[deliverable/linux.git] / Documentation / devicetree / bindings / dma / brcm,bcm2835-dma.txt

* BCM2835 DMA controller

The BCM2835 DMA controller has 16 channels in total.
Only the lower 13 channels have an associated IRQ.
Some arbitrary channels are used by the firmware
(1,3,6,7 in the current firmware version).
The channels 0,2 and 3 have special functionality
and should not be used by the driver.

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.
- interrupt-names: Should contain the names of the interrupt
		   in the form "dmaXX".
		   Use "dma-shared-all" for the common interrupt line
		   that is shared by all dma channels.
- #dma-cells: Must be <1>, the cell in the dmas property of the
		client device represents the DREQ number.
- brcm,dma-channel-mask: Bit mask representing the channels
			 not used by the firmware in ascending order,
			 i.e. first channel corresponds to LSB.

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>,
		     /* dma channel 11-14 share one irq */
		     <1 27>,
		     <1 27>,
		     <1 27>,
		     <1 27>,
		     /* unused shared irq for all channels */
		     <1 28>;
	interrupt-names = "dma0",
			  "dma1",
			  "dma2",
			  "dma3",
			  "dma4",
			  "dma5",
			  "dma6",
			  "dma7",
			  "dma8",
			  "dma9",
			  "dma10",
			  "dma11",
			  "dma12",
			  "dma13",
			  "dma14",
			  "dma-shared-all";

	#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.

Example:

bcm2835_i2s: i2s@7e203000 {
	compatible = "brcm,bcm2835-i2s";
	reg = <	0x7e203000 0x20>,
	      < 0x7e101098 0x02>;

	dmas = <&dma 2>,
	       <&dma 3>;
	dma-names = "tx", "rx";
};
Commit	Line	Data
96286b57 FM	1	* BCM2835 DMA controller
	2
	3	The BCM2835 DMA controller has 16 channels in total.
	4	Only the lower 13 channels have an associated IRQ.
	5	Some arbitrary channels are used by the firmware
	6	(1,3,6,7 in the current firmware version).
	7	The channels 0,2 and 3 have special functionality
	8	and should not be used by the driver.
	9
	10	Required properties:
	11	- compatible: Should be "brcm,bcm2835-dma".
	12	- reg: Should contain DMA registers location and length.
	13	- interrupts: Should contain the DMA interrupts associated
	14	to the DMA channels in ascending order.
e7679db7 MS	15	- interrupt-names: Should contain the names of the interrupt
	16	in the form "dmaXX".
	17	Use "dma-shared-all" for the common interrupt line
	18	that is shared by all dma channels.
96286b57 FM	19	- #dma-cells: Must be <1>, the cell in the dmas property of the
	20	client device represents the DREQ number.
	21	- brcm,dma-channel-mask: Bit mask representing the channels
	22	not used by the firmware in ascending order,
	23	i.e. first channel corresponds to LSB.
	24
	25	Example:
	26
	27	dma: dma@7e007000 {
	28	compatible = "brcm,bcm2835-dma";
	29	reg = <0x7e007000 0xf00>;
	30	interrupts = <1 16>,
	31	<1 17>,
	32	<1 18>,
	33	<1 19>,
	34	<1 20>,
	35	<1 21>,
	36	<1 22>,
	37	<1 23>,
	38	<1 24>,
	39	<1 25>,
	40	<1 26>,
e7679db7	41	/* dma channel 11-14 share one irq */
96286b57	42	<1 27>,
e7679db7 MS	43	<1 27>,
	44	<1 27>,
	45	<1 27>,
	46	/* unused shared irq for all channels */
96286b57	47	<1 28>;
e7679db7 MS	48	interrupt-names = "dma0",
	49	"dma1",
	50	"dma2",
	51	"dma3",
	52	"dma4",
	53	"dma5",
	54	"dma6",
	55	"dma7",
	56	"dma8",
	57	"dma9",
	58	"dma10",
	59	"dma11",
	60	"dma12",
	61	"dma13",
	62	"dma14",
	63	"dma-shared-all";
96286b57 FM	64
	65	#dma-cells = <1>;
	66	brcm,dma-channel-mask = <0x7f35>;
	67	};
	68
e7679db7	69
96286b57 FM	70	DMA clients connected to the BCM2835 DMA controller must use the format
	71	described in the dma.txt file, using a two-cell specifier for each channel.
	72
	73	Example:
	74
	75	bcm2835_i2s: i2s@7e203000 {
	76	compatible = "brcm,bcm2835-i2s";
	77	reg = < 0x7e203000 0x20>,
	78	< 0x7e101098 0x02>;
	79
	80	dmas = <&dma 2>,
	81	<&dma 3>;
	82	dma-names = "tx", "rx";
	83	};