Hi Rob, > From: Rob Herring <robh@xxxxxxxxxx> > Sent: Wednesday, May 18, 2022 2:32 AM > > On Mon, May 16, 2022 at 08:54:09AM +0800, Chia-Wei Wang wrote: > > Add dt-bindings for Aspeed eSPI controller > > > > Signed-off-by: Chia-Wei Wang <chiawei_wang@xxxxxxxxxxxxxx> > > --- > > .../devicetree/bindings/soc/aspeed/espi.yaml | 162 > > ++++++++++++++++++ > > bindings/spi/ includes SPI slaves. Is there a reason this doesn't fit there? eSPI resues the timing and electrical specification of SPI but runs completely different protocol. Only the flash channel is related to SPI and the other 3 channels are for EC/BMC/SIO. Therefore, an eSPI driver does not fit into the SPI model. > > > 1 file changed, 162 insertions(+) > > create mode 100644 > > Documentation/devicetree/bindings/soc/aspeed/espi.yaml > > > > diff --git a/Documentation/devicetree/bindings/soc/aspeed/espi.yaml > > b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml > > new file mode 100644 > > index 000000000000..aa91ec8caf6a > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml > > @@ -0,0 +1,162 @@ > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) # # > > +Copyright (c) 2021 Aspeed Technology Inc. > > +%YAML 1.2 > > +--- > > +$id: "http://devicetree.org/schemas/soc/aspeed/espi.yaml#"; > > +$schema: "http://devicetree.org/meta-schemas/core.yaml#"; > > + > > +title: Aspeed eSPI Controller > > + > > +maintainers: > > + - Chia-Wei Wang <chiawei_wang@xxxxxxxxxxxxxx> > > + - Ryan Chen <ryan_chen@xxxxxxxxxxxxxx> > > + > > +description: > > + Aspeed eSPI controller implements a slave side eSPI endpoint device > > + supporting the four eSPI channels, namely peripheral, virtual wire, > > + out-of-band, and flash. > > + > > +properties: > > + compatible: > > + items: > > + - enum: > > + - aspeed,ast2500-espi > > + - aspeed,ast2600-espi > > + - const: simple-mfd > > + - const: syscon > > + > > + reg: > > + maxItems: 1 > > + > > + "#address-cells": > > + const: 1 > > + > > + "#size-cells": > > + const: 1 > > + > > + ranges: true > > + > > +patternProperties: > > + "^espi-ctrl@[0-9a-f]+$": > > + type: object > > + > > + description: Control of the four basic eSPI channels > > + > > + properties: > > + compatible: > > + items: > > + - enum: > > + - aspeed,ast2500-espi-ctrl > > + - aspeed,ast2600-espi-ctrl > > + > > + interrupts: > > + maxItems: 1 > > + > > + clocks: > > + maxItems: 1 > > + > > + perif,memcyc-enable: > > What vendor is 'perif'? It refers to the eSPI peripheral channel. > > > + type: boolean > > + description: Enable memory cycle over eSPI peripheral channel > > + > > + perif,memcyc-src-addr: > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + description: The Host side address to be decoded into the > > + memory cycle over eSPI peripheral channel > > + > > + perif,memcyc-size: > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + description: The size of the memory region allocated for the > memory cycle over eSPI peripheral channel > > + minimum: 65536 > > This region is defined by the h/w or just some carveout of system memory? In > the former, perhaps this should be part of 'reg'. In the latter case, use a > /reserved-memory node and memory-region here. The region is going to be allocated at runtime phase. It is a kind of shared memory between Host and BMC. > > > + > > + perif,dma-mode: > > + type: boolean > > + description: Enable DMA support for eSPI peripheral channel > > + > > + oob,dma-mode: > > What vendor is 'oob'? It refers to the eSPI out-of-band channel. > > > + type: boolean > > + description: Enable DMA support for eSPI out-of-band channel > > + > > + oob,dma-tx-desc-num: > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + minimum: 2 > > + maximum: 1023 > > + description: The number of TX descriptors available for eSPI > > + OOB DMA engine > > + > > + oob,dma-rx-desc-num: > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + minimum: 2 > > + maximum: 1023 > > + description: The number of RX descriptors available for eSPI > > + OOB DMA engine > > + > > + flash,dma-mode: > > + type: boolean > > + description: Enable DMA support for eSPI flash channel > > Why does this need to be in DT. It's configuration. The property is used to decide the operation mode (i.e. FIFO or DMA) of the eSPI flash channel. Is it a wrong idea to use the DTS property for? > > > + > > + flash,safs-mode: > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + enum: [ 0, 1, 2 ] > > + default: 0 > > + description: Slave-Attached-Sharing-Flash mode, 0->Mix, > > + 1->SW, 2->HW > > + > > + dependencies: > > + perif,memcyc-src-addr: [ "perif,memcyc-enable" ] > > + perif,memcyc-size: [ "perif,memcyc-enable" ] > > + oob,dma-tx-desc-num: [ "oob,dma-mode" ] > > + oob,dma-rx-desc-num: [ "oob,dma-mode" ] > > + > > + required: > > + - compatible > > + - interrupts > > + - clocks > > + > > + "^espi-mmbi@[0-9a-f]+$": > > + type: object > > + > > + description: Control of the PCH-BMC data exchange over eSPI > > + peripheral memory cycle > > + > > + properties: > > + compatible: > > + const: aspeed,ast2600-espi-mmbi > > + > > + interrupts: > > + maxItems: 1 > > + > > + required: > > + - compatible > > + - interrupts > > + > > +required: > > + - compatible > > + - reg > > + - "#address-cells" > > + - "#size-cells" > > + - ranges > > + > > +additionalProperties: false > > + > > +examples: > > + - | > > + #include <dt-bindings/interrupt-controller/arm-gic.h> > > + #include <dt-bindings/clock/ast2600-clock.h> > > + > > + espi: espi@1e6ee000 { > > + compatible = "aspeed,ast2600-espi", "simple-mfd", "syscon"; > > + reg = <0x1e6ee000 0x1000>; > > + > > + #address-cells = <1>; > > + #size-cells = <1>; > > + ranges = <0x0 0x1e6ee000 0x1000>; > > + > > + espi_ctrl: espi-ctrl@0 { > > + compatible = "aspeed,ast2600-espi-ctrl"; > > + reg = <0x0 0x800>; > > + interrupts = <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>; > > + clocks = <&syscon ASPEED_CLK_GATE_ESPICLK>; > > + }; > > + > > + espi_mmbi: espi-mmbi@800 { > > + compatible = "aspeed,ast2600-espi-mmbi"; > > + reg = <0x800 0x50>; > > + interrupts = <GIC_SPI 108 IRQ_TYPE_LEVEL_HIGH>; > > + }; > > Why do you need these child nodes? Are the subblocks somehow useful on > their own or reuseable in another configuration? If not, looks like this could all > be 1 node. espi-mmbi has individual function and control registers. However, espi-mmbi is also a feature extended based on the memory cycle of eSPI peripheral channel. Thereby, it has dependency on the eSPI channel initialization conducted by espi-ctrl. The scenario is similar to the lpc-ctrl and other lpc-xxx drivers of Aspeed SoCs. Chiawei
