> -----Original Message-----
> From: Daniel Mack <dan...@zonque.org>
> Sent: Wednesday, March 24, 2021 6:36 PM
> To: Radhey Shyam Pandey <radh...@xilinx.com>
> Cc: da...@davemloft.net; k...@kernel.org; netdev@vger.kernel.org;
> Daniel Mack <dan...@zonque.org>
> Subject: [PATCH v2] net: axienet: allow setups without MDIO
>
> In setups with fixed-link settings there is no mdio node in DTS.
> axienet_probe() already handles that gracefully but lp->mii_bus is then
> NULL.
>
> Fix code that tries to blindly grab the MDIO lock by introducing two helper
> functions that make the locking conditional.
>
> Signed-off-by: Daniel Mack <dan...@zonque.org>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pan...@xilinx.com>
Thanks!
> ---
> v2:
> * Also fix axienet_dma_err_handler, as pointed out by Andrew Lunn
>
> drivers/net/ethernet/xilinx/xilinx_axienet.h | 12 ++++++++++++
> drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 12 ++++++------
> 2 files changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h
> b/drivers/net/ethernet/xilinx/xilinx_axienet.h
> index 1e966a39967e5..aca7f82f6791b 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
> @@ -504,6 +504,18 @@ static inline u32 axinet_ior_read_mcr(struct
> axienet_local *lp)
> return axienet_ior(lp, XAE_MDIO_MCR_OFFSET); }
>
> +static inline void axienet_lock_mii(struct axienet_local *lp) {
> + if (lp->mii_bus)
> + mutex_lock(&lp->mii_bus->mdio_lock);
> +}
> +
> +static inline void axienet_unlock_mii(struct axienet_local *lp) {
> + if (lp->mii_bus)
> + mutex_unlock(&lp->mii_bus->mdio_lock);
> +}
> +
> /**
> * axienet_iow - Memory mapped Axi Ethernet register write
> * @lp: Pointer to axienet local structure
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index 3a8775e0ca552..61380c6b65b86 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -1053,9 +1053,9 @@ static int axienet_open(struct net_device *ndev)
> * including the MDIO. MDIO must be disabled before resetting.
> * Hold MDIO bus lock to avoid MDIO accesses during the reset.
> */
> - mutex_lock(&lp->mii_bus->mdio_lock);
> + axienet_lock_mii(lp);
> ret = axienet_device_reset(ndev);
> - mutex_unlock(&lp->mii_bus->mdio_lock);
> + axienet_unlock_mii(lp);
>
> ret = phylink_of_phy_connect(lp->phylink, lp->dev->of_node, 0);
> if (ret) {
> @@ -1148,9 +1148,9 @@ static int axienet_stop(struct net_device *ndev)
> }
>
> /* Do a reset to ensure DMA is really stopped */
> - mutex_lock(&lp->mii_bus->mdio_lock);
> + axienet_lock_mii(lp);
> __axienet_device_reset(lp);
> - mutex_unlock(&lp->mii_bus->mdio_lock);
> + axienet_unlock_mii(lp);
>
> cancel_work_sync(&lp->dma_err_task);
>
> @@ -1709,9 +1709,9 @@ static void axienet_dma_err_handler(struct
> work_struct *work)
> * including the MDIO. MDIO must be disabled before resetting.
> * Hold MDIO bus lock to avoid MDIO accesses during the reset.
> */
> - mutex_lock(&lp->mii_bus->mdio_lock);
> + axienet_lock_mii(lp);
> __axienet_device_reset(lp);
> - mutex_unlock(&lp->mii_bus->mdio_lock);
> + axienet_unlock_mii(lp);
>
> for (i = 0; i < lp->tx_bd_num; i++) {
> cur_p = &lp->tx_bd_v[i];
> --
> 2.30.2
