[PATCH v1] spmi: msm: refine handling of multiple APID mappings

[Aswin Murugan]

PMIC Arbiter may expose multiple owned and non-owned APIDs per SID/PID.
- Keep current mapping if it is OWNED and a NON-OWNED appears.
- Always update when a NEW OWNED APID appears (make writable).
- If current is NON-OWNED and a new NON-OWNED appears, update to it
  (remain read-only).

This avoids write-access violations when not using the newly discovered
owned channels.

Signed-off-by: Aswin Murugan <aswin.murugan at oss.qualcomm.com>
---
 drivers/spmi/spmi-msm.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/spmi/spmi-msm.c b/drivers/spmi/spmi-msm.c
index faae54e9fef..f3cd98c3db8 100644
--- a/drivers/spmi/spmi-msm.c
+++ b/drivers/spmi/spmi-msm.c
@@ -274,10 +274,25 @@ static void msm_spmi_channel_map_v5(struct msm_spmi_priv *priv, unsigned int i,
 		priv->channel_map[slave_id][pid] = i | SPMI_CHANNEL_VALID;
 		if (owner != priv->owner)
 			priv->channel_map[slave_id][pid] |= SPMI_CHANNEL_READ_ONLY;
-	} else if ((owner == priv->owner) && prev_read_only) {
-		/* Read only and we found one we own, switch */
+
+	} else if (owner == priv->owner) {
+		/*
+		 * Found a channel owned by our EE - ALWAYS switch to it!
+		 * even if we already have a mapping, we must prefer the one
+		 * owned by our EE to avoid hardware access violations.
+		 */
 		priv->channel_map[slave_id][pid] = i | SPMI_CHANNEL_VALID;
+		/* Clear READ_ONLY flag since we own this channel */
+
+	} else if (prev_read_only) {
+		/*
+		 * Previous mapping was read-only and this one is also not ours.
+		 * Update to this channel.
+		 */
+		priv->channel_map[slave_id][pid] = i | SPMI_CHANNEL_VALID | SPMI_CHANNEL_READ_ONLY;
+
 	}
+	/* else: Previous was writable and owned by us, this one isn't - keep previous */
 }
 
 static int msm_spmi_probe(struct udevice *dev)
-- 
2.34.1