This patch adds documentation of device tree bindings for the STM32 MDMA
controller.
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@xxxxxxxxx>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxx>
---
Version history:
v2:
* change compatible into st,stm32h7-mdma to be more SoC specific
---
---
.../devicetree/bindings/dma/stm32-mdma.txt | 94 ++++++++++++++++++++++
1 file changed, 94 insertions(+)
create mode 100644 Documentation/devicetree/bindings/dma/stm32-mdma.txt
diff --git a/Documentation/devicetree/bindings/dma/stm32-mdma.txt b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
new file mode 100644
index 0000000..d18772d
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
@@ -0,0 +1,94 @@
+* STMicroelectronics STM32 MDMA controller
+
+The STM32 MDMA is a general-purpose direct memory access controller capable of
+supporting 64 independent DMA channels with 256 HW requests.
+
+Required properties:
+- compatible: Should be "st,stm32h7-mdma"
+- reg: Should contain MDMA registers location and length. This should include
+ all of the per-channel registers.
+- interrupts: Should contain the MDMA interrupt.
+- clocks: Should contain the input clock of the DMA instance.
+- resets: Reference to a reset controller asserting the DMA controller.
+- #dma-cells : Must be <5>. See DMA client paragraph for more details.
+
+Optional properties:
+- dma-channels: Number of DMA channels supported by the controller.
+- dma-requests: Number of DMA request signals supported by the controller.
+- st,ahb-addr-masks: Array of u32 mask to list memory devices addressed via
+ AHB bus.
+
+Example:
+
+ mdma1: dma@52000000 {
+ compatible = "st,stm32h7-mdma";
+ reg = <0x52000000 0x1000>;
+ interrupts = <122>;
+ clocks = <&timer_clk>;
+ resets = <&rcc 992>;
+ #dma-cells = <5>;
+ dma-channels = <16>;
+ dma-requests = <32>;
+ st,ahb-addr-masks = <0x20000000>, <0x00000000>;
+ };
+
+* DMA client
+
+DMA clients connected to the STM32 MDMA controller must use the format
+described in the dma.txt file, using a five-cell specifier for each channel:
+a phandle to the MDMA controller plus the following five integer cells:
+
+1. The request line number
+2. The priority level
+ 0x00: Low
+ 0x01: Medium
+ 0x10: High
+ 0x11: Very high
+3. A 32bit mask specifying the DMA channel configuration
+ -bit 0-1: Source increment mode
+ 0x00: Source address pointer is fixed
+ 0x10: Source address pointer is incremented after each data transfer
+ 0x11: Source address pointer is decremented after each data transfer
+ -bit 2-3: Destination increment mode
+ 0x00: Destination address pointer is fixed
+ 0x10: Destination address pointer is incremented after each data
+ transfer
+ 0x11: Destination address pointer is decremented after each data
+ transfer
+ -bit 8-9: Source increment offset size
+ 0x00: byte (8bit)
+ 0x01: half-word (16bit)
+ 0x10: word (32bit)
+ 0x11: double-word (64bit)
+ -bit 10-11: Destination increment offset size
+ 0x00: byte (8bit)
+ 0x01: half-word (16bit)
+ 0x10: word (32bit)
+ 0x11: double-word (64bit)
+-bit 25-18: The number of bytes to be transferred in a single transfer
+ (min = 1 byte, max = 128 bytes)
+-bit 29:28: Trigger Mode
+ 0x00: Each MDMA request triggers a buffer transfer (max 128 bytes)
+ 0x01: Each MDMA request triggers a block transfer (max 64K bytes)
+ 0x10: Each MDMA request triggers a repeated block transfer
+ 0x11: Each MDMA request triggers a linked list transfer
+4. A 32bit value specifying the register to be used to acknowledge the request
+ if no HW ack signal is used by the MDMA client
+5. A 32bit mask specifying the value to be written to acknowledge the request
+ if no HW ack signal is used by the MDMA client
+
+Example:
+
+ i2c4: i2c@5c002000 {
+ compatible = "st,stm32f7-i2c";
+ reg = <0x5c002000 0x400>;
+ interrupts = <95>,
+ <96>;
+ clocks = <&timer_clk>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ dmas = <&mdma1 36 0x0 0x40008 0x0 0x0>,
+ <&mdma1 37 0x0 0x40002 0x0 0x0>;
+ dma-names = "rx", "tx";
+ status = "disabled";
+ };
--
2.7.4
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