[Intel-gfx] [PATCH v2 3/4] drm/i915: fix 64bit divide

[Lionel Landwerlin]

ERROR: "__udivdi3" [drivers/gpu/drm/i915/i915.ko] undefined!
ERROR: "__divdi3" [drivers/gpu/drm/i915/i915.ko] undefined!

We can also drop an if() as we divide by (value + 1) only if value is
not 0.

Fixes: dab9178333 ("drm/i915: expose command stream timestamp frequency to userspace")
Reported-by: Matthew Auld <matthew.auld at intel.com>
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
---
 drivers/gpu/drm/i915/intel_device_info.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
index 78bf7374fbdd..992ae1bdfb3b 100644
--- a/drivers/gpu/drm/i915/intel_device_info.c
+++ b/drivers/gpu/drm/i915/intel_device_info.c
@@ -336,13 +336,12 @@ static u64 read_reference_ts_freq(struct drm_i915_private *dev_priv)
 
 	base_freq = ((ts_override & GEN9_TIMESTAMP_OVERRIDE_US_COUNTER_DIVIDER_MASK) >>
 		     GEN9_TIMESTAMP_OVERRIDE_US_COUNTER_DIVIDER_SHIFT) + 1;
-	base_freq *= 1000000;
+	base_freq *= 1000000ULL;
 
 	frac_freq = ((ts_override &
 		      GEN9_TIMESTAMP_OVERRIDE_US_COUNTER_DENOMINATOR_MASK) >>
 		     GEN9_TIMESTAMP_OVERRIDE_US_COUNTER_DENOMINATOR_SHIFT);
-	if (frac_freq != 0)
-		frac_freq = 1000000 / (frac_freq + 1);
+	frac_freq = div_u64(1000000ULL, frac_freq + 1);
 
 	return base_freq + frac_freq;
 }
@@ -360,7 +359,7 @@ static u64 read_timestamp_frequency(struct drm_i915_private *dev_priv)
 		 *      hclks." (through the “Clocking Configuration”
 		 *      (“CLKCFG”) MCHBAR register)
 		 */
-		return (dev_priv->rawclk_freq * 1000) / 16;
+		return div_u64(dev_priv->rawclk_freq * 1000ULL, 16);
 	} else if (INTEL_GEN(dev_priv) <= 8) {
 		/* PRMs say:
 		 *
-- 
2.15.0