DMA: shdma: add DT support

This patch adds Device Tree support to the shdma driver. No special DT
properties are used, only standard DMA DT bindings are implemented. Since
shdma controllers reside on SoCs, their configuration is SoC-specific and
shall be passed to the driver from the SoC platform data, using the
auxdata procedure.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/dma/shdma.txt b/Documentation/devicetree/bindings/dma/shdma.txt
new file mode 100644
index 000000000000..c15994aa1939
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/shdma.txt
@@ -0,0 +1,75 @@
+* SHDMA Device Tree bindings
+
+Sh-/r-mobile and r-car systems often have multiple identical DMA controller
+instances, capable of serving any of a common set of DMA slave devices, using
+the same configuration. To describe this topology we require all compatible
+SHDMA DT nodes to be placed under a DMA multiplexer node. All such compatible
+DMAC instances have the same number of channels and use the same DMA
+descriptors. Therefore respective DMA DT bindings can also all be placed in the
+multiplexer node. Even if there is only one such DMAC instance on a system, it
+still has to be placed under such a multiplexer node.
+
+* DMA multiplexer
+
+Required properties:
+- compatible:   should be "renesas,shdma-mux"
+- #dma-cells:   should be <1>, see "dmas" property below
+
+Optional properties (currently unused):
+- dma-channels: number of DMA channels
+- dma-requests: number of DMA request signals
+
+* DMA controller
+
+Required properties:
+- compatible:   should be "renesas,shdma"
+
+Example:
+        dmac: dma-mux0 {
+                compatible = "renesas,shdma-mux";
+                #dma-cells = <1>;
+                dma-channels = <6>;
+                dma-requests = <256>;
+                reg = <0 0>;    /* Needed for AUXDATA */
+                #address-cells = <1>;
+                #size-cells = <1>;
+                ranges;
+
+                dma0: shdma@fe008020 {
+                        compatible = "renesas,shdma";
+                        reg = <0xfe008020 0x270>,
+                                <0xfe009000 0xc>;
+                        interrupt-parent = <&gic>;
+                        interrupts = <0 34 4
+                                        0 28 4
+                                        0 29 4
+                                        0 30 4
+                                        0 31 4
+                                        0 32 4
+                                        0 33 4>;
+                        interrupt-names = "error",
+                                        "ch0", "ch1", "ch2", "ch3",
+                                        "ch4", "ch5";
+                };
+
+                dma1: shdma@fe018020 {
+                        ...
+                };
+
+                dma2: shdma@fe028020 {
+                        ...
+                };
+        };
+
+* DMA client
+
+Required properties:
+- dmas:         a list of <[DMA multiplexer phandle] [MID/RID value]> pairs,
+                where MID/RID values are fixed handles, specified in the SoC
+                manual
+- dma-names:    a list of DMA channel names, one per "dmas" entry
+
+Example:
+        dmas = <&dmac 0xd1
+                &dmac 0xd2>;
+        dma-names = "tx", "rx";