From 33d9b8b23a73d5d8609a740d0adeea8235c2ae52 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 9 Apr 2016 22:14:36 -0700 Subject: serial: 8250: Extract IIR logic steering from rx dma Using fake IIR values to perform rx dma operations unnecessarily conflates separate operations, stopping in-progress dma with starting new dma. Introduce serial8250_rx_dma_flush() to handle stopping in-progress dma [omap8250 already has equivalent omap_8250_rx_dma_flush()]. Replace rx_dma(UART_IIR_RX_TIMEOUT) with the equivalent *_rx_dma_flush(), and rx_dma(0) with the equivalent *_rx_dma(). Handle IIR steering in the irq handler with handle_rx_dma() helper. Signed-off-by: Peter Hurley Reviewed-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 8739d22..7a4c826 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -17,7 +17,7 @@ struct uart_8250_dma { int (*tx_dma)(struct uart_8250_port *p); - int (*rx_dma)(struct uart_8250_port *p, unsigned int iir); + int (*rx_dma)(struct uart_8250_port *p); /* Filter function */ dma_filter_fn fn; @@ -189,7 +189,8 @@ static inline int is_omap1510_8250(struct uart_8250_port *pt) #ifdef CONFIG_SERIAL_8250_DMA extern int serial8250_tx_dma(struct uart_8250_port *); -extern int serial8250_rx_dma(struct uart_8250_port *, unsigned int iir); +extern int serial8250_rx_dma(struct uart_8250_port *); +extern void serial8250_rx_dma_flush(struct uart_8250_port *); extern int serial8250_request_dma(struct uart_8250_port *); extern void serial8250_release_dma(struct uart_8250_port *); #else @@ -197,10 +198,11 @@ static inline int serial8250_tx_dma(struct uart_8250_port *p) { return -1; } -static inline int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir) +static inline int serial8250_rx_dma(struct uart_8250_port *p) { return -1; } +static inline void serial8250_rx_dma_flush(struct uart_8250_port *p) { } static inline int serial8250_request_dma(struct uart_8250_port *p) { return -1; diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 7a26c4d..7f33d1c 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -110,30 +110,11 @@ err: return ret; } -int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir) +int serial8250_rx_dma(struct uart_8250_port *p) { struct uart_8250_dma *dma = p->dma; struct dma_async_tx_descriptor *desc; - switch (iir & 0x3f) { - case UART_IIR_RLSI: - /* 8250_core handles errors and break interrupts */ - return -EIO; - case UART_IIR_RX_TIMEOUT: - /* - * If RCVR FIFO trigger level was not reached, complete the - * transfer and let 8250_core copy the remaining data. - */ - if (dma->rx_running) { - dmaengine_pause(dma->rxchan); - __dma_rx_complete(p); - dmaengine_terminate_all(dma->rxchan); - } - return -ETIMEDOUT; - default: - break; - } - if (dma->rx_running) return 0; @@ -154,6 +135,17 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir) return 0; } +void serial8250_rx_dma_flush(struct uart_8250_port *p) +{ + struct uart_8250_dma *dma = p->dma; + + if (dma->rx_running) { + dmaengine_pause(dma->rxchan); + __dma_rx_complete(p); + dmaengine_terminate_all(dma->rxchan); + } +} + int serial8250_request_dma(struct uart_8250_port *p) { struct uart_8250_dma *dma = p->dma; diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 27702d5..8579b0c 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -115,6 +115,12 @@ struct omap8250_priv { bool rx_dma_broken; }; +#ifdef CONFIG_SERIAL_8250_DMA +static void omap_8250_rx_dma_flush(struct uart_8250_port *p); +#else +static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { } +#endif + static u32 uart_read(struct uart_8250_port *up, u32 reg) { return readl(up->port.membase + (reg << up->port.regshift)); @@ -635,7 +641,7 @@ static int omap_8250_startup(struct uart_port *port) serial_out(up, UART_OMAP_WER, priv->wer); if (up->dma) - up->dma->rx_dma(up, 0); + up->dma->rx_dma(up); pm_runtime_mark_last_busy(port->dev); pm_runtime_put_autosuspend(port->dev); @@ -654,7 +660,7 @@ static void omap_8250_shutdown(struct uart_port *port) flush_work(&priv->qos_work); if (up->dma) - up->dma->rx_dma(up, UART_IIR_RX_TIMEOUT); + omap_8250_rx_dma_flush(up); pm_runtime_get_sync(port->dev); @@ -742,7 +748,7 @@ static void omap_8250_unthrottle(struct uart_port *port) } #ifdef CONFIG_SERIAL_8250_DMA -static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir); +static int omap_8250_rx_dma(struct uart_8250_port *p); static void __dma_rx_do_complete(struct uart_8250_port *p) { @@ -778,7 +784,7 @@ unlock: static void __dma_rx_complete(void *param) { __dma_rx_do_complete(param); - omap_8250_rx_dma(param, 0); + omap_8250_rx_dma(param); } static void omap_8250_rx_dma_flush(struct uart_8250_port *p) @@ -804,7 +810,7 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p) __dma_rx_do_complete(p); } -static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir) +static int omap_8250_rx_dma(struct uart_8250_port *p) { struct omap8250_priv *priv = p->port.private_data; struct uart_8250_dma *dma = p->dma; @@ -812,35 +818,6 @@ static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir) struct dma_async_tx_descriptor *desc; unsigned long flags; - switch (iir & 0x3f) { - case UART_IIR_RLSI: - /* 8250_core handles errors and break interrupts */ - omap_8250_rx_dma_flush(p); - return -EIO; - case UART_IIR_RX_TIMEOUT: - /* - * If RCVR FIFO trigger level was not reached, complete the - * transfer and let 8250_core copy the remaining data. - */ - omap_8250_rx_dma_flush(p); - return -ETIMEDOUT; - case UART_IIR_RDI: - /* - * The OMAP UART is a special BEAST. If we receive RDI we _have_ - * a DMA transfer programmed but it didn't work. One reason is - * that we were too slow and there were too many bytes in the - * FIFO, the UART counted wrong and never kicked the DMA engine - * to do anything. That means once we receive RDI on OMAP then - * the DMA won't do anything soon so we have to cancel the DMA - * transfer and purge the FIFO manually. - */ - omap_8250_rx_dma_flush(p); - return -ETIMEDOUT; - - default: - break; - } - if (priv->rx_dma_broken) return -EINVAL; @@ -1014,6 +991,18 @@ err: return ret; } +static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) +{ + switch (iir & 0x3f) { + case UART_IIR_RLSI: + case UART_IIR_RX_TIMEOUT: + case UART_IIR_RDI: + omap_8250_rx_dma_flush(up); + return true; + } + return omap_8250_rx_dma(up); +} + /* * This is mostly serial8250_handle_irq(). We have a slightly different DMA * hoook for RX/TX and need different logic for them in the ISR. Therefore we @@ -1039,9 +1028,9 @@ static int omap_8250_dma_handle_irq(struct uart_port *port) status = serial_port_in(port, UART_LSR); if (status & (UART_LSR_DR | UART_LSR_BI)) { - if (omap_8250_rx_dma(up, iir)) { + if (handle_rx_dma(up, iir)) { status = serial8250_rx_chars(up, status); - omap_8250_rx_dma(up, 0); + omap_8250_rx_dma(up); } } serial8250_modem_status(up); @@ -1072,7 +1061,7 @@ static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param) #else -static inline int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir) +static inline int omap_8250_rx_dma(struct uart_8250_port *p) { return -EINVAL; } @@ -1383,7 +1372,7 @@ static int omap8250_runtime_suspend(struct device *dev) } if (up->dma && up->dma->rxchan) - omap_8250_rx_dma(up, UART_IIR_RX_TIMEOUT); + omap_8250_rx_dma_flush(up); priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE; schedule_work(&priv->qos_work); @@ -1406,7 +1395,7 @@ static int omap8250_runtime_resume(struct device *dev) omap8250_restore_regs(up); if (up->dma && up->dma->rxchan) - omap_8250_rx_dma(up, 0); + omap_8250_rx_dma(up); priv->latency = priv->calc_latency; schedule_work(&priv->qos_work); diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index b2bbb9d..215e8da 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1788,6 +1788,18 @@ unsigned int serial8250_modem_status(struct uart_8250_port *up) } EXPORT_SYMBOL_GPL(serial8250_modem_status); +static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) +{ + switch (iir & 0x3f) { + case UART_IIR_RX_TIMEOUT: + serial8250_rx_dma_flush(up); + /* fall-through */ + case UART_IIR_RLSI: + return true; + } + return up->dma->rx_dma(up); +} + /* * This handles the interrupt from one port. */ @@ -1807,7 +1819,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) DEBUG_INTR("status = %x...", status); if (status & (UART_LSR_DR | UART_LSR_BI)) { - if (!up->dma || up->dma->rx_dma(up, iir)) + if (!up->dma || handle_rx_dma(up, iir)) status = serial8250_rx_chars(up, status); } serial8250_modem_status(up); -- cgit v0.10.2