[RFC PATCH v2 1/6] Documentation: DT: Add entry for CDX controller

Nipun Gupta
2022-08-17T15:06:32Z

This patch adds a devicetree binding documentation for CDX
controller.

CDX bus controller dynamically detects CDX bus and the
devices on these bus using CDX firmware.

Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
---
.../devicetree/bindings/bus/xlnx,cdx.yaml | 108 ++++++++++++++++++
MAINTAINERS | 6 +
2 files changed, 114 insertions(+)
create mode 100644 Documentation/devicetree/bindings/bus/xlnx,cdx.yaml

diff --git a/Documentation/devicetree/bindings/bus/xlnx,cdx.yaml b/Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
new file mode 100644
index 000000000000..4247a1cff3c1
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
@@ -0,0 +1,108 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/misc/xlnx,cdx.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xilinx CDX bus controller
+
+description: |
+ CDX bus controller for Xilinx devices is implemented to
+ dynamically detect CDX bus and devices on these bus using the
+ firmware. The CDX bus manages multiple FPGA based hardware
+ devices, which can support network, crypto or any other specialized
+ type of device. These FPGA based devices can be added/modified
+ dynamically on run-time.
+
+ All devices on the CDX bus will have a unique streamid (for IOMMU)
+ and a unique device ID (for MSI) corresponding to a requestor ID
+ (one to one associated with the device). The streamid and deviceid
+ are used to configure SMMU and GIC-ITS respectively.
+
+ iommu-map property is used to define the set of stream ids
+ corresponding to each device and the associated IOMMU.
+
+ For generic IOMMU bindings, see:
+ Documentation/devicetree/bindings/iommu/iommu.txt.
+
+ For arm-smmu binding, see:
+ Documentation/devicetree/bindings/iommu/arm,smmu.yaml.
+
+ The MSI writes are accompanied by sideband data (Device ID).
+ The msi-map property is used to associate the devices with the
+ device ID as well as the associated ITS controller.
+
+ For generic MSI bindings, see:
+ Documentation/devicetree/bindings/interrupt-controller/msi.txt.
+
+ For GICv3 and GIC ITS bindings, see:
+ Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.yaml.
+
+maintainers:
+ - Nipun Gupta <nipun.gupta@amd.com>
+ - Nikhil Agarwal <nikhil.agarwal@amd.com>
+
+properties:
+ compatible:
+ const: "xlnx,cdxbus-controller-1.0"
+
+ reg:
+ description: |
+ specifies the CDX firmware region shared memory accessible by the
+ ARM cores.
+
+ iommu-map:
+ description: |
+ Maps device Requestor ID to a stream ID and associated IOMMU. The
+ property is an arbitrary number of tuples of
+ (rid-base,iommu,streamid-base,length).
+
+ Any Requestor ID i in the interval [rid-base, rid-base + length) is
+ associated with the listed IOMMU, with the iommu-specifier
+ (i - streamid-base + streamid-base).
+
+ msi-map:
+ description:
+ Maps an Requestor ID to a GIC ITS and associated msi-specifier
+ data (device ID). The property is an arbitrary number of tuples of
+ (rid-base,gic-its,deviceid-base,length).
+
+ Any Requestor ID in the interval [rid-base, rid-base + length) is
+ associated with the listed GIC ITS, with the msi-specifier
+ (i - rid-base + deviceid-base).
+
+required:
+ - compatible
+ - reg
+ - iommu-map
+ - msi-map
+
+additionalProperties: false
+
+examples:
+ - |
+ smmu@ec000000 {
+ compatible = "arm,smmu-v3";
+ #iommu-cells = <1>;
+ ...
+ };
+
+ gic@e2000000 {
+ compatible = "arm,gic-v3";
+ interrupt-controller;
+ ...
+ its: gic-its@e2040000 {
+ compatible = "arm,gic-v3-its";
+ msi-controller;
+ ...
+ }
+ };
+
+ cdxbus: cdxbus@@4000000 {
+ compatible = "xlnx,cdxbus-controller-1.0";
+ reg = <0x00000000 0x04000000 0 0x1000>;
+ /* define map for RIDs 250-259 */
+ iommu-map = <250 &smmu 250 10>;
+ /* define msi map for RIDs 250-259 */
+ msi-map = <250 &its 250 10>;
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 8a5012ba6ff9..32c5be3d6a53 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22296,6 +22296,12 @@ S: Maintained
F: Documentation/devicetree/bindings/net/can/xilinx,can.yaml
F: drivers/net/can/xilinx_can.c

+XILINX CDX BUS DRIVER
+M: Nipun Gupta <nipun.gupta@amd.com>
+M: Nikhil Agarwal <nikhil.agarwal@amd.com>
+S: Maintained
+F: Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
+
XILINX GPIO DRIVER
M: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
R: Srinivas Neeli <srinivas.neeli@xilinx.com>
--
2.25.1