drm/i915: Read DIMM size in Gb rather than GB

CNL+ can report DIMM sizes in .5 GB units. In order to not trauncate
away the .5 GB let's switch to storing the DIMM size in Gb units.

Cc: Swati Sharma <swati2.sharma@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200929131312.12999-1-ville.syrjala@linux.intel.com

diff --git a/drivers/gpu/drm/i915/intel_dram.c b/drivers/gpu/drm/i915/intel_dram.c
index 8aa12cad93ce370682c66760331dea30b481e829..4754296a250e6c9cb08a3dcbf336d0c23b5c8ee3 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dram.c
+++ b/drivers/gpu/drm/i915/intel_dram.c
@@ -7,7 +7,8 @@
 #include "intel_dram.h"
 
 struct dram_dimm_info {
-       u8 size, width, ranks;
+       u16 size;
+       u8 width, ranks;
 };
 
 struct dram_channel_info {
@@ -41,10 +42,10 @@ static int intel_dimm_num_devices(const struct dram_dimm_info *dimm)
        return dimm->ranks * 64 / (dimm->width ?: 1);
 }
 
-/* Returns total GB for the whole DIMM */
+/* Returns total Gb for the whole DIMM */
 static int skl_get_dimm_size(u16 val)
 {
-       return val & SKL_DRAM_SIZE_MASK;
+       return (val & SKL_DRAM_SIZE_MASK) * 8;
 }
 
 static int skl_get_dimm_width(u16 val)
@@ -74,10 +75,10 @@ static int skl_get_dimm_ranks(u16 val)
        return val + 1;
 }
 
-/* Returns total GB for the whole DIMM */
+/* Returns total Gb for the whole DIMM */
 static int cnl_get_dimm_size(u16 val)
 {
-       return (val & CNL_DRAM_SIZE_MASK) / 2;
+       return (val & CNL_DRAM_SIZE_MASK) * 8 / 2;
 }
 
 static int cnl_get_dimm_width(u16 val)
@@ -110,8 +111,8 @@ static int cnl_get_dimm_ranks(u16 val)
 static bool
 skl_is_16gb_dimm(const struct dram_dimm_info *dimm)
 {
-       /* Convert total GB to Gb per DRAM device */
-       return 8 * dimm->size / (intel_dimm_num_devices(dimm) ?: 1) == 16;
+       /* Convert total Gb to Gb per DRAM device */
+       return dimm->size / (intel_dimm_num_devices(dimm) ?: 1) == 16;
 }
 
 static void
@@ -130,7 +131,7 @@ skl_dram_get_dimm_info(struct drm_i915_private *i915,
        }
 
        drm_dbg_kms(&i915->drm,
-                   "CH%u DIMM %c size: %u GB, width: X%u, ranks: %u, 16Gb DIMMs: %s\n",
+                   "CH%u DIMM %c size: %u Gb, width: X%u, ranks: %u, 16Gb DIMMs: %s\n",
                    channel, dimm_name, dimm->size, dimm->width, dimm->ranks,
                    yesno(skl_is_16gb_dimm(dimm)));
 }
@@ -354,9 +355,9 @@ static void bxt_get_dimm_info(struct dram_dimm_info *dimm, u32 val)
 
        /*
         * Size in register is Gb per DRAM device. Convert to total
-        * GB to match the way we report this for non-LP platforms.
+        * Gb to match the way we report this for non-LP platforms.
         */
-       dimm->size = bxt_get_dimm_size(val) * intel_dimm_num_devices(dimm) / 8;
+       dimm->size = bxt_get_dimm_size(val) * intel_dimm_num_devices(dimm);
 }
 
 static int bxt_get_dram_info(struct drm_i915_private *i915)
@@ -404,7 +405,7 @@ static int bxt_get_dram_info(struct drm_i915_private *i915)
                            dram_info->type != type);
 
                drm_dbg_kms(&i915->drm,
-                           "CH%u DIMM size: %u GB, width: X%u, ranks: %u, type: %s\n",
+                           "CH%u DIMM size: %u Gb, width: X%u, ranks: %u, type: %s\n",
                            i - BXT_D_CR_DRP0_DUNIT_START,
                            dimm.size, dimm.width, dimm.ranks,
                            intel_dram_type_str(type));