Re: [PATCH 2/2] dmaengine: msm_bam_dma: Add device tree binding
From: Stephen Boyd <hidden>
Date: 2013-10-29 06:18:39
Also in:
linux-arm-kernel, linux-arm-msm, lkml
On 10/25, Andy Gross wrote:
quoted hunk ↗ jump to hunk
diff --git a/Documentation/devicetree/bindings/dma/msm_bam_dma.txt b/Documentation/devicetree/bindings/dma/msm_bam_dma.txt new file mode 100644 index 0000000..fe3ed8f --- /dev/null +++ b/Documentation/devicetree/bindings/dma/msm_bam_dma.txt@@ -0,0 +1,49 @@ +MSM BAM DMA controller + +Required properties: +- compatible: Should be "qcom,bam" +- reg: Address range for DMA registers +- interrupts: single interrupt for this controller +- #dma-cells: must be <3> +- clocks: required clock +- clock-names: name of clock + +Example: + + dma0: dma@f9984000 = {
I imagine it's fine to say 'bam0: dma@f9984000' here. The node name should stay dma though. This way we know that we're talking about the first bam. Or if there is a more specific name for the bam we could use that, like system-bam or sdhci-bam.
+ compatible = "qcom,bam"; + reg = <0xf9984000 0x15000>; + interrupts = <0 94 0>; + clocks = <&bam_dma_ahb_cxc>; + clock-names = "bam_clk"; + #dma-cells = <3>; + }; + +Client: +Required properties: +- dmas: List of dma channel requests +- dma-names: Names of aforementioned requested channels + +Clients must use the format described in the dma.txt file, using a four cell +specifier for each channel. + +The four cells in order are: + 1. A phandle pointing to the DMA controller + 2. The channel number + 3. The execution environment value for this channel. + 4. Direction of the fixed unidirectional channel + 0 - Memory to Device + 1 - Device to Memory
Should we add "2 - Device to Device" here? Is there anything more that needs to be done in the binding for device to device transfers. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation