Hi
On Tue, Oct 25, 2022 at 11:32 PM Fabio Estevam festevam@gmail.com wrote:
From: Fabio Estevam festevam@denx.de
Tim Harvey reported the console garbage on imx6 since commit c7878a0483c5 ("serial: mxc: have putc use the TXFIFO").
Do as suggested by Pali Rohár where the the driver should not return -EAGAIN when the TX FIFO is full.
It should keep waiting until the TX FIFO is no longer full.
This also aligns with the implementation of the imx serial driver in the kernel:
static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch) { struct imx_port *sport = (struct imx_port *)port;
while (imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL) barrier(); imx_uart_writel(sport, ch, URTX0);}
Fixes: c7878a0483c5 ("serial: mxc: have putc use the TXFIFO") Reported-by: Tim Harvey tharvey@gateworks.com Suggested-by: Pali Rohár pali@kernel.org Signed-off-by: Fabio Estevam festevam@denx.de
drivers/serial/serial_mxc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/serial/serial_mxc.c b/drivers/serial/serial_mxc.c index 4cf79c1ca24f..332219fa87fc 100644 --- a/drivers/serial/serial_mxc.c +++ b/drivers/serial/serial_mxc.c @@ -311,8 +311,8 @@ static int mxc_serial_putc(struct udevice *dev, const char ch) struct mxc_serial_plat *plat = dev_get_plat(dev); struct mxc_uart *const uart = plat->reg;
if (readl(&uart->ts) & UTS_TXFULL)return -EAGAIN;
while (readl(&uart->ts) & UTS_TXFULL)barrier(); writel(ch, &uart->txd);
_debug_uart_putc
Should not be patched in the same way?
Anyway, does the external loop do the same with -EAGAIN as was discussed in another thread?
Michael
-- 2.25.1