From: Bich Hemon <[email protected]> Two improvements for dma receive in this patch: - usart dma receiver (DMAR) is disabled during receive - dma receive buffer is sync-ed for cpu before reading and given back to the dma just after
Signed-off-by: Gerald Baeza <[email protected]> --- drivers/tty/serial/stm32-usart.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 266dc4f..13fc520 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -393,11 +393,21 @@ static irqreturn_t stm32_threaded_interrupt(int irq, void *ptr) { struct uart_port *port = ptr; struct stm32_port *stm32_port = to_stm32_port(port); + struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; spin_lock(&port->lock); - if (stm32_port->rx_ch) + if (stm32_port->rx_ch) { + stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR); + dma_sync_single_for_cpu(port->dev, + stm32_port->rx_dma_buf, + RX_BUF_L, DMA_FROM_DEVICE); stm32_receive_chars(port, true); + dma_sync_single_for_device(port->dev, + stm32_port->rx_dma_buf, + RX_BUF_L, DMA_FROM_DEVICE); + stm32_set_bits(port, ofs->cr3, USART_CR3_DMAR); + } spin_unlock(&port->lock); -- 1.9.1
