[PATCH v4 11/16] mtd: spi-nor: enable octal DTR mode when possible

Pratyush Yadav
2020-04-24T18:52:13Z

Allow flashes to specify a hook to enable octal DTR mode. Use this hook
whenever possible to get optimal transfer speeds.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
---
drivers/mtd/spi-nor/core.c | 35 +++++++++++++++++++++++++++++++++++
drivers/mtd/spi-nor/core.h | 2 ++
2 files changed, 37 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 6eb2b1781972..c75765f09d62 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3085,6 +3085,35 @@ static int spi_nor_init_params(struct spi_nor *nor)
return 0;
}

+/** spi_nor_octal_dtr_enable() - enable Octal DTR I/O if needed
+ * @nor: pointer to a 'struct spi_nor'
+ * @enable: whether to enable or disable Octal DTR
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_octal_dtr_enable(struct spi_nor *nor, bool enable)
+{
+ int ret;
+
+ if (!nor->params->octal_dtr_enable)
+ return 0;
+
+ if (!(spi_nor_get_protocol_width(nor->read_proto) == 8 ||
+ spi_nor_get_protocol_width(nor->write_proto) == 8))
+ return 0;
+
+ ret = nor->params->octal_dtr_enable(nor, enable);
+ if (ret)
+ return ret;
+
+ if (enable)
+ nor->reg_proto = SNOR_PROTO_8_8_8_DTR;
+ else
+ nor->reg_proto = SNOR_PROTO_1_1_1;
+
+ return 0;
+}
+
/**
* spi_nor_quad_enable() - enable Quad I/O if needed.
* @nor: pointer to a 'struct spi_nor'
@@ -3124,6 +3153,12 @@ static int spi_nor_init(struct spi_nor *nor)
{
int err;

+ err = spi_nor_octal_dtr_enable(nor, true);
+ if (err) {
+ dev_dbg(nor->dev, "octal mode not supported\n");
+ return err;
+ }
+
err = spi_nor_quad_enable(nor);
if (err) {
dev_dbg(nor->dev, "quad mode not supported\n");
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 7e6df8322da0..6338d32a0d77 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -203,6 +203,7 @@ struct spi_nor_locking_ops {
* higher index in the array, the higher priority.
* @erase_map: the erase map parsed from the SFDP Sector Map Parameter
* Table.
+ * @octal_dtr_enable: enables SPI NOR octal DTR mode.
* @quad_enable: enables SPI NOR quad mode.
* @set_4byte_addr_mode: puts the SPI NOR in 4 byte addressing mode.
* @convert_addr: converts an absolute address into something the flash
@@ -226,6 +227,7 @@ struct spi_nor_flash_parameter {

struct spi_nor_erase_map erase_map;

+ int (*octal_dtr_enable)(struct spi_nor *nor, bool enable);
int (*quad_enable)(struct spi_nor *nor);
int (*set_4byte_addr_mode)(struct spi_nor *nor, bool enable);
u32 (*convert_addr)(struct spi_nor *nor, u32 addr);