diff mbox series

[net-next,v2,6/7] net: phy: smsc: Cache interrupt mask

Message ID e4a5d784e47bf919873e520e0c6c5156a1ecdde7.1651574194.git.lukas@wunner.de (mailing list archive)
State Superseded
Headers show
Series Polling be gone on LAN95xx | expand

Commit Message

Lukas Wunner May 3, 2022, 1:15 p.m. UTC 
Cache the interrupt mask to avoid re-reading it from the PHY upon every
interrupt.

This will simplify a subsequent commit which detects hot-removal in the
interrupt handler and bails out.

Analyzing and debugging PHY transactions also becomes simpler if such
redundant reads are avoided.

Last not least, interrupt overhead and latency is slightly improved.

Tested-by: Oleksij Rempel <o.rempel@pengutronix.de> # LAN9514/9512/9500
Tested-by: Ferry Toth <fntoth@gmail.com> # LAN9514
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
Changes since v1:
 * Expand commit message to explain in greater detail why caching the
   interrupt mask is beneficial. (Andrew Lunn)

 drivers/net/phy/smsc.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

Comments

Andrew Lunn May 3, 2022, 10:26 p.m. UTC | #1 
On Tue, May 03, 2022 at 03:15:06PM +0200, Lukas Wunner wrote:
> Cache the interrupt mask to avoid re-reading it from the PHY upon every
> interrupt.
> 
> This will simplify a subsequent commit which detects hot-removal in the
> interrupt handler and bails out.
> 
> Analyzing and debugging PHY transactions also becomes simpler if such
> redundant reads are avoided.
> 
> Last not least, interrupt overhead and latency is slightly improved.
> 
> Tested-by: Oleksij Rempel <o.rempel@pengutronix.de> # LAN9514/9512/9500
> Tested-by: Ferry Toth <fntoth@gmail.com> # LAN9514
> Signed-off-by: Lukas Wunner <lukas@wunner.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew
diff mbox series

Patch

diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index d8cac02a79b9..a521d48b22a7 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -44,6 +44,7 @@  static struct smsc_hw_stat smsc_hw_stats[] = {
 };
 
 struct smsc_phy_priv {
+	u16 intmask;
 	bool energy_enable;
 	struct clk *refclk;
 };
@@ -58,7 +59,6 @@  static int smsc_phy_ack_interrupt(struct phy_device *phydev)
 static int smsc_phy_config_intr(struct phy_device *phydev)
 {
 	struct smsc_phy_priv *priv = phydev->priv;
-	u16 intmask = 0;
 	int rc;
 
 	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
@@ -66,12 +66,15 @@  static int smsc_phy_config_intr(struct phy_device *phydev)
 		if (rc)
 			return rc;
 
-		intmask = MII_LAN83C185_ISF_INT4 | MII_LAN83C185_ISF_INT6;
+		priv->intmask = MII_LAN83C185_ISF_INT4 | MII_LAN83C185_ISF_INT6;
 		if (priv->energy_enable)
-			intmask |= MII_LAN83C185_ISF_INT7;
-		rc = phy_write(phydev, MII_LAN83C185_IM, intmask);
+			priv->intmask |= MII_LAN83C185_ISF_INT7;
+
+		rc = phy_write(phydev, MII_LAN83C185_IM, priv->intmask);
 	} else {
-		rc = phy_write(phydev, MII_LAN83C185_IM, intmask);
+		priv->intmask = 0;
+
+		rc = phy_write(phydev, MII_LAN83C185_IM, 0);
 		if (rc)
 			return rc;
 
@@ -83,13 +86,8 @@  static int smsc_phy_config_intr(struct phy_device *phydev)
 
 static irqreturn_t smsc_phy_handle_interrupt(struct phy_device *phydev)
 {
-	int irq_status, irq_enabled;
-
-	irq_enabled = phy_read(phydev, MII_LAN83C185_IM);
-	if (irq_enabled < 0) {
-		phy_error(phydev);
-		return IRQ_NONE;
-	}
+	struct smsc_phy_priv *priv = phydev->priv;
+	int irq_status;
 
 	irq_status = phy_read(phydev, MII_LAN83C185_ISF);
 	if (irq_status < 0) {
@@ -97,7 +95,7 @@  static irqreturn_t smsc_phy_handle_interrupt(struct phy_device *phydev)
 		return IRQ_NONE;
 	}
 
-	if (!(irq_status & irq_enabled))
+	if (!(irq_status & priv->intmask))
 		return IRQ_NONE;
 
 	phy_trigger_machine(phydev);