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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Fri, 15 May 2020 16:30:24 +0200
Message-ID: <CAK8P3a3RKJo-C5=19oAppx212s7T8NdnKJVmkj+h=34a8aKMNA@mail.gmail.com>
Subject: Re: [PATCH v7 2/2] mtd: rawnand: Add NAND controller support on Intel
 LGM SoC
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     kbuild test robot <lkp@intel.com>,
        "Ramuthevar,Vadivel MuruganX" 
        <vadivel.muruganx.ramuthevar@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:MEMORY TECHNOLOGY..." <linux-mtd@lists.infradead.org>,
        devicetree <devicetree@vger.kernel.org>, kbuild-all@lists.01.org,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh R <vigneshr@ti.com>,
        Brendan Higgins <brendanhiggins@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Boris Brezillon <boris.brezillon@collabora.com>,
        Anders Roxell <anders.roxell@linaro.org>,
        masonccyang@mxic.com.tw
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On Fri, May 15, 2020 at 4:25 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Fri, May 15, 2020 at 4:48 PM kbuild test robot <lkp@intel.com> wrote:
>
> > sparse warnings: (new ones prefixed by >>)
> >
> > >> drivers/mtd/nand/raw/intel-nand-controller.c:441:24: sparse: sparse: incorrect type in argument 1 (different base types) @@    expected unsigned int val @@    got restricted __be32 [assignedunsigned int val @@
> > >> drivers/mtd/nand/raw/intel-nand-controller.c:441:24: sparse:    expected unsigned int val
> > >> drivers/mtd/nand/raw/intel-nand-controller.c:441:24: sparse:    got restricted __be32 [assigned] [usertype] reg
> >    drivers/mtd/nand/raw/intel-nand-controller.c:444:24: sparse: sparse: incorrect type in argument 1 (different base types) @@    expected unsigned int val @@    got restricted __be32 [assignedunsigned int val @@
> >    drivers/mtd/nand/raw/intel-nand-controller.c:444:24: sparse:    expected unsigned int val
> >    drivers/mtd/nand/raw/intel-nand-controller.c:444:24: sparse:    got restricted __be32 [assigned] [usertype] reg
> >
> >    440                  reg = cpu_to_be32(*pdata++);
> >  > 441                  writel(reg, ebu_host->hsnand + HSNAND_CMSG_0);
> >    442
> >    443                  reg = cpu_to_be32(*pdata);
> >    444                  writel(reg, ebu_host->hsnand + HSNAND_CMSG_1);
>
> On BE:
> cpu_to_be32 -> no-op
> writel() -> converts reg to LE
>
> On LE:
> cpu_to_be32 -> converts to BE
> writel() -> no-op (in terms of conversion)
>
> Seems to me that the proper API (if above is intended) should be swab32().
> But something tells me that above is broken (or my understanding is wrong).

iowrite_be32() is the correct way to store word into a big-endian mmio register,
if that is the intention here.

      Arnd