Re: [PATCH v2 5/9] arm64: dts: ls1046a: make dma-coherent global to the SoC

Sean Anderson
2022-09-23T16:12:16Z

Hi All,

On 9/15/22 7:34 PM, Li Yang wrote:
> These SoCs are really completely dma coherent in their entirety so add
> the dma-coherent property at the soc level in the device tree and drop
> the instances where it's specifically added to a few select devices.
>
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Signed-off-by: Li Yang <leoyang.li@nxp.com>
> ---
> arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi
> index 27033c558e3e..e406499a26b4 100644
> --- a/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi
> +++ b/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi
> @@ -273,6 +273,7 @@ soc: soc {
> #size-cells = <2>;
> ranges;
> dma-ranges = <0x0 0x0 0x0 0x0 0x10000 0x00000000>;
> + dma-coherent;
>
> ddr: memory-controller@1080000 {
> compatible = "fsl,qoriq-memory-controller";
> @@ -355,7 +356,6 @@ crypto: crypto@1700000 {
> ranges = <0x0 0x00 0x1700000 0x100000>;
> reg = <0x00 0x1700000 0x0 0x100000>;
> interrupts = <GIC_SPI 75 IRQ_TYPE_LEVEL_HIGH>;
> - dma-coherent;
>
> sec_jr0: jr@10000 {
> compatible = "fsl,sec-v5.4-job-ring",
> @@ -794,7 +794,6 @@ pcie1: pcie@3400000 {
> #address-cells = <3>;
> #size-cells = <2>;
> device_type = "pci";
> - dma-coherent;
> num-viewport = <8>;
> bus-range = <0x0 0xff>;
> ranges = <0x81000000 0x0 0x00000000 0x40 0x00010000 0x0 0x00010000 /* downstream I/O */
> @@ -834,7 +833,6 @@ pcie2: pcie@3500000 {
> #address-cells = <3>;
> #size-cells = <2>;
> device_type = "pci";
> - dma-coherent;
> num-viewport = <8>;
> bus-range = <0x0 0xff>;
> ranges = <0x81000000 0x0 0x00000000 0x48 0x00010000 0x0 0x00010000 /* downstream I/O */
> @@ -874,7 +872,6 @@ pcie3: pcie@3600000 {
> #address-cells = <3>;
> #size-cells = <2>;
> device_type = "pci";
> - dma-coherent;
> num-viewport = <8>;
> bus-range = <0x0 0xff>;
> ranges = <0x81000000 0x0 0x00000000 0x50 0x00010000 0x0 0x00010000 /* downstream I/O */
>

I'd like to summarize the conclusions of [1] below. This patch breaks
I2C0, which is the only user of eDMA at the moment. eDMA is noncoherent
because snooping is not enabled for it. I have submitted a patch [2] to
U-Boot to enable snooping for eDMA. For now, this patch must add
dma-noncoherent to the i2c0 node.

--Sean

[1] https://lore.kernel.org/linux-arm-kernel/29a09f45-24f9-68be-bdc2-8691af41b5db@seco.com/T/#t
[2] https://lore.kernel.org/u-boot/20220923160551.2200873-1-sean.anderson@seco.com/T/#u