drm/radeon: Fix "slow" audio over DP on DCE8+

DP audio is derived from the dfs clock.
Signed-off-by: Slava Grigorev <slava.grigorev@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/radeon/dce6_afmt.c

@@ -301,6 +301,22 @@ void dce6_dp_audio_set_dto(struct radeon_device *rdev,
 	 * is the numerator, DCCG_AUDIO_DTOx_MODULE is the denominator
 	 */
 	if (ASIC_IS_DCE8(rdev)) {
+		unsigned int div = (RREG32(DENTIST_DISPCLK_CNTL) &
+			DENTIST_DPREFCLK_WDIVIDER_MASK) >>
+			DENTIST_DPREFCLK_WDIVIDER_SHIFT;
+
+		if (div < 128 && div >= 96)
+			div -= 64;
+		else if (div >= 64)
+			div = div / 2 - 16;
+		else if (div >= 8)
+			div /= 4;
+		else
+			div = 0;
+
+		if (div)
+			clock = rdev->clock.gpupll_outputfreq * 10 / div;
+
 		WREG32(DCE8_DCCG_AUDIO_DTO1_PHASE, 24000);
 		WREG32(DCE8_DCCG_AUDIO_DTO1_MODULE, clock);
 	} else {

drivers/gpu/drm/radeon/radeon.h

@@ -268,6 +268,7 @@ struct radeon_clock {
 	uint32_t current_dispclk;
 	uint32_t dp_extclk;
 	uint32_t max_pixel_clock;
+	uint32_t gpupll_outputfreq;
 };
 
 /*

drivers/gpu/drm/radeon/radeon_atombios.c

@@ -1263,6 +1263,13 @@ bool radeon_atom_get_clock_info(struct drm_device *dev)
 		rdev->mode_info.firmware_flags =
 			le16_to_cpu(firmware_info->info.usFirmwareCapability.susAccess);
 
+		if (ASIC_IS_DCE8(rdev)) {
+			rdev->clock.gpupll_outputfreq =
+				le32_to_cpu(firmware_info->info_22.ulGPUPLL_OutputFreq);
+			if (rdev->clock.gpupll_outputfreq == 0)
+				rdev->clock.gpupll_outputfreq = 360000;	/* 3.6 GHz */
+		}
+
 		return true;
 	}
 

drivers/gpu/drm/radeon/sid.h

@@ -915,6 +915,11 @@
 #define DCCG_AUDIO_DTO1_PHASE                           0x05c0
 #define DCCG_AUDIO_DTO1_MODULE                          0x05c4
 
+#define DENTIST_DISPCLK_CNTL				0x0490
+#	define DENTIST_DPREFCLK_WDIVIDER(x)		(((x) & 0x7f) << 24)
+#	define DENTIST_DPREFCLK_WDIVIDER_MASK		(0x7f << 24)
+#	define DENTIST_DPREFCLK_WDIVIDER_SHIFT		24
+
 #define AFMT_AUDIO_SRC_CONTROL                          0x713c
 #define		AFMT_AUDIO_SRC_SELECT(x)		(((x) & 7) << 0)
 /* AFMT_AUDIO_SRC_SELECT