Re: [PATCH v3 1/2] mtd: spi-nor: add support to non-uniform SFDP SPI NOR flash memories

[Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>]

Hi, Yogesh,

On 10/16/2018 12:51 PM, Yogesh Narayan Gaur wrote:
> Hi Tudor,
> 
> This patch is breaking the 1-4-4 Read protocol for the spansion flash "s25fl512s".
> 
> Without this patch read request command for Quad mode, 4-byte enable, is coming as 0xEC i.e. SPINOR_OP_READ_1_4_4_4B.
> But after applying this patch, read request command for Quad mode is coming as 0x6C i.e. SPINOR_OP_READ_1_1_4_4B.
> 
> This flash also supports non-uniform erase.
> Can you please check and provide some suggestion?

I don't have this memory to test it, but I'll try to help.

Does s25fl512s support non-uniform erase? I'm looking in datasheet[1] at JEDEC
BFPT table, dwords 8 and 9, page 132/146 and it looks like it supports just
256KB uniform erase.

Thanks,
ta

[1] http://www.cypress.com/file/177971/download

> 
> --
> Regards
> Yogesh Gaur
> 
>> -----Original Message-----
>> From: linux-mtd [mailto:linux-mtd-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of
>> Tudor Ambarus
>> Sent: Tuesday, September 11, 2018 9:10 PM
>> To: marek.vasut@xxxxxxxxx; dwmw2@xxxxxxxxxxxxx;
>> computersforpeace@xxxxxxxxx; boris.brezillon@xxxxxxxxxxx; richard@xxxxxx
>> Cc: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>; linux-
>> kernel@xxxxxxxxxxxxxxx; nicolas.ferre@xxxxxxxxxxxxx;
>> cyrille.pitchen@xxxxxxxxxxxxx; linux-mtd@xxxxxxxxxxxxxxxxxxx; linux-arm-
>> kernel@xxxxxxxxxxxxxxxxxxx; Cristian.Birsan@xxxxxxxxxxxxx
>> Subject: [PATCH v3 1/2] mtd: spi-nor: add support to non-uniform SFDP SPI NOR
>> flash memories
>>
>> Based on Cyrille Pitchen's patch
>> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.or
>> g%2Flkml%2F2017%2F3%2F22%2F935&amp;data=02%7C01%7Cyogeshnarayan.
>> gaur%40nxp.com%7C3c782e52b7fd4a8b9af008d617fd5154%7C686ea1d3bc2b4
>> c6fa92cd99c5c301635%7C0%7C0%7C636722774108718782&amp;sdata=szyc%
>> 2FTumG6eYAmBd0oW3IL7v1yLh9E1SAZqL%2BCWczOA%3D&amp;reserved=0.
>>
>> This patch is a transitional patch in introducing  the support of SFDP SPI
>> memories with non-uniform erase sizes like Spansion s25fs512s.
>> Non-uniform erase maps will be used later when initialized based on the SFDP
>> data.
>>
>> Introduce the memory erase map which splits the memory array into one or
>> many erase regions. Each erase region supports up to 4 erase types, as defined
>> by the JEDEC JESD216B (SFDP) specification.
>>
>> To be backward compatible, the erase map of uniform SPI NOR flash memories
>> is initialized so it contains only one erase region and this erase region supports
>> only one erase command. Hence a single size is used to erase any sector/block
>> of the memory.
>>
>> Besides, since the algorithm used to erase sectors on non-uniform SPI NOR flash
>> memories is quite expensive, when possible, the erase map is tuned to come
>> back to the uniform case.
>>
>> The 'erase with the best command, move forward and repeat' approach was
>> suggested by Cristian Birsan in a brainstorm session, so:
>>
>> Suggested-by: Cristian Birsan <cristian.birsan@xxxxxxxxxxxxx>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
>> ---
>>  drivers/mtd/spi-nor/spi-nor.c | 594
>> +++++++++++++++++++++++++++++++++++++++---
>>  include/linux/mtd/spi-nor.h   | 107 ++++++++
>>  2 files changed, 659 insertions(+), 42 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c index
>> dc8757e..4687345 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -18,6 +18,7 @@
>>  #include <linux/math64.h>
>>  #include <linux/sizes.h>
>>  #include <linux/slab.h>
>> +#include <linux/sort.h>
>>
>>  #include <linux/mtd/mtd.h>
>>  #include <linux/of_platform.h>
>> @@ -261,6 +262,18 @@ static void spi_nor_set_4byte_opcodes(struct spi_nor
>> *nor,
>>  	nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
>>  	nor->program_opcode = spi_nor_convert_3to4_program(nor-
>>> program_opcode);
>>  	nor->erase_opcode = spi_nor_convert_3to4_erase(nor->erase_opcode);
>> +
>> +	if (!spi_nor_has_uniform_erase(nor)) {
>> +		struct spi_nor_erase_map *map = &nor->erase_map;
>> +		struct spi_nor_erase_type *erase;
>> +		int i;
>> +
>> +		for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
>> +			erase = &map->erase_type[i];
>> +			erase->opcode =
>> +				spi_nor_convert_3to4_erase(erase->opcode);
>> +		}
>> +	}
>>  }
>>
>>  /* Enable/disable 4-byte addressing mode. */ @@ -499,6 +512,275 @@ static
>> int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)  }
>>
>>  /*
>> + * spi_nor_div_by_erase_size() - calculate remainder and update new dividend
>> + * @erase:	pointer to a structure that describes a SPI NOR erase type
>> + * @dividend:	dividend value
>> + * @remainder:	pointer to u32 remainder (will be updated)
>> + *
>> + * Returns two values: remainder and the new dividend  */ static u64
>> +spi_nor_div_by_erase_size(const struct spi_nor_erase_type *erase,
>> +				     u64 dividend, u32 *remainder)
>> +{
>> +	/* JEDEC JESD216B Standard imposes erase sizes to be power of 2. */
>> +	*remainder = (u32)dividend & erase->size_mask;
>> +	return dividend >> erase->size_shift;
>> +}
>> +
>> +/*
>> + * spi_nor_find_best_erase_type() - find the best erase type for the
>> +given
>> + * offset in the serial flash memory and the number of bytes to erase.
