st,stm32-dmamux

Vendor: STMicroelectronics N.V.

Description

These nodes are “dmamux” bus nodes.

STM32 DMAMUX controller

The STM32 DMAMUX is a direct memory access multiplexer
capable of supporting independent DMA channels.
DMAMUX clients connected to the STM32 DMA ultiplexer must use a two-cell specifier
for each dmamux channel: a phandle to the DMA multiplexer plus the following 2 integer cells:
  1. channel: the mux channel from 0 to <dma-channels> - 1
  2. slot: the request line Multiplexer ID
  3. channel-config: A 32bit mask specifying the DMA channel configuration
  which is device dependent:
      -bit 6-7 : Direction  (see dma.h)
             0x0: MEM to MEM
             0x1: MEM to PERIPH
             0x2: PERIPH to MEM
             0x3: reserved for PERIPH to PERIPH
      -bit 9 : Peripheral Increment Address
             0x0: no address increment between transfers
             0x1: increment address between transfers
      -bit 10 : Memory Increment Address
             0x0: no address increment between transfers
             0x1: increment address between transfers
      -bit 11-12 : Peripheral data size
             0x0: Byte (8 bits)
             0x1: Half-word (16 bits)
             0x2: Word (32 bits)
             0x3: reserved
      -bit 13-14 : Memory data size
             0x0: Byte (8 bits)
             0x1: Half-word (16 bits)
             0x2: Word (32 bits)
             0x3: reserved
      -bit 15: Peripheral Increment Offset Size not USED for DMA V2
             0x0: offset size is linked to the peripheral bus width
             0x1: offset size is fixed to 4 (32-bit alignment)
      -bit 16-17 : Priority level
             0x0: low
             0x1: medium
             0x2: high
             0x3: very high
 example for stm32wb55x
   dmamux1: dmamux@40020800 {
       compatible = "st,stm32-dmamux";
       ...
       dma-channels = <14>;
       dma-generators = <4>;
       dma-requests= <36>;
       status = "disabled";
      };
  for client SPI of stm32wb55x
   spi1: spi@40013000 {
       compatible = "st,stm32-spi";
       dmas = <&dmamux1 11 7 0x20440
                &dmamux1 1 6 0x20480>;
       dma-names = "tx", "rx";
      };

Properties

Properties not inherited from the base binding file.

Name

Type

Details

#dma-cells

int

Number of items to expect in a DMA specifier (see dma V2)

This property is required.

Constant value: 3

dma-channels

int

Number of DMAMUX output request channels supported by the controller

This property is required.

dma-generators

int

Number of DMAMUX Request generator supported by the controller

dma-requests

int

Number of DMAMUX Peripheral Request Line inputs supported by the controller
This is not directly the value to program in the DMAREQ_ID of the DMAMUX_CxCR

This property is required.

Specifier cell names

  • dma cells: channel, slot, channel-config