libpayload: video: Add support for font scaling with a factor

This introduces support for font scaling with a factor provided via
Kconfig. In practice, the font itself is not scaled at any point in
memory and only the logic to determine whether a pixel should be filled
or not is changed.

Thus, it should not significantly impact either the access time or
memory use.

Change-Id: Idff210617c9ec08c6034aef107cfdb34c7cdf029
Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-on: https://review.coreboot.org/20709
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

5 files changed, 24 insertions, 7 deletions

diff --git a/payloads/libpayload/Kconfig b/payloads/libpayload/Kconfig
index 63cc1527b6..8fd6a9c763 100644
--- a/payloads/libpayload/Kconfig
+++ b/payloads/libpayload/Kconfig
@@ -321,6 +321,14 @@ config COREBOOT_VIDEO_CONSOLE
 	  Say Y here if coreboot switched to a graphics mode and
 	  your payload wants to use it.
 
+config FONT_SCALE_FACTOR
+	int "Scale factor for the included font"
+	depends on GEODELX_VIDEO_CONSOLE || COREBOOT_VIDEO_CONSOLE
+	default 0
+	help
+	  By default (value of 0), the scale factor is automatically
+	  calculated to ensure at least 130 columns (when possible).
+
 config PC_KEYBOARD
 	bool "Allow input from a PC keyboard"
 	default y if ARCH_X86 # uses IO
diff --git a/payloads/libpayload/drivers/video/corebootfb.c b/payloads/libpayload/drivers/video/corebootfb.c
index 69aa1d7f65..b5ad1a511d 100644
--- a/payloads/libpayload/drivers/video/corebootfb.c
+++ b/payloads/libpayload/drivers/video/corebootfb.c
@@ -238,7 +238,7 @@ static int corebootfb_init(void)
 	if (fbaddr == 0)
 		return -1;
 
-	font_init();
+	font_init(FI->x_resolution);
 
 	coreboot_video_console.columns = FI->x_resolution / font_width;
 	coreboot_video_console.rows = FI->y_resolution / font_height;
diff --git a/payloads/libpayload/drivers/video/font.c b/payloads/libpayload/drivers/video/font.c
index 59d476dacf..8758a9646e 100644
--- a/payloads/libpayload/drivers/video/font.c
+++ b/payloads/libpayload/drivers/video/font.c
@@ -27,14 +27,22 @@
  * SUCH DAMAGE.
  */
 
+#include <libpayload.h>
 #include "font8x16.h"
 #include "font.h"
 
+#define COLS_MIN	130
+
 int font_width;
 int font_height;
+int font_scale;
 
-void font_init(void)
+void font_init(int width)
 {
-	font_width = FONT_WIDTH;
-	font_height = FONT_HEIGHT;
+	font_scale = CONFIG_LP_FONT_SCALE_FACTOR;
+	if (!font_scale)
+		font_scale = MAX(width / (FONT_WIDTH * COLS_MIN), 1);
+
+	font_width = FONT_WIDTH * font_scale;
+	font_height = FONT_HEIGHT * font_scale;
 }
diff --git a/payloads/libpayload/drivers/video/font.h b/payloads/libpayload/drivers/video/font.h
index a5e0b85c02..9ea328c78d 100644
--- a/payloads/libpayload/drivers/video/font.h
+++ b/payloads/libpayload/drivers/video/font.h
@@ -34,13 +34,14 @@
 
 extern int font_width;
 extern int font_height;
+extern int font_scale;
 
 inline int font_glyph_filled(unsigned int ch, int x, int y)
 {
 	unsigned char *glyph = font8x16 + ((ch & 0xFF) * FONT_HEIGHT);
-	return glyph[y] & (1 << x);
+	return glyph[y/font_scale] & (1 << x/font_scale);
 }
 
-void font_init(void);
+void font_init(int width);
 
 #endif
diff --git a/payloads/libpayload/drivers/video/geodelx.c b/payloads/libpayload/drivers/video/geodelx.c
index 46fa833ec1..e14a96b332 100644
--- a/payloads/libpayload/drivers/video/geodelx.c
+++ b/payloads/libpayload/drivers/video/geodelx.c
@@ -268,7 +268,7 @@ static int geodelx_init(void)
 	dcaddr = pci_read_resource(dev, 2);
 	vgaddr = pci_read_resource(dev, 3);
 
-	font_init();
+	font_init(vga_mode.hactive);
 
 	init_video_mode();