diff options
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/tty/serial/tegra_hsuart.c | 83 |
1 files changed, 32 insertions, 51 deletions
diff --git a/drivers/tty/serial/tegra_hsuart.c b/drivers/tty/serial/tegra_hsuart.c index b3b8eeaf8cf6..79f607ad0f3f 100644 --- a/drivers/tty/serial/tegra_hsuart.c +++ b/drivers/tty/serial/tegra_hsuart.c @@ -255,19 +255,30 @@ static int tegra_start_dma_rx(struct tegra_uart_port *t) static void tegra_rx_dma_threshold_callback(struct tegra_dma_req *req) { struct tegra_uart_port *t = req->dev; + struct uart_port *u = &t->uport; unsigned long flags; - spin_lock_irqsave(&t->uport.lock, flags); + spin_lock_irqsave(&u->lock, flags); do_handle_rx_dma(t); - spin_unlock_irqrestore(&t->uport.lock, flags); + spin_unlock_irqrestore(&u->lock, flags); } -/* must be called with uart lock held */ -static void tegra_rx_dma_complete_req(struct tegra_uart_port *t, - struct tegra_dma_req *req) +/* It is expected that the callers take the UART lock when this API is called. + * + * There are 2 contexts when this function is called: + * + * 1. DMA ISR - DMA ISR triggers the threshold complete calback, which calls the + * dequue API which in-turn calls this callback. UART lock is taken during + * the call to the threshold callback. + * + * 2. UART ISR - UART calls the dequue API which in-turn will call this API. + * In this case, UART ISR takes the UART lock. + * */ +static void tegra_rx_dma_complete_callback(struct tegra_dma_req *req) { + struct tegra_uart_port *t = req->dev; struct uart_port *u = &t->uport; struct tty_struct *tty = u->state->port.tty; @@ -288,24 +299,9 @@ static void tegra_rx_dma_complete_req(struct tegra_uart_port *t, if (req->status == -TEGRA_DMA_REQ_ERROR_ABORTED) return; + spin_unlock(&u->lock); tty_flip_buffer_push(u->state->port.tty); -} - -static void tegra_rx_dma_complete_callback(struct tegra_dma_req *req) -{ - struct tegra_uart_port *t = req->dev; - unsigned long flags; - - /* - * should never get called, dma should be dequeued during threshold - * callback - */ - - dev_warn(t->uport.dev, "possible rx overflow\n"); - - spin_lock_irqsave(&t->uport.lock, flags); - tegra_rx_dma_complete_req(t, req); - spin_unlock_irqrestore(&t->uport.lock, flags); + spin_lock(&u->lock); } /* Lock already taken */ @@ -314,9 +310,7 @@ static void do_handle_rx_dma(struct tegra_uart_port *t) struct uart_port *u = &t->uport; if (t->rts_active) set_rts(t, false); - if (!tegra_dma_dequeue_req(t->rx_dma, &t->rx_dma_req)) - tegra_rx_dma_complete_req(t, &t->rx_dma_req); - + tegra_dma_dequeue(t->rx_dma); tty_flip_buffer_push(u->state->port.tty); /* enqueue the request again */ tegra_start_dma_rx(t); @@ -487,31 +481,22 @@ static void tegra_tx_dma_complete_work(struct work_struct *work) spin_unlock_irqrestore(&t->uport.lock, flags); } -/* must be called with uart lock held */ -static void tegra_tx_dma_complete_req(struct tegra_uart_port *t, - struct tegra_dma_req *req) +static void tegra_tx_dma_complete_callback(struct tegra_dma_req *req) { + struct tegra_uart_port *t = req->dev; struct circ_buf *xmit = &t->uport.state->xmit; int count = req->bytes_transferred; + unsigned long flags; + + dev_vdbg(t->uport.dev, "%s: %d\n", __func__, count); + spin_lock_irqsave(&t->uport.lock, flags); xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&t->uport); schedule_work(&t->tx_work); -} - -static void tegra_tx_dma_complete_callback(struct tegra_dma_req *req) -{ - struct tegra_uart_port *t = req->dev; - unsigned long flags; - - dev_vdbg(t->uport.dev, "%s: %d\n", __func__, req->bytes_transferred); - - spin_lock_irqsave(&t->uport.lock, flags); - - tegra_tx_dma_complete_req(t, req); spin_unlock_irqrestore(&t->uport.lock, flags); } @@ -607,12 +592,11 @@ static void tegra_stop_rx(struct uart_port *u) uart_writeb(t, ier, UART_IER); t->rx_in_progress = 0; - if (t->use_rx_dma && t->rx_dma) { - if (!tegra_dma_dequeue_req(t->rx_dma, &t->rx_dma_req)) - tegra_rx_dma_complete_req(t, &t->rx_dma_req); - } else { + if (t->use_rx_dma && t->rx_dma) + tegra_dma_dequeue(t->rx_dma); + else do_handle_rx_pio(t); - } + tty_flip_buffer_push(u->state->port.tty); } @@ -1002,10 +986,8 @@ static void tegra_stop_tx(struct uart_port *u) t = container_of(u, struct tegra_uart_port, uport); - if (t->use_tx_dma) { - if (!tegra_dma_dequeue_req(t->tx_dma, &t->tx_dma_req)) - tegra_tx_dma_complete_req(t, &t->tx_dma_req); - } + if (t->use_tx_dma) + tegra_dma_dequeue_req(t->tx_dma, &t->tx_dma_req); return; } @@ -1156,8 +1138,7 @@ static void tegra_flush_buffer(struct uart_port *u) t = container_of(u, struct tegra_uart_port, uport); if (t->use_tx_dma) { - if (!tegra_dma_dequeue_req(t->tx_dma, &t->tx_dma_req)) - tegra_tx_dma_complete_req(t, &t->tx_dma_req); + tegra_dma_dequeue_req(t->tx_dma, &t->tx_dma_req); t->tx_dma_req.size = 0; } return; |