drm/amdgpu: Use software timer to generate vsync interrupt.

For virtual display feature, use the software timer to
simulate the vsync interrupt.
Signed-off-by: Emily Deng <Emily.Deng@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h

@@ -39,6 +39,8 @@
 #include <drm/drm_plane_helper.h>
 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>
+#include <linux/hrtimer.h>
+#include "amdgpu_irq.h"
 
 struct amdgpu_bo;
 struct amdgpu_device;
@@ -339,6 +341,8 @@ struct amdgpu_mode_info {
 	int			num_dig; /* number of dig blocks */
 	int			disp_priority;
 	const struct amdgpu_display_funcs *funcs;
+	struct hrtimer vblank_timer;
+	enum amdgpu_interrupt_state vsync_timer_enabled;
 };
 
 #define AMDGPU_MAX_BL_LEVEL 0xFF

drivers/gpu/drm/amd/amdgpu/dce_virtual.c

@@ -32,6 +32,7 @@
 #endif
 #include "dce_v10_0.h"
 #include "dce_v11_0.h"
+#include "dce_virtual.h"
 
 static void dce_virtual_set_display_funcs(struct amdgpu_device *adev);
 static void dce_virtual_set_irq_funcs(struct amdgpu_device *adev);
@@ -642,16 +643,44 @@ static void dce_virtual_set_display_funcs(struct amdgpu_device *adev)
 		adev->mode_info.funcs = &dce_virtual_display_funcs;
 }
 
+static enum hrtimer_restart dce_virtual_vblank_timer_handle(struct hrtimer *vblank_timer)
+{
+	struct amdgpu_mode_info *mode_info = container_of(vblank_timer, struct amdgpu_mode_info ,vblank_timer);
+	struct amdgpu_device *adev = container_of(mode_info, struct amdgpu_device ,mode_info);
+	unsigned crtc = 0;
+	adev->ddev->vblank[0].count++;
+	drm_handle_vblank(adev->ddev, crtc);
+	hrtimer_start(vblank_timer, ktime_set(0, DCE_VIRTUAL_VBLANK_PERIOD), HRTIMER_MODE_REL);
+	return HRTIMER_NORESTART;
+}
+
 static void dce_virtual_set_crtc_vblank_interrupt_state(struct amdgpu_device *adev,
-                                                    int crtc,
-                                                    enum amdgpu_interrupt_state state)
+						     int crtc,
+						     enum amdgpu_interrupt_state state)
 {
 	if (crtc >= adev->mode_info.num_crtc) {
 		DRM_DEBUG("invalid crtc %d\n", crtc);
 		return;
 	}
+
+	if (state && !adev->mode_info.vsync_timer_enabled) {
+		DRM_DEBUG("Enable software vsync timer\n");
+		hrtimer_init(&adev->mode_info.vblank_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+		hrtimer_set_expires(&adev->mode_info.vblank_timer, ktime_set(0, DCE_VIRTUAL_VBLANK_PERIOD));
+		adev->mode_info.vblank_timer.function = dce_virtual_vblank_timer_handle;
+		hrtimer_start(&adev->mode_info.vblank_timer, ktime_set(0, DCE_VIRTUAL_VBLANK_PERIOD), HRTIMER_MODE_REL);
+	} else if (!state && adev->mode_info.vsync_timer_enabled) {
+		DRM_DEBUG("Disable software vsync timer\n");
+		hrtimer_cancel(&adev->mode_info.vblank_timer);
+	}
+
+	if (!state || (state && !adev->mode_info.vsync_timer_enabled))
+		adev->ddev->vblank[0].count = 0;
+	adev->mode_info.vsync_timer_enabled = state;
+	DRM_DEBUG("[FM]set crtc %d vblank interrupt state %d\n", crtc, state);
 }
 
+
 static int dce_virtual_set_crtc_irq_state(struct amdgpu_device *adev,
                                        struct amdgpu_irq_src *source,
                                        unsigned type,

drivers/gpu/drm/amd/amdgpu/dce_virtual.h

@@ -25,5 +25,7 @@
 #define __DCE_VIRTUAL_H__
 
 extern const struct amd_ip_funcs dce_virtual_ip_funcs;
+#define DCE_VIRTUAL_VBLANK_PERIOD 16666666
+
 #endif