[PATCH dev-5.0 3/4] mtd: spi-nor: aspeed: use memcpy_fromio() to capture the optimization buffer

[Milton Miller II]

About 04/17/2019 09:20AM in some timezone, Cédric Le Goater wrote:


>aspeed_smc_read_from_ahb() only reads the first word which is not
>what
>we want. We want to capture a CALIBRATE_BUF_SIZE size window of the
>flash contents to optimize the read.
>

NACK

This justifcation is false.  The routine reads the whole buffer
because it calls the _rep routine and takes the size.

In addition, the comment just before aspeed_smc_read_from_ahb
tells why memcpy_fromio and memcpy_toio are broken on 32 bit
arm, and this is still the case judging from the recent bug
reportfrom a Nuvaton user [1].

[1] https://github.com/openbmc/openbmc/issues/3521

Andrew, Please revert this patch.

>Signed-off-by: Cédric Le Goater <clg at kaod.org>
>---
> drivers/mtd/spi-nor/aspeed-smc.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/mtd/spi-nor/aspeed-smc.c
>b/drivers/mtd/spi-nor/aspeed-smc.c
>index 1437732fdea1..7e289ecb1c99 100644
>--- a/drivers/mtd/spi-nor/aspeed-smc.c
>+++ b/drivers/mtd/spi-nor/aspeed-smc.c
>@@ -796,8 +796,7 @@ static bool aspeed_smc_check_reads(struct
>aspeed_smc_chip *chip,
> 	int i;
> 
> 	for (i = 0; i < 10; i++) {
>-		aspeed_smc_read_from_ahb(test_buf, chip->ahb_base,
>-					 CALIBRATE_BUF_SIZE);
>+		memcpy_fromio(test_buf, chip->ahb_base, CALIBRATE_BUF_SIZE);
> 		if (memcmp(test_buf, golden_buf, CALIBRATE_BUF_SIZE) != 0)
> 			return false;
> 	}
>@@ -921,8 +920,7 @@ static int aspeed_smc_optimize_read(struct
>aspeed_smc_chip *chip,
> 
> 	writel(chip->ctl_val[smc_read], chip->ctl);
> 
>-	aspeed_smc_read_from_ahb(golden_buf, chip->ahb_base,
>-				 CALIBRATE_BUF_SIZE);
>+	memcpy_fromio(golden_buf, chip->ahb_base, CALIBRATE_BUF_SIZE);
> 
> 	/* Establish our read mode with freq field set to 0 (HCLK/16) */
> 	chip->ctl_val[smc_read] = save_read_val & 0xfffff0ff;
>-- 
>2.20.1
>
>