On 01/19/2017 05:56 PM, Tony Lindgren wrote:
> * Alexandre Bailon <abailon@xxxxxxxxxxxx> [170119 06:09]:
>> The DMA may hung up if a teardown is initiated while an endpoint is still
>> active (Advisory 2.3.27 of DA8xx errata).
>> To workaround this issue, add a delay before to initiate the teardown.
>>
>> Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
>> ---
>> drivers/usb/musb/da8xx.c | 2 +-
>> drivers/usb/musb/musb_core.h | 1 +
>> drivers/usb/musb/musb_cppi41.c | 4 ++++
>> 3 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/musb/da8xx.c b/drivers/usb/musb/da8xx.c
>> index 5f50a78..8c9850c 100644
>> --- a/drivers/usb/musb/da8xx.c
>> +++ b/drivers/usb/musb/da8xx.c
>> @@ -483,7 +483,7 @@ da8xx_dma_controller_create(struct musb *musb, void __iomem *base)
>> #endif
>>
>> static const struct musb_platform_ops da8xx_ops = {
>> - .quirks = MUSB_INDEXED_EP | MUSB_DMA_CPPI41,
>> + .quirks = MUSB_INDEXED_EP | MUSB_DMA_CPPI41 | MUSB_DA8XX,
>> .init = da8xx_musb_init,
>> .exit = da8xx_musb_exit,
>>
>> diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
>> index ade902e..d129278 100644
>> --- a/drivers/usb/musb/musb_core.h
>> +++ b/drivers/usb/musb/musb_core.h
>> @@ -172,6 +172,7 @@ struct musb_io;
>> */
>> struct musb_platform_ops {
>>
>> +#define MUSB_DA8XX BIT(7)
>> #define MUSB_DMA_UX500 BIT(6)
>> #define MUSB_DMA_CPPI41 BIT(5)
>> #define MUSB_DMA_CPPI BIT(4)
>> diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
>> index 1fe7eae..d371d05 100644
>> --- a/drivers/usb/musb/musb_cppi41.c
>> +++ b/drivers/usb/musb/musb_cppi41.c
>> @@ -554,6 +554,10 @@ static int cppi41_dma_channel_abort(struct dma_channel *channel)
>> }
>> }
>>
>> + /* DA8xx Advisory 2.3.27: wait 250 ms before to start the teardown */
>> + if (musb->io.quirks & MUSB_DA8XX)
>> + mdelay(250);
>> +
>> tdbit = 1 << cppi41_channel->port_num;
>> if (is_tx)
>> tdbit <<= 16;
>
> How about replace the do while loop calling dmaengine_terminate_all() with
> deferred work doing that?
That would be great but I don't know how hard to would be to do it.
Right after the teardown, we may have to queue a new request.
But we must be sure that the teardown has completed before to start
a new transfer. And because it happen in atomic section, we must also
defer it.
>
> That way it's more generic as it seems there's no hurry doing that
> after the musb registers are cleared. That would also allow getting rid of
> the two current udelay() calls there that also seems nasty.
>
> Regards,
>
> Tony
>
Regards,
Alexandre
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