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Merge branch 'bits/180-sio' into asahi-wip
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‎Documentation/devicetree/bindings/dma/apple,sio.yaml‎

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# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/dma/apple,sio.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Apple SIO Coprocessor
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description:
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SIO is a coprocessor on Apple M1 and later chips (and maybe also on earlier
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chips). Its role is to offload SPI, UART and DisplayPort audio transfers,
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being a pretend DMA controller.
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maintainers:
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- Martin Povišer <povik+lin@cutebit.org>
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allOf:
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- $ref: dma-controller.yaml#
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properties:
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compatible:
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items:
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- enum:
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- apple,t6000-sio
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- apple,t8103-sio
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- const: apple,sio
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reg:
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maxItems: 1
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'#dma-cells':
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const: 1
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description:
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DMA clients specify a single cell that corresponds to the RTKit endpoint
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number used for arranging the transfers in question
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dma-channels:
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maximum: 128
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mboxes:
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maxItems: 1
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iommus:
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maxItems: 1
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power-domains:
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maxItems: 1
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memory-region:
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minItems: 2
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maxItems: 8
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description:
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A number of references to reserved memory regions among which are the DATA/TEXT
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sections of coprocessor executable firmware and also auxiliary firmware data
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describing the available DMA-enabled peripherals
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apple,sio-firmware-params:
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$ref: /schemas/types.yaml#/definitions/uint32-array
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description: |
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Parameters in the form of opaque key/value pairs that are to be sent to the SIO
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coprocesssor once it boots. These parameters can point into the reserved memory
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regions (in device address space).
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Note that unlike Apple's firmware, we treat the parameters, and the data they
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refer to, as opaque. Apple embed short data blobs into their SIO devicetree node
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that describe the DMA-enabled peripherals (presumably with defined semantics).
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Their driver processes those blobs and sets up data structure in mapped device
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memory, then references this memory in the parameters sent to the SIO. At the
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level of description we are opting for in this binding, we assume the job of
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constructing those data structures has been done in advance, leaving behind an
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opaque list of key/value parameter pairs to be sent by a prospective driver.
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This approach is chosen for two reasons:
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- It means we don't need to try to understand the semantics of Apple's blobs
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as long as we know the transformation we need to do from Apple's devicetree
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data to SIO data (which can be shoved away into a loader). It also means the
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semantics of Apple's blobs (or of something to replace them) need not be part
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of the binding and be kept up with Apple's firmware changes in the future.
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- It leaves less work for the driver attaching on this binding. Instead the work
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is done upfront in the loader which can be better suited for keeping up with
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Apple's firmware changes.
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required:
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- compatible
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- reg
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- '#dma-cells'
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- dma-channels
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- mboxes
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- iommus
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- power-domains
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additionalProperties: false
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examples:
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- |
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sio: dma-controller@36400000 {
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compatible = "apple,t8103-sio", "apple,sio";
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reg = <0x36400000 0x8000>;
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dma-channels = <128>;
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#dma-cells = <1>;
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mboxes = <&sio_mbox>;
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iommus = <&sio_dart 0>;
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power-domains = <&ps_sio_cpu>;
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memory-region = <&sio_text>, <&sio_data>,
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<&sio_auxdata1>, <&sio_auxdata2>; /* Filled by loader */
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apple,sio-firmware-params = <0xb 0x10>, <0xc 0x1b80>, <0xf 0x14>,
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<0x10 0x1e000>, <0x30d 0x34>, <0x30e 0x4000>,
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<0x1a 0x38>, <0x1b 0x50>; /* Filled by loader */
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};

‎MAINTAINERS‎

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L: asahi@lists.linux.dev
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L: alsa-devel@alsa-project.org (moderated for non-subscribers)
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S: Maintained
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F: Documentation/devicetree/bindings/dma/apple,sio.yaml
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F: Documentation/devicetree/bindings/sound/adi,ssm3515.yaml
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F: Documentation/devicetree/bindings/sound/apple,*
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F: drivers/dma/apple-sio.c
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F: sound/soc/apple/*
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F: sound/soc/codecs/cs42l83-i2c.c
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F: sound/soc/codecs/ssm3515.c

‎drivers/dma/Kconfig‎

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tristate "Apple ADMAC support"
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depends on ARCH_APPLE || COMPILE_TEST
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select DMA_ENGINE
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select DMA_VIRTUAL_CHANNELS
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default ARCH_APPLE
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help
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Enable support for Audio DMA Controller found on Apple Silicon SoCs.
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config APPLE_SIO
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tristate "Apple SIO support"
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depends on ARCH_APPLE || COMPILE_TEST
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depends on APPLE_RTKIT
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select DMA_ENGINE
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default m if ARCH_APPLE
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help
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Enable support for the SIO coprocessor found on Apple Silicon SoCs
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where it provides DMA services.
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config AT_HDMAC
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tristate "Atmel AHB DMA support"
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depends on ARCH_AT91

‎drivers/dma/Makefile‎

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obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
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obj-$(CONFIG_AMD_PTDMA) += ptdma/
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obj-$(CONFIG_APPLE_ADMAC) += apple-admac.o
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obj-$(CONFIG_APPLE_SIO) += apple-sio.o
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obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
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obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
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obj-$(CONFIG_AXI_DMAC) += dma-axi-dmac.o

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