pc: add *bootscreen= variable to pass pre-initialized framebuffer info to kernel

EFI system has no cga or vesa anymore, so it becomes neccesary to
pass GOP framebuffer info to the kernel to get some output on the
screen.

2 files changed, 98 insertions, 6 deletions

diff --git a/sys/src/9/pc/main.c b/sys/src/9/pc/main.c
index f1e40b6de..637895575 100644
--- a/sys/src/9/pc/main.c
+++ b/sys/src/9/pc/main.c
@@ -124,6 +124,7 @@ options(void)
 
 extern void mmuinit0(void);
 extern void (*i8237alloc)(void);
+extern void bootscreeninit(void);
 
 void
 main(void)
@@ -153,6 +154,7 @@ main(void)
 	printinit();
 	cpuidprint();
 	mmuinit();
+	bootscreeninit();
 	if(arch->intrinit)	/* launches other processors on an mp */
 		arch->intrinit();
 	timersinit();
diff --git a/sys/src/9/pc/screen.c b/sys/src/9/pc/screen.c
index de742cd84..37fcc5b91 100644
--- a/sys/src/9/pc/screen.c
+++ b/sys/src/9/pc/screen.c
@@ -13,10 +13,6 @@
 #include <cursor.h>
 #include "screen.h"
 
-#define RGB2K(r,g,b)	((156763*(r)+307758*(g)+59769*(b))>>19)
-
-Point ZP = {0, 0};
-
 Rectangle physgscreenr;
 
 Memimage *gscreen;
@@ -531,7 +527,6 @@ vgalinearaddr(VGAscr *scr, ulong paddr, int size)
 	 * later, let's assume that we can just allocate the
 	 * entire window to start with.
 	 */
-
 	if(scr->paddr == paddr && size <= scr->apsize)
 		return;
 
@@ -542,7 +537,7 @@ vgalinearaddr(VGAscr *scr, ulong paddr, int size)
 		 */
 		error("cannot grow vga frame buffer");
 	}
-	
+
 	/* round to page boundary, just in case */
 	x = paddr&(BY2PG-1);
 	npaddr = paddr-x;
@@ -560,9 +555,104 @@ vgalinearaddr(VGAscr *scr, ulong paddr, int size)
 	scr->vaddr = (char*)scr->vaddr+x;
 	scr->paddr = paddr;
 	scr->apsize = nsize;
+
 	/* let mtrr harmlessly fail on old CPUs, e.g., P54C */
 	if(!waserror()){
 		mtrr(npaddr, nsize, "wc");
 		poperror();
 	}
 }
+
+/*
+ * called early on boot to attach to framebuffer
+ * setup by bootloader or firmware.
+ */
+void
+bootscreeninit(void)
+{
+	static Memdata md;
+	VGAscr *scr;
+	int x, y, z;
+	ulong chan, pa, sz;
+	char *s, *p;
+
+	/* *bootscreen=WIDTHxHEIGHTxDEPTH CHAN PA [SZ] */
+	s = getconf("*bootscreen");
+	if(s == nil)
+		return;
+
+	x = strtoul(s, &s, 0);
+	if(x == 0 || *s++ != 'x')
+		return;
+
+	y = strtoul(s, &s, 0);
+	if(y == 0 || *s++ != 'x')
+		return;
+
+	z = strtoul(s, &s, 0);
+	if(*s != ' ')
+		return;
+	if((p = strchr(++s, ' ')) == nil)
+		return;
+	*p = 0;
+	chan = strtochan(s);
+	*p = ' ';
+	if(chan == 0 || chantodepth(chan) != z)
+		return;
+
+	sz = 0;
+	pa = strtoul(p+1, &s, 0);
+	if(pa == 0)
+		return;
+	if(*s++ == ' ')
+		sz = strtoul(s, nil, 0);
+	if(sz < x * y * (z+7)/8)
+		sz = x * y * (z+7)/8;
+
+	/* round to pages */
+	z = pa&(BY2PG-1);
+	pa -= z;
+	sz += z;
+
+	/* map framebuffer */
+	scr = &vgascreen[0];
+	scr->apsize = PGROUND(sz);
+	scr->vaddr = vmap(pa, scr->apsize);
+	if(scr->vaddr == 0){
+		scr->apsize = 0;
+		return;
+	}
+	scr->vaddr = (char*)scr->vaddr + z;
+	scr->paddr = pa + z;
+
+	if(memimageinit() < 0)
+		return;
+
+	md.ref = 1;
+	md.bdata = scr->vaddr;
+	gscreen = allocmemimaged(Rect(0,0,x,y), chan, &md);
+	if(gscreen == nil)
+		return;
+
+	scr->palettedepth = 6;	/* default */
+	scr->memdefont = getmemdefont();
+	scr->gscreen = gscreen;
+	scr->gscreendata = gscreen->data;
+	scr->softscreen = 0;
+	scr->useflush = 0;
+	scr->dev = nil;
+
+	hwblank = 0;
+	hwaccel = 0;
+
+	physgscreenr = gscreen->r;
+
+	vgaimageinit(chan);
+	vgascreenwin(scr);
+
+	/* turn mouse cursor on */
+	swcursorinit();
+	scr->cur = &swcursor;
+	scr->cur->enable(scr);
+	cursoron();
+}