>> +The
>> + * region in which the address fits is expected to be provided.
>> + * @map:	the erase map of the SPI NOR
>> + * @region:	pointer to a structure that describes a SPI NOR erase region
>> + * @addr:	offset in the serial flash memory
>> + * @len:	number of bytes to erase
>> + *
>> + * Returns a pointer to the best fitted erase type, NULL otherwise.
>> + */
>> +static const struct spi_nor_erase_type *
>> +spi_nor_find_best_erase_type(const struct spi_nor_erase_map *map,
>> +			     const struct spi_nor_erase_region *region,
>> +			     u64 addr, u32 len)
>> +{
>> +	const struct spi_nor_erase_type *erase;
>> +	u32 rem;
>> +	int i;
>> +	u8 erase_mask = region->offset & SNOR_ERASE_TYPE_MASK;
>> +
>> +	/*
>> +	 * Erase types are ordered by size, with the biggest erase type at
>> +	 * index 0.
>> +	 */
>> +	for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
>> +		/* Does the erase region support the tested erase type? */
>> +		if (!(erase_mask & BIT(i)))
>> +			continue;
>> +
>> +		erase = &map->erase_type[i];
>> +
>> +		/* Don't erase more than what the user has asked for. */
>> +		if (erase->size > len)
>> +			continue;
>> +
>> +		/* Alignment is not mandatory for overlaid regions */
>> +		if (region->offset & SNOR_OVERLAID_REGION)
>> +			return erase;
>> +
>> +		spi_nor_div_by_erase_size(erase, addr, &rem);
>> +		if (rem)
>> +			continue;
>> +		else
>> +			return erase;
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +/*
>> + * spi_nor_region_next() - get the next spi nor region
>> + * @region:	pointer to a structure that describes a SPI NOR erase region
>> + *
>> + * Returns the next spi nor region or NULL if last region.
>> + */
>> +static struct spi_nor_erase_region *
>> +spi_nor_region_next(struct spi_nor_erase_region *region) {
>> +	if (spi_nor_region_is_last(region))
>> +		return NULL;
>> +	region++;
>> +	return region;
>> +}
>> +
>> +/*
>> + * spi_nor_find_erase_region() - find the region of the serial flash
>> +memory in
>> + * which the offset fits
>> + * @map:	the erase map of the SPI NOR
>> + * @addr:	offset in the serial flash memory
>> + *
>> + * Returns pointer to the spi_nor_erase_region struct, ERR_PTR(-errno)
>> + * otherwise.
>> + */
>> +static struct spi_nor_erase_region *
>> +spi_nor_find_erase_region(const struct spi_nor_erase_map *map, u64
>> +addr) {
>> +	struct spi_nor_erase_region *region = map->regions;
>> +	u64 region_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
>> +	u64 region_end = region_start + region->size;
>> +
>> +	while (addr < region_start || addr >= region_end) {
>> +		region = spi_nor_region_next(region);
>> +		if (!region)
>> +			return ERR_PTR(-EINVAL);
>> +
>> +		region_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
>> +		region_end = region_start + region->size;
>> +	}
>> +
>> +	return region;
>> +}
>> +
>> +/*
>> + * spi_nor_init_erase_cmd() - initialize an erase command
>> + * @region:	pointer to a structure that describes a SPI NOR erase region
>> + * @erase:	pointer to a structure that describes a SPI NOR erase type
>> + *
>> + * Returns the pointer to the allocated erase command, ERR_PTR(-errno)
>> + * otherwise.
