[PATCH v2] drm/xe/xe3p_lpg: Program TR_PTA_MODE

[Matt Roper <matthew.d.roper@intel.com>]

Up until Xe3p_LPG, the PTA_MODE register controlled cacheability of
accesses to the page tables for both PPGTT and TRTT.  Starting with
Xe3p_LPG, PTA_MODE is now only responsible for the PPGTT accesses, and a
separate register, TR_PTA_MODE is used to control the TRTT accesses. The
currently recommeded value for TR_PTA_MODE differs from PTA_MODE on
Xe3p_LPG.  Track and program this value separately in the driver.

Note that even though the Xe3p_LP[G/M] IPs didn't add support for this
new TR_PTA_MODE register until b-stepping, it's safe us to ignore that
detail code-wise.  Writes of the unrecognized registers on a-step
hardware will be silently ignored, and the reads on a-step will come
back as 0x0 which happens to be the value we'd be trying to program on
these IP versions anyway (for both graphics and media).

The new TRTT-specific register also does not exist on Xe3p_XPC
platforms.

v2:
 - Split gt_tr_pta_entry() out from gt_pta_entry().  (Gustavo)
 - Fix copy/paste mistake that caused us to write the PPGTT value to the
   TRTT register in the MCR path.  (Sashiko)

Bspec: 79814, 71582
Cc: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
---
Changes in v2:
- Split gt_tr_pta_entry() our from gt_pta_entry().  (Gustavo)
- Fix copy/paste mistake that caused us to write the PPGTT value to the
  TRTT register in the MCR path.  (Sashiko)
- Link to v1: https://lore.kernel.org/r/20260714-tr_pta_mode-v1-1-6b6544af9d79@intel.com
---
 drivers/gpu/drm/xe/xe_device_types.h |  4 ++++
 drivers/gpu/drm/xe/xe_pat.c          | 44 ++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 56c17cca79c0..860ad322237f 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -404,6 +404,10 @@ struct xe_device {
 		const struct xe_pat_table_entry *pat_primary_pta;
 		/** @pat.pat_media_pta: media GT PAT entry for page table accesses */
 		const struct xe_pat_table_entry *pat_media_pta;
+		/** @pat.pat_primary_tr_pta: primary GT PAT entry for TRTT page table accesses */
+		const struct xe_pat_table_entry *pat_primary_tr_pta;
+		/** @pat.pat_media_tr_pta: media GT PAT entry for TRTT page table accesses */
+		const struct xe_pat_table_entry *pat_media_tr_pta;
 		u16 idx[__XE_CACHE_LEVEL_COUNT];
 	} pat;
 
diff --git a/drivers/gpu/drm/xe/xe_pat.c b/drivers/gpu/drm/xe/xe_pat.c
index fad5b5a5ed4a..a5fe1beec652 100644
--- a/drivers/gpu/drm/xe/xe_pat.c
+++ b/drivers/gpu/drm/xe/xe_pat.c
@@ -25,6 +25,7 @@
 								   0x4800, 0x4804, \
 								   0x4848, 0x484c)
 #define _PAT_PTA				0x4820
+#define _PAT_TR_PTA				0x48cc
 
 #define XE2_NO_PROMOTE				REG_BIT(10)
 #define XE2_COMP_EN				REG_BIT(9)
@@ -256,6 +257,7 @@ static const struct xe_pat_table_entry xe3p_xpc_pat_table[] = {
 
 static const struct xe_pat_table_entry xe3p_primary_pat_pta = XE2_PAT(0, 0, 0, 0, 0, 3);
 static const struct xe_pat_table_entry xe3p_media_pat_pta = XE2_PAT(0, 0, 0, 0, 0, 2);
+static const struct xe_pat_table_entry xe3p_pat_tr_pta = XE2_PAT(0, 0, 0, 0, 0, 0);
 
 static const struct xe_pat_table_entry xe3p_lpg_pat_table[] = {
 	[ 0] = XE2_PAT( 0, 0, 0, 0, 3, 0 ),
@@ -325,11 +327,26 @@ static const struct xe_pat_table_entry *gt_pta_entry(struct xe_gt *gt)
 	return NULL;
 }
 
