[Linux-stm32] [PATCH net v3 2/3] net: stmmac: check if MAC needs to attach to a PHY

[Sit, Michael Wei Hong]

On 6 Apr 2023, at 1:02 AM, Guenter Roeck <linux at roeck-us.net> wrote:

Hi,

On Fri, Mar 24, 2023 at 04:16:55PM +0800, Michael Sit Wei Hong wrote:
After the introduction of the fixed-link support, the MAC driver
no longer attempt to scan for a PHY to attach to. This causes the
non fixed-link setups to stop working.

Using the phylink_expects_phy() to check and determine if the MAC
should expect and attach a PHY.

Fixes: ab21cf920928 ("net: stmmac: make mdio register skips PHY scanning for fixed-link")
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit at intel.com>
Signed-off-by: Lai Peter Jun Ann <peter.jun.ann.lai at intel.com>

With this patch in linux-next, the orangepi-pc qemu emulation fails to
bring up the Ethernet interface. The following error is seen.

[   12.482401] dwmac-sun8i 1c30000.ethernet eth0: Register MEM_TYPE_PAGE_POOL RxQ-0
[   12.487789] dwmac-sun8i 1c30000.ethernet eth0: PHY [mdio_mux-0.1:01] driver [Generic PHY] (irq=POLL)
[   12.488177] dwmac-sun8i 1c30000.ethernet eth0: no phy found
[   12.488295] dwmac-sun8i 1c30000.ethernet eth0: __stmmac_open: Cannot attach to PHY (error: -19)

Reverting this patch fixes the problem.

---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 8f543c3ab5c5..41f0f3b74933 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1135,6 +1135,7 @@ static int stmmac_init_phy(struct net_device *dev)
{
   struct stmmac_priv *priv = netdev_priv(dev);
   struct fwnode_handle *fwnode;
+    bool phy_needed;
   int ret;

   fwnode = of_fwnode_handle(priv->plat->phylink_node);
@@ -1144,10 +1145,11 @@ static int stmmac_init_phy(struct net_device *dev)
   if (fwnode)
       ret = phylink_fwnode_phy_connect(priv->phylink, fwnode, 0);

+    phy_needed = phylink_expects_phy(priv->phylink);
   /* Some DT bindings do not set-up the PHY handle. Let's try to
    * manually parse it
    */
-    if (!fwnode || ret) {
+    if (!fwnode || phy_needed || ret) {

I don't really understand this condition. It starts taking this path even if ret == 0
and fwnode != NULL if phy_needed is set. That means this path is now taken even if
phylink_fwnode_phy_connect() returned no error. That seems odd.

Guenter

Please try the patch here
<https://patchwork.kernel.org/project/netdevbpf/patch/20230405093945.3549491-1-michael.wei.hong.sit@intel.com/>
[net,1/1] net: stmmac: check fwnode for phy device before scanning for phy - Patchwork<https://patchwork.kernel.org/project/netdevbpf/patch/20230405093945.3549491-1-michael.wei.hong.sit@intel.com/>
patchwork.kernel.org<https://patchwork.kernel.org/project/netdevbpf/patch/20230405093945.3549491-1-michael.wei.hong.sit@intel.com/>
[X]<https://patchwork.kernel.org/project/netdevbpf/patch/20230405093945.3549491-1-michael.wei.hong.sit@intel.com/>

       int addr = priv->plat->phy_addr;
       struct phy_device *phydev;

--
2.34.1

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://st-md-mailman.stormreply.com/pipermail/linux-stm32/attachments/20230405/c96c7e97/attachment.html>