kgdb,8250,pl011: Return immediately from console poll
The design of the kdb shell requires that every device that can
provide input to kdb have a polling routine that exits immediately if
there is no character available. This is required in order to get the
page scrolling mechanism working.
Changing the kernel debugger I/O API to require all polling character
routines to exit immediately if there is no data allows the kernel
debugger to process multiple input channels.
NO_POLL_CHAR will be the return code to the polling routine when ever
there is no character available.
CC: linux-serial@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
index 743ebf5..eb4cb48 100644
--- a/drivers/serial/amba-pl011.c
+++ b/drivers/serial/amba-pl011.c
@@ -342,9 +342,9 @@
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int status;
- do {
- status = readw(uap->port.membase + UART01x_FR);
- } while (status & UART01x_FR_RXFE);
+ status = readw(uap->port.membase + UART01x_FR);
+ if (status & UART01x_FR_RXFE)
+ return NO_POLL_CHAR;
return readw(uap->port.membase + UART01x_DR);
}