[PATCH 1/7] tty: vt, cleanup and document con_scroll

[PATCH 1/7] tty: vt, cleanup and document con_scroll

[Jiri Slaby]

Scrolling helpers scrup and scrdown both accept 'top' and 'bottom' as
unsigned int. Number of lines 'nr' is accepted as int, but all callers
pass down unsigned too. So change the type of 'nr' to unsigned too.
Now, promote unsigned int from the helpers up to the con_scroll
hook which actually accepted all those as signed int.

Next, the 'dir' parameter can have only two values and we define
constants for that: SM_UP and SM_DOWN. Switch them to enum and do
proper type checking on 'dir' too.

Finally, document the behaviour of the hook.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-usb@vger.kernel.org>
Cc: <linux-parisc@vger.kernel.org>
---
 drivers/tty/vt/vt.c                     |  6 ++++--
 drivers/usb/misc/sisusbvga/sisusb_con.c | 18 ++++++++++--------
 drivers/video/console/fbcon.c           | 18 ++++++++----------
 drivers/video/console/mdacon.c          |  7 ++++---
 drivers/video/console/newport_con.c     |  8 ++++----
 drivers/video/console/sticon.c          |  7 ++++---
 drivers/video/console/vgacon.c          | 12 +++++-------
 include/linux/console.h                 | 16 +++++++++++-----
 8 files changed, 50 insertions(+), 42 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index e2cad4c2ba5a..a0ccb3950a50 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -315,7 +315,8 @@ void schedule_console_callback(void)
 	schedule_work(&console_work);
 }
 
-static void scrup(struct vc_data *vc, unsigned int t, unsigned int b, int nr)
+static void scrup(struct vc_data *vc, unsigned int t, unsigned int b,
+		unsigned int nr)
 {
 	unsigned short *d, *s;
 
@@ -332,7 +333,8 @@ static void scrup(struct vc_data *vc, unsigned int t, unsigned int b, int nr)
 		    vc->vc_size_row * nr);
 }
 
-static void scrdown(struct vc_data *vc, unsigned int t, unsigned int b, int nr)
+static void scrdown(struct vc_data *vc, unsigned int t, unsigned int b,
+		unsigned int nr)
 {
 	unsigned short *s;
 	unsigned int step;
diff --git a/drivers/usb/misc/sisusbvga/sisusb_con.c b/drivers/usb/misc/sisusbvga/sisusb_con.c
index 460cebf322e3..6331965daa0b 100644
--- a/drivers/usb/misc/sisusbvga/sisusb_con.c
+++ b/drivers/usb/misc/sisusbvga/sisusb_con.c
@@ -808,9 +808,10 @@ sisusbcon_cursor(struct vc_data *c, int mode)
 	mutex_unlock(&sisusb->lock);
 }
 
-static int
+static bool
 sisusbcon_scroll_area(struct vc_data *c, struct sisusb_usb_data *sisusb,
-					int t, int b, int dir, int lines)
+		unsigned int t, unsigned int b, enum con_scroll dir,
+		unsigned int lines)
 {
 	int cols = sisusb->sisusb_num_columns;
 	int length = ((b - t) * cols) * 2;
@@ -852,8 +853,9 @@ sisusbcon_scroll_area(struct vc_data *c, struct sisusb_usb_data *sisusb,
 }
 
 /* Interface routine */
-static int
-sisusbcon_scroll(struct vc_data *c, int t, int b, int dir, int lines)
+static bool
+sisusbcon_scroll(struct vc_data *c, unsigned int t, unsigned int b,
+		enum con_scroll dir, unsigned int lines)
 {
 	struct sisusb_usb_data *sisusb;
 	u16 eattr = c->vc_video_erase_char;
@@ -870,17 +872,17 @@ sisusbcon_scroll(struct vc_data *c, int t, int b, int dir, int lines)
 	 */
 
 	if (!lines)
-		return 1;
+		return true;
 
 	sisusb = sisusb_get_sisusb_lock_and_check(c->vc_num);
 	if (!sisusb)
-		return 0;
+		return false;
 
 	/* sisusb->lock is down */
 
 	if (sisusb_is_inactive(c, sisusb)) {
 		mutex_unlock(&sisusb->lock);
-		return 0;
+		return false;
 	}
 
 	/* Special case */
@@ -971,7 +973,7 @@ sisusbcon_scroll(struct vc_data *c, int t, int b, int dir, int lines)
 
 	mutex_unlock(&sisusb->lock);
 
-	return 1;
+	return true;
 }
 
 /* Interface routine */
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index b87f5cfdaea5..a44f5627b82a 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -164,8 +164,6 @@ static void fbcon_putcs(struct vc_data *vc, const unsigned short *s,
 			int count, int ypos, int xpos);
 static void fbcon_clear_margins(struct vc_data *vc, int bottom_only);
 static void fbcon_cursor(struct vc_data *vc, int mode);
-static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
-			int count);
 static void fbcon_bmove(struct vc_data *vc, int sy, int sx, int dy, int dx,
 			int height, int width);
 static int fbcon_switch(struct vc_data *vc);
@@ -1795,15 +1793,15 @@ static inline void fbcon_softback_note(struct vc_data *vc, int t,
 	softback_curr = softback_in;
 }
 
