From mboxrd@z Thu Jan 1 00:00:00 1970 From: bigeasy@linutronix.de (Sebastian Andrzej Siewior) Date: Fri, 5 Sep 2014 21:02:45 +0200 Subject: [PATCH 10/18] tty: serial: 8250_dma: enqueue RX dma again on completion. In-Reply-To: <1409943773-7874-1-git-send-email-bigeasy@linutronix.de> References: <1409943773-7874-1-git-send-email-bigeasy@linutronix.de> Message-ID: <1409943773-7874-11-git-send-email-bigeasy@linutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The omap needs a DMA request pending right away. If it is enqueued once the bytes are in the FIFO then nothing will happen and the FIFO will be later purged via RX-timeout interrupt. This patch enqueues RX-DMA request on completion but not if it was aborted on error. The first enqueue will happen in the driver in startup. Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/8250/8250.h | 3 ++- drivers/tty/serial/8250/8250_core.c | 3 +++ drivers/tty/serial/8250/8250_dma.c | 12 +++++++++--- 3 files changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index a63d198f8d03..fbed1636e9c4 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -80,7 +80,8 @@ struct serial8250_config { #define UART_BUG_NOMSR (1 << 2) /* UART has buggy MSR status bits (Au1x00) */ #define UART_BUG_THRE (1 << 3) /* UART has buggy THRE reassertion */ #define UART_BUG_PARITY (1 << 4) /* UART mishandles parity if FIFO enabled */ - +#define UART_BUG_DMA_RX (1 << 5) /* UART needs DMA RX req before there is + data in FIFO */ #define PROBE_RSA (1 << 0) #define PROBE_ANY (~0) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 2101134e5031..079048db8c81 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -1590,6 +1590,9 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) if (!up->dma || dma_err) status = serial8250_rx_chars(up, status); + + if (dma_err && up->bugs & UART_BUG_DMA_RX) + serial8250_rx_dma(up, 0); } serial8250_modem_status(up); if ((!up->dma || (up->dma && up->dma->tx_err)) && diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 69e54abb6e71..3674900a1f14 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -50,9 +50,8 @@ static void __dma_tx_complete(void *param) spin_unlock_irqrestore(&p->port.lock, flags); } -static void __dma_rx_complete(void *param) +static void __dma_rx_do_complete(struct uart_8250_port *p, bool error) { - struct uart_8250_port *p = param; struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; @@ -68,10 +67,17 @@ static void __dma_rx_complete(void *param) tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + if (!error && p->bugs & UART_BUG_DMA_RX) + serial8250_rx_dma(p, 0); tty_flip_buffer_push(tty_port); } +static void __dma_rx_complete(void *param) +{ + __dma_rx_do_complete(param, false); +} + int serial8250_tx_dma(struct uart_8250_port *p) { struct uart_8250_dma *dma = p->dma; @@ -139,7 +145,7 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir) */ if (dma_status == DMA_IN_PROGRESS) { dmaengine_pause(dma->rxchan); - __dma_rx_complete(p); + __dma_rx_do_complete(p, true); } return -ETIMEDOUT; default: -- 2.1.0