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Date:   Wed, 24 Oct 2018 23:04:32 +0200
From:   Boris Brezillon <boris.brezillon@bootlin.com>
To:     Grygorii Strashko <grygorii.strashko@ti.com>
Cc:     Wolfram Sang <wsa@the-dreams.de>, <linux-i2c@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>, <linux-doc@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Przemyslaw Sroka <psroka@cadence.com>,
        Arkadiusz Golec <agolec@cadence.com>,
        Alan Douglas <adouglas@cadence.com>,
        Bartosz Folta <bfolta@cadence.com>,
        Damian Kos <dkos@cadence.com>,
        Alicja Jurasik-Urbaniak <alicja@cadence.com>,
        Cyprian Wronka <cwronka@cadence.com>,
        Suresh Punnoose <sureshp@cadence.com>,
        Rafal Ciepiela <rafalc@cadence.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Nishanth Menon <nm@ti.com>, Rob Herring <robh+dt@kernel.org>,
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        Kumar Gala <galak@codeaurora.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Vitor Soares <Vitor.Soares@synopsys.com>,
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        Przemyslaw Gaj <pgaj@cadence.com>,
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        Joe Perches <joe@perches.com>
Subject: Re: [PATCH v9 6/9] i3c: master: Add driver for Cadence IP
Message-ID: <20181024230432.66dd71df@bbrezillon>
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On Wed, 24 Oct 2018 15:25:17 -0500
Grygorii Strashko <grygorii.strashko@ti.com> wrote:

> On 10/24/18 1:20 PM, Boris Brezillon wrote:
> > Hi Arnd,
> > 
> > On Mon, 22 Oct 2018 15:34:01 +0200
> > Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> > 
> >   
> >> +
> >> +static void cdns_i3c_master_rd_from_rx_fifo(struct cdns_i3c_master *master,
> >> +					    u8 *bytes, int nbytes)
> >> +{
> >> +	readsl(master->regs + RX_FIFO, bytes, nbytes / 4);  
> > 
> > Vitor reported a problem with readsl(): this function expects the 2nd
> > argument to be aligned on 32-bit, which is not guaranteed here. Unless
> > you see a better solution, I'll switch back to a loop doing:
> > 
> > 	for (i = 0; i < nbytes; i += 4) {
> > 		u32 tmp = __raw_readl(...);  
> 
> Pls, do not use __raw io.

Except this is exactly what I want here, unless you have a
replacement for "readl() without a mem-barrier and without endianness
conversion"

> 
> > 		memcpy(bytes + i, &tmp,
> > 		       nbytes - i  > 4 ? 4 : nbytes - i);
> > 	}
> >   
> >> +	if (nbytes & 3) {
> >> +		u32 tmp;
> >> +
> >> +		readsl(master->regs + RX_FIFO, &tmp, 1);
> >> +		memcpy(bytes + (nbytes & ~3), &tmp, nbytes & 3);
> >> +	}
> >> +}  
> > 
> > Regards,
> > 
> > Boris
> >   
>