diff options
| -rw-r--r-- | drivers/tty/serial/samsung.c | 13 | ||||
| -rw-r--r-- | drivers/tty/serial/samsung.h | 1 |
2 files changed, 12 insertions, 2 deletions
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 8c963d6d9074..faee021c27b0 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -341,7 +341,8 @@ static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport) return; } - if (!ourport->dma || !ourport->dma->tx_chan || count < port->fifosize) + if (!ourport->dma || !ourport->dma->tx_chan || + count < ourport->min_dma_size) s3c24xx_serial_start_tx_pio(ourport); else s3c24xx_serial_start_tx_dma(ourport, count); @@ -741,7 +742,8 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id) count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); - if (ourport->dma && ourport->dma->tx_chan && count >= port->fifosize) { + if (ourport->dma && ourport->dma->tx_chan && + count >= ourport->min_dma_size) { s3c24xx_serial_start_tx_dma(ourport, count); goto out; } @@ -1837,6 +1839,13 @@ static int s3c24xx_serial_probe(struct platform_device *pdev) else if (ourport->info->fifosize) ourport->port.fifosize = ourport->info->fifosize; + /* + * DMA transfers must be aligned at least to cache line size, + * so find minimal transfer size suitable for DMA mode + */ + ourport->min_dma_size = max_t(int, ourport->port.fifosize, + dma_get_cache_alignment()); + probe_index++; dbg("%s: initialising port %p...\n", __func__, ourport); diff --git a/drivers/tty/serial/samsung.h b/drivers/tty/serial/samsung.h index d275032aa68d..fc5deaa4f382 100644 --- a/drivers/tty/serial/samsung.h +++ b/drivers/tty/serial/samsung.h @@ -82,6 +82,7 @@ struct s3c24xx_uart_port { unsigned char tx_claimed; unsigned int pm_level; unsigned long baudclk_rate; + unsigned int min_dma_size; unsigned int rx_irq; unsigned int tx_irq; |