st,stm32-bdma
Vendor: STMicroelectronics N.V.
Note
An implementation of a driver matching this compatible is available in drivers/dma/dma_stm32_bdma.c.
Description
These nodes are “dma” bus nodes.
STM32 BDMA controller
The STM32 BDMA is a general-purpose direct memory access controller
capable of supporting 5 or 6 or 7 or 8 independent BDMA channels.
Each channel can have up to 8 requests.
BDMA clients connected to the STM32 BDMA controller must use the format
described in the dma.txt file, using a four-cell specifier for each
channel: a phandle to the BDMA controller plus the following four integer cells:
1. channel: the bdma stream from 0 to <bdma-requests>
2. slot: bdma request
3. channel-config: A 32bit mask specifying the BDMA 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
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
examples for stm32h7
bdma1: dma-controller@58025400 {
compatible = "st,stm32-bdma";
...
st,mem2mem;
dma-requests = <7>;
status = "disabled";
};
For the client part, example for STM32H743 on BDMA1 instance
using dmamux2
&adc3 {
dmas = < &dmamux2 0 17 0x2C80 >;
dma-names = "dmamux";
};
Properties
Node specific properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
|---|---|---|
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If the BDMA controller supports memory to memory transfer
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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.
|
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Number of items to expect in a DMA specifier
This property is required. Constant value: |
|
|
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.
|
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Number of DMA channels supported by the controller
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Number of DMA request signals supported by the controller.
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Memory address alignment requirement for DMA buffers used by the controller.
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Memory size alignment requirement for DMA buffers used by the controller.
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Minimal chunk of data possible to be copied by the controller.
|
Deprecated node specific properties
Deprecated properties not inherited from the base binding file.
(None)
Base properties
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-bdma” compatible.
Name |
Type |
Details |
|---|---|---|
|
|
register space
This property is required. See Important properties for more information. |
|
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interrupts for device
This property is required. See Important properties for more information. |
|
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indicates the operational status of a device
Legal values: See Important properties for more information. |
|
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compatible strings
This property is required. See Important properties for more information. |
|
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name of each register space
|
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extended interrupt specifier for device
|
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name of each interrupt
|
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phandle to interrupt controller node
|
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Human readable string describing the device (used as device_get_binding() argument)
See Important properties for more information. This property is deprecated. |
|
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Clock gate information
|
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name of each clock
|
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number of address cells in reg property
|
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number of size cells in reg property
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DMA channels specifiers
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Provided names of DMA channel specifiers
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IO channels specifiers
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Provided names of IO channel specifiers
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mailbox / IPM channels specifiers
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Provided names of mailbox / IPM channel specifiers
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Power domain specifiers
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Provided names of power domain specifiers
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Number of cells in power-domains property
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Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
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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.
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Automatically configure the device for runtime power management after the
init function runs.
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List of power states that will disable this device power.
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Specifier cell names
dma cells: channel, slot, channel-config