-static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
-			int count)
+static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
+		enum con_scroll dir, unsigned int count)
 {
 	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
 	struct display *p = &fb_display[vc->vc_num];
 	int scroll_partial = info->flags & FBINFO_PARTIAL_PAN_OK;
 
 	if (fbcon_is_inactive(vc, info))
-		return -EINVAL;
+		return true;
 
 	fbcon_cursor(vc, CM_ERASE);
 
@@ -1831,7 +1829,7 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
 							(b - count)),
 				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			return 1;
+			return true;
 			break;
 
 		case SCROLL_WRAP_MOVE:
@@ -1903,7 +1901,7 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
 							(b - count)),
 				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			return 1;
+			return true;
 		}
 		break;
 
@@ -1922,7 +1920,7 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
 							t),
 				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			return 1;
+			return true;
 			break;
 
 		case SCROLL_WRAP_MOVE:
@@ -1992,10 +1990,10 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
 							t),
 				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			return 1;
+			return true;
 		}
 	}
-	return 0;
+	return false;
 }
 
 
diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
index 24fe55134eb5..d0d427a2f1a3 100644
--- a/drivers/video/console/mdacon.c
+++ b/drivers/video/console/mdacon.c
@@ -501,12 +501,13 @@ static void mdacon_cursor(struct vc_data *c, int mode)
 	}
 }
 
-static int mdacon_scroll(struct vc_data *c, int t, int b, int dir, int lines)
+static bool mdacon_scroll(struct vc_data *c, unsigned int t, unsigned int b,
+		enum con_scroll dir, unsigned int lines)
 {
 	u16 eattr = mda_convert_attr(c->vc_video_erase_char);
 
 	if (!lines)
-		return 0;
+		return false;
 
 	if (lines > c->vc_rows)   /* maximum realistic size */
 		lines = c->vc_rows;
@@ -527,7 +528,7 @@ static int mdacon_scroll(struct vc_data *c, int t, int b, int dir, int lines)
 		break;
 	}
 
-	return 0;
+	return false;
 }
 
 
diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index e3b9521e4ec3..1e11614322fe 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -574,8 +574,8 @@ static int newport_font_set(struct vc_data *vc, struct console_font *font, unsig
 	return newport_set_font(vc->vc_num, font);
 }
 
-static int newport_scroll(struct vc_data *vc, int t, int b, int dir,
-			  int lines)
+static bool newport_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
+		enum con_scroll dir, unsigned int lines)
 {
 	int count, x, y;
 	unsigned short *s, *d;
@@ -595,7 +595,7 @@ static int newport_scroll(struct vc_data *vc, int t, int b, int dir,
 					    (vc->vc_color & 0xf0) >> 4);
 		}
 		npregs->cset.topscan = (topscan - 1) & 0x3ff;
-		return 0;
+		return false;
 	}
 
 	count = (b - t - lines) * vc->vc_cols;
@@ -670,7 +670,7 @@ static int newport_scroll(struct vc_data *vc, int t, int b, int dir,
 			}
 		}
 	}
-	return 1;
+	return true;
 }
 
 static int newport_dummy(struct vc_data *c)
diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
index 3a10ac19598f..79c9bd8d3025 100644
--- a/drivers/video/console/sticon.c
+++ b/drivers/video/console/sticon.c
@@ -153,12 +153,13 @@ static void sticon_cursor(struct vc_data *conp, int mode)
     }
 }
 
-static int sticon_scroll(struct vc_data *conp, int t, int b, int dir, int count)
+static bool sticon_scroll(struct vc_data *conp, unsigned int t,
+		unsigned int b, enum con_scroll dir, unsigned int count)
 {
     struct sti_struct *sti = sticon_sti;
 
     if (vga_is_gfx)
-        return 0;
+        return false;
 
     sticon_cursor(conp, CM_ERASE);
 
@@ -174,7 +175,7 @@ static int sticon_scroll(struct vc_data *conp, int t, int b, int dir, int count)
 	break;
     }
 
-    return 0;
+    return false;
 }
 
 static void sticon_init(struct vc_data *c, int init)
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 11576611a974..4c54a873452e 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -83,8 +83,6 @@ static int vgacon_blank(struct vc_data *c, int blank, int mode_switch);
 static void vgacon_scrolldelta(struct vc_data *c, int lines);
 static int vgacon_set_origin(struct vc_data *c);
 static void vgacon_save_screen(struct vc_data *c);
-static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,
-			 int lines);
 static void vgacon_invert_region(struct vc_data *c, u16 * p, int count);
 static struct uni_pagedir *vgacon_uni_pagedir;
 static int vgacon_refcount;
@@ -1350,17 +1348,17 @@ static void vgacon_save_screen(struct vc_data *c)
 			    c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size);
 }
 
