[PATCH v2] serial: 8250_dw: Improve unwritable LCR workaround
From: Ezequiel Garcia <hidden>
Date: 2013-12-10 12:11:51
Also in:
linux-serial, lkml
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 [off-list ref] wrote:
[..]
quoted hunk ↗ jump to hunk
diff --git a/drivers/tty/serial/8250/8250_dw.cb/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