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>

Documentation/devicetree/bindings/dma/fsl-edma.txt

+* 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";
+};

drivers/dma/Kconfig

@@ -350,6 +350,16 @@ config MOXART_DMA
 	help
 	  Enable support for the MOXA ART SoC DMA controller.
  
+config FSL_EDMA
+	tristate "Freescale eDMA engine support"
+	depends on OF
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Support the Freescale eDMA engine with programmable channel
+	  multiplexing capability for DMA request sources(slot).
+	  This module can be found on Freescale Vybrid and LS-1 SoCs.
+
 config DMA_ENGINE
 	bool
 

drivers/dma/Makefile

@@ -44,3 +44,4 @@ obj-$(CONFIG_DMA_JZ4740) += dma-jz4740.o
 obj-$(CONFIG_TI_CPPI41) += cppi41.o
 obj-$(CONFIG_K3_DMA) += k3dma.o
 obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
+obj-$(CONFIG_FSL_EDMA) += fsl-edma.o