linux-kernel - Re: [PATCH] spi: Mediatek: fix endian warnings

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Date:	Thu, 13 Aug 2015 10:11:59 +0800
From:	lei liu <leilk.liu@...iatek.com>
To:	Jonas Gorski <jogo@...nwrt.org>, Mark Brown <broonie@...nel.org>
CC:	Mark Brown <broonie@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-spi@...r.kernel.org>, <linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH] spi: Mediatek: fix endian warnings

Hello Mark,

 This patch is applied, should I append a new patch or you rollback it?
Thanks.

On Wed, 2015-08-12 at 16:45 +0200, Jonas Gorski wrote:
> Hi,
> 
> On Tue, Aug 11, 2015 at 12:43 PM, Leilk Liu <leilk.liu@...iatek.com> wrote:
> > This patch fixes endian warnings detected by sparse:
> > - sparse: incorrect type in argument 1 (different base types)
> >           expected unsigned int [unsigned] val
> >           got restricted __le32 [usertype] <noident>
> > - sparse: incorrect type in argument 1 (different base types)
> >           expected unsigned int [unsigned] val
> >           got restricted __le32 [usertype] <noident>
> 
> This doesn't "fix" the warning, it only hides the warning and leaves
> the actual issue unfixed.
> 
> >
> > Signed-off-by: Leilk Liu <leilk.liu@...iatek.com>
> > ---
> >  drivers/spi/spi-mt65xx.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
> > index 4676b01..ae645fa 100644
> > --- a/drivers/spi/spi-mt65xx.c
> > +++ b/drivers/spi/spi-mt65xx.c
> > @@ -359,9 +359,11 @@ static void mtk_spi_setup_dma_addr(struct spi_master *master,
> >         struct mtk_spi *mdata = spi_master_get_devdata(master);
> >
> >         if (mdata->tx_sgl)
> > -               writel(cpu_to_le32(xfer->tx_dma), mdata->base + SPI_TX_SRC_REG);
> > +               writel((__force u32)cpu_to_le32(xfer->tx_dma),
> > +                      mdata->base + SPI_TX_SRC_REG);
> >         if (mdata->rx_sgl)
> > -               writel(cpu_to_le32(xfer->rx_dma), mdata->base + SPI_RX_DST_REG);
> > +               writel((__force u32)cpu_to_le32(xfer->rx_dma),
> > +                      mdata->base + SPI_RX_DST_REG);
> 
> The issue here is that writel already does a cpu_to_le32 conversion,
> so the extra cpu_to_le32 calls are actually bogus and need to be
> removed. Else it will do a double conversion on big endian systems,
> resulting in the data being written in big endian.
> 
> 
> Jonas


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