[U-Boot] [PATCH v4 07/13] net: ftgmac100: handle timeouts when transmitting

[Joe Hershberger]

On Mon, Oct 29, 2018 at 1:04 AM Cédric Le Goater <clg at kaod.org> wrote:
>
> Hello Joe,
>
> On 10/22/18 9:55 PM, Joe Hershberger wrote:
> > Hi Cedric,
> >
> > On Tue, Oct 16, 2018 at 4:32 AM Cédric Le Goater <clg at kaod.org> wrote:
> >>
> >> Signed-off-by: Cédric Le Goater <clg at kaod.org>
> >> Reviewed-by: Joel Stanley <joel at jms.id.au>
> >> ---
> >>
> >>  Changes since v3 :
> >>
> >>  - introduced a ftgmac100_wait_for_txdone() function similar to the
> >>    wait_for_bit_*() macros.
> >>
> >>  drivers/net/ftgmac100.c | 44 +++++++++++++++++++++++++++++++++++++++++
> >>  1 file changed, 44 insertions(+)
> >>
> >> diff --git a/drivers/net/ftgmac100.c b/drivers/net/ftgmac100.c
> >> index bf8600814690..9adfe109ebc2 100644
> >> --- a/drivers/net/ftgmac100.c
> >> +++ b/drivers/net/ftgmac100.c
> >> @@ -14,6 +14,7 @@
> >>  #include <dm.h>
> >>  #include <miiphy.h>
> >>  #include <net.h>
> >> +#include <wait_bit.h>
> >>  #include <linux/io.h>
> >>  #include <linux/iopoll.h>
> >>
> >> @@ -28,6 +29,9 @@
> >>  /* PKTBUFSTX/PKTBUFSRX must both be power of 2 */
> >>  #define PKTBUFSTX      4       /* must be power of 2 */
> >>
> >> +/* Timeout for transmit */
> >> +#define FTGMAC100_TX_TIMEOUT_MS                1000
> >> +
> >>  /* Timeout for a mdio read/write operation */
> >>  #define FTGMAC100_MDIO_TIMEOUT_USEC    10000
> >>
> >> @@ -401,6 +405,41 @@ static int ftgmac100_recv(struct udevice *dev, int flags, uchar **packetp)
> >>         return rxlen;
> >>  }
> >>
> >> +/*
> >> + * The wait_for_bit_*() macros require a register value. This define a
> >> + * similar routine which loops on the in-memory transmit descriptor to
> >> + * wait for the MAC to clear the DMA_OWN bit.
> >> + */
> >> +static int ftgmac100_wait_for_txdone(struct ftgmac100_txdes *txdes,
> >> +                                    const unsigned int timeout_ms,
> >> +                                    const bool breakable)
> >> +{
> >
> > I was hoping to see something like this instead:
> >
> > static u32 ftgmac100_read_txdesc(void *desc)
> > {
> >         struct ftgmac100_txdes *txdes = desc;
> >         ulong des_start = (ulong)txdes;
> >         ulong des_end = des_start + roundup(sizeof(*txdes), ARCH_DMA_MINALIGN);
> >
> >         invalidate_dcache_range(des_start, des_end);
> >
> >         return txdes->txdes0;
> > }
> >
> > BUILD_WAIT_FOR_BIT(ftgmac100_txdone, u32, ftgmac100_read_txdesc)
> >
> > [ ... ]
> >
> > ftgmac100_send( ... )
> > {
> > [ ... ]
> >
> >         rc = wait_for_bit_ftgmac100_txdone(curr_des,
> > FTGMAC100_TXDES0_TXDMA_OWN, false, FTGMAC100_TX_TIMEOUT_MS, true);
> >         if (rc)
> >                 return rc;
> >
> > [ ... ]
> > }
>
>
> Yes, this is much better. A few other drivers could make use of a similar
> macro.

I agree... spread the word to people with hardware who can make the
change and test. :)

> Sending a v5 with the proposed change.

Looks great, thanks!

>
> Thanks,
>
> C.
>
>
> >> +       ulong des_start = (ulong)txdes;
> >> +       ulong des_end = des_start + roundup(sizeof(*txdes), ARCH_DMA_MINALIGN);
> >> +       ulong start = get_timer(0);
> >> +
> >> +       while (1) {
> >> +               invalidate_dcache_range(des_start, des_end);
> >> +
> >> +               if (!(txdes->txdes0 & FTGMAC100_TXDES0_TXDMA_OWN))
> >> +                       return 0;
> >> +
> >> +               if (get_timer(start) > timeout_ms)
> >> +                       break;
> >> +
> >> +               if (breakable && ctrlc()) {
> >> +                       puts("Abort\n");
> >> +                       return -EINTR;
> >> +               }
> >> +
> >> +               udelay(1);
> >> +               WATCHDOG_RESET();
> >> +       }
> >> +
> >> +       dev_err(dev, "transmit timeout\n");
> >> +       return -ETIMEDOUT;
> >> +}
> >> +
> >>  /*
> >>   * Send a data block via Ethernet
> >>   */
> >> @@ -414,6 +453,7 @@ static int ftgmac100_send(struct udevice *dev, void *packet, int length)
> >>                 roundup(sizeof(*curr_des), ARCH_DMA_MINALIGN);
> >>         ulong data_start;
> >>         ulong data_end;
> >> +       int rc;
> >>
> >>         invalidate_dcache_range(des_start, des_end);
> >>
> >> @@ -446,6 +486,10 @@ static int ftgmac100_send(struct udevice *dev, void *packet, int length)
> >>         /* Start transmit */
> >>         writel(1, &ftgmac100->txpd);
> >>
> >> +       rc = ftgmac100_wait_for_txdone(curr_des, FTGMAC100_TX_TIMEOUT_MS, true);
> >> +       if (rc)
> >> +               return rc;
> >> +
> >>         debug("%s(): packet sent\n", __func__);
> >>
> >>         /* Move to next descriptor */
> >> --
> >> 2.17.2
> >>
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