Re: [PATCH] dra7: sata: Fix SATA with CONFIG_ARM_LPAE enabled

[Roger Quadros <rogerq@ti.com>]

Tony, Christoph,

On 04/03/2020 18:20, Tony Lindgren wrote:
> * Roger Quadros <rogerq@ti.com> [200304 09:01]:
>> Even though the TRM says that SATA IP has 36 address bits
>> wired in the SoC, we see bus errors whenever any address
>> greater than 32-bit is given to the controller.
>>
>> This happens on dra7-EVM with 4G of RAM with CONFIG_ARM_LPAE=y.
>>
>> As a workaround we limit the DMA address range to 32-bits
>> for SATA.
>>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: Robin Murphy <robin.murphy@arm.com>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Reported-by: Yan Liu <yan-liu@ti.com>
>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>> ---
>>
>> NOTE: Currently ARM dma-mapping code doesn't account for devices
>> bus_dma_limit. This is fixed in [1].
>>
>> [1] https://lkml.org/lkml/2020/2/18/712
> 
> So is this dts patch safe to apply without the series above?
> 

Yes. To my surprise this patch fixes the SATA issue even without [1].
Without this patch dev->bus_dma_limit was being set to 0 and with the patch
it is being set to 0xffffffff.

> And should this dts patch be applied as a fix or can it wait
> until the merge window?

I think we should mark it for stable and apply it right away as fix for v5.6.

Cc: stable@kernel.org

cheers,
-roger
> 
> Regards,
> 
> Tony
> 
>>   arch/arm/boot/dts/dra7.dtsi | 25 ++++++++++++++++---------
>>   1 file changed, 16 insertions(+), 9 deletions(-)
>>
>> diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
>> index d78b684e7fca..895462c22d1c 100644
>> --- a/arch/arm/boot/dts/dra7.dtsi
>> +++ b/arch/arm/boot/dts/dra7.dtsi
>> @@ -642,15 +642,22 @@
>>   		};
>>   
>>   		/* OCP2SCP3 */
>> -		sata: sata@4a141100 {
>> -			compatible = "snps,dwc-ahci";
>> -			reg = <0x4a140000 0x1100>, <0x4a141100 0x7>;
>> -			interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
>> -			phys = <&sata_phy>;
>> -			phy-names = "sata-phy";
>> -			clocks = <&l3init_clkctrl DRA7_L3INIT_SATA_CLKCTRL 8>;
>> -			ti,hwmods = "sata";
>> -			ports-implemented = <0x1>;
>> +		sata_aux_bus {
>> +			#address-cells = <1>;
>> +			#size-cells = <2>;
>> +			compatible = "simple-bus";
>> +			ranges = <0x0 0x4a140000 0x0 0x1200>;
>> +			dma-ranges = <0x0 0x0 0x1 0x00000000>;
>> +			sata: sata@4a141100 {
>> +				compatible = "snps,dwc-ahci";
>> +				reg = <0x0 0x0 0x1100>, <0x1100 0x0 0x7>;
>> +				interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
>> +				phys = <&sata_phy>;
>> +				phy-names = "sata-phy";
>> +				clocks = <&l3init_clkctrl DRA7_L3INIT_SATA_CLKCTRL 8>;
>> +				ti,hwmods = "sata";
>> +				ports-implemented = <0x1>;
>> +			};
>>   		};
>>   
>>   		/* OCP2SCP1 */
>> -- 
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>>

-- 
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki