[U-Boot] [PATCH] riscv : serial: use rx watermark to indicate rx data is present

[Rick Chen]

Hi Sagar

> From: Sagar Kadam [mailto:sagar.kadam at sifive.com]
> Sent: Friday, July 19, 2019 7:37 PM
> To: Rick Jian-Zhi Chen(陳建志)
> Subject: Re: [U-Boot] [PATCH] riscv : serial: use rx watermark to indicate rx data is present
>
> Hello Rick,
>
> I missed to CC you while submitting the patch[1] Can you please provide your view's on the patch.

Sorry for the late response.
I am OK with your patch.
I will pull it into riscv tree ASAP :)

B.R
Rick

>
> [1] https://patchwork.ozlabs.org/patch/1129736/
>
>
> Thanks & Regards,
> Sagar Kadam
>
> > Thank you for the review and testing the changes.
>
> On Fri, Jul 19, 2019 at 5:04 PM Sagar Kadam <sagar.kadam at sifive.com> wrote:
> >
> > Hello Rick,
> >
> Sorry accidently pressed the send button after this :)
>
> > On Mon, Jul 15, 2019 at 5:52 PM Sagar Kadam <sagar.kadam at sifive.com> wrote:
> > >
> > > Hi Padmarao,
> > >
> > > On Mon, Jul 15, 2019 at 5:31 PM Padmarao Begari <padmarao.b at gmail.com> wrote:
> > > >
> > > > Reviewed-by: Padmarao Begari <padmarao.begari at microchip.com>
> > > > Tested-by: Padmarao Begari <padmarao.begari at microchip.com>
> > > >
> > >
> > >
> > > > Regards
> > > > Padmarao
> > > >
> > >
> > > BR,
> > > Sagar Kadam
> > > > On Tue, Jul 9, 2019 at 5:56 PM Sagar Shrikant Kadam <sagar.kadam at sifive.com> wrote:
> > > >>
> > > >> In y-modem transfer mode, tstc/getc fail to check if there is any
> > > >> data available / received in RX FIFO, and so y-modem transfer
> > > >> never succeeds. Using receive watermark bit within ip register
> > > >> fixes the issue.
> > > >>
> > > >> This patch is based on commit c7392b7bc4e1 ("Use the RX watermark
> > > >> interrupt pending bit for TSTC") available at[1]
> > > >>
> > > >> [1] https://github.com/sifive/HiFive_U-Boot/tree/regression
> > > >>
> > > >> Signed-off-by: Sagar Shrikant Kadam <sagar.kadam at sifive.com>
> > > >> ---
> > > >>
> > > >>  drivers/serial/serial_sifive.c | 23 +++++++----------------
> > > >>  1 file changed, 7 insertions(+), 16 deletions(-)
> > > >>
> > > >> diff --git a/drivers/serial/serial_sifive.c
> > > >> b/drivers/serial/serial_sifive.c index fdfef69..c142ccd 100644
> > > >> --- a/drivers/serial/serial_sifive.c
> > > >> +++ b/drivers/serial/serial_sifive.c
> > > >> @@ -22,6 +22,9 @@ DECLARE_GLOBAL_DATA_PTR;
> > > >>  #define UART_TXCTRL_TXEN       0x1
> > > >>  #define UART_RXCTRL_RXEN       0x1
> > > >>
> > > >> +/* IP register */
> > > >> +#define UART_IP_RXWM            0x2
> > > >> +
> > > >>  struct uart_sifive {
> > > >>         u32 txfifo;
> > > >>         u32 rxfifo;
> > > >> @@ -34,7 +37,6 @@ struct uart_sifive {
> > > >>
> > > >>  struct sifive_uart_platdata {
> > > >>         unsigned long clock;
> > > >> -       int saved_input_char;
> > > >>         struct uart_sifive *regs;  };
> > > >>
> > > >> @@ -94,7 +96,7 @@ static int _sifive_serial_getc(struct uart_sifive *regs)
> > > >>                 return -EAGAIN;
> > > >>         ch &= UART_RXFIFO_DATA;
> > > >>
> > > >> -       return (!ch) ? -EAGAIN : ch;
> > > >> +       return ch;
> > > >>  }
> > > >>
> > > >>  static int sifive_serial_setbrg(struct udevice *dev, int
> > > >> baudrate) @@ -133,7 +135,6 @@ static int sifive_serial_probe(struct udevice *dev)
> > > >>         if (gd->flags & GD_FLG_RELOC)
> > > >>                 return 0;
> > > >>
> > > >> -       platdata->saved_input_char = 0;
> > > >>         _sifive_serial_init(platdata->regs);
> > > >>
> > > >>         return 0;
> > > >> @@ -145,12 +146,6 @@ static int sifive_serial_getc(struct udevice *dev)
> > > >>         struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
> > > >>         struct uart_sifive *regs = platdata->regs;
> > > >>
> > > >> -       if (platdata->saved_input_char > 0) {
> > > >> -               c = platdata->saved_input_char;
> > > >> -               platdata->saved_input_char = 0;
> > > >> -               return c;
> > > >> -       }
> > > >> -
> > > >>         while ((c = _sifive_serial_getc(regs)) == -EAGAIN) ;
> > > >>
> > > >>         return c;
> > > >> @@ -171,14 +166,10 @@ static int sifive_serial_pending(struct udevice *dev, bool input)
> > > >>         struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
> > > >>         struct uart_sifive *regs = platdata->regs;
> > > >>
> > > >> -       if (input) {
> > > >> -               if (platdata->saved_input_char > 0)
> > > >> -                       return 1;
> > > >> -               platdata->saved_input_char = _sifive_serial_getc(regs);
> > > >> -               return (platdata->saved_input_char > 0) ? 1 : 0;
> > > >> -       } else {
> > > >> +       if (input)
> > > >> +               return (readl(&regs->ip) & UART_IP_RXWM);
> > > >> +       else
> > > >>                 return !!(readl(&regs->txfifo) & UART_TXFIFO_FULL);
> > > >> -       }
> > > >>  }
> > > >>
> > > >>  static int sifive_serial_ofdata_to_platdata(struct udevice *dev)
> > > >> --
> > > >> 2.7.4