[PATCH 6/9] console: add get_size callback for direct size reporting

[Ahmad Fatoum <a.fatoum@barebox.org>]

Add an optional get_size callback to struct console_device that allows
consoles to report their dimensions directly without requiring escape
sequence queries.

Update term_getsize() to try get_size first for consoles that implement
it. These consoles only need CONSOLE_STDOUT to participate in size
detection. Consoles without get_size still require both CONSOLE_STDIN
and CONSOLE_STDOUT for the escape sequence query path.

This enables output-only consoles like fbconsole to report their size
to commands like edit and watch.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 include/console.h | 1 +
 lib/term.c        | 8 ++++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/console.h b/include/console.h
index 1dfaa66d9266..f2b8da1546ef 100644
--- a/include/console.h
+++ b/include/console.h
@@ -43,6 +43,7 @@ struct console_device {
 	int (*set_mode)(struct console_device *cdev, enum console_mode mode);
 	int (*open)(struct console_device *cdev);
 	int (*close)(struct console_device *cdev);
+	int (*get_size)(struct console_device *cdev, int *width, int *height);
 
 	const char *devname;
 	int devid;
diff --git a/lib/term.c b/lib/term.c
index 0a656d79e725..382250c70ddf 100644
--- a/lib/term.c
+++ b/lib/term.c
@@ -79,11 +79,15 @@ int term_cdev_get_size(struct console_device *cdev,
 	const char restore[] = "\e8";
 	int ret, params[2];
 
-	if (!(cdev->f_active & CONSOLE_STDIN))
-		return -ENOENT;
 	if (!(cdev->f_active & CONSOLE_STDOUT))
 		return -ENOENT;
 
+	if (cdev->get_size)
+		return cdev->get_size(cdev, screenwidth, screenheight);
+
+	if (!(cdev->f_active & CONSOLE_STDIN))
+		return -ENOENT;
+
 	term_cdev_drain(cdev);
 
 	console_puts(cdev, esc);
-- 
2.47.3