On Fri, May 08, 2020 at 12:36:20PM +0300, Serge Semin wrote: > Baikal-T1 Boot SPI is a part of the SoC System Controller and is > responsible for the system bootup from an external SPI flash. It's a DW > APB SSI-based SPI-controller with no interrupts, no DMA, with just one > native chip-select available and a single reference clock. Since Baikal-T1 > SoC is normally booted up from an external SPI flash this SPI controller > in most of the cases is supposed to be connected to a single SPI-nor > flash. Additionally in order to provide a transparent from CPU point of > view initial code execution procedure the system designers created an IP > block which physically maps the SPI flash found at CS0 to a memory region. > > Co-developed-by: Ramil Zaripov <Ramil.Zaripov@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Ramil Zaripov <Ramil.Zaripov@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> > Cc: Alexey Malahov <Alexey.Malahov@xxxxxxxxxxxxxxxxxxxx> > Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> > Cc: Paul Burton <paulburton@xxxxxxxxxx> > Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> > Cc: John Garry <john.garry@xxxxxxxxxx> > Cc: Chuanhong Guo <gch981213@xxxxxxxxx> > Cc: Tomer Maimon <tmaimon77@xxxxxxxxx> > Cc: Lee Jones <lee.jones@xxxxxxxxxx> > Cc: Miquel Raynal <miquel.raynal@xxxxxxxxxxx> > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: linux-mips@xxxxxxxxxxxxxxx > Cc: linux-spi@xxxxxxxxxxxxxxx > --- > .../bindings/spi/baikal,bt1-sys-ssi.yaml | 100 ++++++++++++++++++ > 1 file changed, 100 insertions(+) > create mode 100644 Documentation/devicetree/bindings/spi/baikal,bt1-sys-ssi.yaml > > diff --git a/Documentation/devicetree/bindings/spi/baikal,bt1-sys-ssi.yaml b/Documentation/devicetree/bindings/spi/baikal,bt1-sys-ssi.yaml > new file mode 100644 > index 000000000000..d9d3257d78f4 > --- /dev/null > +++ b/Documentation/devicetree/bindings/spi/baikal,bt1-sys-ssi.yaml > @@ -0,0 +1,100 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/spi/baikal,bt1-sys-ssi.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Baikal-T1 System Boot SSI Controller > + > +description: | > + Baikal-T1 System Controller includes a Boot SPI Controller, which is > + responsible for loading chip bootup code from an external SPI flash. In order > + to do this transparently from CPU point of view there is a dedicated IP block > + mapping the 16MB flash to a dedicated MMIO range. The controller is based on > + the DW APB SSI IP-core but equipped with very limited resources: no IRQ, > + no DMA, a single native CS being necessarily connected to a 16MB SPI flash > + (otherwise the system won't bootup from the flash), internal Tx/Rx FIFO of > + just 8 bytes depth. Access to DW APB SSI controller registers is mutually > + exclusive from normal MMIO interface and from physically mapped SPI Flash > + memory. So either one or another way of using the controller functionality > + can be enabled at a time. > + > +maintainers: > + - Serge Semin <fancer.lancer@xxxxxxxxx> > + > +allOf: > + - $ref: spi-controller.yaml# > + > +properties: > + compatible: > + const: baikal,bt1-sys-ssi > + > + reg: > + items: > + - description: Baikal-T1 Boot Controller configuration registers > + - description: Physically mapped SPI flash ROM found at CS0 > + > + reg-names: > + items: > + - const: config > + - const: map > + > + clocks: > + description: SPI Controller reference clock source Can drop this. > + maxItems: 1 > + > + clock-names: > + items: > + - const: ssi_clk > + > + num-cs: > + const: 1 > + > +patternProperties: > + "^.*@[0-9a-f]+": > + type: object > + properties: > + reg: > + minimum: 0 > + maximum: 0 > + > + spi-rx-bus-width: > + const: 1 > + > + spi-tx-bus-width: > + const: 1 What's the point of these 2 properties if they aren't required? > + > +unevaluatedProperties: false > + > +required: > + - compatible > + - reg > + - reg-names > + - "#address-cells" > + - "#size-cells" These 2 are required by spi-controller.yaml, so you can drop here. > + - clocks > + > +examples: > + - | > + spi@1f040000 { > + compatible = "baikal,bt1-sys-ssi"; > + reg = <0x1f040000 0x1000>, > + <0x1c000000 0x1000000>; > + reg-names = "config", "map"; > + #address-cells = <1>; > + #size-cells = <0>; > + > + clocks = <&ccu_sys>; > + clock-names = "ssi_clk"; > + > + boot_flash: flash@0 { > + compatible = "jedec,spi-nor"; > + #address-cells = <1>; > + #size-cells = <1>; > + reg = <0>; > + > + spi-max-frequency = <25000000>; > + }; > + }; > +... > -- > 2.25.1 >
