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SubjectRe: [RFC PATCH v5 6/6] mtd: spi-nor: parse SFDP 4-byte Address Instruction Table
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On 03/23/2017 12:33 AM, Cyrille Pitchen wrote:
> This patch adds supports for SFDP (JESD216B) 4-byte Address Instruction
> Table. This table is optional but when available, we parse it to get the
> 4-byte address op codes supported by the memory.
> Using these op codes is stateless as opposed to entering the 4-byte
> address mode or setting the Base Address Register (BAR).
>
> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
> ---
> drivers/mtd/spi-nor/spi-nor.c | 166 +++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 165 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index ce8722055a9c..ea044efc4e6d 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -1899,6 +1899,7 @@ struct sfdp_parameter_header {
>
>
> #define SFDP_BFPT_ID 0xff00u /* Basic Flash Parameter Table */
> +#define SFDP_4BAIT_ID 0xff84u /* 4-byte Address Instruction Table */
>
> #define SFDP_SIGNATURE 0x50444653u
> #define SFDP_JESD216_MAJOR 1
> @@ -2241,6 +2242,149 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
> return 0;
> }
>
> +struct sfdp_4bait {
> + /* The hardware capability. */
> + u32 hwcaps;
> +
> + /*
> + * The <supported_bit> bit in DWORD1 of the 4BAIT tells us whether
> + * the associated 4-byte address op code is supported.
> + */
> + u32 supported_bit;
> +};
> +
> +static int spi_nor_parse_4bait(struct spi_nor *nor,
> + const struct sfdp_parameter_header *param_header,
> + struct spi_nor_flash_parameter *params)
> +{
> + static const struct sfdp_4bait reads[] = {
> + { SNOR_HWCAPS_READ, BIT(0) },
> + { SNOR_HWCAPS_READ_FAST, BIT(1) },
> + { SNOR_HWCAPS_READ_1_1_2, BIT(2) },
> + { SNOR_HWCAPS_READ_1_2_2, BIT(3) },
> + { SNOR_HWCAPS_READ_1_1_4, BIT(4) },
> + { SNOR_HWCAPS_READ_1_4_4, BIT(5) },
> + { SNOR_HWCAPS_READ_1_1_1_DTR, BIT(13) },
> + { SNOR_HWCAPS_READ_1_2_2_DTR, BIT(14) },
> + { SNOR_HWCAPS_READ_1_4_4_DTR, BIT(15) },
> + };
> + static const struct sfdp_4bait programs[] = {
> + { SNOR_HWCAPS_PP, BIT(6) },
> + { SNOR_HWCAPS_PP_1_1_4, BIT(7) },
> + { SNOR_HWCAPS_PP_1_4_4, BIT(8) },
> + };
> + static const struct sfdp_4bait erases[SNOR_CMD_ERASE_MAX] = {
> + { 0u /* not used */, BIT(9) },
> + { 0u /* not used */, BIT(10) },
> + { 0u /* not used */, BIT(11) },
> + { 0u /* not used */, BIT(12) },
> + };
> + u32 dwords[2], addr, discard_hwcaps, read_hwcaps, pp_hwcaps, erase_mask;
> + struct spi_nor_erase_map *map = &nor->erase_map;
> + int i, err;
> +
> + if (param_header->major != SFDP_JESD216_MAJOR ||
> + param_header->length < ARRAY_SIZE(dwords))
> + return -EINVAL;
> +
> + /* Read the 4-byte Address Instruction Table. */
> + addr = SFDP_PARAM_HEADER_PTP(param_header);
> + err = spi_nor_read_sfdp(nor, addr, sizeof(dwords), dwords);
> + if (err)
> + return err;
> +
> + /* Fix endianness of the 4BAIT DWORDs. */
> + for (i = 0; i < ARRAY_SIZE(dwords); i++)
> + dwords[i] = le32_to_cpu(dwords[i]);
> +
> + /*
> + * Compute the subset of (Fast) Read commands for which the 4-byte
> + * version is supported.
> + */
> + discard_hwcaps = 0;
> + read_hwcaps = 0;
> + for (i = 0; i < ARRAY_SIZE(reads); i++) {
> + const struct sfdp_4bait *read = &reads[i];
> +
> + discard_hwcaps |= read->hwcaps;
> + if ((params->hwcaps.mask & read->hwcaps) &&
> + (dwords[0] & read->supported_bit))
> + read_hwcaps |= read->hwcaps;
> + }

Looks like there is a bit of repeated stuff here, maybe this can be
pulled out ?

