linux-kernel - [PATCH 3/3] mtd: spi-nor: spansion: SMPT fixups for S25FS-S

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Message-Id: <20251022-s25fs-s-smpt-fixup-v1-3-ce26d4084b2d@infineon.com>
Date: Wed, 22 Oct 2025 19:07:22 +0900
From: Takahiro Kuwano <tkuw584924@...il.com>
To: Tudor Ambarus <tudor.ambarus@...aro.org>, 
 Pratyush Yadav <pratyush@...nel.org>, Michael Walle <mwalle@...nel.org>, 
 Miquel Raynal <miquel.raynal@...tlin.com>, 
 Richard Weinberger <richard@....at>, Vignesh Raghavendra <vigneshr@...com>, 
 Marek Vasut <marek.vasut+renesas@...lbox.org>
Cc: linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Takahiro Kuwano <Takahiro.Kuwano@...ineon.com>, tkuw584924@...il.com
Subject: [PATCH 3/3] mtd: spi-nor: spansion: SMPT fixups for S25FS-S

S25FS-S family supports SMPT that helps to detect sector layout settings
in configuration registers, but some of parameters in the table are
wrong or undetermined so the fixups below are required.

Read Any Register op is used to read configuration registers that
related to sector map. The op requires 8 cycles latency by default.
Implement smpt_read_dummy() to set correct dummy cycles.

Map ID is structured by combination of CR3NV[3], CR1NV[2], and CR3NV[1].
However, in S25FS512S, CR3NV[1] is RFU and always 0, while map IDs
defined in the table assume it is always 1. Implement smpt_map_id() to
fix map ID for S25FS512S. Other densities in S25FS-S family (256Mb and
128Mb) don't need this fix as CR3NV[1] in those chips is configurable
and map IDs are correctly defined in SMPT.

Co-developed-by: Marek Vasut <marek.vasut+renesas@...lbox.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@...lbox.org>
Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@...ineon.com>
---
 drivers/mtd/spi-nor/spansion.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c
index a0296c871634678be509cb30d26e18debff3066d..89e85eba2c31a4d74dcbfeffdeff7139b6e0f6b1 100644
--- a/drivers/mtd/spi-nor/spansion.c
+++ b/drivers/mtd/spi-nor/spansion.c
@@ -785,8 +785,42 @@ s25fs_s_nor_post_bfpt_fixups(struct spi_nor *nor,
 	return 0;
 }
 
+static void s25fs_s_nor_smpt_read_dummy(const struct spi_nor *nor,
+					u8 *read_dummy)
+{
+	/*
+	 * The configuration detection dwords in S25FS-S SMPT has 65h as
+	 * command instruction and 'variable' as configuration detection command
+	 * latency. Set 8 dummy cycles as it is factory default for 65h (read
+	 * any register) op.
+	 */
+	*read_dummy = 8;
+}
+
+static void s25fs_s_nor_smpt_map_id_dummy(const struct spi_nor *nor, u8 *map_id)
+{
+	/*
+	 * The S25FS512S chip datasheet rev.O Table 71 on page 153
+	 * JEDEC Sector Map Parameter Dword-6 Config. Detect-3 does
+	 * use CR3NV bit 1 to discern 64kiB/256kiB uniform sectors
+	 * device configuration, however according to section 7.5.5.1
+	 * Configuration Register 3 Non-volatile (CR3NV) page 61, the
+	 * CR3NV bit 1 is RFU Reserved for Future Use, and is set to
+	 * 0 on newly manufactured devices, which means 64kiB sectors.
+	 * Since the device does not support 64kiB uniform sectors in
+	 * any configuration, parsing SMPT table cannot find a valid
+	 * sector map entry and fails. Fix this up by setting SMPT
+	 * configuration index bit 0, which is populated exactly by
+	 * the CR3NV bit 1 being 1.
+	 */
+	if (nor->params->size == SZ_64M)
+		*map_id |= BIT(0);
+}
+
 static const struct spi_nor_fixups s25fs_s_nor_fixups = {
 	.post_bfpt = s25fs_s_nor_post_bfpt_fixups,
+	.smpt_read_dummy = s25fs_s_nor_smpt_read_dummy,
+	.smpt_map_id = s25fs_s_nor_smpt_map_id_dummy,
 };
 
 static const struct flash_info spansion_nor_parts[] = {

-- 
2.34.1