Re: [PATCH 2/9] PCI: host: brcmstb: add DT docs for Brcmstb PCIe device

From: Brian Norris
Date: Wed Oct 11 2017 - 20:55:32 EST


Hi Jim,

On Wed, Oct 11, 2017 at 06:34:22PM -0400, Jim Quinlan wrote:
> The DT bindings description of the Brcmstb PCIe device is described. This
> node can be used by almost all Broadcom settop box chips, using
> ARM, ARM64, or MIPS CPU architectures.
>
> Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx>
> ---
> .../devicetree/bindings/pci/brcmstb-pci.txt | 106 +++++++++++++++++++++
> 1 file changed, 106 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pci/brcmstb-pci.txt
>
> diff --git a/Documentation/devicetree/bindings/pci/brcmstb-pci.txt b/Documentation/devicetree/bindings/pci/brcmstb-pci.txt
> new file mode 100644
> index 0000000..2f699da
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/brcmstb-pci.txt
> @@ -0,0 +1,106 @@
> +Brcmstb PCIe Host Controller Device Tree Bindings
> +
> +Introduction:
> + The brcmstb host controller closely follows the example set in
> +
> + [1] http://devicetree.org/Device_Tree_Usage#PCI_Host_Bridge
> +
> + The rest of this document explains some added customizations and
> + offers an example Brcmstb PCIe host controller DT node.
> +
> +Required Properties:
> + reg -- the register start address and length for the PCIe block.
> + Additional start,length pairs may be specified for clock addresses.
> + interrupts -- two interrupts are specified; the first interrupt is for
> + the PCI host controller and the second is for MSI if the built-in
> + MSI controller is to be used.
> + interrupt-names -- names of the interrupts (above): "pcie" and "msi".
> + compatible -- must be one of: "brcm,bcm7425-pcie", "brcm,bcm7435-pcie",
> + or "brcm,bcm7278-pcie".
> + #address-cells -- the number of address cells for PCI-space.
> + #size-cells -- the number of size cells for PCI-space.
> + ranges -- See [1]; a specification of the outbound windows for the host
> + controller. Each outbound window is described by a n-tuple:
> + (3 cells) -- PCIe space start address; one cell for attributes
> + and two cells for the 64-bit PCIe address.
> + (x cells) -- CPU/System start address, number of cells is determined
> + by the parent node's #address-cells.
> + (y cells) -- Size of region, number of cells determined by the
> + parent node's #size-cells.
> + Due to hardware limitations, there may be a maximum of four
> + non-contiguous ranges specified.
> + #interrupt-cells -- number of cells used to describe the interrupt.
> + interrupt-map-mask -- see [1]; four cells, the first three are zero
> + for our uses and the fourth cell is the mask (val = 0x7) for
> + the legacy interrupt number [1..4].
> + interrupt-map -- See [1]; there are four interrupts (INTA, INTB,
> + INTC, and INTD) to be mapped; each interrupt requires 5 cells
> + plus the size of the interrupt specifier.
> + linux,pci-domain -- the domain of the host controller.
> +
> +Optional Properties:
> + clocks -- list of clock phandles. If specified, this should list one
> + clock.
> + clock-names -- the "local" names of the clocks specified in 'clocks'. Note
> + that if the 'clocks' property is given, 'clock-names' is mandatory,
> + and the name of the clock is expected to be "sw_pcie".
> + dma-ranges -- Similar in structure to ranges, each dma region is
> + specified with a n-tuple. Dma-regions describe the inbound
> + accesses from EP to RC; it translates the pci address that the
> + EP "sees" to the CPU address in memory. This property is needed
> + because the design of the Brcmstb memory subsystem often precludes
> + idenity-mapping between CPU address space and PCIe address space.
> + Each range is described by a n-tuple:
> + (3 cells) -- PCIe space start address; one cell for attributes
> + and two cells for the 64-bit PCIe address.
> + (x cells) -- CPU/System start address, number of cells is determined
> + by the parent node's #address-cells.
> + (y cells) -- Size of region, number of cells determined by the
> + parent node's #size-cells.
> + msi-parent -- if MSI is to be used, this must be a phandle to the
> + msi-parent. If this prop is set to the phandle of the PCIe
> + node, or if the msi-parent prop is missing, the PCIE controller
> + will attempt to use its built in MSI controller.
> + msi-controller -- this property should only be specified if the
> + PCIe controller is using its internal MSI controller.
> + brcm,ssc -- (boolean) indicates usage of spread-spectrum clocking.
> + brcm,gen -- (integer) indicates desired generation of link:
> + 1 => 2.5 Gbps, 2 => 5.0 Gbps, 3 => 8.0 Gbps.

Does this differ from the 'max-link-speed' now documented in
Documentation/devicetree/bindings/pci/pci.txt? If not, might as well use
it, and of_pci_get_max_link_speed().

> + supply-names -- the names of voltage regulators that the root
> + complex should turn off/on/on on suspend/resume/boot. This
> + is a string list.
> + supplies -- A collection of phandles to a regulator nodes, see
> + Documentation/devicetree/bindings/regulator/ for specific
> + bindings. The number and order of phandles must match
> + exactly the number of strings in the "supply-names" property.
> +
> +Example Node:
> +
> +pcie0: pcie@f0460000 {

^^ You've got a tab after the colon. Makes this look funky in my
vim/mutt :)

Brian

> + reg = <0x0 0xf0460000 0x0 0x9310>;
> + interrupts = <0x0 0x0 0x4>;
> + compatible = "brcm,pci-plat-dev";
> + #address-cells = <3>;
> + #size-cells = <2>;
> + ranges = <0x02000000 0x00000000 0x00000000 0x00000000 0xc0000000 0x00000000 0x08000000
> + 0x02000000 0x00000000 0x08000000 0x00000000 0xc8000000 0x00000000 0x08000000>;
> + #interrupt-cells = <1>;
> + interrupt-map-mask = <0 0 0 7>;
> + interrupt-map = <0 0 0 1 &intc 0 47 3
> + 0 0 0 2 &intc 0 48 3
> + 0 0 0 3 &intc 0 49 3
> + 0 0 0 4 &intc 0 50 3>;
> + interrupt-names = "pcie_0_inta",
> + "pcie_0_intb",
> + "pcie_0_intc",
> + "pcie_0_intd";
> + clocks = <&sw_pcie0>;
> + clock-names = "sw_pcie";
> + msi-parent = <&pcie0>; /* use PCIe's internal MSI controller */
> + msi-controller; /* use PCIe's internal MSI controller */
> + brcm,ssc;
> + brcm,gen = <1>;
> + supply-names = "vreg-wifi-pwr";
> + supplies = <&vreg-wifi-pwr>;
> + linux,pci-domain = <0>;
> + };
> --
> 1.9.0.138.g2de3478
>