> + /*
> + * Compute the subset of Page Program commands for which the 4-byte
> + * version is supported.
> + */
> + pp_hwcaps = 0;
> + for (i = 0; i < ARRAY_SIZE(programs); i++) {
> + const struct sfdp_4bait *program = &programs[i];
> +
> + discard_hwcaps |= program->hwcaps;
> + if ((params->hwcaps.mask & program->hwcaps) &&
> + (dwords[0] & program->supported_bit))
> + pp_hwcaps |= program->hwcaps;
> + }
> +
> + /*
> + * Compute the subet of Sector Erase commands for which the 4-byte
> + * version is supported.
> + */
> + erase_mask = 0;
> + for (i = 0; i < SNOR_CMD_ERASE_MAX; i++) {
> + const struct sfdp_4bait *erase = &erases[i];
> +
> + if ((map->commands[i].size > 0) &&
> + (dwords[0] & erase->supported_bit))
> + erase_mask |= BIT(i);
> + }
> +
> + /*
> + * We need at least one 4-byte op code per read, program and erase
> + * operation; the .read(), .write() and .erase() hooks share the
> + * nor->addr_width value.
> + */
> + if (!read_hwcaps || !pp_hwcaps || !erase_mask)
> + return 0;
> +
> + /*
> + * Discard all operations from the 4-byte instruction set which are
> + * not supported by this memory.
> + */
> + params->hwcaps.mask &= ~discard_hwcaps;
> + params->hwcaps.mask |= (read_hwcaps | pp_hwcaps);
> +
> + /* Use the 4-byte address instruction set. */
> + for (i = 0; i < SNOR_CMD_READ_MAX; i++) {
> + struct spi_nor_read_command *read_cmd = &params->reads[i];
> +
> + read_cmd->opcode = spi_nor_convert_3to4_read(read_cmd->opcode);
> + }
> + for (i = 0; i < SNOR_CMD_PP_MAX; i++) {
> + struct spi_nor_pp_command *pp_cmd = &params->page_programs[i];
> +
> + pp_cmd->opcode = spi_nor_convert_3to4_program(pp_cmd->opcode);
> + }
> + for (i = 0; i < SNOR_CMD_ERASE_MAX; i++) {
> + struct spi_nor_erase_command *erase_cmd = &map->commands[i];
> +
> + if (erase_mask & BIT(i))
> + erase_cmd->opcode = (dwords[1] >> (i * 8)) & 0xFF;
> + else
> + spi_nor_set_erase_command(erase_cmd, 0u, 0xFF);
> + }
> +
> + /*
> + * We set nor->addr_width here to skip spi_nor_set_4byte_opcodes()
> + * later because this latest function implements a legacy quirk for
> + * the erase size of Spansion memory. However this quirk is no longer
> + * needed with new SFDP compliant memories.
> + */
> + nor->addr_width = 4;
> + nor->flags |= SNOR_F_4B_OPCODES;
> + return 0;
> +}
> +
> static int spi_nor_parse_sfdp(struct spi_nor *nor,
> struct spi_nor_flash_parameter *params)
> {
> @@ -2308,6 +2452,23 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
> if (err)
> goto exit;
>
> + /* Parse other parameter headers. */
> + for (i = 0; i < header.nph; i++) {
> + param_header = &param_headers[i];
> +
> + switch (SFDP_PARAM_HEADER_ID(param_header)) {
> + case SFDP_4BAIT_ID:
> + err = spi_nor_parse_4bait(nor, param_header, params);
> + break;
> +
> + default:
> + break;
> + }
> +
> + if (err)
> + goto exit;
> + }
> +
> exit:
> kfree(param_headers);
> return err;
> @@ -2885,7 +3046,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> if (ret)
> return ret;
>
> - if (info->addr_width)
> + if (nor->addr_width)
> + /* already configured by spi_nor_setup() */
> + ;

I think you can drop this part.

> + else if (info->addr_width)
> nor->addr_width = info->addr_width;
> else if (mtd->size > 0x1000000) {
> /* enable 4-byte addressing if the device exceeds 16MiB */
>


--
Best regards,
Marek Vasut

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