[Intel-gfx] [PATCH 2/3] drm/i915/display: Do both crawl and squash when changing cdclk
Anusha Srivatsa
anusha.srivatsa at intel.com
Thu Nov 17 23:00:01 UTC 2022
From: Ville Syrjälä <ville.syrjala at linux.intel.com>
For MTL, changing cdclk from between certain frequencies has
both squash and crawl. Use the current cdclk config and
the new(desired) cdclk config to construtc a mid cdclk config.
Set the cdclk twice:
- Current cdclk -> mid cdclk
- mid cdclk -> desired cdclk
Driver should not take some Pcode mailbox communication
in the cdclk path for platforms that are Display version 14 and later.
v2: Add check in intel_modeset_calc_cdclk() to avoid cdclk
change via modeset for platforms that support squash_crawl sequences(Ville)
v3: Add checks for:
- scenario where only slow clock is used and
cdclk is actually 0 (bringing up display).
- PLLs are on before looking up the waveform.
- Squash and crawl capability checks.(Ville)
v4: Rebase
- Move checks to be more consistent (Ville)
- Add comments (Bala)
v5:
- Further small changes. Move checks around.
- Make if-else better looking (Ville)
v6: MTl should not follow PUnit mailbox communication as the rest of
gen11+ platforms.(Anusha)
Cc: Clint Taylor <Clinton.A.Taylor at intel.com>
Cc: Balasubramani Vivekanandan <balasubramani.vivekanandan at intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
drivers/gpu/drm/i915/display/intel_cdclk.c | 181 +++++++++++++++++----
1 file changed, 150 insertions(+), 31 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 25d01271dc09..1280a08b9c72 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -1727,37 +1727,79 @@ static bool cdclk_pll_is_unknown(unsigned int vco)
return vco == ~0;
}
-static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
- const struct intel_cdclk_config *cdclk_config,
- enum pipe pipe)
+static int cdclk_squash_divider(u16 waveform)
+{
+ return hweight16(waveform ?: 0xffff);
+}
+
+static bool cdclk_compute_crawl_and_squash_midpoint(struct drm_i915_private *i915,
+ const struct intel_cdclk_config *old_cdclk_config,
+ const struct intel_cdclk_config *new_cdclk_config,
+ struct intel_cdclk_config *mid_cdclk_config)
+{
+ u16 old_waveform, new_waveform, mid_waveform;
+ int size = 16;
+ int div = 2;
+
+ /* Return for vco ~0 (-1) and follow complete PLL disable and enable */
+ if (cdclk_pll_is_unknown(old_cdclk_config->vco))
+ return false;
+
+ /* Return if both Squash and Crawl are not present */
+ if (!HAS_CDCLK_CRAWL(i915) || !HAS_CDCLK_SQUASH(i915))
+ return false;
+
+ old_waveform = cdclk_squash_waveform(i915, old_cdclk_config->cdclk);
+ new_waveform = cdclk_squash_waveform(i915, new_cdclk_config->cdclk);
+
+ /* Return if Squash only or Crawl only is the desired action */
+ if (old_cdclk_config->vco == 0 || new_cdclk_config->vco == 0 ||
+ old_cdclk_config->vco == new_cdclk_config->vco ||
+ old_waveform == new_waveform)
+ return false;
+
+ *mid_cdclk_config = *new_cdclk_config;
+
+ /*
+ * Populate the mid_cdclk_config accordingly.
+ * - If moving to a higher cdclk, the desired action is squashing.
+ * The mid cdclk config should have the new (squash) waveform.
+ * - If moving to a lower cdclk, the desired action is crawling.
+ * The mid cdclk config should have the new vco.
+ */
+
+ if (cdclk_squash_divider(new_waveform) > cdclk_squash_divider(old_waveform)) {
+ mid_cdclk_config->vco = old_cdclk_config->vco;
+ mid_waveform = new_waveform;
+ } else {
+ mid_cdclk_config->vco = new_cdclk_config->vco;
+ mid_waveform = old_waveform;
+ }
+
+ mid_cdclk_config->cdclk = DIV_ROUND_CLOSEST(cdclk_squash_divider(mid_waveform) *
+ mid_cdclk_config->vco, size * div);
+
+ /* make sure the mid clock came out sane */
+
+ drm_WARN_ON(&i915->drm, mid_cdclk_config->cdclk <
+ min(old_cdclk_config->cdclk, new_cdclk_config->cdclk));
+ drm_WARN_ON(&i915->drm, mid_cdclk_config->cdclk >
+ i915->display.cdclk.max_cdclk_freq);
+ drm_WARN_ON(&i915->drm, cdclk_squash_waveform(i915, mid_cdclk_config->cdclk) !=
+ mid_waveform);
+
+ return true;
+}
+
+static void _bxt_set_cdclk(struct drm_i915_private *dev_priv,
+ const struct intel_cdclk_config *cdclk_config,
+ enum pipe pipe)
{
int cdclk = cdclk_config->cdclk;
int vco = cdclk_config->vco;
u32 val;
u16 waveform;
int clock;
- int ret;
-
- /* Inform power controller of upcoming frequency change. */
- if (DISPLAY_VER(dev_priv) >= 11)
- ret = skl_pcode_request(&dev_priv->uncore, SKL_PCODE_CDCLK_CONTROL,
- SKL_CDCLK_PREPARE_FOR_CHANGE,
- SKL_CDCLK_READY_FOR_CHANGE,
- SKL_CDCLK_READY_FOR_CHANGE, 3);
- else
- /*
- * BSpec requires us to wait up to 150usec, but that leads to
- * timeouts; the 2ms used here is based on experiment.
