net: axienet: Wait for PhyRstCmplt after core reset

commit b400c2f4f4c53c86594dd57098970d97d488bfde upstream.

When resetting the device, wait for the PhyRstCmplt bit to be set
in the interrupt status register before continuing initialization, to
ensure that the core is actually ready. When using an external PHY, this
also ensures we do not start trying to access the PHY while it is still
in reset. The PHY reset is initiated by the core reset which is
triggered just above, but remains asserted for 5ms after the core is
reset according to the documentation.

The MgtRdy bit could also be waited for, but unfortunately when using
7-series devices, the bit does not appear to work as documented (it
seems to behave as some sort of link state indication and not just an
indication the transceiver is ready) so it can't really be relied on for
this purpose.

Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 137c3d33ea6855a919a9233233142402326a7029..811f15eace9f5f2e992ea33b9394862f743bdee3 100644 (file)
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -516,6 +516,16 @@ static int __axienet_device_reset(struct axienet_local *lp)
                return ret;
        }
 
+       /* Wait for PhyRstCmplt bit to be set, indicating the PHY reset has finished */
+       ret = read_poll_timeout(axienet_ior, value,
+                               value & XAE_INT_PHYRSTCMPLT_MASK,
+                               DELAY_OF_ONE_MILLISEC, 50000, false, lp,
+                               XAE_IS_OFFSET);
+       if (ret) {
+               dev_err(lp->dev, "%s: timeout waiting for PhyRstCmplt\n", __func__);
+               return ret;
+       }
+
        return 0;
 }