[PATCH 1/3] drm/i915: Use GPLL ref clock to calculate GPU freqs on VLV/CHV

ville.syrjala
2016-03-04T19:43:10Z

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

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.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_reg.h | 1 +
drivers/gpu/drm/i915/intel_display.c | 19 ++++++---
drivers/gpu/drm/i915/intel_drv.h | 2 +
drivers/gpu/drm/i915/intel_pm.c | 74 +++++++++++++-----------------------
5 files changed, 44 insertions(+), 53 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f37ac120a29d..95f77cd0ce17 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1166,6 +1166,7 @@ struct intel_gen6_power_mgmt {
u8 efficient_freq; /* AKA RPe. Pre-determined balanced frequency */
u8 rp1_freq; /* "less than" RP0 power/freqency */
u8 rp0_freq; /* Non-overclocked max frequency. */
+ u16 gpll_ref_freq; /* vlv/chv GPLL reference frequency */

u8 up_threshold; /* Current %busy required to uplock */
u8 down_threshold; /* Current %busy required to downclock */
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 7dfc4007f3fa..aa21bfc06a24 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -785,6 +785,7 @@ enum skl_disp_power_wells {
#define DSI_PLL_M1_DIV_SHIFT 0
#define DSI_PLL_M1_DIV_MASK (0x1ff << 0)
#define CCK_CZ_CLOCK_CONTROL 0x62
+#define CCK_GPLL_CLOCK_CONTROL 0x67
#define CCK_DISPLAY_CLOCK_CONTROL 0x6b
#define CCK_DISPLAY_REF_CLOCK_CONTROL 0x6c
#define CCK_TRUNK_FORCE_ON (1 << 17)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 62d36a7b3398..ba50de534f9a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -147,15 +147,12 @@ static int valleyview_get_vco(struct drm_i915_private *dev_priv)
return vco_freq[hpll_freq] * 1000;
}

-static int vlv_get_cck_clock_hpll(struct drm_i915_private *dev_priv,
- const char *name, u32 reg)
+int vlv_get_cck_clock(struct drm_i915_private *dev_priv,
+ const char *name, u32 reg, int ref_freq)
{
u32 val;
int divider;

- if (dev_priv->hpll_freq == 0)
- dev_priv->hpll_freq = valleyview_get_vco(dev_priv);
-
mutex_lock(&dev_priv->sb_lock);
val = vlv_cck_read(dev_priv, reg);
mutex_unlock(&dev_priv->sb_lock);
@@ -166,7 +163,17 @@ static int vlv_get_cck_clock_hpll(struct drm_i915_private *dev_priv,
(divider << CCK_FREQUENCY_STATUS_SHIFT),
"%s change in progress\n", name);

- return DIV_ROUND_CLOSEST(dev_priv->hpll_freq << 1, divider + 1);
+ return DIV_ROUND_CLOSEST(ref_freq << 1, divider + 1);
+}
+
+static int vlv_get_cck_clock_hpll(struct drm_i915_private *dev_priv,
+ const char *name, u32 reg)
+{
+ if (dev_priv->hpll_freq == 0)
+ dev_priv->hpll_freq = valleyview_get_vco(dev_priv);
+
+ return vlv_get_cck_clock(dev_priv, name, reg,
+ dev_priv->hpll_freq);
}

static int
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index cd0b4eacbddf..c416f0adae48 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1116,6 +1116,8 @@ void i915_audio_component_init(struct drm_i915_private *dev_priv);
void i915_audio_component_cleanup(struct drm_i915_private *dev_priv);

/* intel_display.c */
+int vlv_get_cck_clock(struct drm_i915_private *dev_priv,
+ const char *name, u32 reg, int ref_freq);
extern const struct drm_plane_funcs intel_plane_funcs;
unsigned int intel_rotation_info_size(const struct intel_rotation_info *rot_info);
bool intel_has_pending_fb_unpin(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index f65e84137060..c53b8c4d381c 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5364,6 +5364,17 @@ static void valleyview_cleanup_pctx(struct drm_device *dev)
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;
@@ -5371,6 +5382,8 @@ static void valleyview_init_gt_powersave(struct drm_device *dev)

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);
@@ -5428,6 +5441,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)

cherryview_setup_pctx(dev);

+ vlv_init_gpll_ref_freq(dev_priv);
+
mutex_lock(&dev_priv->rps.hw_lock);

mutex_lock(&dev_priv->sb_lock);
@@ -7261,68 +7276,33 @@ int sandybridge_pcode_write(struct drm_i915_private *dev_priv, u32 mbox, u32 val
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 = CU2x / 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)
--
2.4.10