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

[Cédric Le Goater]

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.

Sending a v5 with the proposed change.

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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