[PATCH 4/4] drm/i915: reorganize the get_cdclk assignment

Paulo Zanoni
2017-02-17T13:22:22Z

Possible problems of the current if-ladder:
- It's a huge if ladder with almost a different check for each of
our platforms.
- It mixes 3 different types of checks: IS_GENX, IS_PLATFORM and
IS_GROUP_OF_PLATFORMS.
- As demonstrated by the recent IS_G4X commit, it's not easy to be
sure if a platform down on the list isn't also checked earlier.
- As demonstrated by the WARN at the end, it's not easy to be sure
if we're actually checking for every single platform.

Possible advantages of the new switch statement:
- It may be easier for the compiler to optimize stuff (I didn't
check this), especially since the values are labels of an enum.
- The compiler will tell us in case we miss some platform.
- All platforms are explicitly there instead of maybe hidden in some
check for a certain group of platforms such as IS_GEN9_BC.

Possible disadvantages with the new code:
- A few lines bigger.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
drivers/gpu/drm/i915/intel_cdclk.c | 103 ++++++++++++++++++++++---------------
1 file changed, 62 insertions(+), 41 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
index 7c92dc7..58a2f5c 100644
--- a/drivers/gpu/drm/i915/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/intel_cdclk.c
@@ -1789,49 +1789,70 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
dev_priv->display.modeset_calc_cdclk = skl_modeset_calc_cdclk;
}

- if (IS_GEN9_BC(dev_priv))
- dev_priv->display.get_cdclk = skl_get_cdclk;
- else if (IS_GEN9_LP(dev_priv))
- dev_priv->display.get_cdclk = bxt_get_cdclk;
- else if (IS_BROADWELL(dev_priv))
- dev_priv->display.get_cdclk = bdw_get_cdclk;
- else if (IS_HASWELL(dev_priv))
- dev_priv->display.get_cdclk = hsw_get_cdclk;
- else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
- dev_priv->display.get_cdclk = vlv_get_cdclk;
- else if (IS_GEN6(dev_priv) || IS_IVYBRIDGE(dev_priv))
+ switch (INTEL_INFO(dev_priv)->platform) {
+ case INTEL_PLATFORM_UNINITIALIZED:
+ MISSING_CASE(INTEL_INFO(dev_priv)->platform);
+ /* Fall through. */
+ case INTEL_I830:
+ dev_priv->display.get_cdclk = fixed_133mhz_get_cdclk;
+ break;
+ case INTEL_I845G:
+ dev_priv->display.get_cdclk = fixed_200mhz_get_cdclk;
+ break;
+ case INTEL_I85X:
+ dev_priv->display.get_cdclk = i85x_get_cdclk;
+ break;
+ case INTEL_I865G:
+ dev_priv->display.get_cdclk = fixed_266mhz_get_cdclk;
+ break;
+ case INTEL_I915G:
+ dev_priv->display.get_cdclk = fixed_333mhz_get_cdclk;
+ break;
+ case INTEL_I915GM:
+ dev_priv->display.get_cdclk = i915gm_get_cdclk;
+ break;
+ case INTEL_I945G:
+ case INTEL_I965G:
+ case INTEL_SANDYBRIDGE:
+ case INTEL_IVYBRIDGE:
dev_priv->display.get_cdclk = fixed_400mhz_get_cdclk;
- else if (IS_GEN5(dev_priv))
- dev_priv->display.get_cdclk = fixed_450mhz_get_cdclk;
- else if (IS_GM45(dev_priv))
- dev_priv->display.get_cdclk = gm45_get_cdclk;
- else if (IS_G45(dev_priv))
+ break;
+ case INTEL_I945GM:
+ dev_priv->display.get_cdclk = i945gm_get_cdclk;
+ break;
+ case INTEL_G33:
+ case INTEL_G45:
dev_priv->display.get_cdclk = g33_get_cdclk;
- else if (IS_I965GM(dev_priv))
- dev_priv->display.get_cdclk = i965gm_get_cdclk;
- else if (IS_I965G(dev_priv))
- dev_priv->display.get_cdclk = fixed_400mhz_get_cdclk;
- else if (IS_PINEVIEW(dev_priv))
+ break;
+ case INTEL_PINEVIEW:
dev_priv->display.get_cdclk = pnv_get_cdclk;
- else if (IS_G33(dev_priv))
- dev_priv->display.get_cdclk = g33_get_cdclk;
- else if (IS_I945GM(dev_priv))
- dev_priv->display.get_cdclk = i945gm_get_cdclk;
- else if (IS_I945G(dev_priv))
- dev_priv->display.get_cdclk = fixed_400mhz_get_cdclk;
- else if (IS_I915GM(dev_priv))
- dev_priv->display.get_cdclk = i915gm_get_cdclk;
- else if (IS_I915G(dev_priv))
- dev_priv->display.get_cdclk = fixed_333mhz_get_cdclk;
- else if (IS_I865G(dev_priv))
- dev_priv->display.get_cdclk = fixed_266mhz_get_cdclk;
- else if (IS_I85X(dev_priv))
- dev_priv->display.get_cdclk = i85x_get_cdclk;
- else if (IS_I845G(dev_priv))
- dev_priv->display.get_cdclk = fixed_200mhz_get_cdclk;
- else { /* 830 */
- WARN(!IS_I830(dev_priv),
- "Unknown platform. Assuming 133 MHz CDCLK\n");
- dev_priv->display.get_cdclk = fixed_133mhz_get_cdclk;
+ break;
+ case INTEL_I965GM:
+ dev_priv->display.get_cdclk = i965gm_get_cdclk;
+ break;
+ case INTEL_GM45:
+ dev_priv->display.get_cdclk = gm45_get_cdclk;
+ break;
+ case INTEL_IRONLAKE:
+ dev_priv->display.get_cdclk = fixed_450mhz_get_cdclk;
+ break;
+ case INTEL_VALLEYVIEW:
+ case INTEL_CHERRYVIEW:
+ dev_priv->display.get_cdclk = vlv_get_cdclk;
+ break;
+ case INTEL_HASWELL:
+ dev_priv->display.get_cdclk = hsw_get_cdclk;
+ break;
+ case INTEL_BROADWELL:
+ dev_priv->display.get_cdclk = bdw_get_cdclk;
+ break;
+ case INTEL_SKYLAKE:
+ case INTEL_KABYLAKE:
+ dev_priv->display.get_cdclk = skl_get_cdclk;
+ break;
+ case INTEL_BROXTON:
+ case INTEL_GEMINILAKE:
+ dev_priv->display.get_cdclk = bxt_get_cdclk;
+ break;
}
}
--
2.7.4