Commit 773bbe10 authored by Michael Walle's avatar Michael Walle Committed by Tudor Ambarus
Browse files

mtd: spi-nor: add generic flash driver 



Our SFDP 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.

Signed-off-by: default avatarMichael Walle <michael@walle.cc>
Signed-off-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Tested-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: default avatarTakahiro Kuwano <Takahiro.Kuwano@infineon.com>
Link: https://lore.kernel.org/r/20220810220654.1297699-7-michael@walle.cc
parent 39eece67

drivers/mtd/spi-nor/core.c

+24 −2
Original line number Diff line number Diff line
@@ -1634,6 +1634,16 @@ static const struct spi_nor_manufacturer *manufacturers[] = { 
	&spi_nor_xmc,

};



static const struct flash_info spi_nor_generic_flash = {

	.name = "spi-nor-generic",

	/*

	 * JESD216 rev A doesn't specify the page size, therefore we need a

	 * sane default.

	 */

	.page_size = 256,

	.parse_sfdp = true,

};



static const struct flash_info *spi_nor_match_id(struct spi_nor *nor,

						 const u8 *id)

{
@@ -1672,6 +1682,14 @@ 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);
@@ -2098,8 +2116,12 @@ static int spi_nor_select_pp(struct spi_nor *nor, 
 * spi_nor_select_uniform_erase() - select optimum uniform erase type

 * @map:		the erase map of the SPI NOR

 * @wanted_size:	the erase type size to search for. Contains the value of

 *			info->sector_size or of the "small sector" size in case

 *			CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined.

 *			info->sector_size, the "small sector" size in case

 *			CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined or 0 if

 *			there is no information about the sector size. The

 *			latter is the case if the flash parameters are parsed

 *			solely by SFDP, then the largest supported erase type

 *			is selected.

 *

 * Once the optimum uniform sector erase command is found, disable all the

 * other.

drivers/mtd/spi-nor/core.h

+1 −0
Original line number Diff line number Diff line
@@ -701,6 +701,7 @@ 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)

drivers/mtd/spi-nor/sfdp.c

+27 −0
Original line number Diff line number Diff line
@@ -1256,6 +1256,33 @@ static void spi_nor_post_sfdp_fixups(struct spi_nor *nor) 
		nor->info->fixups->post_sfdp(nor);

}



/**

 * spi_nor_check_sfdp_signature() - check for a valid SFDP signature

 * @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'