On 2020-03-13 9:47 am, Roger Quadros wrote:
The L3 interconnect's memory map is from 0x0 to 0xffffffff. Out of this, System memory (SDRAM) can be accessed from 0x80000000 to 0xffffffff (2GB) DRA7 does support 4GB of SDRAM but upper 2GB can only be accessed by the MPU subsystem. Add the dma-ranges property to reflect the physical address limit of the L3 bus. Issues ere observed only with SATA on DRA7-EVM with 4GB RAM and CONFIG_ARM_LPAE enabled. This is because the controller supports 64-bit DMA and its driver sets the dma_mask to 64-bit thus resulting in DMA accesses beyond L3 limit of 2G. Setting the correct bus_dma_limit fixes the issue.
Neat! In principle you should no longer need the specific dma-ranges on the PCIe nodes, since AIUI those really only represent a subset of this general limitation, but given the other inheritance issue you saw it's probably safer to leave them as-is for now.
FWIW, Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Roger Quadros <rogerq@xxxxxx> Cc: stable@xxxxxxxxxx --- Changelog: v2: - Revised patch with minimal intrusion. i.e. don't change #size-cells of device node. arch/arm/boot/dts/dra7.dtsi | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi index d78b684e7fca..058b8cbb8ef3 100644 --- a/arch/arm/boot/dts/dra7.dtsi +++ b/arch/arm/boot/dts/dra7.dtsi @@ -148,6 +148,7 @@ #address-cells = <1>; #size-cells = <1>; ranges = <0x0 0x0 0x0 0xc0000000>; + dma-ranges = <0x80000000 0x0 0x80000000 0x80000000>; ti,hwmods = "l3_main_1", "l3_main_2"; reg = <0x0 0x44000000 0x0 0x1000000>, <0x0 0x45000000 0x0 0x1000>;
