[PATCH 1/4] drm/i915/cdclk: Extract cdclk_divider()

[Gustavo Sousa]

Quoting Ville Syrjala (2024-02-06 22:33:31-03:00)
>From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
>Extract the cdclk divider calculation into a helper. We'll have
>more users of this soon. We can now also get rid of the intermediate
>'unsquashed_cdclk' variable.
>
>Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>---
> drivers/gpu/drm/i915/display/intel_cdclk.c | 31 ++++++++++++----------
> 1 file changed, 17 insertions(+), 14 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
>index 26200ee3e23f..d79485e17ed1 100644
>--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
>+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
>@@ -1406,6 +1406,20 @@ 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 +1758,10 @@ 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} */

Not sure if it would make sense to keep the comment above now.

Reviewed-by: Gustavo Sousa <gustavo.sousa at intel.com>

>-        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);
>@@ -1826,13 +1840,6 @@ 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,
>@@ -1906,16 +1913,12 @@ 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);
> 
>         /*
>-- 
>2.43.0
>