>> + */
>> +static struct spi_nor_erase_command *
>> +spi_nor_init_erase_cmd(const struct spi_nor_erase_region *region,
>> +		       const struct spi_nor_erase_type *erase) {
>> +	struct spi_nor_erase_command *cmd;
>> +
>> +	cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
>> +	if (!cmd)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	INIT_LIST_HEAD(&cmd->list);
>> +	cmd->opcode = erase->opcode;
>> +	cmd->count = 1;
>> +
>> +	if (region->offset & SNOR_OVERLAID_REGION)
>> +		cmd->size = region->size;
>> +	else
>> +		cmd->size = erase->size;
>> +
>> +	return cmd;
>> +}
>> +
>> +/*
>> + * spi_nor_destroy_erase_cmd_list() - destroy erase command list
>> + * @erase_list:	list of erase commands
>> + */
>> +static void spi_nor_destroy_erase_cmd_list(struct list_head
>> +*erase_list) {
>> +	struct spi_nor_erase_command *cmd, *next;
>> +
>> +	list_for_each_entry_safe(cmd, next, erase_list, list) {
>> +		list_del(&cmd->list);
>> +		kfree(cmd);
>> +	}
>> +}
>> +
>> +/*
>> + * spi_nor_init_erase_cmd_list() - initialize erase command list
>> + * @nor:	pointer to a 'struct spi_nor'
>> + * @erase_list:	list of erase commands to be executed once we validate that
>> the
>> + *		erase can be performed
>> + * @addr:	offset in the serial flash memory
>> + * @len:	number of bytes to erase
>> + *
>> + * Builds the list of best fitted erase commands and verifies if the
>> +erase can
>> + * be performed.
>> + *
>> + * Returns 0 on success, -errno otherwise.
>> + */
>> +static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
>> +				       struct list_head *erase_list,
>> +				       u64 addr, u32 len)
>> +{
>> +	const struct spi_nor_erase_map *map = &nor->erase_map;
>> +	const struct spi_nor_erase_type *erase, *prev_erase = NULL;
>> +	struct spi_nor_erase_region *region;
>> +	struct spi_nor_erase_command *cmd = NULL;
>> +	u64 region_end;
>> +	int ret = -EINVAL;
>> +
>> +	region = spi_nor_find_erase_region(map, addr);
>> +	if (IS_ERR(region))
>> +		return PTR_ERR(region);
>> +
>> +	region_end = spi_nor_region_end(region);
>> +
>> +	while (len) {
>> +		erase = spi_nor_find_best_erase_type(map, region, addr, len);
>> +		if (!erase)
>> +			goto destroy_erase_cmd_list;
>> +
>> +		if (prev_erase != erase ||
>> +		    region->offset & SNOR_OVERLAID_REGION) {
>> +			cmd = spi_nor_init_erase_cmd(region, erase);
>> +			if (IS_ERR(cmd)) {
>> +				ret = PTR_ERR(cmd);
>> +				goto destroy_erase_cmd_list;
>> +			}
>> +
>> +			list_add_tail(&cmd->list, erase_list);
>> +		} else {
>> +			cmd->count++;
>> +		}
>> +
>> +		addr += cmd->size;
>> +		len -= cmd->size;
>> +
>> +		if (len && addr >= region_end) {
>> +			region = spi_nor_region_next(region);
>> +			if (!region)
>> +				goto destroy_erase_cmd_list;
>> +			region_end = spi_nor_region_end(region);
>> +		}
>> +
>> +		prev_erase = erase;
>> +	}
>> +
>> +	return 0;
>> +
>> +destroy_erase_cmd_list:
>> +	spi_nor_destroy_erase_cmd_list(erase_list);
>> +	return ret;
>> +}
>> +
>> +/*
>> + * spi_nor_erase_multi_sectors() - perform a non-uniform erase
>> + * @nor:	pointer to a 'struct spi_nor'
>> + * @addr:	offset in the serial flash memory
>> + * @len:	number of bytes to erase
>> + *
>> + * Build a list of best fitted erase commands and execute it once we
>> + * validate that the erase can be performed.
>> + *
>> + * Returns 0 on success, -errno otherwise.
>> + */
>> +static int spi_nor_erase_multi_sectors(struct spi_nor *nor, u64 addr,
>> +u32 len) {
>> +	LIST_HEAD(erase_list);
>> +	struct spi_nor_erase_command *cmd, *next;
>> +	int ret;
>> +
>> +	ret = spi_nor_init_erase_cmd_list(nor, &erase_list, addr, len);
>> +	if (ret)
>> +		return ret;
>> +
>> +	list_for_each_entry_safe(cmd, next, &erase_list, list) {
>> +		nor->erase_opcode = cmd->opcode;
>> +		while (cmd->count) {
>> +			write_enable(nor);
>> +
>> +			ret = spi_nor_erase_sector(nor, addr);
>> +			if (ret)
>> +				goto destroy_erase_cmd_list;
>> +
>> +			addr += cmd->size;
>> +			cmd->count--;
>> +
>> +			ret = spi_nor_wait_till_ready(nor);
>> +			if (ret)
>> +				goto destroy_erase_cmd_list;
>> +		}
>> +		list_del(&cmd->list);
>> +		kfree(cmd);
>> +	}
>> +
>> +	return 0;
>> +
>> +destroy_erase_cmd_list:
>> +	spi_nor_destroy_erase_cmd_list(&erase_list);
>> +	return ret;
>> +}
>> +
>> +/*
>>   * Erase an address range on the nor chip.  The address range may extend
>>   * one or more erase sectors.  Return an error is there is a problem erasing.
