[PATCH] ARM: davinci: da850-evm: fix read access to SPI flash

[PATCH] ARM: davinci: da850-evm: fix read access to SPI flash

[Fabien Parent]

Read access to the SPI flash are broken on da850-evm, i.e. the data
read is not what is actually programmed on the flash.
According to the datasheet for the M25P64 part present on the da850-evm,
if the SPI frequency is higher than 20MHz then the READ command is not
usable anymore and only the FAST_READ command can be used to read data.

This commit specifies in the DTS that we should use FAST_READ command
instead of the READ command.

Signed-off-by: Fabien Parent <fparent@baylibre.com>
---
 arch/arm/boot/dts/da850-evm.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/da850-evm.dts b/arch/arm/boot/dts/da850-evm.dts
index 41de15fe15a2..78492a0bbbab 100644
--- a/arch/arm/boot/dts/da850-evm.dts
+++ b/arch/arm/boot/dts/da850-evm.dts
@@ -99,6 +99,7 @@
 				#size-cells = <1>;
 				compatible = "m25p64";
 				spi-max-frequency = <30000000>;
+				m25p,fast-read;
 				reg = <0>;
 				partition@0 {
 					label = "U-Boot-SPL";
-- 
2.11.0

Re: [PATCH] ARM: davinci: da850-evm: fix read access to SPI flash

[Kevin Hilman]

Fabien Parent <fparent-rdvid1DuHRBWk0Htik3J/w@public.gmane.org> writes:

> Read access to the SPI flash are broken on da850-evm, i.e. the data
> read is not what is actually programmed on the flash.
> According to the datasheet for the M25P64 part present on the da850-evm,
> if the SPI frequency is higher than 20MHz then the READ command is not
> usable anymore and only the FAST_READ command can be used to read data.
>
> This commit specifies in the DTS that we should use FAST_READ command
> instead of the READ command.
>
> Signed-off-by: Fabien Parent <fparent-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>

Tested on da850-evm on top of v4.10-rc3.  This gets the DT boot
functionatliy in line with the legacy (board-file) boot.

Tested-by: Kevin Hilman <khilman-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>

Kevin
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] ARM: davinci: da850-evm: fix read access to SPI flash

[Sekhar Nori]

On Wednesday 18 January 2017 05:55 AM, Kevin Hilman wrote:
> Fabien Parent <fparent@baylibre.com> writes:
> 
>> Read access to the SPI flash are broken on da850-evm, i.e. the data
>> read is not what is actually programmed on the flash.
>> According to the datasheet for the M25P64 part present on the da850-evm,
>> if the SPI frequency is higher than 20MHz then the READ command is not
>> usable anymore and only the FAST_READ command can be used to read data.
>>
>> This commit specifies in the DTS that we should use FAST_READ command
>> instead of the READ command.
>>
>> Signed-off-by: Fabien Parent <fparent@baylibre.com>
> 
> Tested on da850-evm on top of v4.10-rc3.  This gets the DT boot
> functionatliy in line with the legacy (board-file) boot.
> 
> Tested-by: Kevin Hilman <khilman@baylibre.com>

Applied with Kevin's Tested-by and also marked for stable. Sending pull
request for v4.10-rc shortly.

Thanks,
Sekhar