vgabios: Add support for VBE get/set display start function.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

9 files changed, 121 insertions, 79 deletions

diff --git a/vgasrc/bochsvga.c b/vgasrc/bochsvga.c
index 2a4b0d5b..384e2cbf 100644
--- a/vgasrc/bochsvga.c
+++ b/vgasrc/bochsvga.c
@@ -232,6 +232,27 @@ bochsvga_set_linelength(struct vgamode_s *vmode_g, int val)
     return 0;
 }
 
+int
+bochsvga_get_displaystart(struct vgamode_s *vmode_g)
+{
+    int bpp = vga_bpp(vmode_g);
+    int linelength = dispi_read(VBE_DISPI_INDEX_VIRT_WIDTH) * bpp / 8;
+    int x = dispi_read(VBE_DISPI_INDEX_X_OFFSET);
+    int y = dispi_read(VBE_DISPI_INDEX_Y_OFFSET);
+    return x * bpp / 8 + linelength * y;
+}
+
+int
+bochsvga_set_displaystart(struct vgamode_s *vmode_g, int val)
+{
+    stdvga_set_displaystart(vmode_g, val);
+    int bpp = vga_bpp(vmode_g);
+    int linelength = dispi_read(VBE_DISPI_INDEX_VIRT_WIDTH) * bpp / 8;
+    dispi_write(VBE_DISPI_INDEX_X_OFFSET, (val % linelength) * 8 / bpp);
+    dispi_write(VBE_DISPI_INDEX_Y_OFFSET, val / linelength);
+    return 0;
+}
+
 static void
 bochsvga_clear_scr(void)
 {
diff --git a/vgasrc/bochsvga.h b/vgasrc/bochsvga.h
index b6abf0a1..d36c92a3 100644
--- a/vgasrc/bochsvga.h
+++ b/vgasrc/bochsvga.h
@@ -59,6 +59,8 @@ int bochsvga_get_window(struct vgamode_s *vmode_g, int window);
 int bochsvga_set_window(struct vgamode_s *vmode_g, int window, int val);
 int bochsvga_get_linelength(struct vgamode_s *vmode_g);
 int bochsvga_set_linelength(struct vgamode_s *vmode_g, int val);
+int bochsvga_get_displaystart(struct vgamode_s *vmode_g);
+int bochsvga_set_displaystart(struct vgamode_s *vmode_g, int val);
 int bochsvga_set_mode(struct vgamode_s *vmode_g, int flags);
 
 #endif // bochsvga.h
diff --git a/vgasrc/clext.c b/vgasrc/clext.c
index 27af8109..06407529 100644
--- a/vgasrc/clext.c
+++ b/vgasrc/clext.c
@@ -435,6 +435,32 @@ clext_set_linelength(struct vgamode_s *vmode_g, int val)
     return 0;
 }
 
+int
+clext_get_displaystart(struct vgamode_s *vmode_g)
+{
+    u16 crtc_addr = stdvga_get_crtc();
+    u8 b2 = stdvga_crtc_read(crtc_addr, 0x0c);
+    u8 b1 = stdvga_crtc_read(crtc_addr, 0x0d);
+    u8 b3 = stdvga_crtc_read(crtc_addr, 0x1b);
+    u8 b4 = stdvga_crtc_read(crtc_addr, 0x1d);
+    int val = (b1 | (b2<<8) | ((b3 & 0x01) << 16) | ((b3 & 0x0c) << 15)
+               | ((b4 & 0x80) << 12));
+    return val * stdvga_bpp_factor(vmode_g);
+}
+
+int
+clext_set_displaystart(struct vgamode_s *vmode_g, int val)
+{
+    u16 crtc_addr = stdvga_get_crtc();
+    val /= stdvga_bpp_factor(vmode_g);
+    stdvga_crtc_write(crtc_addr, 0x0d, val);
+    stdvga_crtc_write(crtc_addr, 0x0c, val >> 8);
+    stdvga_crtc_mask(crtc_addr, 0x1d, 0x80, (val & 0x0800) >> 4);
+    stdvga_crtc_mask(crtc_addr, 0x1b, 0x0d
+                     , ((val & 0x0100) >> 8) | ((val & 0x0600) >> 7));
+    return 0;
+}
+
 static void
 cirrus_enable_16k_granularity(void)
 {
@@ -601,70 +627,6 @@ clext_list_modes(u16 seg, u16 *dest, u16 *last)
     stdvga_list_modes(seg, dest, last);
 }
 
