diff options
| -rw-r--r-- | drivers/tty/serial/serial-tegra.c | 78 |
1 files changed, 46 insertions, 32 deletions
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index b6ace6290e23..3b495e7c9534 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -141,6 +141,7 @@ struct tegra_uart_port { int configured_rate; bool use_rx_pio; bool use_tx_pio; + bool rx_dma_active; }; static void tegra_uart_start_next_tx(struct tegra_uart_port *tup); @@ -731,6 +732,7 @@ static void tegra_uart_rx_dma_complete(void *args) if (tup->rts_active) set_rts(tup, false); + tup->rx_dma_active = false; tegra_uart_rx_buffer_push(tup, 0); tegra_uart_start_rx_dma(tup); @@ -742,18 +744,27 @@ done: spin_unlock_irqrestore(&u->lock, flags); } -static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup) +static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup) { struct dma_tx_state state; - /* Deactivate flow control to stop sender */ - if (tup->rts_active) - set_rts(tup, false); + if (!tup->rx_dma_active) + return; dmaengine_terminate_all(tup->rx_dma_chan); dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); + tegra_uart_rx_buffer_push(tup, state.residue); - tegra_uart_start_rx_dma(tup); + tup->rx_dma_active = false; +} + +static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup) +{ + /* Deactivate flow control to stop sender */ + if (tup->rts_active) + set_rts(tup, false); + + tegra_uart_terminate_rx_dma(tup); if (tup->rts_active) set_rts(tup, true); @@ -763,6 +774,9 @@ static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup) { unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE; + if (tup->rx_dma_active) + return 0; + tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan, tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); @@ -771,6 +785,7 @@ static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup) return -EIO; } + tup->rx_dma_active = true; tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete; tup->rx_dma_desc->callback_param = tup; dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys, @@ -820,6 +835,7 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) struct uart_port *u = &tup->uport; unsigned long iir; unsigned long ier; + bool is_rx_start = false; bool is_rx_int = false; unsigned long flags; @@ -832,10 +848,12 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) if (tup->rx_in_progress) { ier = tup->ier_shadow; ier |= (UART_IER_RLSI | UART_IER_RTOIE | - TEGRA_UART_IER_EORD); + TEGRA_UART_IER_EORD | UART_IER_RDI); tup->ier_shadow = ier; tegra_uart_write(tup, ier, UART_IER); } + } else if (is_rx_start) { + tegra_uart_start_rx_dma(tup); } spin_unlock_irqrestore(&u->lock, flags); return IRQ_HANDLED; @@ -854,17 +872,23 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) case 4: /* End of data */ case 6: /* Rx timeout */ - case 2: /* Receive */ - if (!tup->use_rx_pio && !is_rx_int) { - is_rx_int = true; + if (!tup->use_rx_pio) { + is_rx_int = tup->rx_in_progress; /* Disable Rx interrupts */ ier = tup->ier_shadow; - ier |= UART_IER_RDI; - tegra_uart_write(tup, ier, UART_IER); ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE | TEGRA_UART_IER_EORD); tup->ier_shadow = ier; tegra_uart_write(tup, ier, UART_IER); + break; + } + /* Fall through */ + case 2: /* Receive */ + if (!tup->use_rx_pio) { + is_rx_start = tup->rx_in_progress; + tup->ier_shadow &= ~UART_IER_RDI; + tegra_uart_write(tup, tup->ier_shadow, + UART_IER); } else { do_handle_rx_pio(tup); } @@ -886,7 +910,6 @@ static void tegra_uart_stop_rx(struct uart_port *u) { struct tegra_uart_port *tup = to_tegra_uport(u); struct tty_port *port = &tup->uport.state->port; - struct dma_tx_state state; unsigned long ier; if (tup->rts_active) @@ -903,13 +926,11 @@ static void tegra_uart_stop_rx(struct uart_port *u) tup->ier_shadow = ier; tegra_uart_write(tup, ier, UART_IER); tup->rx_in_progress = 0; - if (tup->rx_dma_chan && !tup->use_rx_pio) { - dmaengine_terminate_all(tup->rx_dma_chan); - dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); - tegra_uart_rx_buffer_push(tup, state.residue); - } else { + + if (!tup->use_rx_pio) + tegra_uart_terminate_rx_dma(tup); + else tegra_uart_handle_rx_pio(tup, port); - } } static void tegra_uart_hw_deinit(struct tegra_uart_port *tup) @@ -1052,12 +1073,6 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup) tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR; tup->fcr_shadow |= UART_FCR_DMA_SELECT; tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); - - ret = tegra_uart_start_rx_dma(tup); - if (ret < 0) { - dev_err(tup->uport.dev, "Not able to start Rx DMA\n"); - return ret; - } } else { tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); } @@ -1067,10 +1082,6 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup) * Enable IE_RXS for the receive status interrupts like line errros. * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd. * - * If using DMA mode, enable EORD instead of receive interrupt which - * will interrupt after the UART is done with the receive instead of - * the interrupt when the FIFO "threshold" is reached. - * * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when * the DATA is sitting in the FIFO and couldn't be transferred to the * DMA as the DMA size alignment (4 bytes) is not met. EORD will be @@ -1081,11 +1092,14 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup) * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first * then the EORD. */ + tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI; + + /* + * If using DMA mode, enable EORD interrupt to notify about RX + * completion. + */ if (!tup->use_rx_pio) - tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | - TEGRA_UART_IER_EORD; - else - tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI; + tup->ier_shadow |= TEGRA_UART_IER_EORD; tegra_uart_write(tup, tup->ier_shadow, UART_IER); return 0; |