>>   */
>> @@ -512,9 +794,11 @@ static int spi_nor_erase(struct mtd_info *mtd, struct
>> erase_info *instr)
>>  	dev_dbg(nor->dev, "at 0x%llx, len %lld\n", (long long)instr->addr,
>>  			(long long)instr->len);
>>
>> -	div_u64_rem(instr->len, mtd->erasesize, &rem);
>> -	if (rem)
>> -		return -EINVAL;
>> +	if (spi_nor_has_uniform_erase(nor)) {
>> +		div_u64_rem(instr->len, mtd->erasesize, &rem);
>> +		if (rem)
>> +			return -EINVAL;
>> +	}
>>
>>  	addr = instr->addr;
>>  	len = instr->len;
>> @@ -553,7 +837,7 @@ static int spi_nor_erase(struct mtd_info *mtd, struct
>> erase_info *instr)
>>  	 */
>>
>>  	/* "sector"-at-a-time erase */
>> -	} else {
>> +	} else if (spi_nor_has_uniform_erase(nor)) {
>>  		while (len) {
>>  			write_enable(nor);
>>
>> @@ -568,6 +852,12 @@ static int spi_nor_erase(struct mtd_info *mtd, struct
>> erase_info *instr)
>>  			if (ret)
>>  				goto erase_err;
>>  		}
>> +
>> +	/* erase multiple sectors */
>> +	} else {
>> +		ret = spi_nor_erase_multi_sectors(nor, addr, len);
>> +		if (ret)
>> +			goto erase_err;
>>  	}
>>
>>  	write_disable(nor);
>> @@ -2190,6 +2480,113 @@ static const struct sfdp_bfpt_erase
>> sfdp_bfpt_erases[] = {
>>
>>  static int spi_nor_hwcaps_read2cmd(u32 hwcaps);
>>
>> +/*
>> + * spi_nor_set_erase_type() - set a SPI NOR erase type
>> + * @erase:	pointer to a structure that describes a SPI NOR erase type
>> + * @size:	the size of the sector/block erased by the erase type
>> + * @opcode:	the SPI command op code to erase the sector/block
>> + */
>> +static void spi_nor_set_erase_type(struct spi_nor_erase_type *erase,
>> +				   u32 size, u8 opcode)
>> +{
>> +	erase->size = size;
>> +	erase->opcode = opcode;
>> +	/* JEDEC JESD216B Standard imposes erase sizes to be power of 2. */
>> +	erase->size_shift = ffs(erase->size) - 1;
>> +	erase->size_mask = (1 << erase->size_shift) - 1; }
>> +
>> +/*
>> + * spi_nor_set_erase_settings_from_bfpt() - set erase type settings from BFPT
>> + * @erase:	pointer to a structure that describes a SPI NOR erase type
>> + * @size:	the size of the sector/block erased by the erase type
>> + * @opcode:	the SPI command op code to erase the sector/block
>> + * @i:		erase type index as sorted in the Basic Flash Parameter Table
>> + *
>> + * The supported Erase Types will be sorted at init in ascending order,
>> +with
>> + * the smallest Erase Type size being the first member in the
>> +erase_type array
>> + * of the spi_nor_erase_map structure. Save the Erase Type index as
>> +sorted in
>> + * the Basic Flash Parameter Table since it will be used later on to
>> + * synchronize with the supported Erase Types defined in SFDP optional tables.
>> + */
>> +static void
>> +spi_nor_set_erase_settings_from_bfpt(struct spi_nor_erase_type *erase,
>> +				     u32 size, u8 opcode, u8 i)
>> +{
>> +	erase->idx = i;
>> +	spi_nor_set_erase_type(erase, size, opcode); }
>> +
>> +/* spi_nor_map_cmp_erase_type() - compare the map's erase types by size
>> + * @l:	member in the left half of the map's erase_type array
>> + * @r:	member in the right half of the map's erase_type array
>> + *
>> + * Comparison function used in the sort() call to sort in ascending
>> +order the
>> + * map's erase types, the smallest erase type size being the first
>> +member in the
>> + * sorted erase_type array.
>> + */
>> +static int spi_nor_map_cmp_erase_type(const void *l, const void *r) {
>> +	const struct spi_nor_erase_type *left = l, *right = r;
>> +
>> +	return left->size - right->size;
>> +}
>> +
>> +/*
>> + * spi_nor_regions_sort_erase_types() - sort erase types in each region
>> + * @map:	the erase map of the SPI NOR
>> + *
>> + * Function assumes that the erase types defined in the erase map are
>> +already
>> + * sorted in ascending order, with the smallest erase type size being
>> +the first
>> + * member in the erase_type array. It replicates the sort done for the
>> +map's
>> + * erase types. Each region's erase bitmask will indicate which erase
>> +types are
>> + * supported from the sorted erase types defined in the erase map.
