virtio: console: Add emergency writeonly register to config space

This patch adds an emerg_wr register (writeonly) in config space
of virtio console device which can be used for debugging.

Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Signed-off-by: Anup Patel <anup.patel@linaro.org>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/include/uapi/linux/virtio_console.h b/include/uapi/linux/virtio_console.h
index ee13ab6c361409b31216da2e54790f804401fe51..3fd0dce3cb25d2aa26caeb518caff2cdc3a9177b 100644 (file)
--- a/include/uapi/linux/virtio_console.h
+++ b/include/uapi/linux/virtio_console.h
@@ -38,6 +38,7 @@
 /* Feature bits */
 #define VIRTIO_CONSOLE_F_SIZE  0       /* Does host provide console size? */
 #define VIRTIO_CONSOLE_F_MULTIPORT 1   /* Does host provide multiple ports? */
+#define VIRTIO_CONSOLE_F_EMERG_WRITE 2 /* Does host support emergency write? */
 
 #define VIRTIO_CONSOLE_BAD_ID          (~(u32)0)
 
@@ -48,6 +49,8 @@ struct virtio_console_config {
        __u16 rows;
        /* max. number of ports this device can hold */
        __u32 max_nr_ports;
+       /* emergency write register */
+       __u32 emerg_wr;
 } __attribute__((packed));
 
 /*