- */
- ret = snb_pcode_write_timeout(&dev_priv->uncore,
- HSW_PCODE_DE_WRITE_FREQ_REQ,
- 0x80000000, 150, 2);
- if (ret) {
- drm_err(&dev_priv->drm,
- "Failed to inform PCU about cdclk change (err %d, freq %d)\n",
- ret, cdclk);
- return;
- }
if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 && vco > 0 &&
!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco)) {
@@ -1793,11 +1835,62 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
if (pipe != INVALID_PIPE)
intel_crtc_wait_for_next_vblank(intel_crtc_for_pipe(dev_priv, pipe));
+}
+
+static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
+ const struct intel_cdclk_config *cdclk_config,
+ enum pipe pipe)
+{
+ struct intel_cdclk_config mid_cdclk_config;
+ int cdclk = cdclk_config->cdclk;
+ int ret = 0;
+
+ /*
+ * Inform power controller of upcoming frequency change.
+ * Display versions 14 and beyond do not follow the PUnit
+ * mailbox communication, skip
+ * this step.
+ */
+ if (DISPLAY_VER(dev_priv) >= 14)
+ /* NOOP */;
+ else if (DISPLAY_VER(dev_priv) >= 11)
+ ret = skl_pcode_request(&dev_priv->uncore, SKL_PCODE_CDCLK_CONTROL,
+ SKL_CDCLK_PREPARE_FOR_CHANGE,
+ SKL_CDCLK_READY_FOR_CHANGE,
+ SKL_CDCLK_READY_FOR_CHANGE, 3);
+ else
+ /*
+ * BSpec requires us to wait up to 150usec, but that leads to
+ * timeouts; the 2ms used here is based on experiment.
+ */
+ ret = snb_pcode_write_timeout(&dev_priv->uncore,
+ HSW_PCODE_DE_WRITE_FREQ_REQ,
+ 0x80000000, 150, 2);
+
+ if (ret) {
+ drm_err(&dev_priv->drm,
+ "Failed to inform PCU about cdclk change (err %d, freq %d)\n",
+ ret, cdclk);
+ return;
+ }
- if (DISPLAY_VER(dev_priv) >= 11) {
+ if (cdclk_compute_crawl_and_squash_midpoint(dev_priv, &dev_priv->display.cdclk.hw,
+ cdclk_config, &mid_cdclk_config)) {
+ _bxt_set_cdclk(dev_priv, &mid_cdclk_config, pipe);
+ _bxt_set_cdclk(dev_priv, cdclk_config, pipe);
+ } else {
+ _bxt_set_cdclk(dev_priv, cdclk_config, pipe);
+ }
+
+ if (DISPLAY_VER(dev_priv) >= 14)
+ /*
+ * NOOP - No Pcode communication needed for
+ * Display versions 14 and beyond
+ */;
+ else if (DISPLAY_VER(dev_priv) >= 11)
ret = snb_pcode_write(&dev_priv->uncore, SKL_PCODE_CDCLK_CONTROL,
cdclk_config->voltage_level);
- } else {
+ else
/*
* The timeout isn't specified, the 2ms used here is based on
* experiment.
@@ -1808,7 +1901,6 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
HSW_PCODE_DE_WRITE_FREQ_REQ,
cdclk_config->voltage_level,
150, 2);
- }
if (ret) {
drm_err(&dev_priv->drm,
@@ -1965,6 +2057,28 @@ void intel_cdclk_uninit_hw(struct drm_i915_private *i915)
skl_cdclk_uninit_hw(i915);
}
+static bool intel_cdclk_can_crawl_and_squash(struct drm_i915_private *i915,
+ const struct intel_cdclk_config *a,
+ const struct intel_cdclk_config *b)
+{
+ u16 old_waveform;
+ u16 new_waveform;
+
+ drm_WARN_ON(&i915->drm, cdclk_pll_is_unknown(a->vco));
+
+ if (a->vco == 0 || b->vco == 0)
+ return false;
+
+ if (!HAS_CDCLK_CRAWL(i915) || !HAS_CDCLK_SQUASH(i915))
+ return false;
+
+ old_waveform = cdclk_squash_waveform(i915, a->cdclk);
+ new_waveform = cdclk_squash_waveform(i915, b->cdclk);
+
+ return a->vco != b->vco &&
+ old_waveform != new_waveform;
+}
+
static bool intel_cdclk_can_crawl(struct drm_i915_private *dev_priv,
const struct intel_cdclk_config *a,
const struct intel_cdclk_config *b)
@@ -2771,9 +2885,14 @@ int intel_modeset_calc_cdclk(struct intel_atomic_state *state)
pipe = INVALID_PIPE;
}
- if (intel_cdclk_can_squash(dev_priv,
- &old_cdclk_state->actual,
- &new_cdclk_state->actual)) {
+ if (intel_cdclk_can_crawl_and_squash(dev_priv,
+ &old_cdclk_state->actual,
+ &new_cdclk_state->actual)) {
+ drm_dbg_kms(&dev_priv->drm,
+ "Can change cdclk via crawling and squashing\n");
+ } else if (intel_cdclk_can_squash(dev_priv,
+ &old_cdclk_state->actual,
+ &new_cdclk_state->actual)) {
drm_dbg_kms(&dev_priv->drm,
"Can change cdclk via squashing\n");
} else if (intel_cdclk_can_crawl(dev_priv,
--
2.25.1
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