phy: lynx-28g: lock PHY while performing CDR lock workaround

[ Upstream commit 0ac87fe54a171d18c5fb5345e3ee8d14e1b06f4b ]

lynx_28g_cdr_lock_check() runs once per second in a workqueue to reset
the lane receiver if the CDR has not locked onto bit transitions in the
RX stream. But the PHY consumer may do stuff with the PHY simultaneously,
and that isn't okay. Block concurrent generic PHY calls by holding the
PHY mutex from this workqueue.

Fixes: 8f73b37cf3fb ("phy: add support for the Layerscape SerDes 28G")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/phy/freescale/phy-fsl-lynx-28g.c b/drivers/phy/freescale/phy-fsl-lynx-28g.c
index 9d55dbee2e0a56357821bb92a5f74f2292685e45..d49aa59c7d812e86876e72612ed34bbfc00be504 100644 (file)
--- a/drivers/phy/freescale/phy-fsl-lynx-28g.c
+++ b/drivers/phy/freescale/phy-fsl-lynx-28g.c
@@ -507,11 +507,12 @@ static void lynx_28g_cdr_lock_check(struct work_struct *work)
        for (i = 0; i < LYNX_28G_NUM_LANE; i++) {
                lane = &priv->lane[i];
 
-               if (!lane->init)
-                       continue;
+               mutex_lock(&lane->phy->mutex);
 
-               if (!lane->powered_up)
+               if (!lane->init || !lane->powered_up) {
+                       mutex_unlock(&lane->phy->mutex);
                        continue;
+               }
 
                rrstctl = lynx_28g_lane_read(lane, LNaRRSTCTL);
                if (!(rrstctl & LYNX_28G_LNaRRSTCTL_CDR_LOCK)) {
@@ -520,6 +521,8 @@ static void lynx_28g_cdr_lock_check(struct work_struct *work)
                                rrstctl = lynx_28g_lane_read(lane, LNaRRSTCTL);
                        } while (!(rrstctl & LYNX_28G_LNaRRSTCTL_RST_DONE));
                }
+
+               mutex_unlock(&lane->phy->mutex);
        }
        queue_delayed_work(system_power_efficient_wq, &priv->cdr_check,
                           msecs_to_jiffies(1000));