Thread (7 messages) 7 messages, 4 authors, 2019-10-16

Re: lan78xx and phy_state_machine

From: Stefan Wahren <wahrenst@gmx.net>
Date: 2019-10-16 05:48:30
Also in: linux-arm-kernel

Am 15.10.19 um 21:38 schrieb Heiner Kallweit:
On 15.10.2019 00:12, Russell King - ARM Linux admin wrote:
quoted
On Mon, Oct 14, 2019 at 10:20:15PM +0200, Heiner Kallweit wrote:
quoted
On 14.10.2019 21:51, Stefan Wahren wrote:
quoted
[add more recipients]

Am 14.10.19 um 21:25 schrieb Daniel Wagner:
quoted
Moving the phy_prepare_link() up in phy_connect_direct() ensures that
phydev->adjust_link is set when the phy_check_link_status() is called.
diff --git a/drivers/net/phy/phy_device.c
b/drivers/net/phy/phy_device.c index 9d2bbb13293e..2a61812bcb0d 100644
--- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c
@@ -951,11 +951,12 @@ int phy_connect_direct(struct net_device *dev,
struct phy_device *phydev, if (!dev) return -EINVAL;

+       phy_prepare_link(phydev, handler);
+
        rc = phy_attach_direct(dev, phydev, phydev->dev_flags, interface);
        if (rc)
If phy_attach_direct() fails we may have to reset phydev->adjust_link to NULL,
as we do in phy_disconnect(). Apart from that change looks good to me.
Sorry, but it doesn't look good to me.

I think there's a deeper question here - why is the phy state machine
trying to call the link change function during attach?
After your comment I had a closer look at the lm78xx driver and few things
look suspicious:

- lan78xx_phy_init() (incl. the call to phy_connect_direct()) is called
  after register_netdev(). This may cause races.

- The following is wrong, irq = 0 doesn't mean polling.
  PHY_POLL is defined as -1. Also in case of irq = 0 phy_interrupt_is_valid()
  returns true.

	/* if phyirq is not set, use polling mode in phylib */
	if (dev->domain_data.phyirq > 0)
		phydev->irq = dev->domain_data.phyirq;
	else
		phydev->irq = 0;

- Manually calling genphy_config_aneg() in lan78xx_phy_init() isn't
  needed, however this should not cause our problem.
Thanks for this review. This may help to fix at least a one of all the
other issues with lan78xx.
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