[PATCH v2 1/5] drm/ttm: add ttm_device_prepare_hibernation() api

[Samuel Zhang]

This new api is used for hibernation to move GTT BOs to shmem after
VRAM eviction. shmem will be flushed to swap disk later to reduce
the system memory usage for hibernation.

Signed-off-by: Samuel Zhang <guoqing.zhang at amd.com>
---
 drivers/gpu/drm/ttm/ttm_device.c | 29 +++++++++++++++++++++++++++++
 include/drm/ttm/ttm_device.h     |  1 +
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index 02e797fd1891..19ab35ffeead 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -123,6 +123,35 @@ static int ttm_global_init(void)
 	return ret;
 }
 
+/**
+ * move GTT BOs to shmem for hibernation.
+ *
+ * returns 0 on success, negative on failure.
+ */
+int ttm_device_prepare_hibernation(void)
+{
+	struct ttm_operation_ctx ctx = {
+		.interruptible = false,
+		.no_wait_gpu = false,
+		.force_alloc = true
+	};
+	struct ttm_global *glob = &ttm_glob;
+	struct ttm_device *bdev;
+	int ret = 0;
+
+	mutex_lock(&ttm_global_mutex);
+	list_for_each_entry(bdev, &glob->device_list, device_list) {
+		do {
+			ret = ttm_device_swapout(bdev, &ctx, GFP_KERNEL);
+		} while (ret > 0);
+		if (ret < 0)
+			break;
+	}
+	mutex_unlock(&ttm_global_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(ttm_device_prepare_hibernation);
+
 /*
  * A buffer object shrink method that tries to swap out the first
  * buffer object on the global::swap_lru list.
diff --git a/include/drm/ttm/ttm_device.h b/include/drm/ttm/ttm_device.h
index 39b8636b1845..b45498b398dd 100644
--- a/include/drm/ttm/ttm_device.h
+++ b/include/drm/ttm/ttm_device.h
@@ -272,6 +272,7 @@ struct ttm_device {
 int ttm_global_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags);
 int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 		       gfp_t gfp_flags);
+int ttm_device_prepare_hibernation(void);
 
 static inline struct ttm_resource_manager *
 ttm_manager_type(struct ttm_device *bdev, int mem_type)
-- 
2.43.5