The latest development version of this page may be more current than this released 3.7.0 version.

st,stm32-dma-v2

Description

These nodes are “dma” bus nodes.

STM32 DMA controller (V2)

It is present on stm32 devices like stm32L4 or stm32WB.
This DMA controller includes several channels with different requests.
DMA clients connected to the STM32 DMA controller must use the format
described in the dma.txt file, using a four-cell specifier for each
capable of supporting 5 or 6 or 7 or 8 independent DMA channels.
DMA clients connected to the STM32 DMA controller must use the format
described in the dma.txt file, using a 3-cell specifier for each
channel: a phandle to the DMA controller plus the following four integer cells:
  1. channel: the dma stream from 1 to <dma-requests>
  2. slot: DMA periph request ID, which is written in the DMAREQ_ID of the DMAMUX_CxCR
  this value is 0 for Memory-to-memory transfers
  or a value between <1> .. <dma-generators> (not supported yet)
  or a value between <dma-generators>+1  ..  <dma-generators>+<dma-requests>
  3. channel-config: A 32bit mask specifying the DMA channel configuration
  A name custom DMA flags for channel configuration is used
  which is device dependent. See stm32_dma.h:
    -bit 5 : DMA  cyclic mode config
              0x0: STM32_DMA_MODE_NORMAL
              0x1: STM32_DMA_MODE_CYCLIC
    -bit 6-7 : Direction (see dma.h)
              0x0: STM32_DMA_MEMORY_TO_MEMORY: MEM to MEM
              0x1: STM32_DMA_MEMORY_TO_PERIPH: MEM to PERIPH
              0x2: STM32_DMA_PERIPH_TO_MEMORY: PERIPH to MEM
              0x3: reserved for PERIPH to PERIPH
    -bit 9 : Peripheral Increment Address
             0x0: STM32_DMA_PERIPH_NO_INC: no address increment between transfers
             0x1: STM32_DMA_PERIPH_INC: increment address between transfers
    -bit 10 : Memory Increment Address
             0x0: STM32_DMA_MEM_NO_INC: no address increment between transfers
             0x1: STM32_DMA_MEM_INC: increment address between transfers
    -bit 11-12 : Peripheral data size
             0x0: STM32_DMA_PERIPH_8BITS: Byte (8 bits)
             0x1: STM32_DMA_PERIPH_16BITS: Half-word (16 bits)
             0x2: STM32_DMA_PERIPH_32BITS: Word (32 bits)
             0x3: reserved
    -bit 13-14 : Memory data size
             0x0: STM32_DMA_MEM_8BITS: Byte (8 bits)
             0x1: STM32_DMA_MEM_16BITS: Half-word (16 bits)
             0x2: STM32_DMA_MEM_32BITS: Word (32 bits)
             0x3: reserved
    -bit 15: Reserved
    -bit 16-17 : Priority level
             0x0: STM32_DMA_PRIORITY_LOW: low
             0x1: STM32_DMA_PRIORITY_MEDIUM: medium
             0x2: STM32_DMA_PRIORITY_HIGH: high
             0x3: STM32_DMA_PRIORITY_VERY_HIGH: very high

Example of dma usual combination for peripheral transfer
     #define STM32_DMA_PERIPH_TX     (STM32_DMA_MEMORY_TO_PERIPH | STM32_DMA_MEM_INC)
     #define STM32_DMA_PERIPH_RX     (STM32_DMA_PERIPH_TO_MEMORY | STM32_DMA_MEM_INC)

Example of dma node for stm32wb55x
   dma2: dma-controller@40020400 {
       compatible = "st,stm32-dma-v2";
       ...
       dma-requests = <7>;
       status = "disabled";
      };

For the client part, example for stm32l476 on DMA1 instance
  Tx using channel 3 with request 1
  Rx using channel 2 with request 1
  spi1 {
   compatible = "st,stm32-spi";
   dmas = <&dma1 3 1 (STM32_DMA_PERIPH_TX | STM32_DMA_PRIORITY_HIGH)>,
          <&dma1 2 1 (STM32_DMA_PERIPH_RX | STM32_DMA_PRIORITY_HIGH)>;
   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 This property is required. Constant value: `3`
`dma-channel-mask`	`int`	Bitmask of available DMA channels in ascending order that are not reserved by firmware and are available to the kernel. i.e. first channel corresponds to LSB.
`dma-channels`	`int`	Number of DMA channels supported by the controller
`dma-requests`	`int`	Number of DMA request signals supported by the controller.
`dma-buf-addr-alignment`	`int`	Memory address alignment requirement for DMA buffers used by the controller.
`dma-buf-size-alignment`	`int`	Memory size alignment requirement for DMA buffers used by the controller.
`dma-copy-alignment`	`int`	Minimal chunk of data possible to be copied by the controller.
`st,mem2mem`	`boolean`	If the DMA controller V1 supports memory to memory transfer
`dma-offset`	`int`	offset in the table of channels when mapping to a DMAMUX for 1st dma instance, offset is 0, for 2nd dma instance, offset is the nb of dma channels of the 1st dma, for 3rd dma instance, offset is the nb of dma channels of the 2nd dma plus the nb of dma channels of the 1st dma instance, etc.

Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “st,stm32-dma-v2” compatible.

Name	Type	Details
`wakeup-source`	`boolean`	Property to identify that a device can be used as wake up source. When this property is provided a specific flag is set into the device that tells the system that the device is capable of wake up the system. Wake up capable devices are disabled (interruptions will not wake up the system) by default but they can be enabled at runtime if necessary.
`power-domain`	`phandle`	Power domain the device belongs to. The device will be notified when the power domain it belongs to is either suspended or resumed.
`zephyr,pm-device-runtime-auto`	`boolean`	Automatically configure the device for runtime power management after the init function runs.
`zephyr,disabling-power-states`	`phandles`	List of power states that will disable this device power.
`status`	`string`	indicates the operational status of a device Legal values: `'ok'`, `'okay'`, `'disabled'`, `'reserved'`, `'fail'`, `'fail-sss'` See Important properties for more information.
`compatible`	`string-array`	compatible strings This property is required. See Important properties for more information.
`reg`	`array`	register space This property is required. See Important properties for more information.
`reg-names`	`string-array`	name of each register space
`interrupts`	`array`	interrupts for device This property is required. See Important properties for more information.
`interrupts-extended`	`compound`	extended interrupt specifier for device
`interrupt-names`	`string-array`	name of each interrupt
`interrupt-parent`	`phandle`	phandle to interrupt controller node
`label`	`string`	Human readable string describing the device (used as device_get_binding() argument) See Important properties for more information. This property is deprecated.
`clocks`	`phandle-array`	Clock gate information
`clock-names`	`string-array`	name of each clock
`#address-cells`	`int`	number of address cells in reg property
`#size-cells`	`int`	number of size cells in reg property
`dmas`	`phandle-array`	DMA channels specifiers
`dma-names`	`string-array`	Provided names of DMA channel specifiers
`io-channels`	`phandle-array`	IO channels specifiers
`io-channel-names`	`string-array`	Provided names of IO channel specifiers
`mboxes`	`phandle-array`	mailbox / IPM channels specifiers
`mbox-names`	`string-array`	Provided names of mailbox / IPM channel specifiers
`zephyr,deferred-init`	`boolean`	Do not initialize device automatically on boot. Device should be manually initialized using device_init().

Specifier cell names

dma cells: channel, slot, channel-config