[PATCH v1] drm/i915/dg2: enable G8 with a workaround

[Raag Jadav <raag.jadav@xxxxxxxxx>]

Host BIOS doesn't enable G8 power mode due to an issue on DG2, so we
enable it from kernel with Wa_14022698589. Currently it is enabled for
all DG2 devices with the exception of a few, for which, it is enabled
only when paired with whitelisted CPU models.

Signed-off-by: Raag Jadav <raag.jadav@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gt/intel_workarounds.c | 43 +++++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h             |  1 +
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index e539a656cfc3..b2db51377488 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -14,11 +14,30 @@
 #include "intel_gt_mcr.h"
 #include "intel_gt_print.h"
 #include "intel_gt_regs.h"
+#include "intel_pcode.h"
 #include "intel_ring.h"
 #include "intel_workarounds.h"
 
 #include "display/intel_fbc_regs.h"
 
+#ifdef CONFIG_X86
+#include <asm/cpu_device_id.h>
+#include <asm/intel-family.h>
+
+static const struct x86_cpu_id g8_cpu_ids[] = {
+	X86_MATCH_VFM(INTEL_ALDERLAKE,		NULL),
+	X86_MATCH_VFM(INTEL_ALDERLAKE_L,	NULL),
+	X86_MATCH_VFM(INTEL_COMETLAKE,		NULL),
+	X86_MATCH_VFM(INTEL_KABYLAKE,		NULL),
+	X86_MATCH_VFM(INTEL_KABYLAKE_L,		NULL),
+	X86_MATCH_VFM(INTEL_RAPTORLAKE,		NULL),
+	X86_MATCH_VFM(INTEL_RAPTORLAKE_P,	NULL),
+	X86_MATCH_VFM(INTEL_RAPTORLAKE_S,	NULL),
+	X86_MATCH_VFM(INTEL_ROCKETLAKE,		NULL),
+	{}
+};
+#endif
+
 /**
  * DOC: Hardware workarounds
  *
@@ -1770,9 +1789,33 @@ static void wa_list_apply(const struct i915_wa_list *wal)
 	intel_gt_mcr_unlock(gt, flags);
 }
 
+#define DG2_G8_WA_RANGE_1		0x56A0 ... 0x56AF
+#define DG2_G8_WA_RANGE_2		0x56B0 ... 0x56B9
+
+/* Wa_14022698589:dg2 */
+static void intel_enable_g8(struct intel_uncore *uncore)
+{
+	if (IS_DG2(uncore->i915)) {
+		switch (INTEL_DEVID(uncore->i915)) {
+		case DG2_G8_WA_RANGE_1:
+		case DG2_G8_WA_RANGE_2:
+#ifdef CONFIG_X86
+			if (!x86_match_cpu(g8_cpu_ids))
+#endif
+				return;
+		}
+
+		snb_pcode_write_p(uncore, PCODE_POWER_SETUP,
+				  POWER_SETUP_SUBCOMMAND_G8_ENABLE, 0, 0);
+	}
+}
+
 void intel_gt_apply_workarounds(struct intel_gt *gt)
 {
 	wa_list_apply(&gt->wa_list);
+
+	/* Special case for pcode mailbox which can't be on wa_list */
+	intel_enable_g8(gt->uncore);
 }
 
 static bool wa_list_verify(struct intel_gt *gt,
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 41f4350a7c6c..e948b194550c 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3568,6 +3568,7 @@
 #define   PCODE_POWER_SETUP			0x7C
 #define     POWER_SETUP_SUBCOMMAND_READ_I1	0x4
 #define     POWER_SETUP_SUBCOMMAND_WRITE_I1	0x5
+#define     POWER_SETUP_SUBCOMMAND_G8_ENABLE	0x6
 #define	    POWER_SETUP_I1_WATTS		REG_BIT(31)
 #define	    POWER_SETUP_I1_SHIFT		6	/* 10.6 fixed point format */
 #define	    POWER_SETUP_I1_DATA_MASK		REG_GENMASK(15, 0)
-- 
2.34.1