From 139ad1143151a07be93bf741d4ea7c89e59f89ce Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Wed, 4 Oct 2023 14:17:08 +0300 Subject: [PATCH] phy: lynx-28g: serialize concurrent phy_set_mode_ext() calls to shared registers 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 Signed-off-by: David S. Miller --- 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,