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authorJingchang Lu <b35083@freescale.com>2014-02-18 10:17:12 +0800
committerVinod Koul <vinod.koul@intel.com>2014-02-18 16:52:35 +0530
commitd6be34fbd39b7d577d25cb4edec538e8990ba07c (patch)
treed3a4381df8b6dd1d18ff563e9708cbc992a5bcd1 /Documentation
parentdd5720b3006210ecdf4e3c8889e6051f432c4ba3 (diff)
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dma: Add Freescale eDMA engine driver support
Add Freescale enhanced direct memory(eDMA) controller support. This module can be found on Vybrid and LS-1 SoCs. Signed-off-by: Alison Wang <b18965@freescale.com> Signed-off-by: Jingchang Lu <b35083@freescale.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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+* Freescale enhanced Direct Memory Access(eDMA) Controller
+
+ The eDMA channels have multiplex capability by programmble memory-mapped
+registers. channels are split into two groups, called DMAMUX0 and DMAMUX1,
+specific DMA request source can only be multiplexed by any channel of certain
+group, DMAMUX0 or DMAMUX1, but not both.
+
+* eDMA Controller
+Required properties:
+- compatible :
+ - "fsl,vf610-edma" for eDMA used similar to that on Vybrid vf610 SoC
+- reg : Specifies base physical address(s) and size of the eDMA registers.
+ The 1st region is eDMA control register's address and size.
+ The 2nd and the 3rd regions are programmable channel multiplexing
+ control register's address and size.
+- interrupts : A list of interrupt-specifiers, one for each entry in
+ interrupt-names.
+- interrupt-names : Should contain:
+ "edma-tx" - the transmission interrupt
+ "edma-err" - the error interrupt
+- #dma-cells : Must be <2>.
+ The 1st cell specifies the DMAMUX(0 for DMAMUX0 and 1 for DMAMUX1).
+ Specific request source can only be multiplexed by specific channels
+ group called DMAMUX.
+ The 2nd cell specifies the request source(slot) ID.
+ See the SoC's reference manual for all the supported request sources.
+- dma-channels : Number of channels supported by the controller
+- clock-names : A list of channel group clock names. Should contain:
+ "dmamux0" - clock name of mux0 group
+ "dmamux1" - clock name of mux1 group
+- clocks : A list of phandle and clock-specifier pairs, one for each entry in
+ clock-names.
+
+Optional properties:
+- big-endian: If present registers and hardware scatter/gather descriptors
+ of the eDMA are implemented in big endian mode, otherwise in little
+ mode.
+
+
+Examples:
+
+edma0: dma-controller@40018000 {
+ #dma-cells = <2>;
+ compatible = "fsl,vf610-edma";
+ reg = <0x40018000 0x2000>,
+ <0x40024000 0x1000>,
+ <0x40025000 0x1000>;
+ interrupts = <0 8 IRQ_TYPE_LEVEL_HIGH>,
+ <0 9 IRQ_TYPE_LEVEL_HIGH>;
+ interrupt-names = "edma-tx", "edma-err";
+ dma-channels = <32>;
+ clock-names = "dmamux0", "dmamux1";
+ clocks = <&clks VF610_CLK_DMAMUX0>,
+ <&clks VF610_CLK_DMAMUX1>;
+};
+
+
+* DMA clients
+DMA client drivers that uses the DMA function must use the format described
+in the dma.txt file, using a two-cell specifier for each channel: the 1st
+specifies the channel group(DMAMUX) in which this request can be multiplexed,
+and the 2nd specifies the request source.
+
+Examples:
+
+sai2: sai@40031000 {
+ compatible = "fsl,vf610-sai";
+ reg = <0x40031000 0x1000>;
+ interrupts = <0 86 IRQ_TYPE_LEVEL_HIGH>;
+ clock-names = "sai";
+ clocks = <&clks VF610_CLK_SAI2>;
+ dma-names = "tx", "rx";
+ dmas = <&edma0 0 21>,
+ <&edma0 0 20>;
+ status = "disabled";
+};
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