diff options
Diffstat (limited to 'Documentation/devicetree')
| -rw-r--r-- | Documentation/devicetree/bindings/dma/arm-pl330.txt | 21 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/dma/dma.txt | 81 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/dma/snps-dma.txt | 44 |
3 files changed, 141 insertions, 5 deletions
diff --git a/Documentation/devicetree/bindings/dma/arm-pl330.txt b/Documentation/devicetree/bindings/dma/arm-pl330.txt index 36e27d54260b..267565894db9 100644 --- a/Documentation/devicetree/bindings/dma/arm-pl330.txt +++ b/Documentation/devicetree/bindings/dma/arm-pl330.txt @@ -10,7 +10,11 @@ Required properties: - interrupts: interrupt number to the cpu. Optional properties: -- dma-coherent : Present if dma operations are coherent + - dma-coherent : Present if dma operations are coherent + - #dma-cells: must be <1>. used to represent the number of integer + cells in the dmas property of client device. + - dma-channels: contains the total number of DMA channels supported by the DMAC + - dma-requests: contains the total number of DMA requests supported by the DMAC Example: @@ -18,16 +22,23 @@ Example: compatible = "arm,pl330", "arm,primecell"; reg = <0x12680000 0x1000>; interrupts = <99>; + #dma-cells = <1>; + #dma-channels = <8>; + #dma-requests = <32>; }; Client drivers (device nodes requiring dma transfers from dev-to-mem or -mem-to-dev) should specify the DMA channel numbers using a two-value pair +mem-to-dev) should specify the DMA channel numbers and dma channel names as shown below. [property name] = <[phandle of the dma controller] [dma request id]>; + [property name] = <[dma channel name]> where 'dma request id' is the dma request number which is connected - to the client controller. The 'property name' is recommended to be - of the form <name>-dma-channel. + to the client controller. The 'property name' 'dmas' and 'dma-names' + as required by the generic dma device tree binding helpers. The dma + names correspond 1:1 with the dma request ids in the dmas property. - Example: tx-dma-channel = <&pdma0 12>; + Example: dmas = <&pdma0 12 + &pdma1 11>; + dma-names = "tx", "rx"; diff --git a/Documentation/devicetree/bindings/dma/dma.txt b/Documentation/devicetree/bindings/dma/dma.txt new file mode 100644 index 000000000000..8f504e6bae14 --- /dev/null +++ b/Documentation/devicetree/bindings/dma/dma.txt @@ -0,0 +1,81 @@ +* Generic DMA Controller and DMA request bindings + +Generic binding to provide a way for a driver using DMA Engine to retrieve the +DMA request or channel information that goes from a hardware device to a DMA +controller. + + +* DMA controller + +Required property: +- #dma-cells: Must be at least 1. Used to provide DMA controller + specific information. See DMA client binding below for + more details. + +Optional properties: +- dma-channels: Number of DMA channels supported by the controller. +- dma-requests: Number of DMA requests signals supported by the + controller. + +Example: + + dma: dma@48000000 { + compatible = "ti,omap-sdma"; + reg = <0x48000000 0x1000>; + interrupts = <0 12 0x4 + 0 13 0x4 + 0 14 0x4 + 0 15 0x4>; + #dma-cells = <1>; + dma-channels = <32>; + dma-requests = <127>; + }; + + +* DMA client + +Client drivers should specify the DMA property using a phandle to the controller +followed by DMA controller specific data. + +Required property: +- dmas: List of one or more DMA specifiers, each consisting of + - A phandle pointing to DMA controller node + - A number of integer cells, as determined by the + #dma-cells property in the node referenced by phandle + containing DMA controller specific information. This + typically contains a DMA request line number or a + channel number, but can contain any data that is used + required for configuring a channel. +- dma-names: Contains one identifier string for each DMA specifier in + the dmas property. The specific strings that can be used + are defined in the binding of the DMA client device. + Multiple DMA specifiers can be used to represent + alternatives and in this case the dma-names for those + DMA specifiers must be identical (see examples). + +Examples: + +1. A device with one DMA read channel, one DMA write channel: + + i2c1: i2c@1 { + ... + dmas = <&dma 2 /* read channel */ + &dma 3>; /* write channel */ + dma-names = "rx", "tx"; + ... + }; + +2. A single read-write channel with three alternative DMA controllers: + + dmas = <&dma1 5 + &dma2 7 + &dma3 2>; + dma-names = "rx-tx", "rx-tx", "rx-tx"; + +3. A device with three channels, one of which has two alternatives: + + dmas = <&dma1 2 /* read channel */ + &dma1 3 /* write channel */ + &dma2 0 /* error read */ + &dma3 0>; /* alternative error read */ + dma-names = "rx", "tx", "error", "error"; diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt index c0d85dbcada5..5bb3dfb6f1d8 100644 --- a/Documentation/devicetree/bindings/dma/snps-dma.txt +++ b/Documentation/devicetree/bindings/dma/snps-dma.txt @@ -6,6 +6,26 @@ Required properties: - interrupt-parent: Should be the phandle for the interrupt controller that services interrupts for this device - interrupt: Should contain the DMAC interrupt number +- nr_channels: Number of channels supported by hardware +- is_private: The device channels should be marked as private and not for by the + general purpose DMA channel allocator. False if not passed. +- chan_allocation_order: order of allocation of channel, 0 (default): ascending, + 1: descending +- chan_priority: priority of channels. 0 (default): increase from chan 0->n, 1: + increase from chan n->0 +- block_size: Maximum block size supported by the controller +- nr_masters: Number of AHB masters supported by the controller +- data_width: Maximum data width supported by hardware per AHB master + (0 - 8bits, 1 - 16bits, ..., 5 - 256bits) +- slave_info: + - bus_id: name of this device channel, not just a device name since + devices may have more than one channel e.g. "foo_tx". For using the + dw_generic_filter(), slave drivers must pass exactly this string as + param to filter function. + - cfg_hi: Platform-specific initializer for the CFG_HI register + - cfg_lo: Platform-specific initializer for the CFG_LO register + - src_master: src master for transfers on allocated channel. + - dst_master: dest master for transfers on allocated channel. Example: @@ -14,4 +34,28 @@ Example: reg = <0xfc000000 0x1000>; interrupt-parent = <&vic1>; interrupts = <12>; + + nr_channels = <8>; + chan_allocation_order = <1>; + chan_priority = <1>; + block_size = <0xfff>; + nr_masters = <2>; + data_width = <3 3 0 0>; + + slave_info { + uart0-tx { + bus_id = "uart0-tx"; + cfg_hi = <0x4000>; /* 0x8 << 11 */ + cfg_lo = <0>; + src_master = <0>; + dst_master = <1>; + }; + spi0-tx { + bus_id = "spi0-tx"; + cfg_hi = <0x2000>; /* 0x4 << 11 */ + cfg_lo = <0>; + src_master = <0>; + dst_master = <0>; + }; + }; }; |