Re: [PATCH net-next 1/4] net: dsa: move up phy enabling in core

On 09/22/2017 09:32 AM, Andrew Lunn wrote:

On Fri, Sep 22, 2017 at 12:17:50PM -0400, Vivien Didelot wrote:

quoted

bcm_sf2 is currently the only driver using the phy argument passed to
.port_enable. It resets the state machine if the phy has been hard
reset. This check is generic and can be moved to DSA core.
 
 	dsa_port_set_state_now(p->dp, stp_state);
 
-	if (p->phy)
-		phy_start(p->phy);
+	if (phy) {
+		/* If phy_stop() has been called before, phy will be in
+		 * halted state, and phy_start() will call resume.
+		 *
+		 * The resume path does not configure back autoneg
+		 * settings, and since the internal phy may have been
+		 * hard reset, we need to reset the state machine also.
+		 */
+		phy->state = PHY_READY;
+		phy_init_hw(phy);
+		phy_start(phy);
+	}

Hi Vivien

If this is generic, why is it needed at all here? Shouldn't this
actually by in phylib?

This does not belong in the core logic within net/dsa/slave.c. The
reason why this is necessary here is because we are doing a HW-based
reset of the PHY, as the comment explains this is specific to how the HW
works. There may be a cleaner solution to this problem, but in any case,
I don't think other drivers should inherit that logic.
-- 
Florian