diff mbox series

[net-next,v2,5/5] net: stmmac: do not silently change auxiliary snapshot capture channel

Message ID 20231010-stmmac_fix_auxiliary_event_capture-v2-5-51d5f56542d7@pengutronix.de
State New
Headers
Series net: stmmac: use correct PPS input indexing |

Commit Message

Johannes Zink Oct. 18, 2023, 7:09 a.m. UTC 
  Even though the hardware theoretically supports up to 4 simultaneous
auxiliary snapshot capture channels, the stmmac driver does support only
a single channel to be active at a time.

Previously in case of a PTP_CLK_REQ_EXTTS request, previously active
auxiliary snapshot capture channels were silently dropped and the new
channel was activated.

Instead of silently changing the state for all consumers, log an error
and return -EBUSY if a channel is already in use in order to signal to
userspace to disable the currently active channel before enabling another one.

Signed-off-by: Johannes Zink <j.zink@pengutronix.de>

---

Changelog:

v1 -> v2: no changes
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 6b639b62f778..bffa5c017032 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -191,11 +191,23 @@  static int stmmac_enable(struct ptp_clock_info *ptp,
 					     priv->systime_flags);
 		write_unlock_irqrestore(&priv->ptp_lock, flags);
 		break;
-	case PTP_CLK_REQ_EXTTS:
+	case PTP_CLK_REQ_EXTTS: {
+		u8 channel;
+
 		mutex_lock(&priv->aux_ts_lock);
 		acr_value = readl(ptpaddr + PTP_ACR);
+		channel = ilog2(FIELD_GET(PTP_ACR_MASK, acr_value));
 		acr_value &= ~PTP_ACR_MASK;
+
 		if (on) {
+			if (FIELD_GET(PTP_ACR_MASK, acr_value)) {
+				netdev_err(priv->dev,
+					   "Cannot enable auxiliary snapshot %d as auxiliary snapshot %d is already enabled",
+					rq->extts.index, channel);
+				mutex_unlock(&priv->aux_ts_lock);
+				return -EBUSY;
+			}
+
 			priv->plat->flags |= STMMAC_FLAG_EXT_SNAPSHOT_EN;
 
 			/* Enable External snapshot trigger */
@@ -213,6 +225,7 @@  static int stmmac_enable(struct ptp_clock_info *ptp,
 					 !(acr_value & PTP_ACR_ATSFC),
 					 10, 10000);
 		break;
+	}
 
 	default:
 		break;