-static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,
-			 int lines)
+static bool vgacon_scroll(struct vc_data *c, unsigned int t, unsigned int b,
+		enum con_scroll dir, unsigned int lines)
 {
 	unsigned long oldo;
 	unsigned int delta;
 
 	if (t || b != c->vc_rows || vga_is_gfx || c->vc_mode != KD_TEXT)
-		return 0;
+		return false;
 
 	if (!vga_hardscroll_enabled || lines >= c->vc_rows / 2)
-		return 0;
+		return false;
 
 	vgacon_restore_screen(c);
 	oldo = c->vc_origin;
@@ -1396,7 +1394,7 @@ static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,
 	c->vc_visible_origin = c->vc_origin;
 	vga_set_mem_top(c);
 	c->vc_pos = (c->vc_pos - oldo) + c->vc_origin;
-	return 1;
+	return true;
 }
 
 
diff --git a/include/linux/console.h b/include/linux/console.h
index 3672809234a7..508b012bd5bd 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -28,9 +28,17 @@ struct tty_struct;
 #define VT100ID "\033[?1;2c"
 #define VT102ID "\033[?6c"
 
+enum con_scroll {
+	SM_UP,
+	SM_DOWN,
+};
+
 /**
  * struct consw - callbacks for consoles
  *
+ * @con_scroll: move lines from @top to @bottom in direction @dir by @lines.
+ *		Return true if no generic handling should be done.
+ *		Invoked by csi_M and printing to the console.
  * @con_set_palette: sets the palette of the console to @table (optional)
  * @con_scrolldelta: the contents of the console should be scrolled by @lines.
  *		     Invoked by user. (optional)
@@ -44,7 +52,9 @@ struct consw {
 	void	(*con_putc)(struct vc_data *, int, int, int);
 	void	(*con_putcs)(struct vc_data *, const unsigned short *, int, int, int);
 	void	(*con_cursor)(struct vc_data *, int);
-	int	(*con_scroll)(struct vc_data *, int, int, int, int);
+	bool	(*con_scroll)(struct vc_data *, unsigned int top,
+			unsigned int bottom, enum con_scroll dir,
+			unsigned int lines);
 	int	(*con_switch)(struct vc_data *);
 	int	(*con_blank)(struct vc_data *, int, int);
 	int	(*con_font_set)(struct vc_data *, struct console_font *, unsigned);
@@ -99,10 +109,6 @@ static inline int con_debug_leave(void)
 }
 #endif
 
-/* scroll */
-#define SM_UP       (1)
-#define SM_DOWN     (2)
-
 /* cursor */
 #define CM_DRAW     (1)
 #define CM_ERASE    (2)
-- 
2.10.0

[PATCH 2/7] tty: vt, unify scrolling functions

[Jiri Slaby]

Both scrup and scrdown are copies of the same code except source and
destination pointers computation. Unify those functions into a single
one named con_scroll.

Note that scrdown used step to compute the destination, while scrup
did the computation explicitly. We sticked to the latter here.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/vt/vt.c | 47 +++++++++++++++++------------------------------
 1 file changed, 17 insertions(+), 30 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index a0ccb3950a50..ecabed91f444 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -315,40 +315,27 @@ void schedule_console_callback(void)
 	schedule_work(&console_work);
 }
 
-static void scrup(struct vc_data *vc, unsigned int t, unsigned int b,
-		unsigned int nr)
+static void con_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
+		enum con_scroll dir, unsigned int nr)
 {
-	unsigned short *d, *s;
+	u16 *clear, *d, *s;
 
-	if (t+nr >= b)
+	if (t + nr >= b)
 		nr = b - t - 1;
 	if (b > vc->vc_rows || t >= b || nr < 1)
 		return;
-	if (con_is_visible(vc) && vc->vc_sw->con_scroll(vc, t, b, SM_UP, nr))
+	if (con_is_visible(vc) && vc->vc_sw->con_scroll(vc, t, b, dir, nr))
 		return;
-	d = (unsigned short *)(vc->vc_origin + vc->vc_size_row * t);
-	s = (unsigned short *)(vc->vc_origin + vc->vc_size_row * (t + nr));
-	scr_memmovew(d, s, (b - t - nr) * vc->vc_size_row);
-	scr_memsetw(d + (b - t - nr) * vc->vc_cols, vc->vc_video_erase_char,
-		    vc->vc_size_row * nr);
-}
 
-static void scrdown(struct vc_data *vc, unsigned int t, unsigned int b,
-		unsigned int nr)
-{
-	unsigned short *s;
-	unsigned int step;
+	s = clear = (u16 *)(vc->vc_origin + vc->vc_size_row * t);
+	d = (u16 *)(vc->vc_origin + vc->vc_size_row * (t + nr));
 
-	if (t+nr >= b)
-		nr = b - t - 1;
-	if (b > vc->vc_rows || t >= b || nr < 1)
-		return;
-	if (con_is_visible(vc) && vc->vc_sw->con_scroll(vc, t, b, SM_DOWN, nr))
-		return;
-	s = (unsigned short *)(vc->vc_origin + vc->vc_size_row * t);
-	step = vc->vc_cols * nr;
-	scr_memmovew(s + step, s, (b - t - nr) * vc->vc_size_row);
-	scr_memsetw(s, vc->vc_video_erase_char, 2 * step);
+	if (dir == SM_UP) {
+		clear = s + (b - t - nr) * vc->vc_cols;
+		swap(s, d);
+	}
+	scr_memmovew(d, s, (b - t - nr) * vc->vc_size_row);
+	scr_memsetw(clear, vc->vc_video_erase_char, vc->vc_size_row * nr);
 }
 
