From cce15c51f1afbb1aa9d5f7779c9f7c0a17b39701 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Thu, 9 May 2019 19:03:00 +0200 Subject: [PATCH] ARM: bcm283x: Enable DMA support for SPI controller MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Without this, the driver for the BCM2835 SPI controller uses interrupt mode instead of DMA mode, incurring a significant performance penalty. The Foundation's device tree has had these attributes for years, but for some reason they were never upstreamed. They were originally contributed by Noralf Trønnes and Martin Sperl: https://github.com/raspberrypi/linux/commit/25f3e064afc8 https://github.com/raspberrypi/linux/commit/e0edb52b47e6 The DREQ numbers 6 and 7 are documented in section 4.2.1.3 of: https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf Tested-by: Nicolas Saenz Julienne Signed-off-by: Lukas Wunner Reviewed-by: Eric Anholt Reviewed-by: Martin Sperl Signed-off-by: Stefan Wahren Cc: Martin Sperl Cc: Noralf Trønnes --- arch/arm/boot/dts/bcm283x.dtsi | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/arm/boot/dts/bcm283x.dtsi +++ b/arch/arm/boot/dts/bcm283x.dtsi @@ -403,6 +403,8 @@ reg = <0x7e204000 0x200>; interrupts = <2 22>; clocks = <&clocks BCM2835_CLOCK_VPU>; + dmas = <&dma 6>, <&dma 7>; + dma-names = "tx", "rx"; #address-cells = <1>; #size-cells = <0>; status = "disabled";