Re: [PATCH 2/3] dt-bindings: mtd: atmel-quadspi: add an optional property 'dmacap,memcpy'
From: Rob Herring <hidden>
Date: 2017-12-26 23:23:35
Also in:
linux-spi, lkml
On Sun, Dec 24, 2017 at 05:36:05AM +0100, Cyrille Pitchen wrote:
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The optional 'dmacap,memcpy' DT property tells the Atmel QSPI controller driver to reserve some DMA channel then to use it to perform DMA memcpy() during data transfers. This feature relies on the generic bounce buffer helper from spi-nor.c. Signed-off-by: Cyrille Pitchen <redacted> --- Documentation/devicetree/bindings/mtd/atmel-quadspi.txt | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt b/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt index b93c1e2f25dd..002d3f0a445b 100644 --- a/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt +++ b/Documentation/devicetree/bindings/mtd/atmel-quadspi.txt@@ -12,6 +12,10 @@ Required properties: - #address-cells: Should be <1>. - #size-cells: Should be <0>. +Optional properties: +- dmacap,memcpy: Reserve a DMA channel to perform DMA memcpy() between the + system memory and the QSPI mapped memory.
How is this a h/w property? Why would I not want to always enable DMA if possible? Furthermore, you are reusing a property, but giving it a different meaning. The current definition is an indication whether a DMA controller supports memcpy operations or not. It is not a flag for clients to use memcpy channels. Why don't you use "dmas" property to point to the DMA controller.
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+ Example: spi@f0020000 {@@ -24,6 +28,7 @@ spi@f0020000 { #size-cells = <0>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_spi0_default>; + dmacap,memcpy; m25p80@0 { ...-- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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