drm/radeon/kms: add support for semaphores v3

They are used to sync between rings, while fences
sync between a ring and the cpu.

v2 Fix radeon_semaphore_driver_fini when no semaphore were
allocated.

v3 Initialize list early on to avoid issue in case or early
error

Signed-off-by: Christian König <deathsimple@vodafone.de>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_semaphore.c b/drivers/gpu/drm/radeon/radeon_semaphore.c
new file mode 100644
index 0000000..f7d3104
--- /dev/null
+++ b/drivers/gpu/drm/radeon/radeon_semaphore.c
@@ -0,0 +1,161 @@
+/*
+ * Copyright 2011 Christian König.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ */
+/*
+ * Authors:
+ *    Christian König <deathsimple@vodafone.de>
+ */
+#include "drmP.h"
+#include "drm.h"
+#include "radeon.h"
+
+static int allocate_semaphores(struct radeon_device *rdev)
+{
+	const unsigned long bo_size = PAGE_SIZE * 4;
+
+	struct radeon_bo *bo;
+	struct list_head new_entrys;
+	unsigned long irq_flags;
+	uint64_t gpu_addr;
+	void *map;
+	int i, r;
+
+	r = radeon_bo_create(rdev, bo_size, RADEON_GPU_PAGE_SIZE, true,
+			     RADEON_GEM_DOMAIN_GTT, &bo);
+	if (r) {
+		dev_err(rdev->dev, "(%d) failed to allocate semaphore bo\n", r);
+		return r;
+	}
+
+	r = radeon_bo_reserve(bo, false);
+	if (r) {
+		radeon_bo_unref(&bo);
+		dev_err(rdev->dev, "(%d) failed to reserve semaphore bo\n", r);
+		return r;
+	}
+
+	r = radeon_bo_kmap(bo, &map);
+	if (r) {
+		radeon_bo_unreserve(bo);
+		radeon_bo_unref(&bo);
+		dev_err(rdev->dev, "(%d) semaphore map failed\n", r);
+		return r;
+	}
+	memset(map, 0, bo_size);
+	radeon_bo_kunmap(bo);
+
+	r = radeon_bo_pin(bo, RADEON_GEM_DOMAIN_VRAM, &gpu_addr);
+	if (r) {
+		radeon_bo_unreserve(bo);
+		radeon_bo_unref(&bo);
+		dev_err(rdev->dev, "(%d) semaphore pin failed\n", r);
+		return r;
+	}
+
+	INIT_LIST_HEAD(&new_entrys);
+	for (i = 0; i < bo_size/8; ++i) {
+		struct radeon_semaphore *sem = kmalloc(sizeof(struct radeon_semaphore), GFP_KERNEL);
+		ttm_bo_reference(&bo->tbo);
+		sem->robj = bo;
+		sem->gpu_addr = gpu_addr;
+		gpu_addr += 8;
+		list_add_tail(&sem->list, &new_entrys);
+	}
+
+	radeon_bo_unreserve(bo);
+	radeon_bo_unref(&bo);
+
+	write_lock_irqsave(&rdev->semaphore_drv.lock, irq_flags);
+	list_splice_tail(&new_entrys, &rdev->semaphore_drv.free);
+	write_unlock_irqrestore(&rdev->semaphore_drv.lock, irq_flags);
+
+	DRM_INFO("%d new semaphores allocated\n", (int)(bo_size/8));
+
+	return 0;
+}
+
+int radeon_semaphore_create(struct radeon_device *rdev,
+			    struct radeon_semaphore **semaphore)
+{
+	unsigned long irq_flags;
+
+	write_lock_irqsave(&rdev->semaphore_drv.lock, irq_flags);
+	if (list_empty(&rdev->semaphore_drv.free)) {
+		int r;
+		write_unlock_irqrestore(&rdev->semaphore_drv.lock, irq_flags);
+		r = allocate_semaphores(rdev);
+		if (r)
+			return r;
+		write_lock_irqsave(&rdev->semaphore_drv.lock, irq_flags);
+	}
+
+	*semaphore = list_first_entry(&rdev->semaphore_drv.free, struct radeon_semaphore, list);
+	list_del(&(*semaphore)->list);
+
+	write_unlock_irqrestore(&rdev->semaphore_drv.lock, irq_flags);
+	return 0;
+}
+
+void radeon_semaphore_emit_signal(struct radeon_device *rdev, int ring,
+			          struct radeon_semaphore *semaphore)
+{
+	radeon_semaphore_ring_emit(rdev, semaphore, ring, false);
+}
+
+void radeon_semaphore_emit_wait(struct radeon_device *rdev, int ring,
+			        struct radeon_semaphore *semaphore)
+{
+	radeon_semaphore_ring_emit(rdev, semaphore, ring, true);
+}
+
+void radeon_semaphore_free(struct radeon_device *rdev,
+			  struct radeon_semaphore *semaphore)
+{
+	unsigned long irq_flags;
+
+	write_lock_irqsave(&rdev->semaphore_drv.lock, irq_flags);
+	list_add_tail(&semaphore->list, &rdev->semaphore_drv.free);
+	write_unlock_irqrestore(&rdev->semaphore_drv.lock, irq_flags);
+}
+
+void radeon_semaphore_driver_fini(struct radeon_device *rdev)
+{
+	struct radeon_semaphore *i, *n;
+	struct list_head entrys;
+	unsigned long irq_flags;
+
+	INIT_LIST_HEAD(&entrys);
+	write_lock_irqsave(&rdev->semaphore_drv.lock, irq_flags);
+	if (!list_empty(&rdev->semaphore_drv.free)) {
+		list_splice(&rdev->semaphore_drv.free, &entrys);
+	}
+	INIT_LIST_HEAD(&rdev->semaphore_drv.free);
+	write_unlock_irqrestore(&rdev->semaphore_drv.lock, irq_flags);
+
+	list_for_each_entry_safe(i, n, &entrys, list) {
+		radeon_bo_unref(&i->robj);
+		kfree(i);
+	}
+}