drm/i915: Extract BXT DIMM helpers

Polish the bxt DIMM parsing by extracting a few small helpers.

v2: Use struct dram_dimm_info
v3: Document what bxt_get_dimm_size() returns (Jani)

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190306203551.24592-5-ville.syrjala@linux.intel.com

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e35a75be3a2a6d8cc1d8606b4db3b643032ba29d..bba051d9f21d162943ea2966236b0e16de0ab9c3 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1238,6 +1238,60 @@ skl_get_dram_info(struct drm_i915_private *dev_priv)
        return 0;
 }
 
+/* Returns Gb per DRAM device */
+static int bxt_get_dimm_size(u32 val)
+{
+       switch (val & BXT_DRAM_SIZE_MASK) {
+       case BXT_DRAM_SIZE_4GB:
+               return 4;
+       case BXT_DRAM_SIZE_6GB:
+               return 6;
+       case BXT_DRAM_SIZE_8GB:
+               return 8;
+       case BXT_DRAM_SIZE_12GB:
+               return 12;
+       case BXT_DRAM_SIZE_16GB:
+               return 16;
+       default:
+               MISSING_CASE(val);
+               return 0;
+       }
+}
+
+static int bxt_get_dimm_width(u32 val)
+{
+       if (!bxt_get_dimm_size(val))
+               return 0;
+
+       val = (val & BXT_DRAM_WIDTH_MASK) >> BXT_DRAM_WIDTH_SHIFT;
+
+       return 8 << val;
+}
+
+static int bxt_get_dimm_ranks(u32 val)
+{
+       if (!bxt_get_dimm_size(val))
+               return 0;
+
+       switch (val & BXT_DRAM_RANK_MASK) {
+       case BXT_DRAM_RANK_SINGLE:
+               return 1;
+       case BXT_DRAM_RANK_DUAL:
+               return 2;
+       default:
+               MISSING_CASE(val);
+               return 0;
+       }
+}
+
+static void bxt_get_dimm_info(struct dram_dimm_info *dimm,
+                             u32 val)
+{
+       dimm->size = bxt_get_dimm_size(val);
+       dimm->width = bxt_get_dimm_width(val);
+       dimm->ranks = bxt_get_dimm_ranks(val);
+}
+
 static int
 bxt_get_dram_info(struct drm_i915_private *dev_priv)
 {
@@ -1266,41 +1320,19 @@ bxt_get_dram_info(struct drm_i915_private *dev_priv)
         * Now read each DUNIT8/9/10/11 to check the rank of each dimms.
         */
        for (i = BXT_D_CR_DRP0_DUNIT_START; i <= BXT_D_CR_DRP0_DUNIT_END; i++) {
-               u8 size, width, ranks;
-               u32 tmp;
+               struct dram_dimm_info dimm;
 
                val = I915_READ(BXT_D_CR_DRP0_DUNIT(i));
                if (val == 0xFFFFFFFF)
                        continue;
 
                dram_info->num_channels++;
-               tmp = val & BXT_DRAM_RANK_MASK;
-
-               if (tmp == BXT_DRAM_RANK_SINGLE)
-                       ranks = 1;
-               else if (tmp == BXT_DRAM_RANK_DUAL)
-                       ranks = 2;
-               else
-                       ranks = 0;
-
-               tmp = val & BXT_DRAM_SIZE_MASK;
-               if (tmp == BXT_DRAM_SIZE_4GB)
-                       size = 4;
-               else if (tmp == BXT_DRAM_SIZE_6GB)
-                       size = 6;
-               else if (tmp == BXT_DRAM_SIZE_8GB)
-                       size = 8;
-               else if (tmp == BXT_DRAM_SIZE_12GB)
-                       size = 12;
-               else if (tmp == BXT_DRAM_SIZE_16GB)
-                       size = 16;
-               else
-                       size = 0;
-
-               tmp = (val & BXT_DRAM_WIDTH_MASK) >> BXT_DRAM_WIDTH_SHIFT;
-               width = (1 << tmp) * 8;
-               DRM_DEBUG_KMS("dram size:%uGB width:X%u ranks:%u\n",
-                             size, width, ranks);
+
+               bxt_get_dimm_info(&dimm, val);
+
+               DRM_DEBUG_KMS("CH%u DIMM size: %u GB, width: X%u, ranks: %u\n",
+                             i - BXT_D_CR_DRP0_DUNIT_START,
+                             dimm.size, dimm.width, dimm.ranks);
 
                /*
                 * If any of the channel is single rank channel,
@@ -1308,8 +1340,8 @@ bxt_get_dram_info(struct drm_i915_private *dev_priv)
                 * memory, so consider single rank memory.
                 */
                if (dram_info->ranks == 0)
-                       dram_info->ranks = ranks;
-               else if (ranks == 1)
+                       dram_info->ranks = dimm.ranks;
+               else if (dimm.ranks == 1)
                        dram_info->ranks = 1;
        }