87 lines
2.7 KiB
Plaintext
87 lines
2.7 KiB
Plaintext
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* STMicroelectronics Flexible Direct Memory Access Device Tree bindings
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The FDMA is a general-purpose direct memory access controller capable of
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supporting 16 independent DMA channels. It accepts up to 32 DMA requests.
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The FDMA is based on a Slim processor which requires a firmware.
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* FDMA Controller
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Required properties:
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- compatible : Should be one of
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- st,stih407-fdma-mpe31-11, "st,slim-rproc";
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- st,stih407-fdma-mpe31-12, "st,slim-rproc";
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- st,stih407-fdma-mpe31-13, "st,slim-rproc";
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- reg : Should contain an entry for each name in reg-names
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- reg-names : Must contain "slimcore", "dmem", "peripherals", "imem" entries
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- interrupts : Should contain one interrupt shared by all channels
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- dma-channels : Number of channels supported by the controller
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- #dma-cells : Must be <3>. See DMA client section below
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- clocks : Must contain an entry for each clock
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See: Documentation/devicetree/bindings/clock/clock-bindings.txt
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Example:
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fdma0: dma-controller@8e20000 {
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compatible = "st,stih407-fdma-mpe31-11", "st,slim-rproc";
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reg = <0x8e20000 0x8000>,
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<0x8e30000 0x3000>,
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<0x8e37000 0x1000>,
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<0x8e38000 0x8000>;
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reg-names = "slimcore", "dmem", "peripherals", "imem";
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clocks = <&clk_s_c0_flexgen CLK_FDMA>,
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<&clk_s_c0_flexgen CLK_EXT2F_A9>,
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<&clk_s_c0_flexgen CLK_EXT2F_A9>,
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<&clk_s_c0_flexgen CLK_EXT2F_A9>;
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interrupts = <GIC_SPI 5 IRQ_TYPE_NONE>;
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dma-channels = <16>;
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#dma-cells = <3>;
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};
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* DMA client
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Required properties:
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- dmas: Comma separated list of dma channel requests
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- dma-names: Names of the aforementioned requested channels
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Each dmas request consists of 4 cells:
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1. A phandle pointing to the FDMA controller
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2. The request line number
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3. A 32bit mask specifying (see include/linux/platform_data/dma-st-fdma.h)
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-bit 2-0: Holdoff value, dreq will be masked for
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0x0: 0-0.5us
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0x1: 0.5-1us
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0x2: 1-1.5us
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-bit 17: data swap
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0x0: disabled
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0x1: enabled
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-bit 21: Increment Address
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0x0: no address increment between transfers
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0x1: increment address between transfers
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-bit 22: 2 STBus Initiator Coprocessor interface
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0x0: high priority port
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0x1: low priority port
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4. transfers type
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0 free running
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1 paced
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Example:
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sti_uni_player2: sti-uni-player@2 {
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compatible = "st,sti-uni-player";
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#sound-dai-cells = <0>;
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st,syscfg = <&syscfg_core>;
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clocks = <&clk_s_d0_flexgen CLK_PCM_2>;
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assigned-clocks = <&clk_s_d0_flexgen CLK_PCM_2>;
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assigned-clock-parents = <&clk_s_d0_quadfs 2>;
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assigned-clock-rates = <50000000>;
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reg = <0x8D82000 0x158>;
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interrupts = <GIC_SPI 86 IRQ_TYPE_NONE>;
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dmas = <&fdma0 4 0 1>;
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dai-name = "Uni Player #1 (DAC)";
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dma-names = "tx";
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st,uniperiph-id = <2>;
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st,version = <5>;
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st,mode = "PCM";
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};
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