[PATCH 20/20] serial: stm32: fix rx interrupt handling in startup
From: Bich HEMON <hidden>
Date: 2017-06-26 12:53:56
Also in:
linux-devicetree, linux-serial, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
From: Bich Hemon <redacted> When stm32 dma is used, Data register has to be read in order to clear the RXNE interrupt in case we received data before usart probe. Signed-off-by: Bich Hemon <redacted> --- drivers/tty/serial/stm32-usart.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 06a92c8..b1f3aab 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c@@ -568,9 +568,18 @@ static int stm32_startup(struct uart_port *port) struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; struct stm32_usart_config *cfg = &stm32_port->info->cfg; const char *name = to_platform_device(port->dev)->name; - u32 val; + u32 val, sr, dr; int ret; + sr = readl_relaxed(port->membase + ofs->isr); + + if ((sr & USART_SR_RXNE) && (stm32_port->rx_ch)) + ret = readl_relaxed_poll_timeout_atomic(port->membase + + ofs->rdr, + dr, + !(sr & USART_SR_RXNE), + 10, 100000); + ret = request_threaded_irq(port->irq, stm32_interrupt, stm32_threaded_interrupt, IRQF_NO_SUSPEND, name, port);
--
1.9.1