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Subject[PATCH v2] mtd: spi-nor: parse SFDP 4-byte Address Instruction Table
Date
From: Cyrille Pitchen <cyrille.pitchen@microchip.com>

Add support 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).

Flashes that have the 4BAIT table declared can now support
SPINOR_OP_PP_1_1_4_4B and SPINOR_OP_PP_1_4_4_4B opcodes.

Tested on MX25L25673G.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@microchip.com>
[tudor.ambarus@microchip.com:
- rework erase and page program logic,
- pass DMA-able buffer to spi_nor_read_sfdp(),
- introduce SPI_NOR_HAS_4BAIT
- various minor updates.]
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
v2:
- introduce SPI_NOR_HAS_4BAIT
- use SNOR_F_4B_OPCODES

This patch depends on:
- "mtd: spi-nor: fix selection of uniform erase type in flexible conf"
which was already applied as a fix
- "mtd: spi-nor: Add the SNOR_F_4B_OPCODES flag" which will be present
in spi-nor/next

drivers/mtd/spi-nor/spi-nor.c | 193 +++++++++++++++++++++++++++++++++++++++++-
include/linux/mtd/spi-nor.h | 1 +
2 files changed, 193 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index a9508db58d7f..e77efc153736 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -121,6 +121,7 @@ struct sfdp_parameter_header {

#define SFDP_BFPT_ID 0xff00 /* Basic Flash Parameter Table */
#define SFDP_SECTOR_MAP_ID 0xff81 /* Sector Map Table */
+#define SFDP_4BAIT_ID 0xff84 /* 4-byte Address Instruction Table */

#define SFDP_SIGNATURE 0x50444653U
#define SFDP_JESD216_MAJOR 1
@@ -3179,6 +3180,191 @@ static int spi_nor_parse_smpt(struct spi_nor *nor,
return ret;
}

+#define SFDP_4BAIT_DWORD_MAX 2
+
+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;
+};
+
+/**
+ * spi_nor_parse_4bait() - parse the 4-Byte Address Instruction Table
+ * @nor: pointer to a 'struct spi_nor'.
+ * @param_header: pointer to the 'struct sfdp_parameter_header' describing
+ * the 4-Byte Address Instruction Table length and version.
+ * @params: pointer to the 'struct spi_nor_flash_parameter' to be.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+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_ERASE_TYPE_MAX] = {
+ { 0u /* not used */, BIT(9) },
+ { 0u /* not used */, BIT(10) },
+ { 0u /* not used */, BIT(11) },
+ { 0u /* not used */, BIT(12) },
+ };
+ struct spi_nor_pp_command *params_pp = params->page_programs;
+ struct spi_nor_erase_map *map = &nor->erase_map;
+ struct spi_nor_erase_type *erase_type = map->erase_type;
+ u32 *dwords;
+ size_t len;
+ u32 addr, discard_hwcaps, read_hwcaps, pp_hwcaps, erase_mask;
+ int i, ret;
+
+ if (param_header->major != SFDP_JESD216_MAJOR ||
+ param_header->length < SFDP_4BAIT_DWORD_MAX)
+ return -EINVAL;
+
+ /* Read the 4-byte Address Instruction Table. */
+ len = sizeof(*dwords) * SFDP_4BAIT_DWORD_MAX;
+
+ /* Use a kmalloc'ed bounce buffer to guarantee it is DMA-able. */
+ dwords = kmalloc(len, GFP_KERNEL);
+ if (!dwords)
+ return -ENOMEM;
+
+ addr = SFDP_PARAM_HEADER_PTP(param_header);
+ ret = spi_nor_read_sfdp(nor, addr, len, dwords);
+ if (ret)
+ return ret;
+
+ /* Fix endianness of the 4BAIT DWORDs. */
+ for (i = 0; i < SFDP_4BAIT_DWORD_MAX; 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;
+ }
+
+ /*
+ * 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];
+
+ /*
+ * The 4 Byte Address Instruction (Optional) Table is the only
+ * SFDP table that indicates support for Page Program Commands.
+ * Bypass the params->hwcaps.mask and consider 4BAIT the biggest
+ * authority for specifying Page Program support.
+ */
+ discard_hwcaps |= program->hwcaps;
+ if (dwords[0] & program->supported_bit)
+ pp_hwcaps |= program->hwcaps;
+ }
+
+ /*
+ * Compute the subset of Sector Erase commands for which the 4-byte
+ * version is supported.
+ */
+ erase_mask = 0;
+ for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
+ const struct sfdp_4bait *erase = &erases[i];
+
+ if (dwords[0] & erase->supported_bit)
+ erase_mask |= BIT(i);
+ }
+
+ /* Replicate the sort done for the map's erase types in BFPT. */
+ erase_mask = spi_nor_sort_erase_mask(map, erase_mask);
+
+ /*
+ * 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)
+ goto out;
+
+ /*
+ * 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);
+ }
+
+ /* 4BAIT is the only SFDP table that indicates page program support. */
+ if (pp_hwcaps & SNOR_HWCAPS_PP)
+ spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP],
+ SPINOR_OP_PP_4B, SNOR_PROTO_1_1_1);
+ if (pp_hwcaps & SNOR_HWCAPS_PP_1_1_4)
+ spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_1_1_4],
+ SPINOR_OP_PP_1_1_4_4B,
+ SNOR_PROTO_1_1_4);
+ if (pp_hwcaps & SNOR_HWCAPS_PP_1_4_4)
+ spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_1_4_4],
+ SPINOR_OP_PP_1_4_4_4B,
+ SNOR_PROTO_1_4_4);
+
+ for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
+ if (erase_mask & BIT(i))
+ erase_type[i].opcode = (dwords[1] >>
+ erase_type[i].idx * 8) & 0xFF;
+ else
+ spi_nor_set_erase_type(&erase_type[i], 0u, 0xFF);
+ }
+
+ /*
+ * We set SNOR_F_HAS_4BAIT in order to skip spi_nor_set_4byte_opcodes()
+ * later because we already did the conversion to 4byte opcodes. Also,
+ * 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 | SNOR_F_HAS_4BAIT;
+
+ /* fall through */
+out:
+ kfree(dwords);
+ return ret;
+}
+
/**
* spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
* @nor: pointer to a 'struct spi_nor'
@@ -3276,6 +3462,10 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
err = spi_nor_parse_smpt(nor, param_header);
break;

+ case SFDP_4BAIT_ID:
+ err = spi_nor_parse_4bait(nor, param_header, params);
+ break;
+
default:
break;
}
@@ -3857,7 +4047,8 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
(JEDEC_MFR(info) == SNOR_MFR_SPANSION && mtd->size > SZ_16M))
nor->flags |= SNOR_F_4B_OPCODES;

- if (nor->addr_width == 4 && nor->flags & SNOR_F_4B_OPCODES)
+ if (nor->addr_width == 4 && nor->flags & SNOR_F_4B_OPCODES &&
+ !(nor->flags & SNOR_F_HAS_4BAIT))
spi_nor_set_4byte_opcodes(nor);

if (nor->addr_width > SPI_NOR_MAX_ADDR_WIDTH) {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 5f177aa39f68..fa2d89e38e40 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -234,6 +234,7 @@ enum spi_nor_option_flags {
SNOR_F_USE_CLSR = BIT(5),
SNOR_F_BROKEN_RESET = BIT(6),
SNOR_F_4B_OPCODES = BIT(7),
+ SNOR_F_HAS_4BAIT = BIT(8),
};

/**
--
2.9.4
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