From mboxrd@z Thu Jan  1 00:00:00 1970
From: Boris Brezillon <boris.brezillon@bootlin.com>
Subject: Re: [PATCH v9 6/9] i3c: master: Add driver for Cadence IP
Date: Wed, 24 Oct 2018 20:20:48 +0200
Message-ID: <20181024202048.7e3534f7@bbrezillon>
References: <20181022133404.2061-1-boris.brezillon@bootlin.com>
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To: 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>
Cc: 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>, Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Kumar Gala <galak@codeaurora.org>, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Vitor Soares <Vitor.Soares@synopsys.com>, Geert Uytterhoeven <geert@linux-m68k.org>, Linus
List-Id: linux-gpio@vger.kernel.org

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(...);
		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