 static void do_update_region(struct vc_data *vc, unsigned long start, int count)
@@ -1117,7 +1104,7 @@ static void lf(struct vc_data *vc)
 	 * if below scrolling region
 	 */
     	if (vc->vc_y + 1 == vc->vc_bottom)
-		scrup(vc, vc->vc_top, vc->vc_bottom, 1);
+		con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_UP, 1);
 	else if (vc->vc_y < vc->vc_rows - 1) {
 	    	vc->vc_y++;
 		vc->vc_pos += vc->vc_size_row;
@@ -1132,7 +1119,7 @@ static void ri(struct vc_data *vc)
 	 * if above scrolling region
 	 */
 	if (vc->vc_y == vc->vc_top)
-		scrdown(vc, vc->vc_top, vc->vc_bottom, 1);
+		con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_DOWN, 1);
 	else if (vc->vc_y > 0) {
 		vc->vc_y--;
 		vc->vc_pos -= vc->vc_size_row;
@@ -1628,7 +1615,7 @@ static void csi_L(struct vc_data *vc, unsigned int nr)
 		nr = vc->vc_rows - vc->vc_y;
 	else if (!nr)
 		nr = 1;
-	scrdown(vc, vc->vc_y, vc->vc_bottom, nr);
+	con_scroll(vc, vc->vc_y, vc->vc_bottom, SM_DOWN, nr);
 	vc->vc_need_wrap = 0;
 }
 
@@ -1649,7 +1636,7 @@ static void csi_M(struct vc_data *vc, unsigned int nr)
 		nr = vc->vc_rows - vc->vc_y;
 	else if (!nr)
 		nr=1;
-	scrup(vc, vc->vc_y, vc->vc_bottom, nr);
+	con_scroll(vc, vc->vc_y, vc->vc_bottom, SM_UP, nr);
 	vc->vc_need_wrap = 0;
 }
 
-- 
2.10.0

[PATCH 3/7] tty: vgacon+sisusb, move scrolldelta to a common helper

[Jiri Slaby]

The code is mirrorred in scrolldelta implementations of both vgacon
and sisusb. Let's move the code to a separate helper where we will
perform a common cleanup and further changes.

While we are moving the code, make it linear and save one indentation
level. This is done by returning from the "!lines" then-branch
immediatelly. This allows flushing the else-branch 1 level to the
left, obviously.

Few more new lines and comments were added too.

And do not forget to export the helper function given sisusb can be
built as module.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-usb@vger.kernel.org>
---
 drivers/tty/vt/vt.c                     | 38 +++++++++++++++++++++++++++++++++
 drivers/usb/misc/sisusbvga/sisusb_con.c | 37 ++------------------------------
 drivers/video/console/vgacon.c          | 27 ++---------------------
 include/linux/vt_kern.h                 |  2 ++
 4 files changed, 44 insertions(+), 60 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index ecabed91f444..397c72c2fcb8 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -4275,6 +4275,44 @@ void vcs_scr_updated(struct vc_data *vc)
 	notify_update(vc);
 }
 
+void vc_scrolldelta_helper(struct vc_data *c, int lines,
+		unsigned int rolled_over, void *base, unsigned int size)
+{
+	unsigned long ubase = (unsigned long)base;
+	int margin = c->vc_size_row * 4;
+	int ul, we, p, st;
+
+	/* Turn scrollback off */
+	if (!lines) {
+		c->vc_visible_origin = c->vc_origin;
+		return;
+	}
+
+	/* Do we have already enough to allow jumping from 0 to the end? */
+	if (rolled_over > (c->vc_scr_end - ubase) + margin) {
+		ul = c->vc_scr_end - ubase;
+		we = rolled_over + c->vc_size_row;
+	} else {
+		ul = 0;
+		we = size;
+	}
+
+	p = (c->vc_visible_origin - ubase - ul + we) % we +
+		lines * c->vc_size_row;
+	st = (c->vc_origin - ubase - ul + we) % we;
+
+	/* Only a little piece would be left? Show all incl. the piece! */
+	if (st < 2 * margin)
+		margin = 0;
+	if (p < margin)
+		p = 0;
+	if (p > st - margin)
+		p = st;
+
+	c->vc_visible_origin = ubase + (p + ul) % we;
+}
+EXPORT_SYMBOL_GPL(vc_scrolldelta_helper);
+
 /*
  *	Visible symbols for modules
  */
diff --git a/drivers/usb/misc/sisusbvga/sisusb_con.c b/drivers/usb/misc/sisusbvga/sisusb_con.c
index 6331965daa0b..4b5777ec1501 100644
--- a/drivers/usb/misc/sisusbvga/sisusb_con.c
+++ b/drivers/usb/misc/sisusbvga/sisusb_con.c
@@ -686,8 +686,6 @@ static void
 sisusbcon_scrolldelta(struct vc_data *c, int lines)
 {
 	struct sisusb_usb_data *sisusb;
-	int margin = c->vc_size_row * 4;
-	int ul, we, p, st;
 
 	sisusb = sisusb_get_sisusb_lock_and_check(c->vc_num);
 	if (!sisusb)
@@ -700,39 +698,8 @@ sisusbcon_scrolldelta(struct vc_data *c, int lines)
 		return;
 	}
 
