Updating Tim Kryger's e-mail address. On 25 June 2014 00:20, Wang Nan <[email protected]> wrote: > From: James Hogan <[email protected]> > > upstream unclusion > DTS: DTS2014060600056 > directory: cherry-pick > > ---------------------------------------- > > commit 6979f8d28049879e6147767d93ba6732c8bd94f4 upstream > > Commit c49436b657d0 (serial: 8250_dw: Improve unwritable LCR workaround) > caused a regression. It added a check that the LCR was written properly > to detect and workaround the busy quirk, but the behaviour of bit 5 > (UART_LCR_SPAR) differs between IP versions 3.00a and 3.14c per the > docs. On older versions this caused the check to fail and it would > repeatedly force idle and rewrite the LCR register, causing delays and > preventing any input from serial being received. > > This is fixed by masking out UART_LCR_SPAR before making the comparison. > > Signed-off-by: James Hogan <[email protected]> > Cc: Greg Kroah-Hartman <[email protected]> > Cc: Jiri Slaby <[email protected]> > Cc: Tim Kryger <[email protected]>
Tim Kryger <[email protected]> > Cc: Ezequiel Garcia <[email protected]> > Cc: Matt Porter <[email protected]> > Cc: Markus Mayer <[email protected]> > Tested-by: Tim Kryger <[email protected]> > Tested-by: Ezequiel Garcia <[email protected]> > Tested-by: Heikki Krogerus <[email protected]> > Signed-off-by: Greg Kroah-Hartman <[email protected]> > --- > drivers/tty/serial/8250/8250_dw.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_dw.c > b/drivers/tty/serial/8250/8250_dw.c > index 1b55923..345b5dd 100644 > --- a/drivers/tty/serial/8250/8250_dw.c > +++ b/drivers/tty/serial/8250/8250_dw.c > @@ -92,7 +92,8 @@ static void dw8250_serial_out(struct uart_port *p, int > offset, int value) > if (offset == UART_LCR) { > int tries = 1000; > while (tries--) { > - if (value == p->serial_in(p, UART_LCR)) > + unsigned int lcr = p->serial_in(p, UART_LCR); > + if ((value & ~UART_LCR_SPAR) == (lcr & > ~UART_LCR_SPAR)) > return; > dw8250_force_idle(p); > writeb(value, p->membase + (UART_LCR << p->regshift)); > @@ -121,7 +122,8 @@ static void dw8250_serial_out32(struct uart_port *p, int > offset, int value) > if (offset == UART_LCR) { > int tries = 1000; > while (tries--) { > - if (value == p->serial_in(p, UART_LCR)) > + unsigned int lcr = p->serial_in(p, UART_LCR); > + if ((value & ~UART_LCR_SPAR) == (lcr & > ~UART_LCR_SPAR)) > return; > dw8250_force_idle(p); > writel(value, p->membase + (UART_LCR << p->regshift)); > -- > 1.8.4 > -- Markus Mayer Broadcom Landing Team -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