>> + * Sort the all region's erase type at init in order to speed up the
>> +process of
>> + * finding the best erase command at runtime.
>> + */
>> +static void spi_nor_regions_sort_erase_types(struct spi_nor_erase_map
>> +*map) {
>> +	struct spi_nor_erase_region *region = map->regions;
>> +	struct spi_nor_erase_type *erase_type = map->erase_type;
>> +	int i;
>> +	u8 region_erase_mask, sorted_erase_mask;
>> +
>> +	while (region) {
>> +		region_erase_mask = region->offset &
>> SNOR_ERASE_TYPE_MASK;
>> +
>> +		/* Replicate the sort done for the map's erase types. */
>> +		sorted_erase_mask = 0;
>> +		for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++)
>> +			if (erase_type[i].size &&
>> +			    region_erase_mask & BIT(erase_type[i].idx))
>> +				sorted_erase_mask |= BIT(i);
>> +
>> +		/* Overwrite erase mask. */
>> +		region->offset = (region->offset & ~SNOR_ERASE_TYPE_MASK)
>> |
>> +				 sorted_erase_mask;
>> +
>> +		region = spi_nor_region_next(region);
>> +	}
>> +}
>> +
>> +/*
>> + *spi_nor_init_uniform_erase_map() - Initialize uniform erase map
>> + * @map:		the erase map of the SPI NOR
>> + * @erase_mask:		bitmask encoding erase types that can erase
>> the entire
>> + *			flash memory
>> + * @flash_size:		the spi nor flash memory size
>> + */
>> +static void spi_nor_init_uniform_erase_map(struct spi_nor_erase_map *map,
>> +					   u8 erase_mask, u64 flash_size)
>> +{
>> +	/* Offset 0 with erase_mask and SNOR_LAST_REGION bit set */
>> +	map->uniform_region.offset = (erase_mask &
>> SNOR_ERASE_TYPE_MASK) |
>> +				     SNOR_LAST_REGION;
>> +	map->uniform_region.size = flash_size;
>> +	map->regions = &map->uniform_region;
>> +	map->uniform_erase_type = erase_mask;
>> +}
>> +
>>  /**
>>   * spi_nor_parse_bfpt() - read and parse the Basic Flash Parameter Table.
>>   * @nor:		pointer to a 'struct spi_nor'
>> @@ -2224,12 +2621,14 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>>  			      const struct sfdp_parameter_header *bfpt_header,
>>  			      struct spi_nor_flash_parameter *params)  {
>> -	struct mtd_info *mtd = &nor->mtd;
>> +	struct spi_nor_erase_map *map = &nor->erase_map;
>> +	struct spi_nor_erase_type *erase_type = map->erase_type;
>>  	struct sfdp_bfpt bfpt;
>>  	size_t len;
>>  	int i, cmd, err;
>>  	u32 addr;
>>  	u16 half;
>> +	u8 erase_mask;
>>
>>  	/* JESD216 Basic Flash Parameter Table length is at least 9 DWORDs. */
>>  	if (bfpt_header->length < BFPT_DWORD_MAX_JESD216) @@ -2298,7
>> +2697,12 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>>  		spi_nor_set_read_settings_from_bfpt(read, half, rd->proto);
>>  	}
>>
>> -	/* Sector Erase settings. */
>> +	/*
>> +	 * Sector Erase settings. Reinitialize the uniform erase map using the
>> +	 * Erase Types defined in the bfpt table.
>> +	 */
>> +	erase_mask = 0;
>> +	memset(&nor->erase_map, 0, sizeof(nor->erase_map));
>>  	for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_erases); i++) {
>>  		const struct sfdp_bfpt_erase *er = &sfdp_bfpt_erases[i];
>>  		u32 erasesize;
>> @@ -2313,18 +2717,25 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>>
>>  		erasesize = 1U << erasesize;
>>  		opcode = (half >> 8) & 0xff;
>> -#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
>> -		if (erasesize == SZ_4K) {
>> -			nor->erase_opcode = opcode;
>> -			mtd->erasesize = erasesize;
>> -			break;
>> -		}
>> -#endif
>> -		if (!mtd->erasesize || mtd->erasesize < erasesize) {
>> -			nor->erase_opcode = opcode;
>> -			mtd->erasesize = erasesize;
>> -		}
>> +		erase_mask |= BIT(i);
>> +		spi_nor_set_erase_settings_from_bfpt(&erase_type[i],
>> erasesize,
>> +						     opcode, i);
>>  	}
>> +	spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
>> +	/*
>> +	 * Sort all the map's Erase Types in ascending order with the smallest
>> +	 * erase size being the first member in the erase_type array.
>> +	 */
>> +	sort(erase_type, SNOR_ERASE_TYPE_MAX, sizeof(erase_type[0]),
>> +	     spi_nor_map_cmp_erase_type, NULL);
>> +	/*
>> +	 * Sort the erase types in the uniform region in order to update the
>> +	 * uniform_erase_type bitmask. The bitmask will be used later on when
>> +	 * selecting the uniform erase.