+static const struct xe_pat_table_entry *gt_tr_pta_entry(struct xe_gt *gt)
+{
+	struct xe_device *xe = gt_to_xe(gt);
+
+	if (xe_gt_is_main_type(gt))
+		return xe->pat.pat_primary_tr_pta;
+
+	if (xe_gt_is_media_type(gt))
+		return xe->pat.pat_media_tr_pta;
+
+	xe_assert(xe, false);
+	return NULL;
+}
+
 static void program_pat(struct xe_gt *gt, const struct xe_pat_table_entry table[],
 			int n_entries)
 {
 	struct xe_device *xe = gt_to_xe(gt);
 	const struct xe_pat_table_entry *pta_entry = gt_pta_entry(gt);
+	const struct xe_pat_table_entry *tr_pta_entry = gt_tr_pta_entry(gt);
 
 	for (int i = 0; i < n_entries; i++) {
 		struct xe_reg reg = XE_REG(_PAT_INDEX(i));
@@ -342,6 +359,9 @@ static void program_pat(struct xe_gt *gt, const struct xe_pat_table_entry table[
 
 	if (pta_entry)
 		xe_mmio_write32(&gt->mmio, XE_REG(_PAT_PTA), pta_entry->value);
+
+	if (tr_pta_entry)
+		xe_mmio_write32(&gt->mmio, XE_REG(_PAT_TR_PTA), tr_pta_entry->value);
 }
 
 static void program_pat_mcr(struct xe_gt *gt, const struct xe_pat_table_entry table[],
@@ -349,6 +369,7 @@ static void program_pat_mcr(struct xe_gt *gt, const struct xe_pat_table_entry ta
 {
 	struct xe_device *xe = gt_to_xe(gt);
 	const struct xe_pat_table_entry *pta_entry = gt_pta_entry(gt);
+	const struct xe_pat_table_entry *tr_pta_entry = gt_tr_pta_entry(gt);
 
 	for (int i = 0; i < n_entries; i++) {
 		struct xe_reg_mcr reg_mcr = XE_REG_MCR(_PAT_INDEX(i));
@@ -361,6 +382,9 @@ static void program_pat_mcr(struct xe_gt *gt, const struct xe_pat_table_entry ta
 
 	if (pta_entry)
 		xe_gt_mcr_multicast_write(gt, XE_REG_MCR(_PAT_PTA), pta_entry->value);
+
+	if (tr_pta_entry)
+		xe_gt_mcr_multicast_write(gt, XE_REG_MCR(_PAT_TR_PTA), tr_pta_entry->value);
 }
 
 static int xelp_dump(struct xe_gt *gt, struct drm_printer *p)
@@ -531,6 +555,16 @@ static int xe2_dump(struct xe_gt *gt, struct drm_printer *p)
 	drm_printf(p, "Page Table Access:\n");
 	xe->pat.ops->entry_dump(p, "PTA_MODE", pat, false);
 
+	if (gt_tr_pta_entry(gt)) {
+		if (xe_gt_is_media_type(gt))
+			pat = xe_mmio_read32(&gt->mmio, XE_REG(_PAT_TR_PTA));
+		else
+			pat = xe_gt_mcr_unicast_read_any(gt, XE_REG_MCR(_PAT_TR_PTA));
+
+		drm_printf(p, "TRTT Page Table Access:\n");
+		xe->pat.ops->entry_dump(p, "TR_PTA_MODE", pat, false);
+	}
+
 	if (xe_gt_is_media_type(gt))
 		pat = xe_mmio_read32(&gt->mmio, XE_REG(_PAT_ATS));
 	else
@@ -577,6 +611,8 @@ void xe_pat_init_early(struct xe_device *xe)
 		if (!IS_DGFX(xe)) {
 			xe->pat.pat_primary_pta = &xe3p_primary_pat_pta;
 			xe->pat.pat_media_pta = &xe3p_media_pat_pta;
+			xe->pat.pat_primary_tr_pta = &xe3p_pat_tr_pta;
+			xe->pat.pat_media_tr_pta = &xe3p_pat_tr_pta;
 		}
 		xe->pat.n_entries = ARRAY_SIZE(xe3p_lpg_pat_table);
 		xe->pat.idx[XE_CACHE_NONE] = 3;
@@ -701,6 +737,7 @@ int xe_pat_dump_sw_config(struct xe_gt *gt, struct drm_printer *p)
 {
 	struct xe_device *xe = gt_to_xe(gt);
 	const struct xe_pat_table_entry *pta_entry = gt_pta_entry(gt);
+	const struct xe_pat_table_entry *tr_pta_entry = gt_tr_pta_entry(gt);
 	char label[PAT_LABEL_LEN];
 
 	if (!xe->pat.table || !xe->pat.n_entries)
@@ -731,6 +768,13 @@ int xe_pat_dump_sw_config(struct xe_gt *gt, struct drm_printer *p)
 		xe->pat.ops->entry_dump(p, "PTA_MODE", pat, false);
 	}
 
+	if (tr_pta_entry) {
+		u32 pat = tr_pta_entry->value;
+
+		drm_printf(p, "TRTT Page Table Access:\n");
+		xe->pat.ops->entry_dump(p, "TR_PTA_MODE", pat, false);
+	}
+
 	if (xe->pat.pat_ats) {
 		u32 pat = xe->pat.pat_ats->value;
 

---
base-commit: 0fcee361fa4cf13207af78b95e71bbbaeb046319
change-id: 20260629-tr_pta_mode-b45fbb593987

Best regards,
-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation