netdev - RE: [PATCH v2] net: axienet: allow setups without MDIO

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Message-ID: <BY5PR02MB6520E81C2A99992B1008FFA0C7629@BY5PR02MB6520.namprd02.prod.outlook.com>
Date:   Thu, 25 Mar 2021 12:44:30 +0000
From:   Radhey Shyam Pandey <radheys@...inx.com>
To:     Daniel Mack <daniel@...que.org>
CC:     "davem@...emloft.net" <davem@...emloft.net>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH v2] net: axienet: allow setups without MDIO

> -----Original Message-----
> From: Daniel Mack <daniel@...que.org>
> Sent: Wednesday, March 24, 2021 6:36 PM
> To: Radhey Shyam Pandey <radheys@...inx.com>
> Cc: davem@...emloft.net; kuba@...nel.org; netdev@...r.kernel.org;
> Daniel Mack <daniel@...que.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 <daniel@...que.org>

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@...inx.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