>> +	 */
>> +	spi_nor_regions_sort_erase_types(map);
>> +	map->uniform_erase_type = map->uniform_region.offset &
>> +				  SNOR_ERASE_TYPE_MASK;
>>
>>  	/* Stop here if not JESD216 rev A or later. */
>>  	if (bfpt_header->length < BFPT_DWORD_MAX) @@ -2480,6 +2891,9
>> @@ static int spi_nor_init_params(struct spi_nor *nor,
>>  			       const struct flash_info *info,
>>  			       struct spi_nor_flash_parameter *params)  {
>> +	struct spi_nor_erase_map *map = &nor->erase_map;
>> +	u8 i, erase_mask;
>> +
>>  	/* Set legacy flash parameters as default. */
>>  	memset(params, 0, sizeof(*params));
>>
>> @@ -2519,6 +2933,28 @@ static int spi_nor_init_params(struct spi_nor *nor,
>>  	spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP],
>>  				SPINOR_OP_PP, SNOR_PROTO_1_1_1);
>>
>> +	/*
>> +	 * Sector Erase settings. Sort Erase Types in ascending order, with the
>> +	 * smallest erase size starting at BIT(0).
>> +	 */
>> +	erase_mask = 0;
>> +	i = 0;
>> +	if (info->flags & SECT_4K_PMC) {
>> +		erase_mask |= BIT(i);
>> +		spi_nor_set_erase_type(&map->erase_type[i], 4096u,
>> +				       SPINOR_OP_BE_4K_PMC);
>> +		i++;
>> +	} else if (info->flags & SECT_4K) {
>> +		erase_mask |= BIT(i);
>> +		spi_nor_set_erase_type(&map->erase_type[i], 4096u,
>> +				       SPINOR_OP_BE_4K);
>> +		i++;
>> +	}
>> +	erase_mask |= BIT(i);
>> +	spi_nor_set_erase_type(&map->erase_type[i], info->sector_size,
>> +			       SPINOR_OP_SE);
>> +	spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
>> +
>>  	/* Select the procedure to set the Quad Enable bit. */
>>  	if (params->hwcaps.mask & (SNOR_HWCAPS_READ_QUAD |
>>  				   SNOR_HWCAPS_PP_QUAD)) {
>> @@ -2546,20 +2982,20 @@ static int spi_nor_init_params(struct spi_nor *nor,
>>  			params->quad_enable = info->quad_enable;
>>  	}
>>
>> -	/* Override the parameters with data read from SFDP tables. */
>> -	nor->addr_width = 0;
>> -	nor->mtd.erasesize = 0;
>>  	if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
>>  	    !(info->flags & SPI_NOR_SKIP_SFDP)) {
>>  		struct spi_nor_flash_parameter sfdp_params;
>> +		struct spi_nor_erase_map prev_map;
>>
>>  		memcpy(&sfdp_params, params, sizeof(sfdp_params));
>> -		if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
>> -			nor->addr_width = 0;
>> -			nor->mtd.erasesize = 0;
>> -		} else {
>> +		memcpy(&prev_map, &nor->erase_map, sizeof(prev_map));
>> +
>> +		if (spi_nor_parse_sfdp(nor, &sfdp_params))
>> +			/* restore previous erase map */
>> +			memcpy(&nor->erase_map, &prev_map,
>> +			       sizeof(nor->erase_map));
>> +		else
>>  			memcpy(params, &sfdp_params, sizeof(*params));
>> -		}
>>  	}
>>
>>  	return 0;
>> @@ -2668,29 +3104,103 @@ static int spi_nor_select_pp(struct spi_nor *nor,
>>  	return 0;
>>  }
>>
>> -static int spi_nor_select_erase(struct spi_nor *nor,
>> -				const struct flash_info *info)
>> +/*
>> + * 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.
>> + *
>> + * Once the optimum uniform sector erase command is found, disable all
>> +the
>> + * other.
>> + *
>> + * Return: pointer to erase type on success, NULL otherwise.
>> + */
>> +static const struct spi_nor_erase_type *
>> +spi_nor_select_uniform_erase(struct spi_nor_erase_map *map,
>> +			     const u32 wanted_size)
>>  {
>> -	struct mtd_info *mtd = &nor->mtd;
>> +	const struct spi_nor_erase_type *tested_erase, *erase = NULL;
>> +	int i;
>> +	u8 uniform_erase_type = map->uniform_erase_type;
>>
>> -	/* Do nothing if already configured from SFDP. */
>> -	if (mtd->erasesize)
>> -		return 0;
>> +	for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
>> +		if (!(uniform_erase_type & BIT(i)))
>> +			continue;
>> +
>> +		tested_erase = &map->erase_type[i];
>> +
>> +		/*
>> +		 * If the current erase size is the one, stop here:
>> +		 * we have found the right uniform Sector Erase command.
