nvsched: Initial core data

Add software scheduler and domain data structures for a general
scheduler and bookkeeping code to create, remove and list them and to
keep logs for debugging and development; as a first step, this will only
serve as the heart of nvgpu-internal domain scheduler.

Long term, this code is intended to work in arbitrary configurations -
running on GSP, CPU, or elsewhere, and controlling the GPU or something
else.

Jira NVGPU-6427

Change-Id: I2a1577fa9120bb8ae6b9552dd2a187cb2cdfe504
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Signed-off-by: Konsta Hölttä <kholtta@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2632286
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

nvsched/include/nvs/log.h

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2021 NVIDIA Corporation.  All rights reserved.
+ *
+ * NVIDIA Corporation and its licensors retain all intellectual property
+ * and proprietary rights in and to this software, related documentation
+ * and any modifications thereto.  Any use, reproduction, disclosure or
+ * distribution of this software and related documentation without an express
+ * license agreement from NVIDIA Corporation is strictly prohibited.
+ */
+
+#ifndef NVS_LOG_H
+#define NVS_LOG_H
+
+#include <nvs/types-internal.h>
+
+/*
+ * Default log size; 64K entries at 8 bytes each is 512Kb of space. For a space
+ * constrained system this is obviously a lot. It can be overridden.
+ */
+#ifndef NVS_LOG_ENTRIES
+#define NVS_LOG_ENTRIES		(64 * 1024)
+#endif
+
+/*
+ * Fast and efficient logging, even on microcontrollers, is an absolute
+ * must for nvsched. The logging provided here is binary encoded to take up
+ * a small amount of space and reduce time spent writing the logs.
+ *
+ * An implementation of nvsched should decode the logs later, when not in
+ * a time critical path. The event type can be decoded with nvs_log_event_string().
+ */
+enum nvs_event {
+	NVS_EV_NO_EVENT,
+	NVS_EV_CREATE_SCHED,
+	NVS_EV_CREATE_DOMAIN,
+	NVS_EV_REMOVE_DOMAIN,
+	NVS_EV_MAX = 0xffffffff /* Force to 32 bit enum size. */
+};
+
+struct nvs_sched;
+
+/**
+ * @brief A single log event used to track event type, timestamp, etc. Note this
+ * is 8 byte aligned.
+ */
+struct nvs_log_event {
+	u64		timestamp;
+	u32		data;
+	enum nvs_event	event;
+};
+
+/**
+ * Simple circular buffer for putting and getting events.
+ */
+struct nvs_log_buffer {
+	struct nvs_log_event	*events;
+	u32			 entries;
+
+	u32			 get;
+	u32			 put;
+
+	u64			 ts_offset;
+};
+
+int  nvs_log_init(struct nvs_sched *sched);
+void nvs_log_destroy(struct nvs_sched *sched);
+void nvs_log_event(struct nvs_sched *sched, enum nvs_event event, u32 data);
+void nvs_log_get(struct nvs_sched *sched, struct nvs_log_event *ev);
+const char *nvs_log_event_string(enum nvs_event ev);
+
+#endif