ARM: bcm283x: Enable DMA support for SPI controller

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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:
25f3e064af
e0edb52b47

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 <nsaenzjulienne@suse.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>

...

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Lukas Wunner 2019-05-09 19:03:00 +02:00 • committed by Florian Fainelli

parent e8bd76dccd

commit cbbe883330

1 changed files with 2 additions and 0 deletions

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arch/arm/boot/dts/bcm283x.dtsi

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