net: macb: Use pm_runtime_force_resume/suspend APIs in MDIO helper fu…

…nctions

In usecase like SOM KR260 there is a constraint that ethernet
interface(ff0c0000) MDIO bus producer has to be resumed before
the consumer ethernet interface(ff0b0000).

However above constraint is not met when GEM0(ff0b0000) is resumed first.
There is phy_error on GEM0 and interface becomes non-functional on resume.
The suspend/resume is dependent on probe order which can also be modified
in DT but it seems less scalable and might not work with defer probe and
overlays.

suspend:
[ 46.477795] macb ff0c0000.ethernet eth1: Link is Down
[ 46.483058] macb ff0c0000.ethernet: gem-ptp-timer ptp clock unregistered.
[ 46.490097] macb ff0b0000.ethernet eth0: Link is Down
[ 46.495298] macb ff0b0000.ethernet: gem-ptp-timer ptp clock unregistered.

resume:
[ 46.633840] macb ff0b0000.ethernet eth0: configuring for phy/sgmii link mode
macb_mdio_read -> pm_runtime_get_sync(GEM1) it return -EACCES error.

To fix this dependency - we make use of pm_runtime_force_resume/suspend
APIs variants. This seems to be a temporary fix till we discuss about the
usecase in mainline and see on how can these dependencies are defined
and resume of consumer is deferred until the producer interface is up.

Signed-off-by: Radhey Shyam Pandey <[email protected]>
Reviewed-by: Harini Katakam <[email protected]>

drivers/net/ethernet/cadence/macb_main.c

@@ -341,11 +341,13 @@ static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 {
 	struct macb *bp = bus->priv;
 	int status;
+	bool force_resume;
 
-	status = pm_runtime_get_sync(&bp->pdev->dev);
-	if (status < 0) {
-		pm_runtime_put_noidle(&bp->pdev->dev);
-		goto mdio_pm_exit;
+	force_resume = pm_runtime_status_suspended(&bp->pdev->dev);
+	if (force_resume) {
+		status = pm_runtime_force_resume(&bp->pdev->dev);
+		if (status < 0)
+			goto mdio_pm_exit;
 	}
 
 	status = macb_mdio_wait_for_idle(bp);
@@ -384,8 +386,8 @@ static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 	status = MACB_BFEXT(DATA, macb_readl(bp, MAN));
 
 mdio_read_exit:
-	pm_runtime_mark_last_busy(&bp->pdev->dev);
-	pm_runtime_put_autosuspend(&bp->pdev->dev);
+	if (force_resume)
+		pm_runtime_force_suspend(&bp->pdev->dev);
 mdio_pm_exit:
 	return status;
 }
@@ -395,11 +397,13 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 {
 	struct macb *bp = bus->priv;
 	int status;
+	bool force_resume;
 
-	status = pm_runtime_get_sync(&bp->pdev->dev);
-	if (status < 0) {
-		pm_runtime_put_noidle(&bp->pdev->dev);
-		goto mdio_pm_exit;
+	force_resume = pm_runtime_status_suspended(&bp->pdev->dev);
+	if (force_resume) {
+		status = pm_runtime_force_resume(&bp->pdev->dev);
+		if (status < 0)
+			goto mdio_pm_exit;
 	}
 
 	status = macb_mdio_wait_for_idle(bp);
@@ -438,8 +442,8 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 		goto mdio_write_exit;
 
 mdio_write_exit:
-	pm_runtime_mark_last_busy(&bp->pdev->dev);
-	pm_runtime_put_autosuspend(&bp->pdev->dev);
+	if (force_resume)
+		pm_runtime_force_suspend(&bp->pdev->dev);
 mdio_pm_exit:
 	return status;
 }