>> +		 */
>> +		if (tested_erase->size == wanted_size) {
>> +			erase = tested_erase;
>> +			break;
>> +		}
>>
>> +		/*
>> +		 * Otherwise, the current erase size is still a valid canditate.
>> +		 * Select the biggest valid candidate.
>> +		 */
>> +		if (!erase && tested_erase->size)
>> +			erase = tested_erase;
>> +			/* keep iterating to find the wanted_size */
>> +	}
>> +
>> +	if (!erase)
>> +		return NULL;
>> +
>> +	/* Disable all other Sector Erase commands. */
>> +	map->uniform_erase_type &= ~SNOR_ERASE_TYPE_MASK;
>> +	map->uniform_erase_type |= BIT(erase - map->erase_type);
>> +	return erase;
>> +}
>> +
>> +static int spi_nor_select_erase(struct spi_nor *nor, u32 wanted_size) {
>> +	struct spi_nor_erase_map *map = &nor->erase_map;
>> +	const struct spi_nor_erase_type *erase = NULL;
>> +	struct mtd_info *mtd = &nor->mtd;
>> +	int i;
>> +
>> +	/*
>> +	 * The previous implementation handling Sector Erase commands
>> assumed
>> +	 * that the SPI flash memory has an uniform layout then used only one
>> +	 * of the supported erase sizes for all Sector Erase commands.
>> +	 * So to be backward compatible, the new implementation also tries to
>> +	 * manage the SPI flash memory as uniform with a single erase sector
>> +	 * size, when possible.
>> +	 */
>>  #ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
>>  	/* prefer "small sector" erase if possible */
>> -	if (info->flags & SECT_4K) {
>> -		nor->erase_opcode = SPINOR_OP_BE_4K;
>> -		mtd->erasesize = 4096;
>> -	} else if (info->flags & SECT_4K_PMC) {
>> -		nor->erase_opcode = SPINOR_OP_BE_4K_PMC;
>> -		mtd->erasesize = 4096;
>> -	} else
>> +	wanted_size = 4096u;
>>  #endif
>> -	{
>> -		nor->erase_opcode = SPINOR_OP_SE;
>> -		mtd->erasesize = info->sector_size;
>> +
>> +	if (spi_nor_has_uniform_erase(nor)) {
>> +		erase = spi_nor_select_uniform_erase(map, wanted_size);
>> +		if (!erase)
>> +			return -EINVAL;
>> +		nor->erase_opcode = erase->opcode;
>> +		mtd->erasesize = erase->size;
>> +		return 0;
>>  	}
>> +
>> +	/*
>> +	 * For non-uniform SPI flash memory, set mtd->erasesize to the
>> +	 * maximum erase sector size. No need to set nor->erase_opcode.
>> +	 */
>> +	for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
>> +		if (map->erase_type[i].size) {
>> +			erase = &map->erase_type[i];
>> +			break;
>> +		}
>> +	}
>> +
>> +	if (!erase)
>> +		return -EINVAL;
>> +
>> +	mtd->erasesize = erase->size;
>>  	return 0;
>>  }
>>
>> @@ -2737,7 +3247,7 @@ static int spi_nor_setup(struct spi_nor *nor, const
>> struct flash_info *info,
>>  	}
>>
>>  	/* Select the Sector Erase command. */
>> -	err = spi_nor_select_erase(nor, info);
>> +	err = spi_nor_select_erase(nor, info->sector_size);
>>  	if (err) {
>>  		dev_err(nor->dev,
>>  			"can't select erase settings supported by both the SPI
>> controller and memory.\n"); diff --git a/include/linux/mtd/spi-nor.h
>> b/include/linux/mtd/spi-nor.h index 09a10fd..a873a0b 100644
>> --- a/include/linux/mtd/spi-nor.h
>> +++ b/include/linux/mtd/spi-nor.h
>> @@ -240,6 +240,94 @@ enum spi_nor_option_flags {  };
>>
>>  /**
>> + * struct spi_nor_erase_type - Structure to describe a SPI NOR erase type
>> + * @size:		the size of the sector/block erased by the erase type.
>> + *			JEDEC JESD216B imposes erase sizes to be a power of 2.
>> + * @size_shift:		@size is a power of 2, the shift is stored in
>> + *			@size_shift.
>> + * @size_mask:		the size mask based on @size_shift.
>> + * @opcode:		the SPI command op code to erase the sector/block.
>> + * @idx:		Erase Type index as sorted in the Basic Flash Parameter
>> + *			Table. It will be used to synchronize the supported
>> + *			Erase Types with the ones identified in the SFDP
>> + *			optional tables.
>> + */
>> +struct spi_nor_erase_type {
>> +	u32	size;
>> +	u32	size_shift;
>> +	u32	size_mask;
>> +	u8	opcode;
>> +	u8	idx;
>> +};
>> +
>> +/**
>> + * struct spi_nor_erase_command - Used for non-uniform erases
>> + * The structure is used to describe a list of erase commands to be
>> +executed
>> + * once we validate that the erase can be performed. The elements in
>> +the list
>> + * are run-length encoded.
