drm/amdgpu: add new cgs interface to get display info (v2)

BugLink: http://bugs.launchpad.net/bugs/1546572

Add new CGS interfaces to query display info across modules.
This is nedded by the powerplay module for synchronizing with
the display module.

v2: (agd): fold in refresh rate fix, rebase
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 47bf18b5)
Signed-off-by: Alberto Milone <alberto.milone@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

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

@@ -758,6 +758,45 @@ static int amdgpu_cgs_query_system_info(void *cgs_device,
 	return 0;
 }
 
+static int amdgpu_cgs_get_active_displays_info(void *cgs_device,
+					  struct cgs_display_info *info)
+{
+	CGS_FUNC_ADEV;
+	struct amdgpu_crtc *amdgpu_crtc;
+	struct drm_device *ddev = adev->ddev;
+	struct drm_crtc *crtc;
+	uint32_t line_time_us, vblank_lines;
+
+	if (info == NULL)
+		return -EINVAL;
+
+	if (adev->mode_info.num_crtc && adev->mode_info.mode_config_initialized) {
+		list_for_each_entry(crtc,
+				&ddev->mode_config.crtc_list, head) {
+			amdgpu_crtc = to_amdgpu_crtc(crtc);
+			if (crtc->enabled) {
+				info->active_display_mask |= (1 << amdgpu_crtc->crtc_id);
+				info->display_count++;
+			}
+			if (info->mode_info != NULL &&
+				crtc->enabled && amdgpu_crtc->enabled &&
+				amdgpu_crtc->hw_mode.clock) {
+				line_time_us = (amdgpu_crtc->hw_mode.crtc_htotal * 1000) /
+							amdgpu_crtc->hw_mode.clock;
+				vblank_lines = amdgpu_crtc->hw_mode.crtc_vblank_end -
+							amdgpu_crtc->hw_mode.crtc_vdisplay +
+							(amdgpu_crtc->v_border * 2);
+				info->mode_info->vblank_time_us = vblank_lines * line_time_us;
+				info->mode_info->refresh_rate = drm_mode_vrefresh(&amdgpu_crtc->hw_mode);
+				info->mode_info->ref_clock = adev->clock.spll.reference_freq;
+				info->mode_info++;
+			}
+		}
+	}
+
+	return 0;
+}
+
 /** \brief evaluate acpi namespace object, handle or pathname must be valid
  *  \param cgs_device
  *  \param info input/output arguments for the control method
@@ -1006,6 +1045,7 @@ static const struct cgs_ops amdgpu_cgs_ops = {
 	amdgpu_cgs_get_firmware_info,
 	amdgpu_cgs_set_powergating_state,
 	amdgpu_cgs_set_clockgating_state,
+	amdgpu_cgs_get_active_displays_info,
 	amdgpu_cgs_call_acpi_method,
 	amdgpu_cgs_query_system_info,
 };

drivers/gpu/drm/amd/include/cgs_common.h

@@ -142,6 +142,18 @@ struct cgs_firmware_info {
 	void			*kptr;
 };
 
+struct cgs_mode_info {
+	uint32_t		refresh_rate;
+	uint32_t		ref_clock;
+	uint32_t		vblank_time_us;
+};
+
+struct cgs_display_info {
+	uint32_t		display_count;
+	uint32_t		active_display_mask;
+	struct cgs_mode_info *mode_info;
+};
+
 typedef unsigned long cgs_handle_t;
 
 #define CGS_ACPI_METHOD_ATCS          0x53435441
@@ -541,6 +553,10 @@ typedef int(*cgs_set_clockgating_state)(void *cgs_device,
 				  enum amd_ip_block_type block_type,
 				  enum amd_clockgating_state state);
 
+typedef int(*cgs_get_active_displays_info)(
+					void *cgs_device,
+					struct cgs_display_info *info);
+
 typedef int (*cgs_call_acpi_method)(void *cgs_device,
 					uint32_t acpi_method,
 					uint32_t acpi_function,
@@ -592,6 +608,8 @@ struct cgs_ops {
 	/* cg pg interface*/
 	cgs_set_powergating_state set_powergating_state;
 	cgs_set_clockgating_state set_clockgating_state;
+	/* display manager */
+	cgs_get_active_displays_info get_active_displays_info;
 	/* ACPI */
 	cgs_call_acpi_method call_acpi_method;
 	/* get system info */
@@ -682,6 +700,8 @@ struct cgs_device
 	CGS_CALL(set_powergating_state, dev, block_type, state)
 #define cgs_set_clockgating_state(dev, block_type, state)	\
 	CGS_CALL(set_clockgating_state, dev, block_type, state)
+#define cgs_get_active_displays_info(dev, info)	\
+	CGS_CALL(get_active_displays_info, dev, info)
 #define cgs_call_acpi_method(dev, acpi_method, acpi_function, pintput, poutput, output_count, input_size, output_size)	\
 	CGS_CALL(call_acpi_method, dev, acpi_method, acpi_function, pintput, poutput, output_count, input_size, output_size)
 #define cgs_query_system_info(dev, sys_info)	\