diff options
| author | Gerd Hoffmann <kraxel@redhat.com> | 2013-05-30 10:33:38 +0200 |
|---|---|---|
| committer | Ronald G. Minnich <rminnich@gmail.com> | 2013-06-05 18:24:08 +0200 |
| commit | 22f01e611be6fbd3ee5a70b27b96478ff1f4e93a (patch) | |
| tree | 5c07114e40071065c33f0de56865c29bd5f3132a | |
| parent | d7c6e444acfc3284c4a9ff49dd138cd0c37545e2 (diff) | |
console: add qemu debugcon detection
The qemu debugcon port returns 0xe9 on reads in case the device is
present. Use that for detection and write console output to the
port only in case the device is actually present.
Change-Id: I41aabcf11845d24004e4f795dfd799822fd14646
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-on: http://review.coreboot.org/3338
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
| -rw-r--r-- | src/console/qemu_debugcon_console.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/src/console/qemu_debugcon_console.c b/src/console/qemu_debugcon_console.c index 3037e3651c..e2591baa15 100644 --- a/src/console/qemu_debugcon_console.c +++ b/src/console/qemu_debugcon_console.c @@ -21,13 +21,18 @@ #include <console/console.h> #include <arch/io.h> +static unsigned char readback; + static void debugcon_init(void) { + readback = inb(CONFIG_CONSOLE_QEMU_DEBUGCON_PORT); } static void debugcon_tx_byte(unsigned char data) { - outb(data, CONFIG_CONSOLE_QEMU_DEBUGCON_PORT); + if (readback == 0xe9) { + outb(data, CONFIG_CONSOLE_QEMU_DEBUGCON_PORT); + } } static void debugcon_tx_flush(void) |