[PATCH 09/20] fbconsole: precompute foreground/background colors

[Ahmad Fatoum]

We did color format conversion on every drawchar(), when it would have
been sufficient to do this only when the color is actually changed.

As clearing the screen should also be color aware and doesn't
necessarily involve a call to drawchar(), optimize the color conversion
to happen on only when the color actually changes.

Signed-off-by: Ahmad Fatoum <a.fatoum at barebox.org>
---
 drivers/video/fbconsole.c | 77 ++++++++++++++++++++++++++-------------
 1 file changed, 52 insertions(+), 25 deletions(-)

diff --git a/drivers/video/fbconsole.c b/drivers/video/fbconsole.c
index 285f22901573..74b37b429f2a 100644
--- a/drivers/video/fbconsole.c
+++ b/drivers/video/fbconsole.c
@@ -39,6 +39,7 @@ enum ansi_color {
 };
 
 #define DEFAULT_COLOR	WHITE
+#define DEFAULT_BGCOLOR	BLACK
 
 struct fbc_priv {
 	struct console_device cdev;
@@ -66,6 +67,9 @@ struct fbc_priv {
 	int color;
 	int bgcolor;
 
+	u32 color_rgb;
+	u32 bgcolor_rgb;
+
 #define ANSI_FLAG_INVERT	(1 << 0)
 #define ANSI_FLAG_BRIGHT	(1 << 1)
 #define SGR_ATTRIBUTES		(ANSI_FLAG_INVERT | ANSI_FLAG_BRIGHT)
@@ -200,8 +204,6 @@ static void drawchar(struct fbc_priv *priv, int x, int y, int c)
 	int i;
 	const uint8_t *inbuf;
 	int line_length;
-	u32 color, bgcolor;
-	struct rgb *rgb;
 	int xstep;
 	int ystep;
 	int startx;
@@ -214,18 +216,6 @@ static void drawchar(struct fbc_priv *priv, int x, int y, int c)
 
 	line_length = priv->fb->line_length;
 
-	color = priv->flags & ANSI_FLAG_INVERT ? priv->bgcolor : priv->color;
-	bgcolor = priv->flags & ANSI_FLAG_INVERT ? priv->color : priv->bgcolor;
-
-	if (priv->flags & ANSI_FLAG_BRIGHT)
-		color += BRIGHT;
-
-	rgb = &colors[color];
-	color = gu_rgb_to_pixel(priv->fb, rgb->r, rgb->g, rgb->b, 0xff);
-
-	rgb = &colors[bgcolor];
-	bgcolor = gu_rgb_to_pixel(priv->fb, rgb->r, rgb->g, rgb->b, 0x0);
-
 	adr = buf;
 
 	switch (priv->rotation) {
@@ -271,9 +261,11 @@ static void drawchar(struct fbc_priv *priv, int x, int y, int c)
 			}
 
 			if (*inbuf & mask)
-				gu_set_pixel(priv->fb, adr + j * xstep, color);
+				gu_set_pixel(priv->fb, adr + j * xstep,
+					     priv->color_rgb);
 			else
-				gu_set_pixel(priv->fb, adr + j * xstep, bgcolor);
+				gu_set_pixel(priv->fb, adr + j * xstep,
+					     priv->bgcolor_rgb);
 
 			mask >>= 1;
 
@@ -497,8 +489,41 @@ static void printchar(struct fbc_priv *priv, int c)
 	toggle_cursor_visibility(priv);
 }
 
+static void fbc_update_colors(struct fbc_priv *priv, int color, int bgcolor)
+{
+	struct rgb *rgb;
+
+	if (color >= 0)
+		priv->color = color;
+	if (bgcolor >= 0)
+		priv->bgcolor = bgcolor;
+
+	if (priv->flags & ANSI_FLAG_INVERT) {
+		color = priv->bgcolor;
+		bgcolor = priv->color;
+	} else {
+		color = priv->color;
+		bgcolor = priv->bgcolor;
+	}
+
+	if (priv->flags & ANSI_FLAG_BRIGHT)
+		color += BRIGHT;
+
+	rgb = &colors[color];
+	priv->color_rgb = gu_rgb_to_pixel(priv->fb, rgb->r, rgb->g, rgb->b, 0xff);
+
+	rgb = &colors[bgcolor];
+	priv->bgcolor_rgb = gu_rgb_to_pixel(priv->fb, rgb->r, rgb->g, rgb->b, 0x0);
+}
+
+static void fbc_reset_colors(struct fbc_priv *priv)
+{
+	fbc_update_colors(priv, DEFAULT_COLOR, DEFAULT_BGCOLOR);
+}
+
 static void fbc_parse_colors(struct fbc_priv *priv)
 {
+	int color = -1, bgcolor = -1;
 	int code;
 	char *str;
 
@@ -509,8 +534,8 @@ static void fbc_parse_colors(struct fbc_priv *priv)
 		switch (code) {
 		case 0:
 			priv->flags &= ~SGR_ATTRIBUTES;
-			priv->color = DEFAULT_COLOR;
-			priv->bgcolor = BLACK;
+			color = DEFAULT_COLOR;
+			bgcolor = DEFAULT_BGCOLOR;
 			break;
 		case 1:
 			priv->flags |= ANSI_FLAG_BRIGHT;
@@ -519,20 +544,20 @@ static void fbc_parse_colors(struct fbc_priv *priv)
 			priv->flags |= ANSI_FLAG_INVERT;
 			break;
 		case 30 ... 37:
-			priv->color = code - 30;
+			color = code - 30;
 			break;
 		case 39:
-			priv->color = DEFAULT_COLOR;
+			color = DEFAULT_COLOR;
 			break;
 		case 40 ... 47:
-			priv->bgcolor = code - 40;
+			bgcolor = code - 40;
 			break;
 		case 49:
-			priv->bgcolor = BLACK;
+			bgcolor = DEFAULT_BGCOLOR;
 			break;
 		case 90 ... 97:
 			priv->flags |= ANSI_FLAG_BRIGHT;
-			priv->color = code - 90;
+			color = code - 90;
 			break;
 		}
 
@@ -540,6 +565,8 @@ static void fbc_parse_colors(struct fbc_priv *priv)
 			break;
 		str++;
 	}
+
+	fbc_update_colors(priv, color, bgcolor);
 }
 
 static void fbc_set_cursor_row(struct fbc_priv *priv, int y)
@@ -872,8 +899,8 @@ int register_fbconsole(struct fb_info *fb)
 	priv->fb = fb;
 	priv->x = 0;
 	priv->y = 0;
-	priv->color = WHITE;
-	priv->bgcolor = BLACK;
+
+	fbc_reset_colors(priv);
 
 	cdev = &priv->cdev;
 	cdev->dev = &fb->dev;
-- 
2.47.3