[PATCH 11/17] drm/xe/oa: Disable overrun mode for Xe2+ OAG

[Ashutosh Dixit]

Xe2+ OAG requires special handling because non-power-of-2 report sizes are
not a sub-multiple of the OA buffer size and there are no partial reports
at the end of the buffer. This issue is present only when overrun mode is
enabled. Avoid adding this special handling by disabling overrun mode for
Xe2+ OAG.

Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
---
 drivers/gpu/drm/xe/regs/xe_oa_regs.h | 1 +
 drivers/gpu/drm/xe/xe_oa.c           | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/xe/regs/xe_oa_regs.h b/drivers/gpu/drm/xe/regs/xe_oa_regs.h
index 4455a5a42b01b..7e2e875ccf80a 100644
--- a/drivers/gpu/drm/xe/regs/xe_oa_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_oa_regs.h
@@ -52,6 +52,7 @@
 #define  OABUFFER_SIZE_4M	REG_FIELD_PREP(OABUFFER_SIZE_MASK, 5)
 #define  OABUFFER_SIZE_8M	REG_FIELD_PREP(OABUFFER_SIZE_MASK, 6)
 #define  OABUFFER_SIZE_16M	REG_FIELD_PREP(OABUFFER_SIZE_MASK, 7)
+#define  OAG_OABUFFER_DISABLE_OVERRUN_MODE	REG_BIT(1)
 #define  OAG_OABUFFER_MEMORY_SELECT		REG_BIT(0) /* 0: PPGTT, 1: GGTT */
 
 #define OAG_OACONTROL				XE_REG(0xdaf4)
diff --git a/drivers/gpu/drm/xe/xe_oa.c b/drivers/gpu/drm/xe/xe_oa.c
index 5744436188dcd..073476721377d 100644
--- a/drivers/gpu/drm/xe/xe_oa.c
+++ b/drivers/gpu/drm/xe/xe_oa.c
@@ -408,6 +408,14 @@ static void xe_oa_init_oa_buffer(struct xe_oa_stream *stream)
 			gtt_offset & OAG_OAHEADPTR_MASK);
 	stream->oa_buffer.head = 0;
 
+	/*
+	 * For Xe2+, OAG buffer is not a multiple of report size and there are no partial
+	 * reports at the end of the buffer when overrun mode is enabled. Disable overrun
+	 * mode to avoid this issue.
+	 */
+	if (GRAPHICS_VER(stream->oa->xe) >= 20 &&
+	    stream->hwe->oa_unit->type == DRM_XE_OA_UNIT_TYPE_OAG)
+		oa_buf |= OAG_OABUFFER_DISABLE_OVERRUN_MODE;
 	/*
 	 * PRM says: "This MMIO must be set before the OATAILPTR register and after the
 	 * OAHEADPTR register. This is to enable proper functionality of the overflow bit".
-- 
2.41.0