diff mbox series

[v5,net-next,07/13] net: enetc: remove ERR050089 workaround for i.MX95

Message ID 20241024065328.521518-8-wei.fang@nxp.com
State New
Headers show
Series add basic support for i.MX95 NETC | expand

Commit Message

Wei Fang Oct. 24, 2024, 6:53 a.m. UTC 
From: Vladimir Oltean <vladimir.oltean@nxp.com>

The ERR050089 workaround causes performance degradation and potential
functional issues (e.g., RCU stalls) under certain workloads. Since
new SoCs like i.MX95 do not require this workaround, use a static key
to compile out enetc_lock_mdio() and enetc_unlock_mdio() at runtime,
improving performance and avoiding unnecessary logic.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
v5: no changes
---
 .../net/ethernet/freescale/enetc/enetc_hw.h   | 34 +++++++++++++------
 .../ethernet/freescale/enetc/enetc_pci_mdio.c | 17 ++++++++++
 2 files changed, 41 insertions(+), 10 deletions(-)

Comments

Vladimir Oltean Oct. 24, 2024, 5:51 p.m. UTC | #1 
On Thu, Oct 24, 2024 at 02:53:22PM +0800, Wei Fang wrote:
> @@ -62,6 +65,12 @@ static int enetc_pci_mdio_probe(struct pci_dev *pdev,
>  		goto err_pci_mem_reg;
>  	}
>  
> +	if (pdev->vendor == PCI_VENDOR_ID_FREESCALE &&
> +	    pdev->device == ENETC_MDIO_DEV_ID) {
> +		static_branch_inc(&enetc_has_err050089);
> +		dev_info(&pdev->dev, "Enabled ERR050089 workaround\n");
> +	}
> +
>  	err = of_mdiobus_register(bus, dev->of_node);
>  	if (err)
>  		goto err_mdiobus_reg;

If of_mdiobus_register() fails, we should disable the static key.

Perhaps the snippets to enable and disable the static key should be in
helper functions to more easily insert the error teardown logic.
Wei Fang Oct. 25, 2024, 3:04 a.m. UTC | #2 
> On Thu, Oct 24, 2024 at 02:53:22PM +0800, Wei Fang wrote:
> > @@ -62,6 +65,12 @@ static int enetc_pci_mdio_probe(struct pci_dev *pdev,
> >  		goto err_pci_mem_reg;
> >  	}
> >
> > +	if (pdev->vendor == PCI_VENDOR_ID_FREESCALE &&
> > +	    pdev->device == ENETC_MDIO_DEV_ID) {
> > +		static_branch_inc(&enetc_has_err050089);
> > +		dev_info(&pdev->dev, "Enabled ERR050089 workaround\n");
> > +	}
> > +
> >  	err = of_mdiobus_register(bus, dev->of_node);
> >  	if (err)
> >  		goto err_mdiobus_reg;
> 
> If of_mdiobus_register() fails, we should disable the static key.

> 
> Perhaps the snippets to enable and disable the static key should be in
> helper functions to more easily insert the error teardown logic.

Okay, I will refine it
diff mbox series

Patch

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_hw.h b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
index 1619943fb263..6a7b9b75d660 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_hw.h
+++ b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
@@ -396,18 +396,22 @@  struct enetc_hw {
  */
 extern rwlock_t enetc_mdio_lock;
 
+DECLARE_STATIC_KEY_FALSE(enetc_has_err050089);
+
 /* use this locking primitive only on the fast datapath to
  * group together multiple non-MDIO register accesses to
  * minimize the overhead of the lock
  */
 static inline void enetc_lock_mdio(void)
 {
-	read_lock(&enetc_mdio_lock);
+	if (static_branch_unlikely(&enetc_has_err050089))
+		read_lock(&enetc_mdio_lock);
 }
 
 static inline void enetc_unlock_mdio(void)
 {
-	read_unlock(&enetc_mdio_lock);
+	if (static_branch_unlikely(&enetc_has_err050089))
+		read_unlock(&enetc_mdio_lock);
 }
 
