diff options
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_cdclk.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_cdclk.c | 61 |
1 files changed, 44 insertions, 17 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c index 26200ee3e23f..ed89b86ea625 100644 --- a/drivers/gpu/drm/i915/display/intel_cdclk.c +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c @@ -63,6 +63,16 @@ * DMC will not change the active CDCLK frequency however, so that part * will still be performed by the driver directly. * + * Several methods exist to change the CDCLK frequency, which ones are + * supported depends on the platform: + * + * - Full PLL disable + re-enable with new VCO frequency. Pipes must be inactive. + * - CD2X divider update. Single pipe can be active as the divider update + * can be synchronized with the pipe's start of vblank. + * - Crawl the PLL smoothly to the new VCO frequency. Pipes can be active. + * - Squash waveform update. Pipes can be active. + * - Crawl and squash can also be done back to back. Pipes can be active. + * * RAWCLK is a fixed frequency clock, often used by various auxiliary * blocks such as AUX CH or backlight PWM. Hence the only thing we * really need to know about RAWCLK is its frequency so that various @@ -1406,6 +1416,20 @@ static const struct intel_cdclk_vals lnl_cdclk_table[] = { {} }; +static const int cdclk_squash_len = 16; + +static int cdclk_squash_divider(u16 waveform) +{ + return hweight16(waveform ?: 0xffff); +} + +static int cdclk_divider(int cdclk, int vco, u16 waveform) +{ + /* 2 * cd2x divider */ + return DIV_ROUND_CLOSEST(vco * cdclk_squash_divider(waveform), + cdclk * cdclk_squash_len); +} + static int bxt_calc_cdclk(struct drm_i915_private *dev_priv, int min_cdclk) { const struct intel_cdclk_vals *table = dev_priv->display.cdclk.table; @@ -1744,10 +1768,10 @@ static u32 bxt_cdclk_cd2x_pipe(struct drm_i915_private *dev_priv, enum pipe pipe } static u32 bxt_cdclk_cd2x_div_sel(struct drm_i915_private *dev_priv, - int cdclk, int vco) + int cdclk, int vco, u16 waveform) { /* cdclk = vco / 2 / div{1,1.5,2,4} */ - switch (DIV_ROUND_CLOSEST(vco, cdclk)) { + switch (cdclk_divider(cdclk, vco, waveform)) { default: drm_WARN_ON(&dev_priv->drm, cdclk != dev_priv->display.cdclk.hw.bypass); @@ -1764,7 +1788,7 @@ static u32 bxt_cdclk_cd2x_div_sel(struct drm_i915_private *dev_priv, } } -static u32 cdclk_squash_waveform(struct drm_i915_private *dev_priv, +static u16 cdclk_squash_waveform(struct drm_i915_private *dev_priv, int cdclk) { const struct intel_cdclk_vals *table = dev_priv->display.cdclk.table; @@ -1826,20 +1850,13 @@ static bool cdclk_pll_is_unknown(unsigned int vco) return vco == ~0; } -static const int cdclk_squash_len = 16; - -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 div = 2; + int old_div, new_div, mid_div; /* Return if PLL is in an unknown state, force a complete disable and re-enable. */ if (cdclk_pll_is_unknown(old_cdclk_config->vco)) @@ -1858,6 +1875,18 @@ static bool cdclk_compute_crawl_and_squash_midpoint(struct drm_i915_private *i91 old_waveform == new_waveform) return false; + old_div = cdclk_divider(old_cdclk_config->cdclk, + old_cdclk_config->vco, old_waveform); + new_div = cdclk_divider(new_cdclk_config->cdclk, + new_cdclk_config->vco, new_waveform); + + /* + * Should not happen currently. We might need more midpoint + * transitions if we need to also change the cd2x divider. + */ + if (drm_WARN_ON(&i915->drm, old_div != new_div)) + return false; + *mid_cdclk_config = *new_cdclk_config; /* @@ -1870,15 +1899,17 @@ static bool cdclk_compute_crawl_and_squash_midpoint(struct drm_i915_private *i91 if (cdclk_squash_divider(new_waveform) > cdclk_squash_divider(old_waveform)) { mid_cdclk_config->vco = old_cdclk_config->vco; + mid_div = old_div; mid_waveform = new_waveform; } else { mid_cdclk_config->vco = new_cdclk_config->vco; + mid_div = new_div; mid_waveform = old_waveform; } mid_cdclk_config->cdclk = DIV_ROUND_CLOSEST(cdclk_squash_divider(mid_waveform) * mid_cdclk_config->vco, - cdclk_squash_len * div); + cdclk_squash_len * mid_div); /* make sure the mid clock came out sane */ @@ -1906,16 +1937,12 @@ static u32 bxt_cdclk_ctl(struct drm_i915_private *i915, { int cdclk = cdclk_config->cdclk; int vco = cdclk_config->vco; - int unsquashed_cdclk; u16 waveform; u32 val; waveform = cdclk_squash_waveform(i915, cdclk); - unsquashed_cdclk = DIV_ROUND_CLOSEST(cdclk * cdclk_squash_len, - cdclk_squash_divider(waveform)); - - val = bxt_cdclk_cd2x_div_sel(i915, unsquashed_cdclk, vco) | + val = bxt_cdclk_cd2x_div_sel(i915, cdclk, vco, waveform) | bxt_cdclk_cd2x_pipe(i915, pipe); /* |