FogBugz #172665: Sample driver for DMA transfer to FPGA soft IP (FIFO)

-This fpga-dma driver is an example driver for a specific FPGA soft IP
-The soft IP presents a FIFO which can be read and written through
the debugfs interface
-The DMA transfer code uses 'generic' dma interfaces
-The fpga-dma driver uses generic register and DMA definitions
in the devicetree

V2:
-Device tree changes removed from socfpga_cyclone5.dts and
documented in Documentation/devicetree/bindings/arm/altera/fpga-dma.txt

V3:
-Formatting changes, used Lindent script to format fpga-dma.c

V4:
-More formatting changes, lined up #defines, alphabetize headers

Signed-off-by: Graham Moore <[email protected]>

Author: Graham Moore

Documentation/devicetree/bindings/arm/altera/fpga-dma.txt

@@ -0,0 +1,25 @@
+Altera FPGA DMA FIFO driver
+
+Required properties:
+- compatible : "altr,fpga-dma";
+
+- reg : CSR and DATA register resource definitions (address and length).
+
+- reg-names : Names of the register resources.  Should be "csr", "data".
+
+- dmas : DMA request lines.  Should be <&pdma 0 &pdma 1>
+
+- dma-names : Names of DMA request lines. Should be "tx", "rx".
+
+Example:
+
+	fpgadma: fifo {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "altr,fpga-dma";
+		reg = <0xff230000 0x20>, <0xc0011000 0x400>;
+		reg-names = "csr", "data";
+		dmas = <&pdma 0 &pdma 1>;
+		dma-names = "tx", "rx";
+	};
+

arch/arm/mach-socfpga/Kconfig

@@ -27,3 +27,8 @@ config SOCFPGA_SUSPEND
 	  Select this if you want to enable Suspend-to-RAM on SOCFPGA
 	  platforms.
 endif
+config FPGADMA
+	tristate "FPGA DMA FIFO driver"
+	depends on DMA_ENGINE
+	help
+		Sample FPGA DMA driver, for testing with special FPGA FIFO image

arch/arm/mach-socfpga/Makefile

@@ -8,3 +8,4 @@ obj-$(CONFIG_SMP)	+= headsmp.o platsmp.o
 obj-$(CONFIG_SOCFPGA_SUSPEND)	+= pm.o self-refresh.o
 obj-$(CONFIG_EDAC_ALTERA_L2C)	+= l2_cache.o
 obj-$(CONFIG_EDAC_ALTERA_OCRAM)	+= ocram.o
+obj-$(CONFIG_FPGADMA)	+= fpga-dma.o