Re: dma_mask limited to 32-bits with OF platform device

Rob,

On 18/02/2020 19:22, Rob Herring wrote:

On Tue, Feb 18, 2020 at 2:28 AM Roger Quadros [off-list ref] wrote:

quoted

Chrishtoph,

The branch works fine for SATA on DRA7 with CONFIG_LPAE once I
have the below DT fix.

Do you intend to send these fixes to -stable?

------------------------- arch/arm/boot/dts/dra7.dtsi -------------------------
index d78b684e7fca..853ecf3cfb37 100644

@@ -645,6 +645,8 @@
                 sata: sata@4a141100 {
                         compatible = "snps,dwc-ahci";
                         reg = <0x4a140000 0x1100>, <0x4a141100 0x7>;
+                       #size-cells = <2>;
+                       dma-ranges = <0x00000000 0x00000000 0x1 0x00000000>;

dma-ranges should be in the parent (bus) node, not the device node.

I didn't understand why.

There are many devices on the parent bus node and all devices might not have the 32-bit DMA limit
the SATA controller has.

SATA controller is the bus master and the ATA devices are children of the SATA controller.

 From Documentation/devicetree/booting-without-of.txt

* DMA Bus master
Optional property:
- dma-ranges: <prop-encoded-array> encoded as arbitrary number of triplets of
         (child-bus-address, parent-bus-address, length). Each triplet specified
         describes a contiguous DMA address range.
         The dma-ranges property is used to describe the direct memory access (DMA)
         structure of a memory-mapped bus whose device tree parent can be accessed
         from DMA operations originating from the bus. It provides a means of
         defining a mapping or translation between the physical address space of
         the bus and the physical address space of the parent of the bus.
         (for more information see the Devicetree Specification)

* DMA Bus child
Optional property:
- dma-ranges: <empty> value. if present - It means that DMA addresses
         translation has to be enabled for this device.
- dma-coherent: Present if dma operations are coherent

quoted

                         interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
                         phys = <&sata_phy>;
                         phy-names = "sata-phy";


cheers,
-roger

On 17/02/2020 15:21, Christoph Hellwig wrote:

quoted

Roger,

can you try the branch below and check if that helps?

      git://git.infradead.org/users/hch/misc.git arm-dma-bus-limit

Gitweb:

      http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/arm-dma-bus-limit

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