[PATCH 2/6] dt-bindings: PCI: tegra: Add DT support for PCIe EP nodes in Tegra194

[Vidya Sagar]

Add support for PCIe controllers that can operate in endpoint mode
in Tegra194.

Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
---
 .../bindings/pci/nvidia,tegra194-pcie-ep.txt  | 138 ++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie-ep.txt

diff --git a/Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie-ep.txt b/Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie-ep.txt
new file mode 100644
index 000000000000..4676ccf7dfa5
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie-ep.txt
@@ -0,0 +1,138 @@
+NVIDIA Tegra PCIe Endpoint mode controller (Synopsys DesignWare Core based)
+
+Some of the PCIe controllers which are based on Synopsys DesignWare PCIe IP
+are dual mode i.e. they can work in root port mode or endpoint mode but one
+ at a time. Since they are based on DesignWare IP, they inherit all the common
+properties defined in designware-pcie.txt.
+
+Required properties:
+- compatible: For Tegra19x, must contain "nvidia,tegra194-pcie".
+  Tegra194: Only C0, C4 & C5 controllers are dual mode controllers.
+- power-domains: A phandle to the node that controls power to the respective
+  PCIe controller and a specifier name for the PCIe controller. Following are
+  the specifiers for the different PCIe controllers
+    TEGRA194_POWER_DOMAIN_PCIEX8B: C0
+    TEGRA194_POWER_DOMAIN_PCIEX4A: C4
+    TEGRA194_POWER_DOMAIN_PCIEX8A: C5
+  these specifiers are defined in
+  "include/dt-bindings/power/tegra194-powergate.h" file.
+- reg: A list of physical base address and length pairs for each set of
+  controller registers. Must contain an entry for each entry in the reg-names
+  property.
+- reg-names: Must include the following entries:
+  "appl": Controller's application logic registers
+  "atu_dma": iATU and DMA registers. This is where the iATU (internal Address
+             Translation Unit) registers of the PCIe core are made available
+             for SW access.
+  "dbi": The aperture where root port's own configuration registers are
+         available
+  "addr_space": Used to map remote RC address space
+- interrupts: A list of interrupt outputs of the controller. Must contain an
+  entry for each entry in the interrupt-names property.
+- interrupt-names: Must include the following entry:
+  "intr": The Tegra interrupt that is asserted for controller interrupts
+- clocks: Must contain an entry for each entry in clock-names.
+  See ../clocks/clock-bindings.txt for details.
+- clock-names: Must include the following entries:
+  - core
+- resets: Must contain an entry for each entry in reset-names.
+  See ../reset/reset.txt for details.
+- reset-names: Must include the following entries:
+  - apb
+  - core
+- phys: Must contain a phandle to P2U PHY for each entry in phy-names.
+- phy-names: Must include an entry for each active lane.
+  "p2u-N": where N ranges from 0 to one less than the total number of lanes
+- nvidia,bpmp: Must contain a pair of phandle to BPMP controller node followed
+  by controller-id. Following are the controller ids for each controller.
+    0: C0
+    4: C4
+    5: C5
+- vddio-pex-ctl-supply: Regulator supply for PCIe side band signals
+- nvidia,pex-rst-gpio: Must contain a phandle to a GPIO controller followed by
+  GPIO that is being used as PERST signal
+
+Optional properties:
+- pinctrl-names: A list of pinctrl state names.
