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From:   Radhey Shyam Pandey <radheys@xilinx.com>
To:     Andrew Lunn <andrew@lunn.ch>
CC:     "davem@davemloft.net" <davem@davemloft.net>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Anirudha Sarangi <anirudh@xilinx.com>,
        Michal Simek <michals@xilinx.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "mchehab+samsung@kernel.org" <mchehab+samsung@kernel.org>,
        John Linn <linnj@xilinx.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH v3 -next 4/4] net: emaclite: Fix restricted cast warning
 of sparse
Thread-Topic: [PATCH v3 -next 4/4] net: emaclite: Fix restricted cast warning
 of sparse
Thread-Index: AQHV2CxS+JD6AxkE/EyzRBxtS7+UeKgEyfuAgA/Il2A=
Date:   Mon, 10 Feb 2020 14:55:20 +0000
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> -----Original Message-----
> From: Andrew Lunn <andrew@lunn.ch>
> Sent: Friday, January 31, 2020 7:19 PM
> To: Radhey Shyam Pandey <radheys@xilinx.com>
> Cc: davem@davemloft.net; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; Anirudha Sarangi <anirudh@xilinx.com>; Michal Sim=
ek
> <michals@xilinx.com>; gregkh@linuxfoundation.org;
> mchehab+samsung@kernel.org; John Linn <linnj@xilinx.com>; linux-arm-
> kernel@lists.infradead.org
> Subject: Re: [PATCH v3 -next 4/4] net: emaclite: Fix restricted cast warn=
ing of
> sparse
>=20
> On Fri, Jan 31, 2020 at 05:17:50PM +0530, Radhey Shyam Pandey wrote:
> > Explicitly cast xemaclite_readl return value when it's passed to ntohl.
> > Fixes below reported sparse warnings:
> >
> > xilinx_emaclite.c:411:24: sparse: sparse: cast to restricted __be32
> > xilinx_emaclite.c:420:36: sparse: sparse: cast to restricted __be32
> >
> > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
> > Reported-by: kbuild test robot <lkp@intel.com>
> > ---
> >  drivers/net/ethernet/xilinx/xilinx_emaclite.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > index 96e9d21..3273d4f 100644
> > --- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > +++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > @@ -408,7 +408,8 @@ static u16 xemaclite_recv_data(struct net_local
> *drvdata, u8 *data, int maxlen)
> >
> >  	/* Get the protocol type of the ethernet frame that arrived
> >  	 */
> > -	proto_type =3D ((ntohl(xemaclite_readl(addr + XEL_HEADER_OFFSET +
> > +	proto_type =3D ((ntohl((__force __be32)xemaclite_readl(addr +
> > +			XEL_HEADER_OFFSET +
> >  			XEL_RXBUFF_OFFSET)) >> XEL_HEADER_SHIFT) &
> >  			XEL_RPLR_LENGTH_MASK);
> >
> > @@ -417,7 +418,7 @@ static u16 xemaclite_recv_data(struct net_local
> *drvdata, u8 *data, int maxlen)
> >  	 */
> >  	if (proto_type > ETH_DATA_LEN) {
> >  		if (proto_type =3D=3D ETH_P_IP) {
> > -			length =3D ((ntohl(xemaclite_readl(addr +
> > +			length =3D ((ntohl((__force __be32)xemaclite_readl(addr
> +
> >  					XEL_HEADER_IP_LENGTH_OFFSET +
> >  					XEL_RXBUFF_OFFSET)) >>
> >  					XEL_HEADER_SHIFT) &
>=20
> If i understand this code correctly, you need the ntohl because you
> are poking around inside the packet. All the other uses of
> xemaclite_readl() are for descriptors etc.
>=20
> It would be cleaner if you defined a xemaclite_readlbe32. If you use
> ioread32be() it will do the endinness swap for you, so you don't need
> the ntohl() and the horrible cast.
Thanks for the review. Yes, defining xemaclite_readlbe32 would eliminate th=
e
cast need.  I will address it in the next version.=20

>=20
>     Andrew