[PATCH 08/16] serial: mvebu-uart: clear state register before IRQ request
From: Gregory CLEMENT <hidden>
Date: 2017-10-06 12:40:47
Also in:
linux-devicetree, linux-gpio, linux-serial
Hi Miquel, On ven., oct. 06 2017, Miquel Raynal [off-list ref] wrote:
From: Allen Yan <redacted> When receiving data on RX pin before ->uart_startup() is called, some error bits in the state register could be set up (like BRK_DET). This is harmless when using only the standard UART (error bits are read-only), but may procude an endless loop once in the extended UART
produce
RX interrupt handler (error bits must be cleared). Clear the status register in ->uart_startup() to avoid this situation. Signed-off-by: Allen Yan <redacted> Signed-off-by: Miquel Raynal <redacted>
Reviewed-by: Gregory CLEMENT <redacted> Thanks, Gregory
quoted hunk
--- drivers/tty/serial/mvebu-uart.c | 6 ++++++ 1 file changed, 6 insertions(+)diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index 81a3d2714fd3..67f302748b78 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c@@ -322,6 +322,12 @@ static int mvebu_uart_startup(struct uart_port *port) writel(CTRL_TXFIFO_RST | CTRL_RXFIFO_RST, port->membase + UART_CTRL(port)); udelay(1); + + /* Clear the error bits of state register before IRQ request */ + ret = readl(port->membase + UART_STAT); + ret |= STAT_BRK_ERR; + writel(ret, port->membase + UART_STAT); + writel(CTRL_BRK_INT, port->membase + UART_CTRL(port)); ctl = readl(port->membase + UART_INTR(port));-- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel at lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
-- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com