mtd: spi-nor: parse SFDP 4-byte Address Instruction Table

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>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 4896b9a..69ed5f2 100644 (file)
--- 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
@@ -3239,6 +3240,191 @@ out:
        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'
@@ -3336,6 +3522,10 @@ 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;
                }
@@ -3925,7 +4115,8 @@ 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 5f177aa..fa2d89e 100644 (file)
--- 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),
 };
 
 /**