linuxdebug/Documentation/devicetree/bindings/dma/ti/k3-bcdma.yaml

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YAML

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
# Copyright (C) 2020 Texas Instruments Incorporated
# Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
%YAML 1.2
---
$id: http://devicetree.org/schemas/dma/ti/k3-bcdma.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Texas Instruments K3 DMSS BCDMA Device Tree Bindings
maintainers:
- Peter Ujfalusi <peter.ujfalusi@gmail.com>
description: |
The Block Copy DMA (BCDMA) is intended to perform similar functions as the TR
mode channels of K3 UDMA-P.
BCDMA includes block copy channels and Split channels.
Block copy channels mainly used for memory to memory transfers, but with
optional triggers a block copy channel can service peripherals by accessing
directly to memory mapped registers or area.
Split channels can be used to service PSI-L based peripherals.
The peripherals can be PSI-L native or legacy, non PSI-L native peripherals
with PDMAs. PDMA is tasked to act as a bridge between the PSI-L fabric and the
legacy peripheral.
PDMAs can be configured via BCDMA split channel's peer registers to match with
the configuration of the legacy peripheral.
allOf:
- $ref: /schemas/dma/dma-controller.yaml#
- $ref: /schemas/arm/keystone/ti,k3-sci-common.yaml#
properties:
compatible:
const: ti,am64-dmss-bcdma
"#dma-cells":
const: 3
description: |
cell 1: type of the BCDMA channel to be used to service the peripheral:
0 - split channel
1 - block copy channel using global trigger 1
2 - block copy channel using global trigger 2
3 - block copy channel using local trigger
cell 2: parameter for the channel:
if cell 1 is 0 (split channel):
PSI-L thread ID of the remote (to BCDMA) end.
Valid ranges for thread ID depends on the data movement direction:
for source thread IDs (rx): 0 - 0x7fff
for destination thread IDs (tx): 0x8000 - 0xffff
Please refer to the device documentation for the PSI-L thread map and
also the PSI-L peripheral chapter for the correct thread ID.
if cell 1 is 1 or 2 (block copy channel using global trigger):
Unused, ignored
The trigger must be configured for the channel externally to BCDMA,
channels using global triggers should not be requested directly, but
via DMA event router.
if cell 1 is 3 (block copy channel using local trigger):
bchan number of the locally triggered channel
cell 3: ASEL value for the channel
reg:
maxItems: 5
reg-names:
items:
- const: gcfg
- const: bchanrt
- const: rchanrt
- const: tchanrt
- const: ringrt
msi-parent: true
ti,asel:
$ref: /schemas/types.yaml#/definitions/uint32
description: ASEL value for non slave channels
ti,sci-rm-range-bchan:
$ref: /schemas/types.yaml#/definitions/uint32-array
description: |
Array of BCDMA block-copy channel resource subtypes for resource
allocation for this host
minItems: 1
# Should be enough
maxItems: 255
items:
maximum: 0x3f
ti,sci-rm-range-tchan:
$ref: /schemas/types.yaml#/definitions/uint32-array
description: |
Array of BCDMA split tx channel resource subtypes for resource allocation
for this host
minItems: 1
# Should be enough
maxItems: 255
items:
maximum: 0x3f
ti,sci-rm-range-rchan:
$ref: /schemas/types.yaml#/definitions/uint32-array
description: |
Array of BCDMA split rx channel resource subtypes for resource allocation
for this host
minItems: 1
# Should be enough
maxItems: 255
items:
maximum: 0x3f
required:
- compatible
- "#dma-cells"
- reg
- reg-names
- msi-parent
- ti,sci
- ti,sci-dev-id
- ti,sci-rm-range-bchan
- ti,sci-rm-range-tchan
- ti,sci-rm-range-rchan
unevaluatedProperties: false
examples:
- |+
cbass_main {
#address-cells = <2>;
#size-cells = <2>;
main_dmss {
compatible = "simple-mfd";
#address-cells = <2>;
#size-cells = <2>;
dma-ranges;
ranges;
ti,sci-dev-id = <25>;
main_bcdma: dma-controller@485c0100 {
compatible = "ti,am64-dmss-bcdma";
reg = <0x0 0x485c0100 0x0 0x100>,
<0x0 0x4c000000 0x0 0x20000>,
<0x0 0x4a820000 0x0 0x20000>,
<0x0 0x4aa40000 0x0 0x20000>,
<0x0 0x4bc00000 0x0 0x100000>;
reg-names = "gcfg", "bchanrt", "rchanrt", "tchanrt", "ringrt";
msi-parent = <&inta_main_dmss>;
#dma-cells = <3>;
ti,sci = <&dmsc>;
ti,sci-dev-id = <26>;
ti,sci-rm-range-bchan = <0x20>; /* BLOCK_COPY_CHAN */
ti,sci-rm-range-rchan = <0x21>; /* SPLIT_TR_RX_CHAN */
ti,sci-rm-range-tchan = <0x22>; /* SPLIT_TR_TX_CHAN */
};
};
};