 /* use these accessors only on the fast datapath under
@@ -416,14 +420,16 @@  static inline void enetc_unlock_mdio(void)
  */
 static inline u32 enetc_rd_reg_hot(void __iomem *reg)
 {
-	lockdep_assert_held(&enetc_mdio_lock);
+	if (static_branch_unlikely(&enetc_has_err050089))
+		lockdep_assert_held(&enetc_mdio_lock);
 
 	return ioread32(reg);
 }
 
 static inline void enetc_wr_reg_hot(void __iomem *reg, u32 val)
 {
-	lockdep_assert_held(&enetc_mdio_lock);
+	if (static_branch_unlikely(&enetc_has_err050089))
+		lockdep_assert_held(&enetc_mdio_lock);
 
 	iowrite32(val, reg);
 }
@@ -452,9 +458,13 @@  static inline u32 _enetc_rd_mdio_reg_wa(void __iomem *reg)
 	unsigned long flags;
 	u32 val;
 
-	write_lock_irqsave(&enetc_mdio_lock, flags);
-	val = ioread32(reg);
-	write_unlock_irqrestore(&enetc_mdio_lock, flags);
+	if (static_branch_unlikely(&enetc_has_err050089)) {
+		write_lock_irqsave(&enetc_mdio_lock, flags);
+		val = ioread32(reg);
+		write_unlock_irqrestore(&enetc_mdio_lock, flags);
+	} else {
+		val = ioread32(reg);
+	}
 
 	return val;
 }
@@ -463,9 +473,13 @@  static inline void _enetc_wr_mdio_reg_wa(void __iomem *reg, u32 val)
 {
 	unsigned long flags;
 
-	write_lock_irqsave(&enetc_mdio_lock, flags);
-	iowrite32(val, reg);
-	write_unlock_irqrestore(&enetc_mdio_lock, flags);
+	if (static_branch_unlikely(&enetc_has_err050089)) {
+		write_lock_irqsave(&enetc_mdio_lock, flags);
+		iowrite32(val, reg);
+		write_unlock_irqrestore(&enetc_mdio_lock, flags);
+	} else {
+		iowrite32(val, reg);
+	}
 }
 
 #ifdef ioread64
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pci_mdio.c b/drivers/net/ethernet/freescale/enetc/enetc_pci_mdio.c
index a1b595bd7993..2445e35a764a 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pci_mdio.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pci_mdio.c
@@ -9,6 +9,9 @@ 
 #define ENETC_MDIO_BUS_NAME	ENETC_MDIO_DEV_NAME " Bus"
 #define ENETC_MDIO_DRV_NAME	ENETC_MDIO_DEV_NAME " driver"
 
+DEFINE_STATIC_KEY_FALSE(enetc_has_err050089);
+EXPORT_SYMBOL_GPL(enetc_has_err050089);
+
 static int enetc_pci_mdio_probe(struct pci_dev *pdev,
 				const struct pci_device_id *ent)
 {
@@ -62,6 +65,12 @@  static int enetc_pci_mdio_probe(struct pci_dev *pdev,
 		goto err_pci_mem_reg;
 	}
 
+	if (pdev->vendor == PCI_VENDOR_ID_FREESCALE &&
+	    pdev->device == ENETC_MDIO_DEV_ID) {
+		static_branch_inc(&enetc_has_err050089);
+		dev_info(&pdev->dev, "Enabled ERR050089 workaround\n");
+	}
+
 	err = of_mdiobus_register(bus, dev->of_node);
 	if (err)
 		goto err_mdiobus_reg;
@@ -88,6 +97,14 @@  static void enetc_pci_mdio_remove(struct pci_dev *pdev)
 	struct enetc_mdio_priv *mdio_priv;
 
 	mdiobus_unregister(bus);
+
+	if (pdev->vendor == PCI_VENDOR_ID_FREESCALE &&
+	    pdev->device == ENETC_MDIO_DEV_ID) {
+		static_branch_dec(&enetc_has_err050089);
+		if (!static_key_enabled(&enetc_has_err050089.key))
+			dev_info(&pdev->dev, "Disabled ERR050089 workaround\n");
+	}
+
 	mdio_priv = bus->priv;
 	iounmap(mdio_priv->hw->port);
 	pci_release_region(pdev, 0);