The STM32 DMA3 is a Direct Memory Access controller with different features depending on its hardware configuration. The channels have not the same capabilities, some have a larger FIFO, so their performance is higher. This patch describes STM32 DMA3 bindings, used to select a channel that fits client requirements, and to pre-configure the channel depending on the client needs. Reviewed-by: Rob Herring (Arm) <robh@xxxxxxxxxx> Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx> --- v3: - add Rob's Reviewed-by after fixing lines length at 80 and useless '|' v2: - DMA controller specific information description has been moved and added as description of #dma-cells property - description has been added to interrupts property specifying the expected format for channel interrupts - compatible has been updated to st,stm32mp25-dma3 (SoC specific) --- .../bindings/dma/stm32/st,stm32-dma3.yaml | 135 ++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml diff --git a/Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml b/Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml new file mode 100644 index 000000000000..7fdc44b2e646 --- /dev/null +++ b/Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml @@ -0,0 +1,135 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dma/stm32/st,stm32-dma3.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: STMicroelectronics STM32 DMA3 Controller + +description: | + The STM32 DMA3 is a direct memory access controller with different features + depending on its hardware configuration. + It is either called LPDMA (Low Power), GPDMA (General Purpose) or HPDMA (High + Performance). + Its hardware configuration registers allow to dynamically expose its features. + + GPDMA and HPDMA support 16 independent DMA channels, while only 4 for LPDMA. + GPDMA and HPDMA support 256 DMA requests from peripherals, 8 for LPDMA. + + Bindings are generic for these 3 STM32 DMA3 configurations. + + DMA clients connected to the STM32 DMA3 controller must use the format + described in "#dma-cells" property description below, using a three-cell + specifier for each channel. + +maintainers: + - Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx> + +allOf: + - $ref: /schemas/dma/dma-controller.yaml# + +properties: + compatible: + const: st,stm32mp25-dma3 + + reg: + maxItems: 1 + + interrupts: + minItems: 4 + maxItems: 16 + description: + Should contain all of the per-channel DMA interrupts in ascending order + with respect to the DMA channel index. + + clocks: + maxItems: 1 + + resets: + maxItems: 1 + + power-domains: + maxItems: 1 + + "#dma-cells": + const: 3 + description: | + Specifies the number of cells needed to provide DMA controller specific + information. + The first cell is the request line number. + The second cell is a 32-bit mask specifying the DMA channel requirements: + -bit 0-1: The priority level + 0x0: low priority, low weight + 0x1: low priority, mid weight + 0x2: low priority, high weight + 0x3: high priority + -bit 4-7: The FIFO requirement for queuing source/destination transfers + 0x0: no FIFO requirement/any channel can fit + 0x2: FIFO of 8 bytes (2^2+1) + 0x4: FIFO of 32 bytes (2^4+1) + 0x6: FIFO of 128 bytes (2^6+1) + 0x7: FIFO of 256 bytes (2^7+1) + The third cell is a 32-bit mask specifying the DMA transfer requirements: + -bit 0: The source incrementing burst + 0x0: fixed burst + 0x1: contiguously incremented burst + -bit 1: The source allocated port + 0x0: port 0 is allocated to the source transfer + 0x1: port 1 is allocated to the source transfer + -bit 4: The destination incrementing burst + 0x0: fixed burst + 0x1: contiguously incremented burst + -bit 5: The destination allocated port + 0x0: port 0 is allocated to the destination transfer + 0x1: port 1 is allocated to the destination transfer + -bit 8: The type of hardware request + 0x0: burst + 0x1: block + -bit 9: The control mode + 0x0: DMA controller control mode + 0x1: peripheral control mode + -bit 12-13: The transfer complete event mode + 0x0: at block level, transfer complete event is generated at the end + of a block + 0x2: at LLI level, the transfer complete event is generated at the end + of the LLI transfer + including the update of the LLI if any + 0x3: at channel level, the transfer complete event is generated at the + end of the last LLI + +required: + - compatible + - reg + - interrupts + - clocks + - "#dma-cells" + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/interrupt-controller/arm-gic.h> + #include <dt-bindings/clock/st,stm32mp25-rcc.h> + dma-controller@40400000 { + compatible = "st,stm32mp25-dma3"; + reg = <0x40400000 0x1000>; + interrupts = <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 37 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 38 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 39 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 40 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 41 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 43 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 45 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 46 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 47 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&rcc CK_BUS_HPDMA1>; + #dma-cells = <3>; + }; +... -- 2.25.1
