drm/i915: use i9xx_fsb_freq() for GT clock frequency

Reuse i9xx_fsb_freq() for GT clock frequency initialization instead of
depending on rawclk_freq.

Note: If the init order was changed, we could use i915->fsb_freq
directly. However, GT clock initialization is done in
i915_driver_mmio_probe(), but intel_dram_detect() later in
i915_driver_hw_probe(), with a dependency on intel_pcode_init().

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/0678d8ec9772725b47d4fa5b14e3b3a34256d5cf.1718356614.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c

@@ -9,6 +9,7 @@
 #include "intel_gt_clock_utils.h"
 #include "intel_gt_print.h"
 #include "intel_gt_regs.h"
+#include "soc/intel_dram.h"
 
 static u32 read_reference_ts_freq(struct intel_uncore *uncore)
 {
@@ -151,7 +152,7 @@ static u32 gen4_read_clock_frequency(struct intel_uncore *uncore)
 	 *
 	 * Testing on actual hardware has shown there is no /16.
 	 */
-	return RUNTIME_INFO(uncore->i915)->rawclk_freq * 1000;
+	return DIV_ROUND_CLOSEST(i9xx_fsb_freq(uncore->i915), 4) * 1000;
 }
 
 static u32 read_clock_frequency(struct intel_uncore *uncore)

drivers/gpu/drm/i915/soc/intel_dram.c

@@ -142,7 +142,7 @@ static void detect_mem_freq(struct drm_i915_private *i915)
 		drm_dbg(&i915->drm, "DDR speed: %d kHz\n", i915->mem_freq);
 }
 
-static unsigned int i9xx_fsb_freq(struct drm_i915_private *i915)
+unsigned int i9xx_fsb_freq(struct drm_i915_private *i915)
 {
 	u32 fsb;
 

drivers/gpu/drm/i915/soc/intel_dram.h

@@ -10,5 +10,6 @@ struct drm_i915_private;
 
 void intel_dram_edram_detect(struct drm_i915_private *i915);
 void intel_dram_detect(struct drm_i915_private *i915);
+unsigned int i9xx_fsb_freq(struct drm_i915_private *i915);
 
 #endif /* __INTEL_DRAM_H__ */