savagefb: VGA state save and restore

Allow the saving and restoration of VGA text mode.  The state is saved on the
first open and restored on the last close. Because of the VGA registers are
linearly mapped to the MMIO space, MMIO access is used which is not limited to
X86 platforms nor to the primary display device.

An echo 0 > /sys/class/vtconsole/vtcon1/bind will convert the display from
graphics to text mode.
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/Makefile

@@ -38,7 +38,7 @@ obj-$(CONFIG_FB_ATY128)		  += aty/ macmodes.o
 obj-$(CONFIG_FB_RADEON)		  += aty/
 obj-$(CONFIG_FB_SIS)		  += sis/
 obj-$(CONFIG_FB_KYRO)             += kyro/
-obj-$(CONFIG_FB_SAVAGE)		  += savage/
+obj-$(CONFIG_FB_SAVAGE)		  += savage/ vgastate.o
 obj-$(CONFIG_FB_GEODE)		  += geode/
 obj-$(CONFIG_FB_MBX)		  += mbx/
 obj-$(CONFIG_FB_I810)             += vgastate.o

drivers/video/savage/savagefb.h

@@ -15,6 +15,8 @@
 #include <linux/i2c.h>
 #include <linux/i2c-id.h>
 #include <linux/i2c-algo-bit.h>
+#include <linux/mutex.h>
+#include <video/vga.h>
 #include "../edid.h"
 
 #ifdef SAVAGEFB_DEBUG
@@ -189,8 +191,12 @@ struct savagefb_par {
 	struct savagefb_i2c_chan chan;
 	struct savage_reg state;
 	struct savage_reg save;
+	struct savage_reg initial;
+	struct vgastate vgastate;
+	struct mutex open_lock;
 	unsigned char   *edid;
 	u32 pseudo_palette[16];
+	u32 open_count;
 	int paletteEnabled;
 	int pm_state;
 	int display_type;
@@ -203,7 +209,7 @@ struct savagefb_par {
 	int clock[4];
 	int MCLK, REFCLK, LCDclk;
 	struct {
-		u8   __iomem *vbase;
+		void   __iomem *vbase;
 		u32    pbase;
 		u32    len;
 #ifdef CONFIG_MTRR
@@ -212,7 +218,7 @@ struct savagefb_par {
 	} video;
 
 	struct {
-		volatile u8  __iomem *vbase;
+		void  __iomem *vbase;
 		u32           pbase;
 		u32           len;
 	} mmio;

drivers/video/savage/savagefb_driver.c

@@ -1623,8 +1623,46 @@ static void savagefb_restore_state(struct fb_info *info)
 	savagefb_blank(FB_BLANK_UNBLANK, info);
 }
 
+static int savagefb_open(struct fb_info *info, int user)
+{
+	struct savagefb_par *par = info->par;
+
+	mutex_lock(&par->open_lock);
+
+	if (!par->open_count) {
+		memset(&par->vgastate, 0, sizeof(par->vgastate));
+		par->vgastate.flags = VGA_SAVE_CMAP | VGA_SAVE_FONTS |
+			VGA_SAVE_MODE;
+		par->vgastate.vgabase = par->mmio.vbase + 0x8000;
+		save_vga(&par->vgastate);
+		savage_get_default_par(par, &par->initial);
+	}
+
+	par->open_count++;
+	mutex_unlock(&par->open_lock);
+	return 0;
+}
+
+static int savagefb_release(struct fb_info *info, int user)
+{
+	struct savagefb_par *par = info->par;
+
+	mutex_lock(&par->open_lock);
+
+	if (par->open_count == 1) {
+		savage_set_default_par(par, &par->initial);
+		restore_vga(&par->vgastate);
+	}
+
+	par->open_count--;
+	mutex_unlock(&par->open_lock);
+	return 0;
+}
+
 static struct fb_ops savagefb_ops = {
 	.owner          = THIS_MODULE,
+	.fb_open        = savagefb_open,
+	.fb_release     = savagefb_release,
 	.fb_check_var   = savagefb_check_var,
 	.fb_set_par     = savagefb_set_par,
 	.fb_setcolreg   = savagefb_setcolreg,
@@ -2173,6 +2211,7 @@ static int __devinit savagefb_probe(struct pci_dev* dev,
 	if (!info)
 		return -ENOMEM;
 	par = info->par;
+	mutex_init(&par->open_lock);
 	err = pci_enable_device(dev);
 	if (err)
 		goto failed_enable;