+  It is mandatory for C5 controller and optional for other controllers.
+  - "default": Configures PCIe I/O for proper operation.
+- pinctrl-0: phandle for the 'default' state of pin configuration.
+  It is mandatory for C5 controller and optional for other controllers.
+- supports-clkreq: Refer to Documentation/devicetree/bindings/pci/pci.txt
+- nvidia,update-fc-fixup: This is a boolean property and needs to be present to
+    improve performance when a platform is designed in such a way that it
+    satisfies at least one of the following conditions thereby enabling root
+    port to exchange optimum number of FC (Flow Control) credits with
+    downstream devices
+    1. If C0/C4/C5 run at x1/x2 link widths (irrespective of speed and MPS)
+    2. If C0/C4/C5 operate at their respective max link widths and
+       a) speed is Gen-2 and MPS is 256B
+       b) speed is >= Gen-3 with any MPS
+- nvidia,aspm-cmrt-us: Common Mode Restore Time for proper operation of ASPM
+   to be specified in microseconds
+- nvidia,aspm-pwr-on-t-us: Power On time for proper operation of ASPM to be
+   specified in microseconds
+- nvidia,aspm-l0s-entrance-latency-us: ASPM L0s entrance latency to be
+   specified in microseconds
+
+NOTE:- On Tegra194's P2972-0000 platform, only C5 controller can be enabled to
+operate in the endpoint mode because of the way the platform is designed.
+There is a mux that needs to be programmed to let the REFCLK from the host to
+flow into C5 controller when it operates in the endpoint mode. This mux is
+controlled by the GPIO (AA, 5) and it needs to be driven 'high'. For this to
+happen, set status of "pex-refclk-sel-high" node under "gpio@c2f0000" node to
+'okay'.
+	When any dual mode controller is made to operate in the endpoint mode,
+please make sure that its respective root port node's status is set to
+'disabled'.
+
+Examples:
+=========
+
+Tegra194:
+--------
+
+	pcie_ep@141a0000 {
+		compatible = "nvidia,tegra194-pcie-ep", "snps,dw-pcie-ep";
+		power-domains = <&bpmp TEGRA194_POWER_DOMAIN_PCIEX8A>;
+		reg = <0x00 0x141a0000 0x0 0x00020000   /* appl registers (128K)      */
+		       0x00 0x3a040000 0x0 0x00040000   /* iATU_DMA reg space (256K)  */
+		       0x00 0x3a080000 0x0 0x00040000   /* DBI reg space (256K)       */
+		       0x1c 0x00000000 0x4 0x00000000>; /* Address Space (16G)        */
+		reg-names = "appl", "atu_dma", "dbi", "addr_space";
+
+		num-lanes = <8>;
+		num-ib-windows = <2>;
+		num-ob-windows = <8>;
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&clkreq_c5_bi_dir_state>;
+
+		clocks = <&bpmp TEGRA194_CLK_PEX1_CORE_5>;
+		clock-names = "core";
+
+		resets = <&bpmp TEGRA194_RESET_PEX1_CORE_5_APB>,
+			 <&bpmp TEGRA194_RESET_PEX1_CORE_5>;
+		reset-names = "apb", "core";
+
+		interrupts = <GIC_SPI 53 IRQ_TYPE_LEVEL_HIGH>;	/* controller interrupt */
+		interrupt-names = "intr";
+
+		nvidia,bpmp = <&bpmp 5>;
+
+		nvidia,aspm-cmrt-us = <60>;
+		nvidia,aspm-pwr-on-t-us = <20>;
+		nvidia,aspm-l0s-entrance-latency-us = <3>;
+
+		vddio-pex-ctl-supply = <&vdd_1v8ao>;
+
+		nvidia,pex-rst-gpio = <&gpio TEGRA194_MAIN_GPIO(GG, 1)
+					GPIO_ACTIVE_LOW>;
+
+		phys = <&p2u_nvhs_0>, <&p2u_nvhs_1>, <&p2u_nvhs_2>,
+		       <&p2u_nvhs_3>, <&p2u_nvhs_4>, <&p2u_nvhs_5>,
+		       <&p2u_nvhs_6>, <&p2u_nvhs_7>;
+
+		phy-names = "p2u-0", "p2u-1", "p2u-2", "p2u-3", "p2u-4",
+			    "p2u-5", "p2u-6", "p2u-7";
+	};
-- 
2.17.1