[PATCH v4 1/1] drm/xe: Expose number of dss per group and helpers

[Zhanjun Dong <zhanjun.dong@intel.com>]

Expose helper for dss per group. This is a precursor patch to allow
for easier iteration through MCR registers and other per-DSS uses.

Signed-off-by: Zhanjun Dong <zhanjun.dong@intel.com>
---
 drivers/gpu/drm/xe/xe_gt_mcr.c      | 40 ++++++++++++++++++++++++++++-
 drivers/gpu/drm/xe/xe_gt_mcr.h      | 17 ++++++++++++
 drivers/gpu/drm/xe/xe_gt_topology.c |  1 -
 drivers/gpu/drm/xe/xe_gt_types.h    |  1 +
 4 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_mcr.c b/drivers/gpu/drm/xe/xe_gt_mcr.c
index 77925b35cf8d..7cd93bcb811f 100644
--- a/drivers/gpu/drm/xe/xe_gt_mcr.c
+++ b/drivers/gpu/drm/xe/xe_gt_mcr.c
@@ -291,11 +291,16 @@ static void init_steering_mslice(struct xe_gt *gt)
 	gt->steering[LNCF].instance_target = 0;		/* unused */
 }
 
+int xe_gt_mcr_get_dss_per_group(struct xe_gt *gt)
+{
+	return gt_to_xe(gt)->info.platform == XE_PVC ? 8 : 4;
+}
+
 static void init_steering_dss(struct xe_gt *gt)
 {
 	unsigned int dss = min(xe_dss_mask_group_ffs(gt->fuse_topo.g_dss_mask, 0, 0),
 			       xe_dss_mask_group_ffs(gt->fuse_topo.c_dss_mask, 0, 0));
-	unsigned int dss_per_grp = gt_to_xe(gt)->info.platform == XE_PVC ? 8 : 4;
+	unsigned int dss_per_grp = xe_gt_mcr_get_dss_per_group(gt);
 
 	gt->steering[DSS].group_target = dss / dss_per_grp;
 	gt->steering[DSS].instance_target = dss % dss_per_grp;
@@ -683,3 +688,36 @@ void xe_gt_mcr_steering_dump(struct xe_gt *gt, struct drm_printer *p)
 		}
 	}
 }
+
+/**
+ * xe_gt_mcr_get_dss_steering - returns the group/instance steering for a SS
+ * @gt: GT structure
+ * @dss: DSS ID to obtain steering for
+ * @group: pointer to storage for steering group ID
+ * @instance: pointer to storage for steering instance ID
+ *
+ * Returns the steering IDs (via the @group and @instance parameters) that
+ * correspond to a specific subslice/DSS ID.
+ */
+void xe_gt_mcr_get_dss_steering(struct xe_gt *gt, unsigned int dss, unsigned int *group,
+				unsigned int *instance)
+{
+	int dss_per_grp = xe_gt_mcr_get_dss_per_group(gt);
+
+	*group = dss / dss_per_grp;
+	*instance = dss % dss_per_grp;
+}
+
+bool xe_gt_mcr_dss_has_subslice(struct xe_gt *gt, int slice, int subslice)
+{
+	int dss_per_grp = xe_gt_mcr_get_dss_per_group(gt);
+	int index = slice * dss_per_grp + subslice;
+
+	if (index >= XE_MAX_DSS_FUSE_BITS) {
+		xe_gt_dbg(gt, "DSS id out of range: slice:%d subslice:%d\n", slice, subslice);
+		return false;
+	}
+
+	return test_bit(index, gt->fuse_topo.g_dss_mask) ||
+	       test_bit(index, gt->fuse_topo.c_dss_mask);
+}
diff --git a/drivers/gpu/drm/xe/xe_gt_mcr.h b/drivers/gpu/drm/xe/xe_gt_mcr.h
index 27ca1bc880a0..7d1eb180befd 100644
--- a/drivers/gpu/drm/xe/xe_gt_mcr.h
+++ b/drivers/gpu/drm/xe/xe_gt_mcr.h
@@ -7,6 +7,7 @@
 #define _XE_GT_MCR_H_
 
 #include "regs/xe_reg_defs.h"
+#include "xe_gt_types.h"
 
 struct drm_printer;
 struct xe_gt;
@@ -25,5 +26,21 @@ void xe_gt_mcr_multicast_write(struct xe_gt *gt, struct xe_reg_mcr mcr_reg,
 			       u32 value);
 
 void xe_gt_mcr_steering_dump(struct xe_gt *gt, struct drm_printer *p);
+int xe_gt_mcr_get_dss_per_group(struct xe_gt *gt);
+void xe_gt_mcr_get_dss_steering(struct xe_gt *gt, unsigned int dss, unsigned int *group,
+				unsigned int *instance);
+bool xe_gt_mcr_dss_has_subslice(struct xe_gt *gt, int slice, int subslice);
+
+#define _HAS_SS(gt_, group_, instance_) xe_gt_mcr_dss_has_subslice(gt_, group_, instance_)
+
+/*
+ * Loop over each subslice/DSS and determine the group and instance IDs that
+ * should be used to steer MCR accesses toward this DSS.
+ */
+#define for_each_dss_steering(dss_, gt_, group_, instance_) \
+	for (dss_ = 0, xe_gt_mcr_get_dss_steering(gt_, 0, &group_, &instance_); \
+	     dss_ < XE_MAX_DSS_FUSE_BITS; \
+	     dss_++, xe_gt_mcr_get_dss_steering(gt_, dss_, &group_, &instance_)) \
+		for_each_if(_HAS_SS(gt_, group_, instance_))
 
 #endif /* _XE_GT_MCR_H_ */
diff --git a/drivers/gpu/drm/xe/xe_gt_topology.c b/drivers/gpu/drm/xe/xe_gt_topology.c
index a8d7f272c30a..c4942f2b3775 100644
--- a/drivers/gpu/drm/xe/xe_gt_topology.c
+++ b/drivers/gpu/drm/xe/xe_gt_topology.c
@@ -11,7 +11,6 @@
 #include "xe_gt.h"
 #include "xe_mmio.h"
 
-#define XE_MAX_DSS_FUSE_BITS (32 * XE_MAX_DSS_FUSE_REGS)
 #define XE_MAX_EU_FUSE_BITS (32 * XE_MAX_EU_FUSE_REGS)
 
 static void
diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
index 70c615dd1498..b4df7d35dec7 100644
--- a/drivers/gpu/drm/xe/xe_gt_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_types.h
@@ -25,6 +25,7 @@ enum xe_gt_type {
 };
 
 #define XE_MAX_DSS_FUSE_REGS	3
+#define XE_MAX_DSS_FUSE_BITS	(32 * XE_MAX_DSS_FUSE_REGS)
 #define XE_MAX_EU_FUSE_REGS	1
 
 typedef unsigned long xe_dss_mask_t[BITS_TO_LONGS(32 * XE_MAX_DSS_FUSE_REGS)];
-- 
2.34.1