[PATCH net 3/3] phy: lynx-28g: serialize concurrent phy_set_mode_ext() calls to shared registers
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2023-10-04 11:17:41
Also in:
linux-phy, lkml
Subsystem:
generic phy framework, lynx serdes phy drivers, the rest · Maintainers:
Vinod Koul, Ioana Ciornei, Vladimir Oltean, Linus Torvalds
The protocol converter configuration registers PCC8, PCCC, PCCD
(implemented by the driver), as well as others, control protocol
converters from multiple lanes (each represented as a different
struct phy). So, if there are simultaneous calls to phy_set_mode_ext()
to lanes sharing the same PCC register (either for the "old" or for the
"new" protocol), corruption of the values programmed to hardware is
possible, because lynx_28g_rmw() has no locking.
Add a spinlock in the struct lynx_28g_priv shared by all lanes, and take
the global spinlock from the phy_ops :: set_mode() implementation. There
are no other callers which modify PCC registers.
Fixes: 8f73b37cf3fb ("phy: add support for the Layerscape SerDes 28G")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
drivers/phy/freescale/phy-fsl-lynx-28g.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/phy/freescale/phy-fsl-lynx-28g.c b/drivers/phy/freescale/phy-fsl-lynx-28g.c
index d5385d36735d..e2187767ce00 100644
--- a/drivers/phy/freescale/phy-fsl-lynx-28g.c
+++ b/drivers/phy/freescale/phy-fsl-lynx-28g.c@@ -127,6 +127,10 @@ struct lynx_28g_lane { struct lynx_28g_priv { void __iomem *base; struct device *dev; + /* Serialize concurrent access to registers shared between lanes, + * like PCCn + */ + spinlock_t pcc_lock; struct lynx_28g_pll pll[LYNX_28G_NUM_PLL]; struct lynx_28g_lane lane[LYNX_28G_NUM_LANE];
@@ -397,6 +401,8 @@ static int lynx_28g_set_mode(struct phy *phy, enum phy_mode mode, int submode) if (powered_up) lynx_28g_power_off(phy); + spin_lock(&priv->pcc_lock); + switch (submode) { case PHY_INTERFACE_MODE_SGMII: case PHY_INTERFACE_MODE_1000BASEX:
@@ -413,6 +419,8 @@ static int lynx_28g_set_mode(struct phy *phy, enum phy_mode mode, int submode) lane->interface = submode; out: + spin_unlock(&priv->pcc_lock); + /* Power up the lane if necessary */ if (powered_up) lynx_28g_power_on(phy);
@@ -596,6 +604,7 @@ static int lynx_28g_probe(struct platform_device *pdev) dev_set_drvdata(dev, priv); + spin_lock_init(&priv->pcc_lock); INIT_DELAYED_WORK(&priv->cdr_check, lynx_28g_cdr_lock_check); queue_delayed_work(system_power_efficient_wq, &priv->cdr_check,
--
2.34.1