gd,gd32-dma

Description

These nodes are “dma” bus nodes.

GD32 DMA controller

channel: Select channel for data transmitting

config: A 32bit mask specifying the DMA channel configuration
  - bit 6-7:   Direction  (see dma.h)
               - 0x0: MEMORY to MEMORY
               - 0x1: MEMORY to PERIPH
               - 0x2: PERIPH to MEMORY
               - 0x3: reserved for PERIPH to PERIPH

  - bit 9:     Peripheral address increase
               - 0x0: no address increment between transfers
               - 0x1: increment address between transfers

  - bit 10:    Memory address increase
               - 0x0: no address increase between transfers
               - 0x1: increase address between transfers

  - bit 11-12: Peripheral data width
               - 0x0: 8 bits
               - 0x1: 16 bits
               - 0x2: 32 bits
               - 0x3: reserved

  - bit 13-14: Memory data width
               - 0x0: 8 bits
               - 0x1: 16 bits
               - 0x2: 32 bits
               - 0x3: reserved

  - bit 15:    Peripheral Increment Offset Size
               - 0x0: offset size is linked to the peripheral bus width
               - 0x1: offset size is fixed to 4 (32-bit alignment)

  - bit 16-17: Priority
               - 0x0: low
               - 0x1: medium
               - 0x2: high
               - 0x3: very high

Example of devicetree configuration

&spi0 {
      status = "okay";
      pinctrl-0 = <&spi0_default>;
      pinctrl-names = "default";
      cs-gpios = <&gpioa 4 GPIO_ACTIVE_LOW>;

      dmas = <&dma0 3 0>, <&dma0 5 GD32_DMA_PRIORITY_HIGH>;
      dma-names = "rx", "tx";
};

"spi0" uses dma0 for transmitting and receiving in the example.
Each is named "rx" and "tx".
The channel cell assigns channel 3 to receive and channel 5 to transmit.
The config cell can take various configs.
But the setting used depends on each driver implementation.
Set the priority for the transmitting channel as HIGH, LOW(the default) for receive channel.

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: `2`
`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 This property is required.
`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.
`gd,mem2mem`	`boolean`	The DMA controller supporting memory to memory transfer

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 “gd,gd32-dma” 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 This property is required.
`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, config