[PATCH 04/15] drm/msm/a6xx: Factor out RPMh arc-vote helpers

[Akhil P Oommen]

The GMU RPMh vote construction repeats two patterns across
a6xx_gmu_rpmh_arc_votes_init() and a6xx_gmu_rpmh_dep_votes_init():
reading a cmd-db aux-data resource (with the same "halve the byte count
and reject empty" handling), and scanning an arc level array for the
first corner that satisfies a target level.

Refactor out a6xx_gmu_rpmh_read_arc() and a6xx_gmu_rpmh_arc_index() to
reduce code duplication and improve code readability.

Assisted-by: LLM
Signed-off-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 138 ++++++++++++++++------------------
 1 file changed, 63 insertions(+), 75 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 161b360bf3eb..0ed01ce1c5c5 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -1711,74 +1711,85 @@ static unsigned int a6xx_gmu_get_arc_level(struct device *dev,
 	return val;
 }
 
+static const u16 *a6xx_gmu_rpmh_read_arc(const char *id, size_t *count)
+{
+	const u16 *vals;
+
+	vals = cmd_db_read_aux_data(id, count);
+	if (IS_ERR(vals))
+		return vals;
+
+	*count >>= 1;
+	/* Exclude the trailing zero paddings if there are any */
+	while (*count && !vals[*count - 1])
+		(*count)--;
+
+	if (!*count)
+		return ERR_PTR(-EINVAL);
+
+	return vals;
+}
+
+/*
+ * Find the first index in an arc level array whose level is greater than or
+ * equal to the target. If no level is high enough, either clamp to the
+ * highest available level (@clamp) or fail, dumping the list.
+ */
+static int a6xx_gmu_rpmh_arc_index(struct device *dev, const u16 *arc,
+				   size_t arc_count, unsigned int level, bool clamp)
+{
+	int j;
+
+	for (j = 0; j < arc_count; j++) {
+		if (arc[j] >= level)
+			return j;
+	}
+
+	if (clamp)
+		return arc_count - 1;
+
+	DRM_DEV_ERROR(dev, "Level %u not found in the RPMh list\n", level);
+	DRM_DEV_ERROR(dev, "Available levels:\n");
+	for (j = 0; j < arc_count; j++)
+		DRM_DEV_ERROR(dev, "  %u\n", arc[j]);
+
+	return -EINVAL;
+}
+
 static int a6xx_gmu_rpmh_arc_votes_init(struct device *dev, u32 *votes,
 		unsigned long *freqs, int freqs_count,
 		const char *pri_id, const char *sec_id)
 {
-	int i, j;
+	int i;
 	const u16 *pri, *sec;
 	size_t pri_count, sec_count;
 
-	pri = cmd_db_read_aux_data(pri_id, &pri_count);
+	pri = a6xx_gmu_rpmh_read_arc(pri_id, &pri_count);
 	if (IS_ERR(pri))
 		return PTR_ERR(pri);
-	/*
-	 * The data comes back as an array of unsigned shorts so adjust the
-	 * count accordingly
-	 */
-	pri_count >>= 1;
-	if (!pri_count)
-		return -EINVAL;
 
-	sec = cmd_db_read_aux_data(sec_id, &sec_count);
+	sec = a6xx_gmu_rpmh_read_arc(sec_id, &sec_count);
 	if (IS_ERR(sec))
 		return PTR_ERR(sec);
 
-	sec_count >>= 1;
-	if (!sec_count)
-		return -EINVAL;
-
 	/* Construct a vote for each frequency */
 	for (i = 0; i < freqs_count; i++) {
-		u8 pindex = 0, sindex = 0;
 		unsigned int level = a6xx_gmu_get_arc_level(dev, freqs[i]);
+		int pindex, sindex;
 
-		/* Get the primary index that matches the arc level */
-		for (j = 0; j < pri_count; j++) {
-			if (pri[j] >= level) {
-				pindex = j;
-				break;
-			}
-		}
-
-		if (j == pri_count) {
-			DRM_DEV_ERROR(dev,
-				      "Level %u not found in the RPMh list\n",
-				      level);
-			DRM_DEV_ERROR(dev, "Available levels:\n");
-			for (j = 0; j < pri_count; j++)
-				DRM_DEV_ERROR(dev, "  %u\n", pri[j]);
-
-			return -EINVAL;
-		}
+		pindex = a6xx_gmu_rpmh_arc_index(dev, pri, pri_count, level, false);
+		if (pindex < 0)
+			return pindex;
 
 		/*
-		 * Look for a level in in the secondary list that matches. If
-		 * nothing fits, use the maximum non zero vote
-		 *
-		 * The secondary rail depends on the primary rail, so match it
-		 * against the quantized primary voltage (which is >= the
-		 * requested level), not the requested level itself.
+		 * Look for a matching level in the secondary list; if nothing
+		 * fits, clamp to the highest available vote. The secondary rail
+		 * depends on the primary rail, so match it against the selected
+		 * primary voltage (which is >= the requested level), not the
+		 * requested level itself.
 		 */
-
-		for (j = 0; j < sec_count; j++) {
-			if (sec[j] >= pri[pindex]) {
-				sindex = j;
-				break;
-			} else if (sec[j]) {
-				sindex = j;
-			}
-		}
+		sindex = a6xx_gmu_rpmh_arc_index(dev, sec, sec_count,
+						 pri[pindex], true);
 
 		/* Construct the vote */
 		votes[i] = ((pri[pindex] & 0xffff) << 16) |
@@ -1794,16 +1805,9 @@ static int a6xx_gmu_rpmh_dep_votes_init(struct device *dev, u32 *votes,
 	const u16 *mx;
 	size_t count;
 
-	mx = cmd_db_read_aux_data("mx.lvl", &count);
+	mx = a6xx_gmu_rpmh_read_arc("mx.lvl", &count);
 	if (IS_ERR(mx))
 		return PTR_ERR(mx);
-	/*
-	 * The data comes back as an array of unsigned shorts so adjust the
-	 * count accordingly
-	 */
-	count >>= 1;
-	if (!count)
-		return -EINVAL;
 
 	/* Fix the vote for zero frequency */
 	votes[0] = 0xffffffff;
@@ -1811,26 +1815,10 @@ static int a6xx_gmu_rpmh_dep_votes_init(struct device *dev, u32 *votes,
 	/* Construct a vote for rest of the corners */
 	for (int i = 1; i < freqs_count; i++) {
 		unsigned int level = a6xx_gmu_get_arc_level(dev, freqs[i]);
-		u8 j, index = 0;
+		int index = a6xx_gmu_rpmh_arc_index(dev, mx, count, level, false);
 
-		/* Get the primary index that matches the arc level */
-		for (j = 0; j < count; j++) {
-			if (mx[j] >= level) {
-				index = j;
-				break;
-			}
-		}
-
-		if (j == count) {
-			DRM_DEV_ERROR(dev,
-				      "Mx Level %u not found in the RPMh list\n",
-				      level);
-			DRM_DEV_ERROR(dev, "Available levels:\n");
-			for (j = 0; j < count; j++)
-				DRM_DEV_ERROR(dev, "  %u\n", mx[j]);
-
-			return -EINVAL;
-		}
+		if (index < 0)
+			return index;
 
 		/* Construct the vote */
 		votes[i] = (0x3fff << 14) | (index << 8) | (0xff);

-- 
2.55.0