-	if (!lines)		/* Turn scrollback off */
-		c->vc_visible_origin = c->vc_origin;
-	else {
-
-		if (sisusb->con_rolled_over >
-				(c->vc_scr_end - sisusb->scrbuf) + margin) {
-
-			ul = c->vc_scr_end - sisusb->scrbuf;
-			we = sisusb->con_rolled_over + c->vc_size_row;
-
-		} else {
-
-			ul = 0;
-			we = sisusb->scrbuf_size;
-
-		}
-
-		p = (c->vc_visible_origin - sisusb->scrbuf - ul + we) % we +
-				lines * c->vc_size_row;
-
-		st = (c->vc_origin - sisusb->scrbuf - ul + we) % we;
-
-		if (st < 2 * margin)
-			margin = 0;
-
-		if (p < margin)
-			p = 0;
-
-		if (p > st - margin)
-			p = st;
-
-		c->vc_visible_origin = sisusb->scrbuf + (p + ul) % we;
-	}
+	vc_scrolldelta_helper(c, lines, sisusb->con_rolled_over,
+			(void *)sisusb->scrbuf, sisusb->scrbuf_size);
 
 	sisusbcon_set_start_address(sisusb, c);
 
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 4c54a873452e..ede6a5a85ccd 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -332,31 +332,8 @@ static void vgacon_restore_screen(struct vc_data *c)
 
 static void vgacon_scrolldelta(struct vc_data *c, int lines)
 {
-	if (!lines)		/* Turn scrollback off */
-		c->vc_visible_origin = c->vc_origin;
-	else {
-		int margin = c->vc_size_row * 4;
-		int ul, we, p, st;
-
-		if (vga_rolled_over >
-		    (c->vc_scr_end - vga_vram_base) + margin) {
-			ul = c->vc_scr_end - vga_vram_base;
-			we = vga_rolled_over + c->vc_size_row;
-		} else {
-			ul = 0;
-			we = vga_vram_size;
-		}
-		p = (c->vc_visible_origin - vga_vram_base - ul + we) % we +
-		    lines * c->vc_size_row;
-		st = (c->vc_origin - vga_vram_base - ul + we) % we;
-		if (st < 2 * margin)
-			margin = 0;
-		if (p < margin)
-			p = 0;
-		if (p > st - margin)
-			p = st;
-		c->vc_visible_origin = vga_vram_base + (p + ul) % we;
-	}
+	vc_scrolldelta_helper(c, lines, vga_rolled_over, (void *)vga_vram_base,
+			vga_vram_size);
 	vga_set_mem_top(c);
 }
 #endif /* CONFIG_VGACON_SOFT_SCROLLBACK */
diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h
index 6abd24f258bc..833fdd4794a0 100644
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -191,5 +191,7 @@ extern void vt_set_led_state(int console, int leds);
 extern void vt_kbd_con_start(int console);
 extern void vt_kbd_con_stop(int console);
 
+void vc_scrolldelta_helper(struct vc_data *c, int lines,
+		unsigned int rolled_over, void *_base, unsigned int size);
 
 #endif /* _VT_KERN_H */
-- 
2.10.0

[PATCH 4/7] tty: vt, compute vc offsets in advance

[Jiri Slaby]

Only improves readability, no functional changes.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/vt/vt.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 397c72c2fcb8..3cd999ef5257 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -4279,6 +4279,9 @@ void vc_scrolldelta_helper(struct vc_data *c, int lines,
 		unsigned int rolled_over, void *base, unsigned int size)
 {
 	unsigned long ubase = (unsigned long)base;
+	ptrdiff_t scr_end = (void *)c->vc_scr_end - base;
+	ptrdiff_t vorigin = (void *)c->vc_visible_origin - base;
+	ptrdiff_t origin = (void *)c->vc_origin - base;
 	int margin = c->vc_size_row * 4;
 	int ul, we, p, st;
 
@@ -4289,17 +4292,16 @@ void vc_scrolldelta_helper(struct vc_data *c, int lines,
 	}
 
 	/* Do we have already enough to allow jumping from 0 to the end? */
-	if (rolled_over > (c->vc_scr_end - ubase) + margin) {
-		ul = c->vc_scr_end - ubase;
+	if (rolled_over > scr_end + margin) {
+		ul = scr_end;
 		we = rolled_over + c->vc_size_row;
 	} else {
 		ul = 0;
 		we = size;
 	}
 
-	p = (c->vc_visible_origin - ubase - ul + we) % we +
-		lines * c->vc_size_row;
-	st = (c->vc_origin - ubase - ul + we) % we;
+	p = (vorigin - ul + we) % we + lines * c->vc_size_row;
+	st = (origin - ul + we) % we;
 
 	/* Only a little piece would be left? Show all incl. the piece! */
 	if (st < 2 * margin)
-- 
2.10.0

[PATCH 5/7] tty: vt, rename variables to sane names

[Jiri Slaby]

