drm/i915: Use GPLL ref clock to calculate GPU freqs on VLV/CHV
Extract the GPLL reference frequency from CCK and use it in the
GPU freq<->opcode conversions on VLV/CHV. This eliminates all the
assumptions we have about which divider is used for which czclk
frequency.
Note that unlike most clocks from CCK, the GPLL ref clock is a divided
down version of the CZ clock rather than the HPLL clock. CZ clock itself
is a divided down version of the HPLL clock though, so in effect it just
gets divided down twice.
While at it, throw in a few comments explaining the remaining constants
for anyone who later wants to compare this to the spreadsheets.
v2: Add slow/fast notes for CHV clocks (Imre)
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1457120584-26080-2-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com> (v1)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 9bc9c25..6420776 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5366,6 +5366,17 @@
dev_priv->vlv_pctx = NULL;
}
+static void vlv_init_gpll_ref_freq(struct drm_i915_private *dev_priv)
+{
+ dev_priv->rps.gpll_ref_freq =
+ vlv_get_cck_clock(dev_priv, "GPLL ref",
+ CCK_GPLL_CLOCK_CONTROL,
+ dev_priv->czclk_freq);
+
+ DRM_DEBUG_DRIVER("GPLL reference freq: %d kHz\n",
+ dev_priv->rps.gpll_ref_freq);
+}
+
static void valleyview_init_gt_powersave(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -5373,6 +5384,8 @@
valleyview_setup_pctx(dev);
+ vlv_init_gpll_ref_freq(dev_priv);
+
mutex_lock(&dev_priv->rps.hw_lock);
val = vlv_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS);
@@ -5430,6 +5443,8 @@
cherryview_setup_pctx(dev);
+ vlv_init_gpll_ref_freq(dev_priv);
+
mutex_lock(&dev_priv->rps.hw_lock);
mutex_lock(&dev_priv->sb_lock);
@@ -7280,68 +7295,33 @@
return 0;
}
-static int vlv_gpu_freq_div(unsigned int czclk_freq)
-{
- switch (czclk_freq) {
- case 200:
- return 10;
- case 267:
- return 12;
- case 320:
- case 333:
- return 16;
- case 400:
- return 20;
- default:
- return -1;
- }
-}
-
static int byt_gpu_freq(struct drm_i915_private *dev_priv, int val)
{
- int div, czclk_freq = DIV_ROUND_CLOSEST(dev_priv->czclk_freq, 1000);
-
- div = vlv_gpu_freq_div(czclk_freq);
- if (div < 0)
- return div;
-
- return DIV_ROUND_CLOSEST(czclk_freq * (val + 6 - 0xbd), div);
+ /*
+ * N = val - 0xb7
+ * Slow = Fast = GPLL ref * N
+ */
+ return DIV_ROUND_CLOSEST(dev_priv->rps.gpll_ref_freq * (val - 0xb7), 1000);
}
static int byt_freq_opcode(struct drm_i915_private *dev_priv, int val)
{
- int mul, czclk_freq = DIV_ROUND_CLOSEST(dev_priv->czclk_freq, 1000);
-
- mul = vlv_gpu_freq_div(czclk_freq);
- if (mul < 0)
- return mul;
-
- return DIV_ROUND_CLOSEST(mul * val, czclk_freq) + 0xbd - 6;
+ return DIV_ROUND_CLOSEST(1000 * val, dev_priv->rps.gpll_ref_freq) + 0xb7;
}
static int chv_gpu_freq(struct drm_i915_private *dev_priv, int val)
{
- int div, czclk_freq = DIV_ROUND_CLOSEST(dev_priv->czclk_freq, 1000);
-
- div = vlv_gpu_freq_div(czclk_freq);
- if (div < 0)
- return div;
- div /= 2;
-
- return DIV_ROUND_CLOSEST(czclk_freq * val, 2 * div) / 2;
+ /*
+ * N = val / 2
+ * CU (slow) = CU2x (fast) / 2 = GPLL ref * N / 2
+ */
+ return DIV_ROUND_CLOSEST(dev_priv->rps.gpll_ref_freq * val, 2 * 2 * 1000);
}
static int chv_freq_opcode(struct drm_i915_private *dev_priv, int val)
{
- int mul, czclk_freq = DIV_ROUND_CLOSEST(dev_priv->czclk_freq, 1000);
-
- mul = vlv_gpu_freq_div(czclk_freq);
- if (mul < 0)
- return mul;
- mul /= 2;
-
/* CHV needs even values */
- return DIV_ROUND_CLOSEST(val * 2 * mul, czclk_freq) * 2;
+ return DIV_ROUND_CLOSEST(2 * 1000 * val, dev_priv->rps.gpll_ref_freq) * 2;
}
int intel_gpu_freq(struct drm_i915_private *dev_priv, int val)