[RFC PATCH v5 6/6] mtd: spi-nor: parse SFDP 4-byte Address Instruction Table
Cyrille Pitchen
cyrille.pitchen at atmel.com
Wed Mar 22 16:33:56 PDT 2017
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 at 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;
+ }
+
+ /*
+ * 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 = ¶ms->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 = ¶ms->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 = ¶m_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() */
+ ;
+ 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 */
--
2.9.3
More information about the linux-mtd
mailing list