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>

2 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/kdb.h b/include/linux/kdb.h
index 4d93790faec3..d72fa3908128 100644
--- a/include/linux/kdb.h
+++ b/include/linux/kdb.h
@@ -19,6 +19,7 @@
 #include <asm/atomic.h>
 
 #define KDB_POLL_FUNC_MAX       5
+extern int kdb_poll_idx;
 
 /*
  * kdb_initial_cpu is initialized to -1, and is set to the cpu
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 78dd1e7120a9..ad839963fa68 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -246,6 +246,7 @@ struct uart_ops {
 #endif
 };
 
+#define NO_POLL_CHAR            0x00ff0000
 #define UART_CONFIG_TYPE        (1 << 0)
 #define UART_CONFIG_IRQ         (1 << 1)