[PATCH 2/6] drm/i915/gt: Split wa_add into smaller functions

[Umesh Nerlige Ramappa]

We prepare to enable user to allow and deny registers to be whitelisted
for an engine. Split wa_add to smaller functions that can be reused when
adding/removing workarounds to/from the wal->list.

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_workarounds.c | 89 +++++++++++++--------
 1 file changed, 54 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index 6c580d0d9ea8..0daaf82c60bc 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -112,55 +112,74 @@ static void wa_init_finish(struct i915_wa_list *wal)
 			 wal->wa_count, wal->name, wal->engine_name);
 }
 
-static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
+static int _wa_index(struct i915_wa_list *wal, i915_reg_t reg)
 {
-	unsigned int addr = i915_mmio_reg_offset(wa->reg);
-	unsigned int start = 0, end = wal->count;
-	const unsigned int grow = WA_LIST_CHUNK;
-	struct i915_wa *wa_;
+	unsigned int addr = i915_mmio_reg_offset(reg);
+	int start = 0, end = wal->count;
 
-	GEM_BUG_ON(!is_power_of_2(grow));
+	/* addr and wal->list[].reg, both include the R/W flags */
+	while (start < end) {
+		unsigned int mid = start + (end - start) / 2;
 
-	if (IS_ALIGNED(wal->count, grow)) { /* Either uninitialized or full. */
-		struct i915_wa *list;
+		if (i915_mmio_reg_offset(wal->list[mid].reg) < addr)
+			start = mid + 1;
+		else if (i915_mmio_reg_offset(wal->list[mid].reg) > addr)
+			end = mid;
+		else
+			return mid;
+	}
 
-		list = kmalloc_array(ALIGN(wal->count + 1, grow), sizeof(*wa),
-				     GFP_KERNEL);
-		if (!list) {
-			DRM_ERROR("No space for workaround init!\n");
-			return;
-		}
+	return -ENOENT;
+}
 
-		if (wal->list)
-			memcpy(list, wal->list, sizeof(*wa) * wal->count);
+static int _wa_list_grow(struct i915_wa_list *wal, size_t count)
+{
+	struct i915_wa *list;
 
-		wal->list = list;
+	list = kmalloc_array(ALIGN(count + 1, WA_LIST_CHUNK), sizeof(*list),
+			     GFP_KERNEL);
+	if (!list) {
+		DRM_ERROR("No space for workaround init!\n");
+		return -ENOMEM;
 	}
 
-	while (start < end) {
-		unsigned int mid = start + (end - start) / 2;
+	if (wal->list)
+		memcpy(list, wal->list, sizeof(*list) * count);
 
-		if (i915_mmio_reg_offset(wal->list[mid].reg) < addr) {
-			start = mid + 1;
-		} else if (i915_mmio_reg_offset(wal->list[mid].reg) > addr) {
-			end = mid;
-		} else {
-			wa_ = &wal->list[mid];
+	wal->list = list;
 
-			if ((wa->clr | wa_->clr) && !(wa->clr & ~wa_->clr)) {
-				DRM_ERROR("Discarding overwritten w/a for reg %04x (clear: %08x, set: %08x)\n",
-					  i915_mmio_reg_offset(wa_->reg),
-					  wa_->clr, wa_->set);
+	return 0;
+}
 
-				wa_->set &= ~wa->clr;
-			}
+static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
+{
+	int index;
+	const unsigned int grow = WA_LIST_CHUNK;
+	struct i915_wa *wa_;
 
-			wal->wa_count++;
-			wa_->set |= wa->set;
-			wa_->clr |= wa->clr;
-			wa_->read |= wa->read;
+	GEM_BUG_ON(!is_power_of_2(grow));
+
+	if (IS_ALIGNED(wal->count, grow)) /* Either uninitialized or full. */
+		if (_wa_list_grow(wal, wal->count) < 0)
 			return;
+
+	index = _wa_index(wal, wa->reg);
+	if (index >= 0) {
+		wa_ = &wal->list[index];
+
+		if ((wa->clr | wa_->clr) && !(wa->clr & ~wa_->clr)) {
+			DRM_ERROR("Discarding overwritten w/a for reg %04x (clear: %08x, set: %08x)\n",
+				  i915_mmio_reg_offset(wa_->reg),
+				  wa_->clr, wa_->set);
+
+			wa_->set &= ~wa->clr;
 		}
+
+		wal->wa_count++;
+		wa_->set |= wa->set;
+		wa_->clr |= wa->clr;
+		wa_->read |= wa->read;
+		return;
 	}
 
 	wal->wa_count++;
-- 
2.20.1