From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx Date: Wed, 17 Sep 2014 18:34:45 +0200 Message-ID: <5419B825.5000201@linutronix.de> References: <1410377411-26656-1-git-send-email-bigeasy@linutronix.de> <1410377411-26656-10-git-send-email-bigeasy@linutronix.de> <20140911111721.GB17476@xps8300> <54118AAB.2010205@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <54118AAB.2010205@linutronix.de> Sender: linux-omap-owner@vger.kernel.org To: Heikki Krogerus Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, tony@atomide.com, balbi@ti.com, gregkh@linuxfoundation.org, Alan Cox List-Id: linux-serial@vger.kernel.org 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 s= o >> that the probe drivers can replace serial8250_tx_dma and >> seria8250_rx_dma, like I think Alan already suggested. >=20 > 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 DMA=E2=80=A6 >=20 > If this is really what we want, I would need to refactor a few things= =E2=80=A6 >=20 >> 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. >=20 > keep in mind that both (RX & TX bugs/hacks) need also a bit of handli= ng > 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 preferences? [0] [PATCH 10/16] tty: serial: 8250_dma: optimize the xmit path due to UART_BUG_DMA_TX Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html