This makes the code understandable at least. No functional changes.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/vt/vt.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 3cd999ef5257..d26b6303647d 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -4283,7 +4283,7 @@ void vc_scrolldelta_helper(struct vc_data *c, int lines,
 	ptrdiff_t vorigin = (void *)c->vc_visible_origin - base;
 	ptrdiff_t origin = (void *)c->vc_origin - base;
 	int margin = c->vc_size_row * 4;
-	int ul, we, p, st;
+	int from, wrap, from_off, avail;
 
 	/* Turn scrollback off */
 	if (!lines) {
@@ -4293,25 +4293,25 @@ void vc_scrolldelta_helper(struct vc_data *c, int lines,
 
 	/* Do we have already enough to allow jumping from 0 to the end? */
 	if (rolled_over > scr_end + margin) {
-		ul = scr_end;
-		we = rolled_over + c->vc_size_row;
+		from = scr_end;
+		wrap = rolled_over + c->vc_size_row;
 	} else {
-		ul = 0;
-		we = size;
+		from = 0;
+		wrap = size;
 	}
 
-	p = (vorigin - ul + we) % we + lines * c->vc_size_row;
-	st = (origin - ul + we) % we;
+	from_off = (vorigin - from + wrap) % wrap + lines * c->vc_size_row;
+	avail = (origin - from + wrap) % wrap;
 
 	/* Only a little piece would be left? Show all incl. the piece! */
-	if (st < 2 * margin)
+	if (avail < 2 * margin)
 		margin = 0;
-	if (p < margin)
-		p = 0;
-	if (p > st - margin)
-		p = st;
+	if (from_off < margin)
+		from_off = 0;
+	if (from_off > avail - margin)
+		from_off = avail;
 
-	c->vc_visible_origin = ubase + (p + ul) % we;
+	c->vc_visible_origin = ubase + (from + from_off) % wrap;
 }
 EXPORT_SYMBOL_GPL(vc_scrolldelta_helper);
 
-- 
2.10.0

[PATCH 6/7] vgacon: switch boolean variables to bool

[Jiri Slaby]

These variables:
* vga_can_do_color
* vgacon_text_mode_force
* vga_font_is_default
* vga_hardscroll_enabled
* vga_hardscroll_user_enable
* vga_init_done
* vga_is_gfx
* vga_palette_blanked
* vga_512_chars
are used exclusively as a boolean value, so make them really a bool.

Remove also useless "? true : false".

__read_mostly annotations removed too as they obfuscate the code and I
doubt they improve anything measurable given the variables are used
from .con_scroll, .con_startup and such.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: <linux-fbdev@vger.kernel.org>
---
 drivers/video/console/vgacon.c | 45 +++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index ede6a5a85ccd..d13d5d372604 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -88,7 +88,7 @@ static struct uni_pagedir *vgacon_uni_pagedir;
 static int vgacon_refcount;
 
 /* Description of the hardware situation */
-static int		vga_init_done		__read_mostly;
+static bool		vga_init_done;
 static unsigned long	vga_vram_base		__read_mostly;	/* Base of video memory */
 static unsigned long	vga_vram_end		__read_mostly;	/* End of video memory */
 static unsigned int	vga_vram_size		__read_mostly;	/* Size of video memory */
@@ -96,31 +96,31 @@ static u16		vga_video_port_reg	__read_mostly;	/* Video register select port */
 static u16		vga_video_port_val	__read_mostly;	/* Video register value port */
 static unsigned int	vga_video_num_columns;			/* Number of text columns */
 static unsigned int	vga_video_num_lines;			/* Number of text lines */
-static int		vga_can_do_color	__read_mostly;	/* Do we support colors? */
+static bool		vga_can_do_color;			/* Do we support colors? */
 static unsigned int	vga_default_font_height __read_mostly;	/* Height of default screen font */
 static unsigned char	vga_video_type		__read_mostly;	/* Card type */
-static unsigned char	vga_hardscroll_enabled	__read_mostly;
-static unsigned char	vga_hardscroll_user_enable __read_mostly = 1;
-static unsigned char	vga_font_is_default = 1;
+static bool		vga_font_is_default = true;
 static int		vga_vesa_blanked;
-static int 		vga_palette_blanked;
-static int 		vga_is_gfx;
-static int 		vga_512_chars;
+static bool 		vga_palette_blanked;
+static bool 		vga_is_gfx;
+static bool 		vga_512_chars;
 static int 		vga_video_font_height;
 static int 		vga_scan_lines		__read_mostly;
 static unsigned int 	vga_rolled_over;
 
-static int vgacon_text_mode_force;
+static bool vgacon_text_mode_force;
+static bool vga_hardscroll_enabled;
+static bool vga_hardscroll_user_enable = true;
 
 bool vgacon_text_force(void)
 {
-	return vgacon_text_mode_force ? true : false;
+	return vgacon_text_mode_force;
 }
 EXPORT_SYMBOL(vgacon_text_force);
 
 static int __init text_mode(char *str)
 {
-	vgacon_text_mode_force = 1;
+	vgacon_text_mode_force = true;
 	return 1;
 }
 
@@ -134,7 +134,7 @@ static int __init no_scroll(char *str)
 	 * Braille reader made by F.H. Papenmeier (Germany).
 	 * Use the "no-scroll" bootflag.
 	 */
-	vga_hardscroll_user_enable = vga_hardscroll_enabled = 0;
+	vga_hardscroll_user_enable = vga_hardscroll_enabled = false;
 	return 1;
 }
 
