Re: [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx

From: Sebastian Andrzej Siewior
Date: Wed Sep 17 2014 - 12:34:56 EST

On 09/11/2014 01:42 PM, Sebastian Andrzej Siewior wrote:
>> We should add hooks like tx_dma and rx_dma to struct uart_8250_dma so
>> that the probe drivers can replace serial8250_tx_dma and
>> seria8250_rx_dma, like I think Alan already suggested.
> Okay. Wasn't aware that Alan already suggested that.
> I also need a watchdog timer for TX since it seems that on omap3 the
> DMA engine suddenly forgets to continue with DMAâ
> If this is really what we want, I would need to refactor a few thingsâ
>> Let's keep serial8250_tx_dma/rx_dma as the default, and not add any
>> quirks to them. Only if there is a very common case should it be
>> handled in those. The case of RX req needing to be sent before data in
>> FIFO maybe one of those, but I'm no sure.
> keep in mind that both (RX & TX bugs/hacks) need also a bit of handling
> in the 8250-core so it works together (like the tx_err member so we
> fall back to manual xmit)

Done. I've kept the RX workarounds in the 8250_dma and moved the TX
part into the omap driver.
I needed to add the 8250_core pieces of patch #10 [0]. Now If you say,
couldn't this done in an other way then I could move the RX workarounds
pieces to the omap driver as well as the interrupt routine. Any

[0] [PATCH 10/16] tty: serial: 8250_dma: optimize the xmit path due to


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