: <1586958510-24012-1-git-send-email-mantas@8devices.com>
+
+There are 2 different chips (w25q256fv and w25q256jv) that share
+the same JEDEC ID. Only w25q256jv fully supports 4-byte opcodes.
+Use SFDP header version to differentiate between them.
+
+for OpenWRT only: rebased to linux-v5.4
+
+Signed-off-by: Mantas Pucka <mantas@8devices.com>
+---
+
+--- a/drivers/mtd/spi-nor/spi-nor.c
++++ b/drivers/mtd/spi-nor/spi-nor.c
+@@ -2170,6 +2170,32 @@ static struct spi_nor_fixups gd25q256_fi
+       .default_init = gd25q256_default_init,
+ };
+ 
++static int
++w25q256_post_bfpt_fixups(struct spi_nor *nor,
++                       const struct sfdp_parameter_header *bfpt_header,
++                       const struct sfdp_bfpt *bfpt,
++                       struct spi_nor_flash_parameter *params)
++{
++      /*
++       * W25Q256JV supports 4B opcodes but W25Q256FV does not.
++       * Unfortunately, Winbond has re-used the same JEDEC ID for both
++       * variants which prevents us from defining a new entry in the parts
++       * table.
++       * To differentiate between W25Q256JV and W25Q256FV check SFDP header
++       * version: only JV has JESD216A compliant structure (version 5)
++       */
++
++      if (bfpt_header->major == SFDP_JESD216_MAJOR &&
++          bfpt_header->minor == SFDP_JESD216A_MINOR)
++              nor->flags |= SNOR_F_4B_OPCODES;
++
++      return 0;
++}
++
++static struct spi_nor_fixups w25q256_fixups = {
++      .post_bfpt = w25q256_post_bfpt_fixups,
++};
++
+ /* NOTE: double check command sets and memory organization when you add
+  * more nor chips.  This current list focusses on newer chips, which
+  * have been converging on command sets which including JEDEC ID.
+@@ -2508,7 +2534,8 @@ static const struct flash_info spi_nor_i
+       { "w25q80", INFO(0xef5014, 0, 64 * 1024,  16, SECT_4K) },
+       { "w25q80bl", INFO(0xef4014, 0, 64 * 1024,  16, SECT_4K) },
+       { "w25q128", INFO(0xef4018, 0, 64 * 1024, 256, SECT_4K) },
+-      { "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
++      { "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)
++                        .fixups = &w25q256_fixups },
+       { "w25q256jvm", INFO(0xef7019, 0, 64 * 1024, 512,
+                            SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
+       { "w25m512jv", INFO(0xef7119, 0, 64 * 1024, 1024,