@@ -402,7 +402,7 @@ static const char *vgacon_startup(void)
 		}
 	} else {
 		/* If not, it is color. */
-		vga_can_do_color = 1;
+		vga_can_do_color = true;
 		vga_vram_base = 0xb8000;
 		vga_video_port_reg = VGA_CRT_IC;
 		vga_video_port_val = VGA_CRT_DC;
@@ -517,7 +517,7 @@ static const char *vgacon_startup(void)
 
 	if (!vga_init_done) {
 		vgacon_scrollback_startup();
-		vga_init_done = 1;
+		vga_init_done = true;
 	}
 
 	return display_desc;
@@ -609,7 +609,7 @@ static u8 vgacon_build_attr(struct vc_data *c, u8 color, u8 intensity,
 
 static void vgacon_invert_region(struct vc_data *c, u16 * p, int count)
 {
-	int col = vga_can_do_color;
+	const bool col = vga_can_do_color;
 
 	while (count--) {
 		u16 a = scr_readw(p);
@@ -981,24 +981,24 @@ static int vgacon_blank(struct vc_data *c, int blank, int mode_switch)
 		}
 		if (vga_palette_blanked) {
 			vga_set_palette(c, color_table);
-			vga_palette_blanked = 0;
+			vga_palette_blanked = false;
 			return 0;
 		}
-		vga_is_gfx = 0;
+		vga_is_gfx = false;
 		/* Tell console.c that it has to restore the screen itself */
 		return 1;
 	case 1:		/* Normal blanking */
 	case -1:	/* Obsolete */
 		if (!mode_switch && vga_video_type == VIDEO_TYPE_VGAC) {
 			vga_pal_blank(&vgastate);
-			vga_palette_blanked = 1;
+			vga_palette_blanked = true;
 			return 0;
 		}
 		vgacon_set_origin(c);
 		scr_memsetw((void *) vga_vram_base, BLANK,
 			    c->vc_screenbuf_size);
 		if (mode_switch)
-			vga_is_gfx = 1;
+			vga_is_gfx = true;
 		return 1;
 	default:		/* VESA blanking */
 		if (vga_video_type == VIDEO_TYPE_VGAC) {
@@ -1029,7 +1029,8 @@ static int vgacon_blank(struct vc_data *c, int blank, int mode_switch)
 #define blackwmap 0xa0000
 #define cmapsz 8192
 
-static int vgacon_do_font_op(struct vgastate *state,char *arg,int set,int ch512)
+static int vgacon_do_font_op(struct vgastate *state, char *arg, int set,
+		bool ch512)
 {
 	unsigned short video_port_status = vga_video_port_reg + 6;
 	int font_select = 0x00, beg, i;
@@ -1055,7 +1056,7 @@ static int vgacon_do_font_op(struct vgastate *state,char *arg,int set,int ch512)
 	if (!arg)
 		return -EINVAL;	/* Return to default font not supported */
 
-	vga_font_is_default = 0;
+	vga_font_is_default = false;
 	font_select = ch512 ? 0x04 : 0x00;
 #else
 	/*
@@ -1066,7 +1067,7 @@ static int vgacon_do_font_op(struct vgastate *state,char *arg,int set,int ch512)
 	if (set) {
 		vga_font_is_default = !arg;
 		if (!arg)
-			ch512 = 0;	/* Default font is always 256 */
+			ch512 = false;	/* Default font is always 256 */
 		font_select = arg ? (ch512 ? 0x0e : 0x0a) : 0x00;
 	}
 
-- 
2.10.0

[PATCH 7/7] vgacon: remove prehistoric macros

[Jiri Slaby]

These macros:
* CAN_LOAD_EGA_FONTS
* CAN_LOAD_PALETTE
* TRIDENT_GLITCH
* VGA_CAN_DO_64KB
* SLOW_VGA
are either always set or always unset. They come from the linux 2.1
times. And given nobody switched them to some configurable options, I
assume nobody actually uses them.

So remove the macros and leave in place appropriate branches of the
conditional code.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-doc@vger.kernel.org>
---
 Documentation/VGA-softcursor.txt | 12 ++++------
 drivers/video/console/vgacon.c   | 49 ----------------------------------------
 2 files changed, 5 insertions(+), 56 deletions(-)

diff --git a/Documentation/VGA-softcursor.txt b/Documentation/VGA-softcursor.txt
index 70acfbf399eb..2ea8968b64a6 100644
--- a/Documentation/VGA-softcursor.txt
+++ b/Documentation/VGA-softcursor.txt
@@ -2,13 +2,11 @@ Software cursor for VGA    by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
 =======================    and Martin Mares <mj@atrey.karlin.mff.cuni.cz>
 
    Linux now has some ability to manipulate cursor appearance. Normally, you
-can set the size of hardware cursor (and also work around some ugly bugs in
-those miserable Trident cards--see #define TRIDENT_GLITCH in drivers/video/
-vgacon.c). You can now play a few new tricks:  you can make your cursor look
-like a non-blinking red block, make it inverse background of the character it's
-over or to highlight that character and still choose whether the original
-hardware cursor should remain visible or not.  There may be other things I have
-never thought of.
+can set the size of hardware cursor. You can now play a few new tricks:  you
+can make your cursor look like a non-blinking red block, make it inverse
+background of the character it's over or to highlight that character and still
+choose whether the original hardware cursor should remain visible or not.
+There may be other things I have never thought of.
 
