From mboxrd@z Thu Jan 1 00:00:00 1970 From: ezequiel.garcia@free-electrons.com (Ezequiel Garcia) Date: Tue, 10 Dec 2013 09:11:55 -0300 Subject: [PATCH v2] serial: 8250_dw: Improve unwritable LCR workaround In-Reply-To: References: <1380647888-32473-1-git-send-email-tim.kryger@linaro.org> <5548535.pYirbknue4@radagast> <3010367.6CxxZ6Dpea@radagast> Message-ID: <20131210121154.GA16238@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Tim, James: On Mon, Dec 09, 2013 at 04:42:23PM -0800, Tim Kryger wrote: > On Fri, Dec 6, 2013 at 4:59 PM, James Hogan wrote: > [..] > diff --git a/drivers/tty/serial/8250/8250_dw.c > b/drivers/tty/serial/8250/8250_dw.c > index 4658e3e..5f096c7 100644 > --- a/drivers/tty/serial/8250/8250_dw.c > +++ b/drivers/tty/serial/8250/8250_dw.c > @@ -96,7 +96,8 @@ 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)); > @@ -132,7 +133,8 @@ 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)); > > > Would you mind posting this for proper review so we can get the fix in? > Applying this change fixes all the problems I reported (just did a quick test on the board I have currently on my desk). Nice work! -- Ezequiel Garc?a, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com