[PATCH linux dev-4.7 12/12] mtd: spi-nor: aspeed: use fast read when doing DMAs

[Cédric Le Goater]

Try to improve the speed of transfers when doing DMAs

Signed-off-by: Cédric Le Goater <clg at kaod.org>
---
 drivers/mtd/spi-nor/aspeed-smc.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/spi-nor/aspeed-smc.c b/drivers/mtd/spi-nor/aspeed-smc.c
index ae2d9bc643c3..40e48372865a 100644
--- a/drivers/mtd/spi-nor/aspeed-smc.c
+++ b/drivers/mtd/spi-nor/aspeed-smc.c
@@ -211,6 +211,7 @@ enum smc_ctl_reg_value {
 	smc_base,		/* base value without mode for other commands */
 	smc_read,		/* command reg for (maybe fast) reads */
 	smc_write,		/* command reg for writes with timings */
+	smc_fread,		/* command reg for (maybe faster?) reads */
 	smc_num_ctl_reg_values	/* last value to get count of commands */
 };
 
@@ -347,9 +348,6 @@ static inline void aspeed_smc_chip_configure(struct aspeed_smc_per_chip *chip,
 	writel(ctl, chip->ctl);
 }
 
-/*
- * TODO: configure FREAD mode
- */
 static int aspeed_smc_dma_start(struct aspeed_smc_per_chip *chip,
 				u32 offset, void *buf, size_t length,
 				int is_write)
@@ -359,7 +357,7 @@ static int aspeed_smc_dma_start(struct aspeed_smc_per_chip *chip,
 	int ret;
 
 	aspeed_smc_chip_configure(chip, is_write ? chip->ctl_val[smc_write] :
-		chip->ctl_val[smc_base]);
+		chip->ctl_val[smc_fread]);
 
 	dev_dbg(chip->nor.dev, "DMA %s to=0x%08x len=0x%08x\n",
 		is_write ? "write" : "read", offset, length);
@@ -823,6 +821,11 @@ static int aspeed_smc_probe(struct platform_device *pdev)
 		if (err)
 			continue;
 
+		chip->ctl_val[smc_fread] = chip->ctl_val[smc_base] |
+			/* Not sure this is that fast */
+			spi_control_fill_opcode(SPINOR_OP_READ_FAST) |
+			CONTROL_SPI_COMMAND_MODE_FREAD;
+
 		chip->ctl_val[smc_write] = chip->ctl_val[smc_base] |
 			spi_control_fill_opcode(chip->nor.program_opcode) |
 			CONTROL_SPI_COMMAND_MODE_WRITE;
-- 
2.7.4