[PATCH v16 09/15] mtd: spi-nor: Parse SFDP SCCR Map

Pratyush Yadav
2020-10-05T15:32:24Z

From: Tudor Ambarus <tudor.ambarus@microchip.com>

Parse just the 22nd dword and look for the 'DTR Octal Mode Enable
Volatile bit'.

SPI_NOR_IO_MODE_EN_VOLATILE should be set just for the flashes
that don't define the optional SFDP SCCR Map. For the others,
let the SFDP do its job and fill the SNOR_F_IO_MODE_EN_VOLATILE
flag. We avoid this way polluting the flash flags when declaring
one.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
---
drivers/mtd/spi-nor/sfdp.c | 48 ++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index b2d097b44a55..3efcba5e629a 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -21,6 +21,10 @@
#define SFDP_SECTOR_MAP_ID 0xff81 /* Sector Map Table */
#define SFDP_4BAIT_ID 0xff84 /* 4-byte Address Instruction Table */
#define SFDP_PROFILE1_ID 0xff05 /* xSPI Profile 1.0 table. */
+#define SFDP_SCCR_MAP_ID 0xff87 /*
+ * Status, Control and Configuration
+ * Register Map.
+ */

#define SFDP_SIGNATURE 0x50444653U

@@ -1195,6 +1199,46 @@ static int spi_nor_parse_profile1(struct spi_nor *nor,
return ret;
}

+#define SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE BIT(31)
+
+/**
+ * spi_nor_parse_sccr() - Parse the Status, Control and Configuration Register
+ * Map.
+ * @nor: pointer to a 'struct spi_nor'
+ * @sccr_header: pointer to the 'struct sfdp_parameter_header' describing
+ * the SCCR Map 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_sccr(struct spi_nor *nor,
+ const struct sfdp_parameter_header *sccr_header,
+ struct spi_nor_flash_parameter *params)
+{
+ u32 *dwords, addr;
+ size_t len;
+ int ret;
+
+ len = sccr_header->length * sizeof(*dwords);
+ dwords = kmalloc(len, GFP_KERNEL);
+ if (!dwords)
+ return -ENOMEM;
+
+ addr = SFDP_PARAM_HEADER_PTP(sccr_header);
+ ret = spi_nor_read_sfdp(nor, addr, len, dwords);
+ if (ret)
+ goto out;
+
+ le32_to_cpu_array(dwords, sccr_header->length);
+
+ if (FIELD_GET(SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE, dwords[22]))
+ nor->flags |= SNOR_F_IO_MODE_EN_VOLATILE;
+
+out:
+ kfree(dwords);
+ return ret;
+}
+
/**
* spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
* @nor: pointer to a 'struct spi_nor'
@@ -1300,6 +1344,10 @@ int spi_nor_parse_sfdp(struct spi_nor *nor,
err = spi_nor_parse_profile1(nor, param_header, params);
break;

+ case SFDP_SCCR_MAP_ID:
+ err = spi_nor_parse_sccr(nor, param_header, params);
+ break;
+
default:
break;
}
--
2.28.0