| Message ID | 20180306131327.61174-2-agraf@suse.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | RPi: Drain RX queue on setbrg | expand |
On Tue, Mar 6, 2018 at 1:13 PM, Alexander Graf <agraf@suse.de> wrote: > After the UART was initialized, we may still have bogus data in the > RX queue if it was enabled with incorrect pin muxing before. > > So let's flush the RX queue whenever we initialize baud rates. > > This fixes a regression with the dynamic pinmuxing code when enable_uart=1 > is not set in config.txt. > > Fixes: caf2233b28 ("bcm283x: Add pinctrl driver") > Reported-by: Göran Lundberg <goran@lundberg.email> > Reported-by: Peter Robinson <pbrobinson@gmail.com> > Signed-off-by: Alexander Graf <agraf@suse.de> Tested-by: Peter Robinson <pbrobinson@gmail.com> Tested on both 32 bit using extlinux and 64 bit using uEFI boots. The 32 bit one, the one I saw issues with, didn't enable enable_uart because it's attached to HDMI without a serial console, the 64 does have serial console with the option in config.txt > --- > drivers/serial/serial_bcm283x_mu.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c > index 40029fadbc..d87b44e902 100644 > --- a/drivers/serial/serial_bcm283x_mu.c > +++ b/drivers/serial/serial_bcm283x_mu.c > @@ -51,6 +51,8 @@ struct bcm283x_mu_priv { > struct bcm283x_mu_regs *regs; > }; > > +static int bcm283x_mu_serial_getc(struct udevice *dev); > + > static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) > { > struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); > @@ -59,13 +61,17 @@ static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) > u32 divider; > > if (plat->skip_init) > - return 0; > + goto out; > > divider = plat->clock / (baudrate * 8); > > writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr); > writel(divider - 1, ®s->baud); > > +out: > + /* Flush the RX queue - all data in there is bogus */ > + while (bcm283x_mu_serial_getc(dev) != -EAGAIN) ; > + > return 0; > } > > -- > 2.12.3 >
diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c index 40029fadbc..d87b44e902 100644 --- a/drivers/serial/serial_bcm283x_mu.c +++ b/drivers/serial/serial_bcm283x_mu.c @@ -51,6 +51,8 @@ struct bcm283x_mu_priv { struct bcm283x_mu_regs *regs; }; +static int bcm283x_mu_serial_getc(struct udevice *dev); + static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) { struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); @@ -59,13 +61,17 @@ static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) u32 divider; if (plat->skip_init) - return 0; + goto out; divider = plat->clock / (baudrate * 8); writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr); writel(divider - 1, ®s->baud); +out: + /* Flush the RX queue - all data in there is bogus */ + while (bcm283x_mu_serial_getc(dev) != -EAGAIN) ; + return 0; }
After the UART was initialized, we may still have bogus data in the RX queue if it was enabled with incorrect pin muxing before. So let's flush the RX queue whenever we initialize baud rates. This fixes a regression with the dynamic pinmuxing code when enable_uart=1 is not set in config.txt. Fixes: caf2233b28 ("bcm283x: Add pinctrl driver") Reported-by: Göran Lundberg <goran@lundberg.email> Reported-by: Peter Robinson <pbrobinson@gmail.com> Signed-off-by: Alexander Graf <agraf@suse.de> --- drivers/serial/serial_bcm283x_mu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)