>> + * @list:		for inclusion into the list of erase commands.
>> + * @count:		how many times the same erase command should be
>> + *			consecutively used.
>> + * @size:		the size of the sector/block erased by the command.
>> + * @opcode:		the SPI command op code to erase the sector/block.
>> + */
>> +struct spi_nor_erase_command {
>> +	struct list_head	list;
>> +	u32			count;
>> +	u32			size;
>> +	u8			opcode;
>> +};
>> +
>> +/**
>> + * struct spi_nor_erase_region - Structure to describe a SPI NOR erase region
>> + * @offset:		the offset in the data array of erase region start.
>> + *			LSB bits are used as a bitmask encoding flags to
>> + *			determine if this region is overlaid, if this region is
>> + *			the last in the SPI NOR flash memory and to indicate
>> + *			all the supported erase commands inside this region.
>> + *			The erase types are sorted in ascending order with the
>> + *			smallest Erase Type size being at BIT(0).
>> + * @size:		the size of the region in bytes.
>> + */
>> +struct spi_nor_erase_region {
>> +	u64		offset;
>> +	u64		size;
>> +};
>> +
>> +#define SNOR_ERASE_TYPE_MAX	4
>> +#define SNOR_ERASE_TYPE_MASK
>> 	GENMASK_ULL(SNOR_ERASE_TYPE_MAX - 1, 0)
>> +
>> +#define SNOR_LAST_REGION	BIT(4)
>> +#define SNOR_OVERLAID_REGION	BIT(5)
>> +
>> +#define SNOR_ERASE_FLAGS_MAX	6
>> +#define SNOR_ERASE_FLAGS_MASK
>> 	GENMASK_ULL(SNOR_ERASE_FLAGS_MAX - 1, 0)
>> +
>> +/**
>> + * struct spi_nor_erase_map - Structure to describe the SPI NOR erase map
>> + * @regions:		array of erase regions. The regions are consecutive in
>> + *			address space. Walking through the regions is done
>> + *			incrementally.
>> + * @uniform_region:	a pre-allocated erase region for SPI NOR with a uniform
>> + *			sector size (legacy implementation).
>> + * @erase_type:		an array of erase types shared by all the regions.
>> + *			The erase types are sorted in ascending order, with the
>> + *			smallest Erase Type size being the first member in the
>> + *			erase_type array.
>> + * @uniform_erase_type:	bitmask encoding erase types that can erase
>> the
>> + *			entire memory. This member is completed at init by
>> + *			uniform and non-uniform SPI NOR flash memories if
>> they
>> + *			support at least one erase type that can erase the
>> + *			entire memory.
>> + */
>> +struct spi_nor_erase_map {
>> +	struct spi_nor_erase_region	*regions;
>> +	struct spi_nor_erase_region	uniform_region;
>> +	struct spi_nor_erase_type	erase_type[SNOR_ERASE_TYPE_MAX];
>> +	u8				uniform_erase_type;
>> +};
>> +
>> +/**
>>   * struct flash_info - Forward declaration of a structure used internally by
>>   *		       spi_nor_scan()
>>   */
>> @@ -263,6 +351,7 @@ struct flash_info;
>>   * @write_proto:	the SPI protocol for write operations
>>   * @reg_proto		the SPI protocol for read_reg/write_reg/erase
>> operations
>>   * @cmd_buf:		used by the write_reg
>> + * @erase_map:		the erase map of the SPI NOR
>>   * @prepare:		[OPTIONAL] do some preparations for the
>>   *			read/write/erase/lock/unlock operations
>>   * @unprepare:		[OPTIONAL] do some post work after the
>> @@ -298,6 +387,7 @@ struct spi_nor {
>>  	bool			sst_write_second;
>>  	u32			flags;
>>  	u8			cmd_buf[SPI_NOR_MAX_CMD_SIZE];
>> +	struct spi_nor_erase_map	erase_map;
>>
>>  	int (*prepare)(struct spi_nor *nor, enum spi_nor_ops ops);
>>  	void (*unprepare)(struct spi_nor *nor, enum spi_nor_ops ops); @@ -
>> 318,6 +408,23 @@ struct spi_nor {
>>  	void *priv;
>>  };
>>
>> +static u64 __maybe_unused
>> +spi_nor_region_is_last(const struct spi_nor_erase_region *region) {
>> +	return region->offset & SNOR_LAST_REGION; }
>> +
>> +static u64 __maybe_unused
>> +spi_nor_region_end(const struct spi_nor_erase_region *region) {
>> +	return (region->offset & ~SNOR_ERASE_FLAGS_MASK) + region->size; }
>> +
>> +static bool __maybe_unused spi_nor_has_uniform_erase(const struct
>> +spi_nor *nor) {
>> +	return !!nor->erase_map.uniform_erase_type;
>> +}
>> +
>>  static inline void spi_nor_set_flash_node(struct spi_nor *nor,
>>  					  struct device_node *np)
>>  {
>> --
>> 2.9.4
>>
>>
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