[PATCH] drm/amdgpu/gfx11: update gpu_clock_counter logic

[Alex Deucher]

This code was written prior to previous updates to this
logic for other chips.  The RSC registers are part of
SMUIO which is an always on block so there is no need
to disable gfxoff.  Additionally add the carryover and
preemption checks.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
index ecf8ceb53311..c222b943eb65 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
@@ -4670,14 +4670,22 @@ static int gfx_v11_0_post_soft_reset(void *handle)
 
 static uint64_t gfx_v11_0_get_gpu_clock_counter(struct amdgpu_device *adev)
 {
-	uint64_t clock;
+	uint64_t clock, clock_lo, clock_hi, hi_check;
+
+	preempt_disable();
+	clock_hi = RREG32_SOC15(SMUIO, 0, regGOLDEN_TSC_COUNT_UPPER);
+	clock_lo = RREG32_SOC15(SMUIO, 0, regGOLDEN_TSC_COUNT_LOWER);
+	hi_check = RREG32_SOC15(SMUIO, 0, regGOLDEN_TSC_COUNT_UPPER);
+	/* The SMUIO TSC clock frequency is 100MHz, which sets 32-bit carry over
+	 * roughly every 42 seconds.
+	 */
+	if (hi_check != clock_hi) {
+		clock_lo = RREG32_SOC15(SMUIO, 0, regGOLDEN_TSC_COUNT_LOWER);
+		clock_hi = hi_check;
+	}
+	preempt_enable();
+	clock = clock_lo | (clock_hi << 32ULL);
 
-	amdgpu_gfx_off_ctrl(adev, false);
-	mutex_lock(&adev->gfx.gpu_clock_mutex);
-	clock = (uint64_t)RREG32_SOC15(SMUIO, 0, regGOLDEN_TSC_COUNT_LOWER) |
-		((uint64_t)RREG32_SOC15(SMUIO, 0, regGOLDEN_TSC_COUNT_UPPER) << 32ULL);
-	mutex_unlock(&adev->gfx.gpu_clock_mutex);
-	amdgpu_gfx_off_ctrl(adev, true);
 	return clock;
 }
 
-- 
2.39.2