gpu: nvgpu: Abstract threads

Add abstraction for threads. Implement them using kthreads in Linux kernel.

JIRA NVGPU-14

Change-Id: I26996d844db6bdc4b5e6f3230514a1dadb3fb07c
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1469636
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/Makefile.nvgpu

@@ -37,6 +37,7 @@ nvgpu-y := \
 	common/linux/soc.o \
 	common/linux/driver_common.o \
 	common/linux/firmware.o \
+	common/linux/thread.o \
 	common/mm/nvgpu_allocator.o \
 	common/mm/bitmap_allocator.o \
 	common/mm/buddy_allocator.o \

drivers/gpu/nvgpu/common/linux/thread.c

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2017, 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kthread.h>
+
+#include <nvgpu/thread.h>
+
+int nvgpu_thread_create(struct nvgpu_thread *thread,
+		void *data,
+		int (*threadfn)(void *data), const char *name)
+{
+	struct task_struct *task = kthread_create(threadfn, data, name);
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+
+	thread->task = task;
+	wake_up_process(task);
+	return 0;
+};
+
+void nvgpu_thread_stop(struct nvgpu_thread *thread)
+{
+	kthread_stop(thread->task);
+};
+
+bool nvgpu_thread_should_stop(struct nvgpu_thread *thread)
+{
+	return kthread_should_stop();
+};

drivers/gpu/nvgpu/include/nvgpu/linux/thread.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2017, 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __NVGPU_THREAD_LINUX_H__
+#define __NVGPU_THREAD_LINUX_H__
+
+struct task_struct;
+
+struct nvgpu_thread {
+	struct task_struct *task;
+};
+
+#endif /* __NVGPU_THREAD_LINUX_H__ */

drivers/gpu/nvgpu/include/nvgpu/thread.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2017, 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __NVGPU_THREAD_H__
+#define __NVGPU_THREAD_H__
+
+#ifdef __KERNEL__
+#include <nvgpu/linux/thread.h>
+#endif
+
+/**
+ * nvgpu_thread_create - Create and run a new thread.
+ *
+ * @thread - thread structure to use
+ * @data - data to pass to threadfn
+ * @threadfn - Thread function
+ * @name - name of the thread
+ *
+ * Create a thread and run threadfn in it. The thread stays alive as long as
+ * threadfn is running. As soon as threadfn returns the thread is destroyed.
+ *
+ * threadfn needs to continuously poll nvgpu_thread_should_stop() to determine
+ * if it should exit.
+ */
+int nvgpu_thread_create(struct nvgpu_thread *thread,
+		void *data,
+		int (*threadfn)(void *data), const char *name);
+
+/**
+ * nvgpu_thread_stop - Destroy or request to destroy a thread
+ *
+ * @thread - thread to stop
+ *
+ * Request a thread to stop by setting nvgpu_thread_should_stop() to
+ * true and wait for thread to exit.
+ */
+void nvgpu_thread_stop(struct nvgpu_thread *thread);
+
+/**
+ * nvgpu_thread_should_stop - Query if thread should stop
+ *
+ * @thread
+ *
+ * Return true if thread should exit. Can be run only in the thread's own
+ * context and with the thread as parameter.
+ */
+bool nvgpu_thread_should_stop(struct nvgpu_thread *thread);
+
+#endif /* __NVGPU_THREAD_H__ */