diff options
Diffstat (limited to 'drivers/tty/serial/serial-tegra.c')
| -rw-r--r-- | drivers/tty/serial/serial-tegra.c | 127 |
1 files changed, 70 insertions, 57 deletions
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index b6ace6290e23..8de8bac9c6c7 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); @@ -533,11 +534,12 @@ static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup, struct circ_buf *xmit = &tup->uport.state->xmit; dma_addr_t tx_phys_addr; - dma_sync_single_for_device(tup->uport.dev, tup->tx_dma_buf_phys, - UART_XMIT_SIZE, DMA_TO_DEVICE); - tup->tx_bytes = count & ~(0xF); tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail; + + dma_sync_single_for_device(tup->uport.dev, tx_phys_addr, + tup->tx_bytes, DMA_TO_DEVICE); + tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan, tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT); @@ -679,7 +681,7 @@ static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, return; dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys, - TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE); + count, DMA_FROM_DEVICE); copied = tty_insert_flip_string(tty, ((unsigned char *)(tup->rx_dma_buf_virt)), count); if (copied != count) { @@ -687,14 +689,25 @@ static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, dev_err(tup->uport.dev, "RxData copy to tty layer failed\n"); } dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys, - TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE); + count, DMA_TO_DEVICE); +} + +static void do_handle_rx_pio(struct tegra_uart_port *tup) +{ + struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port); + struct tty_port *port = &tup->uport.state->port; + + tegra_uart_handle_rx_pio(tup, port); + if (tty) { + tty_flip_buffer_push(port); + tty_kref_put(tty); + } } static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup, unsigned int residue) { struct tty_port *port = &tup->uport.state->port; - struct tty_struct *tty = tty_port_tty_get(port); unsigned int count; async_tx_ack(tup->rx_dma_desc); @@ -703,11 +716,7 @@ static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup, /* If we are here, DMA is stopped */ tegra_uart_copy_rx_to_tty(tup, port, count); - tegra_uart_handle_rx_pio(tup, port); - if (tty) { - tty_flip_buffer_push(port); - tty_kref_put(tty); - } + do_handle_rx_pio(tup); } static void tegra_uart_rx_dma_complete(void *args) @@ -731,6 +740,7 @@ 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 +752,29 @@ 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) { + do_handle_rx_pio(tup); + 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 +784,9 @@ 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); @@ -771,10 +795,9 @@ 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, - count, DMA_TO_DEVICE); tup->rx_bytes_requested = count; tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc); dma_async_issue_pending(tup->rx_dma_chan); @@ -802,24 +825,13 @@ static void tegra_uart_handle_modem_signal_change(struct uart_port *u) uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS); } -static void do_handle_rx_pio(struct tegra_uart_port *tup) -{ - struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port); - struct tty_port *port = &tup->uport.state->port; - - tegra_uart_handle_rx_pio(tup, port); - if (tty) { - tty_flip_buffer_push(port); - tty_kref_put(tty); - } -} - static irqreturn_t tegra_uart_isr(int irq, void *data) { struct tegra_uart_port *tup = 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 +844,12 @@ 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 +868,23 @@ 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 +906,6 @@ 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 +922,11 @@ 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 +1069,6 @@ 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 +1078,6 @@ 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 +1088,14 @@ 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; @@ -1140,6 +1150,9 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup, dma_release_channel(dma_chan); return -ENOMEM; } + dma_sync_single_for_device(tup->uport.dev, dma_phys, + TEGRA_UART_RX_DMA_BUFFER_SIZE, + DMA_TO_DEVICE); dma_sconfig.src_addr = tup->uport.mapbase; dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; dma_sconfig.src_maxburst = tup->cdata->max_dma_burst_bytes; |