linux-kernel - RE: [LINUX PATCH v12 3/3] mtd: rawnand: arasan: Add support for Arasan NAND Flash Controller

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Date:   Mon, 12 Nov 2018 12:43:30 +0000
From:   Naga Sureshkumar Relli <nagasure@...inx.com>
To:     Boris Brezillon <boris.brezillon@...tlin.com>,
        Martin Lund <martin.lund@...p-it-simple.com>
CC:     "miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>,
        "richard@....at" <richard@....at>,
        "dwmw2@...radead.org" <dwmw2@...radead.org>,
        "computersforpeace@...il.com" <computersforpeace@...il.com>,
        "marek.vasut@...il.com" <marek.vasut@...il.com>,
        Michal Simek <michals@...inx.com>,
        "nagasuresh12@...il.com" <nagasuresh12@...il.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "robh@...nel.org" <robh@...nel.org>
Subject: RE: [LINUX PATCH v12 3/3] mtd: rawnand: arasan: Add support for
 Arasan NAND Flash Controller

Hi Boris &  Martin,

> -----Original Message-----
> From: Boris Brezillon [mailto:boris.brezillon@...tlin.com]
> Sent: Monday, November 12, 2018 4:28 PM
> To: Martin Lund <martin.lund@...p-it-simple.com>
> Cc: Naga Sureshkumar Relli <nagasure@...inx.com>; miquel.raynal@...tlin.com;
> richard@....at; dwmw2@...radead.org; computersforpeace@...il.com;
> marek.vasut@...il.com; Michal Simek <michals@...inx.com>; nagasuresh12@...il.com;
> linux-mtd@...ts.infradead.org; linux-kernel@...r.kernel.org; robh@...nel.org
> Subject: Re: [LINUX PATCH v12 3/3] mtd: rawnand: arasan: Add support for Arasan NAND
> Flash Controller
> 
> On Mon, 12 Nov 2018 11:55:36 +0100
> Martin Lund <martin.lund@...p-it-simple.com> wrote:
> 
> > Hi Naga,
> >
> > Just a few review comments for the v12 version.
> >
> > On Fri, Nov 9, 2018 at 6:00 AM Naga Sureshkumar Relli
> > <naga.sureshkumar.relli@...inx.com> wrote:
> > > +#define PKT_OFST               0x00
> > > +#define PKT_CNT_SHIFT          12
> > > +
> > > +#define MEM_ADDR1_OFST         0x04
> > > +#define MEM_ADDR2_OFST         0x08
> >
> > For the sake of readability I think *_OFFSET is preferred, especially
> > since the driver already includes short macro names. I think this is
> > similar to the EVNT vs EVENT point.
> > The majority of drivers in the Linux kernel do not shorten OFFSET -> OFST.
> >
> >
> > > +static void anfc_rw_pio_op(struct mtd_info *mtd, u8 *buf, int len,
> > > +                          bool do_read, int prog, int pktcount, int
> > > +pktsize) {
> > > +       struct nand_chip *chip = mtd_to_nand(mtd);
> > > +       struct anfc_nand_controller *nfc = to_anfc(chip->controller);
> > > +       struct anfc_nand_chip *achip = to_anfc_nand(chip);
> > > +       u32 *bufptr = (u32 *)buf;
> > > +       u32 cnt = 0, intr = 0;
> > > +
> > > +       anfc_config_dma(nfc, 0);
> > > +
> > > +       if (pktsize == 0)
> > > +               pktsize = len;
> > > +
> > > +       anfc_setpktszcnt(nfc, pktsize, pktcount);
> > > +
> > > +       if (!achip->strength)
> > > +               intr = MBIT_ERROR;
> > > +
> > > +       if (do_read)
> > > +               intr |= READ_READY;
> > > +       else
> > > +               intr |= WRITE_READY;
> > > +       anfc_enable_intrs(nfc, intr);
> > > +       writel(prog, nfc->base + PROG_OFST);
> > > +       while (cnt < pktcount) {
> > > +               anfc_wait_for_event(nfc);
> > > +               cnt++;
> > > +               if (cnt == pktcount)
> > > +                       anfc_enable_intrs(nfc, XFER_COMPLETE);
> > > +               if (do_read)
> > > +                       ioread32_rep(nfc->base + DATA_PORT_OFST, bufptr,
> > > +                                    pktsize / 4);
> > > +               else
> > > +                       iowrite32_rep(nfc->base + DATA_PORT_OFST, bufptr,
> > > +                                     pktsize / 4);
> > > +               bufptr += (pktsize / 4);
> > > +               if (cnt < pktcount)
> > > +                       anfc_enable_intrs(nfc, intr);
> > > +       }
> > > +       anfc_wait_for_event(nfc);
> > > +}
> >
> > Throughout the driver all calls to anfc_wait_for_event() ignores the
> > timeout return value. It would be nice to see some error handling in
> > case it times out - at minimum consider printing out an error message
> > since timeout on NAND operations are fairly critical and should
> > generally not occur. Perhaps even an argument can be made for
> > returning -ETIMEDOUT in case of timeout.
> 
> Yes please, check anfc_wait_for_event() return code and propagate the error to the upper layer.
Ok, I will update

Thanks,
Naga Sureshkumar Relli