lib/fonts: Implement glyph rotation

Move the glyph rotation helpers from fbcon to the font library. Wrap them
behind clean interfaces. Also clear the output memory to zero. Previously,
the implementation relied on the caller to do that.

Go through the fbcon code and callers of the glyph-rotation helpers. In
addition to the font rotation, there's also the cursor code, which uses
the rotation helpers.

The font-rotation relied on a single memset to zero for the whole font.
This is now multiple memsets on each glyph. This will be sorted out when
the font library also implements font rotation.

Building glyph rotation in the font library still depends on
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y. If we get more users of the code,
we can still add a dedicated Kconfig symbol to the font library.

No changes have been made to the actual implementation of the rotate_*()
and pattern_*() functions. These will be refactored as separate changes.

v2:
- fix typos

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>

4 files changed, 8 insertions, 83 deletions

diff --git a/drivers/video/fbdev/core/fbcon_ccw.c b/drivers/video/fbdev/core/fbcon_ccw.c
index 96ef449ee6ac..72453a2aaca8 100644
--- a/drivers/video/fbdev/core/fbcon_ccw.c
+++ b/drivers/video/fbdev/core/fbcon_ccw.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/font.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
 #include <asm/types.h>
@@ -344,8 +345,7 @@ static void ccw_cursor(struct vc_data *vc, struct fb_info *info, bool enable,
 		size = cur_height * width;
 		while (size--)
 			tmp[i++] = 0xff;
-		memset(mask, 0, w * vc->vc_font.width);
-		rotate_ccw(tmp, mask, vc->vc_font.width, vc->vc_font.height);
+		font_glyph_rotate_270(tmp, vc->vc_font.width, vc->vc_font.height, mask);
 		kfree(tmp);
 	}
 
diff --git a/drivers/video/fbdev/core/fbcon_cw.c b/drivers/video/fbdev/core/fbcon_cw.c
index ea712654edae..5690fc1d7854 100644
--- a/drivers/video/fbdev/core/fbcon_cw.c
+++ b/drivers/video/fbdev/core/fbcon_cw.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/font.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
 #include <asm/types.h>
@@ -327,8 +328,7 @@ static void cw_cursor(struct vc_data *vc, struct fb_info *info, bool enable,
 		size = cur_height * width;
 		while (size--)
 			tmp[i++] = 0xff;
-		memset(mask, 0, w * vc->vc_font.width);
-		rotate_cw(tmp, mask, vc->vc_font.width, vc->vc_font.height);
+		font_glyph_rotate_90(tmp, vc->vc_font.width, vc->vc_font.height, mask);
 		kfree(tmp);
 	}
 
diff --git a/drivers/video/fbdev/core/fbcon_rotate.c b/drivers/video/fbdev/core/fbcon_rotate.c
index 18575c5182db..588dc9d6758a 100644
--- a/drivers/video/fbdev/core/fbcon_rotate.c
+++ b/drivers/video/fbdev/core/fbcon_rotate.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/font.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
 #include <asm/types.h>
@@ -60,30 +61,25 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 	}
 
 	dst = par->fontbuffer;
-	memset(dst, 0, par->fd_size);
 
 	switch (par->rotate) {
 	case FB_ROTATE_UD:
 		for (i = len; i--; ) {
-			rotate_ud(src, dst, vc->vc_font.width,
-				  vc->vc_font.height);
-
+			font_glyph_rotate_180(src, vc->vc_font.width, vc->vc_font.height, dst);
 			src += s_cellsize;
 			dst += d_cellsize;
 		}
 		break;
 	case FB_ROTATE_CW:
 		for (i = len; i--; ) {
-			rotate_cw(src, dst, vc->vc_font.width,
-				  vc->vc_font.height);
+			font_glyph_rotate_90(src, vc->vc_font.width, vc->vc_font.height, dst);
 			src += s_cellsize;
 			dst += d_cellsize;
 		}
 		break;
 	case FB_ROTATE_CCW:
 		for (i = len; i--; ) {
-			rotate_ccw(src, dst, vc->vc_font.width,
-				   vc->vc_font.height);
+			font_glyph_rotate_270(src, vc->vc_font.width, vc->vc_font.height, dst);
 			src += s_cellsize;
 			dst += d_cellsize;
 		}
diff --git a/drivers/video/fbdev/core/fbcon_rotate.h b/drivers/video/fbdev/core/fbcon_rotate.h
index 8cb019e8a9c0..725bcae2df61 100644
--- a/drivers/video/fbdev/core/fbcon_rotate.h
+++ b/drivers/video/fbdev/core/fbcon_rotate.h
@@ -19,77 +19,6 @@
         (fb_scrollmode(s) == SCROLL_REDRAW || fb_scrollmode(s) == SCROLL_MOVE || !(i)->fix.xpanstep) ? \
         (i)->var.xres : (i)->var.xres_virtual; })
 
-
-static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
-{
-	u32 tmp = (y * pitch) + x, index = tmp / 8,  bit = tmp % 8;
-
-	pat +=index;
-	return (*pat) & (0x80 >> bit);
-}
-
-static inline void pattern_set_bit(u32 x, u32 y, u32 pitch, char *pat)
-{
-	u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
-
-	pat += index;
-
-	(*pat) |= 0x80 >> bit;
-}
-
-static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
-{
-	int i, j;
-	int shift = (8 - (width % 8)) & 7;
-
-	width = (width + 7) & ~7;
-
-	for (i = 0; i < height; i++) {
-		for (j = 0; j < width - shift; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(width - (1 + j + shift),
-						height - (1 + i),
-						width, out);
-		}
-
-	}
-}
-
-static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
-{
-	int i, j, h = height, w = width;
-	int shift = (8 - (height % 8)) & 7;
-
-	width = (width + 7) & ~7;
-	height = (height + 7) & ~7;
-
-	for (i = 0; i < h; i++) {
-		for (j = 0; j < w; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(height - 1 - i - shift, j,
-						height, out);
-
-		}
-	}
-}
-
-static inline void rotate_ccw(const char *in, char *out, u32 width, u32 height)
-{
-	int i, j, h = height, w = width;
-	int shift = (8 - (width % 8)) & 7;
-
-	width = (width + 7) & ~7;
-	height = (height + 7) & ~7;
-
-	for (i = 0; i < h; i++) {
-		for (j = 0; j < w; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(i, width - 1 - j - shift,
-						height, out);
-		}
-	}
-}
-
 int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc);
 
 #if defined(CONFIG_FRAMEBUFFER_CONSOLE_ROTATION)