    The cursor appearance is controlled by a "<ESC>[?1;2;3c" escape sequence
 where 1, 2 and 3 are parameters described below. If you omit any of them,
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index d13d5d372604..c22a56232b7c 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -60,15 +60,6 @@ static struct vgastate vgastate;
 
 #define BLANK 0x0020
 
-#define CAN_LOAD_EGA_FONTS	/* undefine if the user must not do this */
-#define CAN_LOAD_PALETTE	/* undefine if the user must not do this */
-
-/* You really do _NOT_ want to define this, unless you have buggy
- * Trident VGA which will resize cursor when moving it between column
- * 15 & 16. If you define this and your VGA is OK, inverse bug will
- * appear.
- */
-#undef TRIDENT_GLITCH
 #define VGA_FONTWIDTH       8   /* VGA does not support fontwidths != 8 */
 /*
  *  Interface used by the world
@@ -157,18 +148,10 @@ static inline void write_vga(unsigned char reg, unsigned int val)
 	 * handlers, thus the write has to be IRQ-atomic.
 	 */
 	raw_spin_lock_irqsave(&vga_lock, flags);
-
-#ifndef SLOW_VGA
 	v1 = reg + (val & 0xff00);
 	v2 = reg + 1 + ((val << 8) & 0xff00);
 	outw(v1, vga_video_port_reg);
 	outw(v2, vga_video_port_reg);
-#else
-	outb_p(reg, vga_video_port_reg);
-	outb_p(val >> 8, vga_video_port_val);
-	outb_p(reg + 1, vga_video_port_reg);
-	outb_p(val & 0xff, vga_video_port_val);
-#endif
 	raw_spin_unlock_irqrestore(&vga_lock, flags);
 }
 
@@ -426,18 +409,6 @@ static const char *vgacon_startup(void)
 				request_resource(&ioport_resource,
 						 &vga_console_resource);
 
-#ifdef VGA_CAN_DO_64KB
-				/*
-				 * get 64K rather than 32K of video RAM.
-				 * This doesn't actually work on all "VGA"
-				 * controllers (it seems like setting MM=01
-				 * and COE=1 isn't necessarily a good idea)
-				 */
-				vga_vram_base = 0xa0000;
-				vga_vram_size = 0x10000;
-				outb_p(6, VGA_GFX_I);
-				outb_p(6, VGA_GFX_D);
-#endif
 				/*
 				 * Normalise the palette registers, to point
 				 * the 16 screen colours to the first 16
@@ -627,11 +598,6 @@ static void vgacon_set_cursor_size(int xpos, int from, int to)
 	unsigned long flags;
 	int curs, cure;
 
-#ifdef TRIDENT_GLITCH
-	if (xpos < 16)
-		from--, to--;
-#endif
-
 	if ((from == cursor_size_lastfrom) && (to == cursor_size_lastto))
 		return;
 	cursor_size_lastfrom = from;
@@ -833,12 +799,10 @@ static void vga_set_palette(struct vc_data *vc, const unsigned char *table)
 
 static void vgacon_set_palette(struct vc_data *vc, const unsigned char *table)
 {
-#ifdef CAN_LOAD_PALETTE
 	if (vga_video_type != VIDEO_TYPE_VGAC || vga_palette_blanked
 	    || !con_is_visible(vc))
 		return;
 	vga_set_palette(vc, table);
-#endif
 }
 
 /* structure holding original VGA register settings */
@@ -1021,8 +985,6 @@ static int vgacon_blank(struct vc_data *c, int blank, int mode_switch)
  * (sizif@botik.yaroslavl.su).
  */
 
-#ifdef CAN_LOAD_EGA_FONTS
-
 #define colourmap 0xa0000
 /* Pauline Middelink <middelin@polyware.iaf.nl> reports that we
    should use 0xA0000 for the bwmap as well.. */
@@ -1039,10 +1001,6 @@ static int vgacon_do_font_op(struct vgastate *state, char *arg, int set,
 	if (vga_video_type != VIDEO_TYPE_EGAM) {
 		charmap = (char *) VGA_MAP_MEM(colourmap, 0);
 		beg = 0x0e;
-#ifdef VGA_CAN_DO_64KB
-		if (vga_video_type == VIDEO_TYPE_VGAC)
-			beg = 0x06;
-#endif
 	} else {
 		charmap = (char *) VGA_MAP_MEM(blackwmap, 0);
 		beg = 0x0a;
@@ -1271,13 +1229,6 @@ static int vgacon_font_get(struct vc_data *c, struct console_font *font)
 	return vgacon_do_font_op(&vgastate, font->data, 0, vga_512_chars);
 }
 
-#else
-
-#define vgacon_font_set NULL
-#define vgacon_font_get NULL
-
-#endif
-
 static int vgacon_resize(struct vc_data *c, unsigned int width,
 			 unsigned int height, unsigned int user)
 {
-- 
2.10.0