[Intel-gfx] [PATCH 2/2] drm/i915/gen9: Calculate edram size

[Mika Kuoppala]

With gen9+ the edram capabilities are defined so
that we can calculate the edram (ellc) size accordingly.

Note that there are undefined combinations for some subset of
edram capability bits. Return the closest size for undefined indexes.
Even if we get it wrong with beginning of future gen enabling, the size
information is currently only used for boot message and in debugfs entry.

Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h     | 14 ++++++++++++++
 drivers/gpu/drm/i915/intel_uncore.c |  9 +++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f88b75ec5047..52283c44a0c1 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6820,6 +6820,20 @@ enum skl_disp_power_wells {
 #define    IDIHASHMSK(x)			(((x) & 0x3f) << 16)
 #define  HSW_EDRAM_CAP				_MMIO(0x120010)
 #define    EDRAM_ENABLED			0x1
+#define    EDRAM_NUM_BANKS(cap)			(((cap) >> 1) & 0xf)
+#define    __EDRAM_WAYS(cap)			(((cap) >> 5) & 0x7)
+#define    EDRAM_NUM_WAYS(cap)			({ \
+			int __ways[8] = { 4, 8, 12, 16, 16, 16, 16, 16 }; \
+			__ways[__EDRAM_WAYS(cap)]; \
+})
+#define    __EDRAM_SETS(cap)			(((cap) >> 8) & 0x3)
+#define    EDRAM_NUM_SETS(cap)			({ \
+			int __sets[4] = { 1, 1, 2, 2 }; \
+			__sets[__EDRAM_SETS(cap)]; \
+})
+#define    EDRAM_SIZE(cap)			(EDRAM_NUM_BANKS(cap) * \
+						 EDRAM_NUM_WAYS(cap) * \
+						 EDRAM_NUM_SETS(cap))
 
 #define GEN6_UCGCTL1				_MMIO(0x9400)
 # define GEN6_EU_TCUNIT_CLOCK_GATE_DISABLE		(1 << 16)
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 0c9059cb3d13..c5fb1937b82d 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -315,12 +315,13 @@ unsigned intel_uncore_edram_size_mb(struct drm_i915_private *dev_priv)
 	if (!HAS_EDRAM(dev_priv))
 		return 0;
 
-	/* The docs do not explain exactly how the calculation can be
-	 * made. It is somewhat guessable, but for now, it's always
-	 * 128MB.
+	/* The needed capability bits for size calculation
+	 * are not there with pre gen9 so return 128MB always.
 	 */
+	if (INTEL_INFO(dev_priv)->gen < 9)
+		return 128;
 
-	return 128;
+	return EDRAM_SIZE(dev_priv->edram_cap);
 }
 
 static void intel_uncore_edram_detect(struct drm_i915_private *dev_priv)
-- 
2.5.0