dmaengine: Add support for BCM2835
Subsystems (4)
PATCH v6 1/1 dmaengine: Add support for BCM2835
Add support for DMA controller of BCM2835 as used in the Raspberry Pi. Currently it only supports cyclic DMA.
Signed-off-by Florian Meier <florian.meier-oZ8rN/[email protected]>
---
Sixth version with some style improvements by Joe. sizeof(s128) doesn't work. Therefore, still hardcoded byte counts.
.../devicetree/bindings/dma/bcm2835-dma.txt | 56 ++ drivers/dma/Kconfig | 6 + drivers/dma/Makefile | 1 + drivers/dma/bcm2835-dma.c | 744 +++++++++++++++++++++ 4 files changed, 807 insertions(+) create mode 100644 Documentation/devicetree/bindings/dma/bcm2835-dma.txt create mode 100644 drivers/dma/bcm2835-dma.c
Documentation/devicetree/bindings/dma/bcm2835-dma.txt new file +56 -0
@@ -0,0 +1,56 @@ +* BCM2835 DMA controller + +Required properties: +- compatible: Should be "brcm,bcm2835-dma". +- reg: Should contain DMA registers location and length. +- interrupts: Should contain the DMA interrupts associated + to the DMA channels in ascending order. + First cell is the IRQ bank. + Second cell is the IRQ number. +- #dma-cells: Must be <1>, used to represent the number of integer cells in + the dmas property of client devices. +- brcm,dma-channel-mask: Bit mask representing the channels + not used by the firmware. + +Example: + +dma: dma@7e007000 { + compatible = "brcm,bcm2835-dma"; + reg = <0x7e007000 0xf00>; + interrupts = <1 16 + 1 17 + 1 18 + 1 19 + 1 20 + 1 21 + 1 22 + 1 23 + 1 24 + 1 25 + 1 26 + 1 27 + 1 28>; + + #dma-cells = <1>; + brcm,dma-channel-mask = <0x7f35>; +}; + +DMA clients connected to the BCM2835 DMA controller must use the format +described in the dma.txt file, using a two-cell specifier for each channel: +a phandle plus one integer cells. +The two cells in order are: + +1. A phandle pointing to the DMA controller. +2. The DREQ number. + +Example: + +bcm2835_i2s: i2s@7e203000 { + compatible = "brcm,bcm2835-i2s"; + reg = < 0x7e203000 0x20 + 0x7e101098 0x02>; + + dmas = <&dma 2 + &dma 3>; + dma-names = "tx", "rx"; +};
drivers/dma/Kconfig +6 -0
@@ -300,6 +300,12 @@ config DMA_OMAP select DMA_ENGINE select DMA_VIRTUAL_CHANNELS +config DMA_BCM2835 + tristate "BCM2835 DMA engine support" + depends on (ARCH_BCM2835 || MACH_BCM2708) + select DMA_ENGINE + select DMA_VIRTUAL_CHANNELS + config TI_CPPI41 tristate "AM33xx CPPI41 DMA support" depends on ARCH_OMAP
drivers/dma/Makefile +1 -0
@@ -38,6 +38,7 @@ obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o obj-$(CONFIG_DMA_OMAP) += omap-dma.o +obj-$(CONFIG_DMA_BCM2835) += bcm2835-dma.o obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o obj-$(CONFIG_DMA_JZ4740) += dma-jz4740.o obj-$(CONFIG_TI_CPPI41) += cppi41.o
drivers/dma/bcm2835-dma.c new file +744 -0
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