platform: tegra: dce: add dce kernel driver

For T23x, we have a separate R5 based cluster
named as Display Controller Engine(DCE) to run
our Display RM code. This driver will run on CPU
with the following functionality:

Via debugfs for test and bring-up purposes:
1. Reads the DCE firmware image into DRAM.
2. Sets up DCE AST to cover the DCE firmware image.
3. Sets up R5 reset vector to point to DCE firmware
entry point
4. Brings DCE out of reset
5. Dumps various regsiters for debug

In production env:
1. Manages interrupts to CPU from DCE
2. Uses bootstrap command interface to define Admin
IPC
3. Locks down bootstrap command interface
4. Uses Admin IPC to define message IPC
5. Uses Admin IPC to define message IPC payload area
6. Uses Admin IPC to set IPC channels
6. Uses Admin IPC to define crashdump area
(optional)
7. Provides IPC interfaces for any DCE Client running
on CCPLEX including Display RM.
8. Uses Admin IPC to set logging level (optional)

This patch puts a framework in place with the
following features :
1. Firmware Loading
2. AST Configuration
3. DCE Reset with EVP Programming
4. Logging Infra
5. Debugfs Support
6. Interrupt Handling
7. Mailbox Programming
8. IPC Programming
9. DCE Client Interface
10. Ftrace Support for debug purposes

Change-Id: Idd28cd9254706c7313f531fcadaa7024a5b344e7
Signed-off-by: Arun Swain <arswain@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-t23x/+/2289865
Reviewed-by: automaticguardword <automaticguardword@nvidia.com>
Reviewed-by: Mahesh Kumar <mahkumar@nvidia.com>
Reviewed-by: Santosh Galma <galmar@nvidia.com>
Reviewed-by: Mitch Luban <mluban@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit
Tested-by: Mahesh Kumar <mahkumar@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

include/linux/platform/tegra/dce/dce-client-ipc.h

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef TEGRA_DCE_CLIENT_IPC_H
+#define TEGRA_DCE_CLIENT_IPC_H
+
+#define DCE_CLIENT_IPC_TYPE_CPU_RM		0U
+#define DCE_CLIENT_IPC_TYPE_HDCP_KMD	1U
+#define DCE_CLIENT_IPC_TYPE_MAX			2U
+
+/**
+ * struct dce_ipc_message - Contains necessary info for an ipc msg.
+ *
+ * @tx : transmit message info
+ * @rx : receive message info
+ */
+struct dce_ipc_message {
+	struct {
+		void *data;
+		size_t size;
+	} tx;
+	struct {
+		void *data;
+		size_t size;
+	} rx;
+};
+
+/*
+ * tegra_dce_client_ipc_callback_t - callback function to notify the
+ * client when the CPU Driver receives an IPC from DCE for the client.
+ *
+ * @client_id: id that represents the corresponding client.
+ * @interface_type: Interface on which the IPC was received.
+ * @msg_length: Length of the message.
+ * @msg_data: Message data.
+ * @usr_ctx: Any user context if present.
+ */
+typedef void (*tegra_dce_client_ipc_callback_t)(u32 handle,
+	      u32 interface_type, u32 msg_length,
+	      void *msg_data, void *usr_ctx);
+
+/*
+ * tegra_dce_register_ipc_client() - used by clients to register with dce driver
+ * @interface_type: Interface for which this client is expected to send rpcs and
+ * receive callbacks.
+ * @callback_fn: callback function to be called by DCE driver on receiving IPCs
+ * from DCE on this interface.
+ * @usr_ctx: Any user context if present.
+ *
+ * Return: valid client_id if no errors else corresponding error value.
+ */
+int tegra_dce_register_ipc_client(u32 interface_type,
+		tegra_dce_client_ipc_callback_t callback_fn,
+		void *usr_ctx, u32 *handlep);
+
+/*
+ * tegra_dce_unregister_client() - used by clients to unregister to dce driver
+ * @client_id : ointer to client's data
+ *
+ * Return: 0 if no errors else corresponding error value.
+ */
+int tegra_dce_unregister_ipc_client(u32 handle);
+
+/*
+ * tegra_dce_client_ipc_send_recv() - used by clients to send rpcs to dce
+ * @client_id : client_id registered with dce driver
+ * @msg : message to be sent and received
+ *
+ * Return: 0 if no errors else corresponding error value.
+ */
+int tegra_dce_client_ipc_send_recv(u32 handle, struct dce_ipc_message *msg);
+
+#endif