diff options
Diffstat (limited to 'drivers/tty/serial/stm32-usart.c')
-rw-r--r-- | drivers/tty/serial/stm32-usart.c | 127 |
1 files changed, 82 insertions, 45 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 3471e23bb02f..0dae05a7abe6 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -291,13 +291,39 @@ static int stm32_usart_init_rs485(struct uart_port *port, static bool stm32_usart_rx_dma_started(struct stm32_port *stm32_port) { + return stm32_port->rx_ch ? stm32_port->rx_dma_busy : false; +} + +static void stm32_usart_rx_dma_terminate(struct stm32_port *stm32_port) +{ + dmaengine_terminate_async(stm32_port->rx_ch); + stm32_port->rx_dma_busy = false; +} + +static int stm32_usart_dma_pause_resume(struct stm32_port *stm32_port, + struct dma_chan *chan, + enum dma_status expected_status, + int dmaengine_pause_or_resume(struct dma_chan *), + bool stm32_usart_xx_dma_started(struct stm32_port *), + void stm32_usart_xx_dma_terminate(struct stm32_port *)) +{ struct uart_port *port = &stm32_port->port; - const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + enum dma_status dma_status; + int ret; + + if (!stm32_usart_xx_dma_started(stm32_port)) + return -EPERM; - if (!stm32_port->rx_ch) - return false; + dma_status = dmaengine_tx_status(chan, chan->cookie, NULL); + if (dma_status != expected_status) + return -EAGAIN; - return !!(readl_relaxed(port->membase + ofs->cr3) & USART_CR3_DMAR); + ret = dmaengine_pause_or_resume(chan); + if (ret) { + dev_err(port->dev, "DMA failed with error code: %d\n", ret); + stm32_usart_xx_dma_terminate(stm32_port); + } + return ret; } /* Return true when data is pending (in pio mode), and false when no data is pending. */ @@ -475,7 +501,7 @@ static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force } } else { /* Disable RX DMA */ - dmaengine_terminate_async(stm32_port->rx_ch); + stm32_usart_rx_dma_terminate(stm32_port); stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); /* Fall back to interrupt mode */ dev_dbg(port->dev, "DMA error, fallback to irq mode\n"); @@ -506,6 +532,22 @@ static bool stm32_usart_tx_dma_started(struct stm32_port *stm32_port) return stm32_port->tx_dma_busy; } +static int stm32_usart_tx_dma_pause(struct stm32_port *stm32_port) +{ + return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch, + DMA_IN_PROGRESS, dmaengine_pause, + stm32_usart_tx_dma_started, + stm32_usart_tx_dma_terminate); +} + +static int stm32_usart_tx_dma_resume(struct stm32_port *stm32_port) +{ + return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch, + DMA_PAUSED, dmaengine_resume, + stm32_usart_tx_dma_started, + stm32_usart_tx_dma_terminate); +} + static void stm32_usart_tx_dma_complete(void *arg) { struct uart_port *port = arg; @@ -606,13 +648,9 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port) int ret; if (stm32_usart_tx_dma_started(stm32port)) { - if (dmaengine_tx_status(stm32port->tx_ch, - stm32port->tx_ch->cookie, - NULL) == DMA_PAUSED) { - ret = dmaengine_resume(stm32port->tx_ch); - if (ret < 0) - goto dma_err; - } + ret = stm32_usart_tx_dma_resume(stm32port); + if (ret < 0 && ret != -EAGAIN) + goto fallback_err; return; } @@ -658,8 +696,12 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port) /* Push current DMA TX transaction in the pending queue */ /* DMA no yet started, safe to free resources */ - if (dma_submit_error(dmaengine_submit(desc))) - goto dma_err; + ret = dma_submit_error(dmaengine_submit(desc)); + if (ret) { + dev_err(port->dev, "DMA failed with error code: %d\n", ret); + stm32_usart_tx_dma_terminate(stm32port); + goto fallback_err; + } /* Issue pending DMA TX requests */ dma_async_issue_pending(stm32port->tx_ch); @@ -668,10 +710,6 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port) return; -dma_err: - dev_err(port->dev, "DMA failed with error code: %d\n", ret); - stm32_usart_tx_dma_terminate(stm32port); - fallback_err: stm32_usart_transmit_chars_pio(port); } @@ -693,16 +731,9 @@ static void stm32_usart_transmit_chars(struct uart_port *port) } if (port->x_char) { - if (stm32_usart_tx_dma_started(stm32_port) && - dmaengine_tx_status(stm32_port->tx_ch, - stm32_port->tx_ch->cookie, - NULL) == DMA_IN_PROGRESS) { - ret = dmaengine_pause(stm32_port->tx_ch); - if (ret < 0) { - dev_err(port->dev, "DMA failed with error code: %d\n", ret); - stm32_usart_tx_dma_terminate(stm32_port); - } - } + /* dma terminate may have been called in case of dma pause failure */ + stm32_usart_tx_dma_pause(stm32_port); + /* Check that TDR is empty before filling FIFO */ ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, @@ -716,13 +747,8 @@ static void stm32_usart_transmit_chars(struct uart_port *port) port->x_char = 0; port->icount.tx++; - if (stm32_usart_tx_dma_started(stm32_port)) { - ret = dmaengine_resume(stm32_port->tx_ch); - if (ret < 0) { - dev_err(port->dev, "DMA failed with error code: %d\n", ret); - stm32_usart_tx_dma_terminate(stm32_port); - } - } + /* dma terminate may have been called in case of dma resume failure */ + stm32_usart_tx_dma_resume(stm32_port); return; } @@ -855,16 +881,11 @@ static void stm32_usart_disable_ms(struct uart_port *port) static void stm32_usart_stop_tx(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - int ret; stm32_usart_tx_interrupt_disable(port); - if (stm32_usart_tx_dma_started(stm32_port)) { - ret = dmaengine_pause(stm32_port->tx_ch); - if (ret < 0) { - dev_err(port->dev, "DMA failed with error code: %d\n", ret); - stm32_usart_tx_dma_terminate(stm32_port); - } - } + + /* dma terminate may have been called in case of dma pause failure */ + stm32_usart_tx_dma_pause(stm32_port); stm32_usart_rs485_rts_disable(port); } @@ -965,8 +986,22 @@ static int stm32_usart_start_rx_dma_cyclic(struct uart_port *port) struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; struct dma_async_tx_descriptor *desc; + enum dma_status rx_dma_status; int ret; + if (stm32_port->rx_dma_busy) { + rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch, + stm32_port->rx_ch->cookie, + NULL); + if (rx_dma_status == DMA_IN_PROGRESS) + return 0; + + dev_err(port->dev, "DMA failed : status error.\n"); + stm32_usart_rx_dma_terminate(stm32_port); + } + + stm32_port->rx_dma_busy = true; + stm32_port->last_res = RX_BUF_L; /* Prepare a DMA cyclic transaction */ desc = dmaengine_prep_dma_cyclic(stm32_port->rx_ch, @@ -976,6 +1011,7 @@ static int stm32_usart_start_rx_dma_cyclic(struct uart_port *port) DMA_PREP_INTERRUPT); if (!desc) { dev_err(port->dev, "rx dma prep cyclic failed\n"); + stm32_port->rx_dma_busy = false; return -ENODEV; } @@ -986,6 +1022,7 @@ static int stm32_usart_start_rx_dma_cyclic(struct uart_port *port) ret = dma_submit_error(dmaengine_submit(desc)); if (ret) { dmaengine_terminate_sync(stm32_port->rx_ch); + stm32_port->rx_dma_busy = false; return ret; } @@ -1074,7 +1111,7 @@ static void stm32_usart_shutdown(struct uart_port *port) /* Disable RX DMA. */ if (stm32_port->rx_ch) - dmaengine_terminate_async(stm32_port->rx_ch); + stm32_usart_rx_dma_terminate(stm32_port); /* flush RX & TX FIFO */ if (ofs->rqr != UNDEF_REG) @@ -1988,7 +2025,7 @@ static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port, stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); /* Poll data from DMA RX buffer if any */ size = stm32_usart_receive_chars(port, true); - dmaengine_terminate_async(stm32_port->rx_ch); + stm32_usart_rx_dma_terminate(stm32_port); uart_unlock_and_check_sysrq_irqrestore(port, flags); if (size) tty_flip_buffer_push(tport); |