Re: [PATCH net-next 4/5] tsnep: Add TSN endpoint Ethernet MAC driver

On Mon, Jul 26, 2021 at 10:50 PM Andrew Lunn [off-list ref] wrote:

Hi Gerhard

Hi Andrew

quoted

+int tsnep_read_md(struct tsnep_adapter *adapter, int phy, int reg, u16 *data)
+{
+     u32 md;
+     int retval = 0;
+
+     if (mutex_lock_interruptible(&adapter->md_lock) != 0)
+             return -ERESTARTSYS;

This probably means you have something wrong with your architecture.
The core mdio layer will serialise access to the mdio bus. So you
should not need such locks.

quoted

+int tsnep_enable_loopback(struct tsnep_adapter *adapter, int speed)
+{
+     int phy_address = adapter->phydev->mdio.addr;
+     u16 val;
+     int retval;
+
+     adapter->loopback = true;
+     adapter->loopback_speed = speed;
+
+     retval = tsnep_read_md(adapter, phy_address, MII_BMCR, &val);

And this might be why you have these locks?

A MAC driver should never directly touch the PHY hardware. Use the
phy_loopback(phydev) call.

I will try to use phy_loopback(phydev) . Thanks for the advice!

Gerhard