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From: Michael Walle <michael@walle.cc>
To: Tudor Ambarus <tudor.ambarus@microchip.com>,
	Pratyush Yadav <p.yadav@ti.com>, Michael Walle <michael@walle.cc>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org
Subject: [PATCH 5/6] mtd: spi-nor: add generic flash driver
Date: Fri, 13 May 2022 15:35:19 +0200	[thread overview]
Message-ID: <20220513133520.3945820-6-michael@walle.cc> (raw)
In-Reply-To: <20220513133520.3945820-1-michael@walle.cc>

Our SFDP is parsing is everything we need to support all basic
operations of a flash device. If the flash isn't found in our in-kernel
flash database, gracefully fall back to a driver described solely by its
SFDP tables.

It is still recommended to add the flash to the in-kernel database.
First, we get a proper partname and secondly, for all features not
described by the SFDP like OTP we need the entry anyway.

Signed-off-by: Michael Walle <michael@walle.cc>
---
 drivers/mtd/spi-nor/core.c | 13 +++++++++++++
 drivers/mtd/spi-nor/core.h |  1 +
 drivers/mtd/spi-nor/sfdp.c | 27 +++++++++++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 65cd8e668579..ee193a61310a 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1632,6 +1632,11 @@ static const struct spi_nor_manufacturer *manufacturers[] = {
 	&spi_nor_xmc,
 };
 
+static const struct flash_info spi_nor_generic_flash = {
+	.name = "spi-nor-generic",
+	.parse_sfdp = true,
+};
+
 static const struct flash_info *spi_nor_match_id(struct spi_nor *nor,
 						 const u8 *id)
 {
@@ -1670,6 +1675,14 @@ static const struct flash_info *spi_nor_detect(struct spi_nor *nor)
 		return ERR_PTR(-ENOMEM);
 
 	info = spi_nor_match_id(nor, id);
+
+	/* Fallback to a generic flash described only by its SFDP data. */
+	if (!info) {
+		ret = spi_nor_check_sfdp_signature(nor);
+		if (!ret)
+			info = &spi_nor_generic_flash;
+	}
+
 	if (!info) {
 		dev_err(nor->dev, "unrecognized JEDEC id bytes: %*ph\n",
 			SPI_NOR_MAX_ID_LEN, id);
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 3a19b8092ab8..aa9f218245a5 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -694,6 +694,7 @@ int spi_nor_controller_ops_read_reg(struct spi_nor *nor, u8 opcode,
 int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode,
 				     const u8 *buf, size_t len);
 
+int spi_nor_check_sfdp_signature(struct spi_nor *nor);
 int spi_nor_parse_sfdp(struct spi_nor *nor);
 
 static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index a5211543d30d..9bdb3d5dc7e8 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -1247,6 +1247,33 @@ static void spi_nor_post_sfdp_fixups(struct spi_nor *nor)
 		nor->info->fixups->post_sfdp(nor);
 }
 
+/**
+ * spi_nor_check_sfdp_header() - check for a valid SFDP header
+ * @nor:		pointer to a 'struct spi_nor'
+ *
+ * Used to detect if the flash supports the RDSFDP command as well as the
+ * presence of a valid SFDP table.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+int spi_nor_check_sfdp_signature(struct spi_nor *nor)
+{
+	u32 signature;
+	int err;
+
+	/* Get the SFDP header. */
+	err = spi_nor_read_sfdp_dma_unsafe(nor, 0, sizeof(signature),
+					   &signature);
+	if (err < 0)
+		return err;
+
+	/* Check the SFDP signature. */
+	if (le32_to_cpu(signature) != SFDP_SIGNATURE)
+		return -EINVAL;
+
+	return 0;
+}
+
 /**
  * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
  * @nor:		pointer to a 'struct spi_nor'
-- 
2.30.2


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  parent reply	other threads:[~2022-05-13 13:36 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-13 13:35 [PATCH 0/6] mtd: spi-nor: generic flash driver Michael Walle
2022-05-13 13:35 ` [PATCH 1/6] mtd: spi-nor: hide jedec_id sysfs attribute if not present Michael Walle
2022-07-26 10:00   ` Takahiro Kuwano
2022-05-13 13:35 ` [PATCH 2/6] mtd: spi-nor: sysfs: hide manufacturer if it is not set Michael Walle
2022-07-26 10:04   ` Takahiro Kuwano
2022-05-13 13:35 ` [PATCH 3/6] mtd: spi-nor: remember full JEDEC flash ID Michael Walle
2022-07-29  1:00   ` Takahiro Kuwano
2022-05-13 13:35 ` [PATCH 4/6] mtd: spi-nor: move function declaration out of sfdp.h Michael Walle
2022-07-26 23:41   ` Takahiro Kuwano
2022-05-13 13:35 ` Michael Walle [this message]
2022-05-13 14:47   ` [PATCH 5/6] mtd: spi-nor: add generic flash driver kernel test robot
2022-07-21  9:32     ` Biju Das
2022-07-21  9:48     ` Michael Walle
2022-07-21  9:52       ` Biju Das
2022-10-28 18:00         ` Biju Das
2022-07-28  3:28   ` Tudor.Ambarus
2022-07-29  1:40   ` Takahiro Kuwano
2022-05-13 13:35 ` [PATCH 6/6] mtd: spi-nor: sysfs: print JEDEC ID for " Michael Walle
2022-07-29  1:25   ` Takahiro Kuwano
2022-07-26  8:06 ` [PATCH 0/6] mtd: spi-nor: " Tudor.Ambarus
2022-07-29  1:52   ` Takahiro Kuwano
2022-07-29  5:34     ` Tudor.Ambarus

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