-static u8
-cirrus_get_bpp_bytes(void)
-{
-    u8 v = stdvga_sequ_read(0x07) & 0x0e;
-    if (v == 0x06)
-        v &= 0x02;
-    v >>= 1;
-    if (v != 0x04)
-        v++;
-    return v;
-}
-
-static u16
-cirrus_get_line_offset(void)
-{
-    u16 crtc_addr = stdvga_get_crtc();
-    u8 reg13 = stdvga_crtc_read(crtc_addr, 0x13);
-    u8 reg1b = stdvga_crtc_read(crtc_addr, 0x1b);
-    return (((reg1b & 0x10) << 4) + reg13) * 8;
-}
-
-static void
-cirrus_set_start_addr(u32 addr)
-{
-    u16 crtc_addr = stdvga_get_crtc();
-    stdvga_crtc_write(crtc_addr, 0x0d, addr);
-    stdvga_crtc_write(crtc_addr, 0x0c, addr >> 8);
-    stdvga_crtc_mask(crtc_addr, 0x1d, 0x80, (addr & 0x0800) >> 4);
-    stdvga_crtc_mask(crtc_addr, 0x1b, 0x0d
-                     , ((addr & 0x0100) >> 8) | ((addr & 0x0600) >> 7));
-}
-
-static u32
-cirrus_get_start_addr(void)
-{
-    u16 crtc_addr = stdvga_get_crtc();
-    u8 b2 = stdvga_crtc_read(crtc_addr, 0x0c);
-    u8 b1 = stdvga_crtc_read(crtc_addr, 0x0d);
-    u8 b3 = stdvga_crtc_read(crtc_addr, 0x1b);
-    u8 b4 = stdvga_crtc_read(crtc_addr, 0x1d);
-    return (b1 | (b2<<8) | ((b3 & 0x01) << 16) | ((b3 & 0x0c) << 15)
-            | ((b4 & 0x80) << 12));
-}
-
-static void
-cirrus_vesa_07h(struct bregs *regs)
-{
-    if (regs->bl == 0x80 || regs->bl == 0x00) {
-        u32 addr = (cirrus_get_bpp_bytes() * regs->cx
-                    + cirrus_get_line_offset() * regs->dx);
-        cirrus_set_start_addr(addr / 4);
-    } else if (regs->bl == 0x01) {
-        u32 addr = cirrus_get_start_addr() * 4;
-        u32 linelength = cirrus_get_line_offset();
-        regs->dx = addr / linelength;
-        regs->cx = (addr % linelength) / cirrus_get_bpp_bytes();
-    } else {
-        regs->ax = 0x0100;
-        return;
-    }
-
-    regs->ax = 0x004f;
-}
-
 static void
 cirrus_vesa_10h(struct bregs *regs)
 {
@@ -697,7 +659,6 @@ void
 cirrus_vesa(struct bregs *regs)
 {
     switch (regs->al) {
-    case 0x07: cirrus_vesa_07h(regs); break;
     case 0x10: cirrus_vesa_10h(regs); break;
     default:   cirrus_vesa_not_handled(regs); break;
     }
diff --git a/vgasrc/clext.h b/vgasrc/clext.h
index 55476a08..1e4506cb 100644
--- a/vgasrc/clext.h
+++ b/vgasrc/clext.h
@@ -8,6 +8,8 @@ int clext_get_window(struct vgamode_s *vmode_g, int window);
 int clext_set_window(struct vgamode_s *vmode_g, int window, int val);
 int clext_get_linelength(struct vgamode_s *vmode_g);
 int clext_set_linelength(struct vgamode_s *vmode_g, int val);
+int clext_get_displaystart(struct vgamode_s *vmode_g);
+int clext_set_displaystart(struct vgamode_s *vmode_g, int val);
 int clext_set_mode(struct vgamode_s *vmode_g, int flags);
 void clext_list_modes(u16 seg, u16 *dest, u16 *last);
 int clext_init(void);
diff --git a/vgasrc/stdvga.c b/vgasrc/stdvga.c
index a310167a..13334ed4 100644
--- a/vgasrc/stdvga.c
+++ b/vgasrc/stdvga.c
@@ -254,14 +254,6 @@ stdvga_set_cursor_shape(u8 start, u8 end)
 }
 
 void
-stdvga_set_active_page(u16 address)
-{
-    u16 crtc_addr = stdvga_get_crtc();
-    stdvga_crtc_write(crtc_addr, 0x0c, address >> 8);
-    stdvga_crtc_write(crtc_addr, 0x0d, address);
-}
-
-void
 stdvga_set_cursor_pos(u16 address)
 {
     u16 crtc_addr = stdvga_get_crtc();
@@ -313,6 +305,25 @@ stdvga_set_linelength(struct vgamode_s *vmode_g, int val)
     return 0;
 }
 
+int
+stdvga_get_displaystart(struct vgamode_s *vmode_g)
+{
+    u16 crtc_addr = stdvga_get_crtc();
+    int addr = (stdvga_crtc_read(crtc_addr, 0x0c) << 8
+                | stdvga_crtc_read(crtc_addr, 0x0d));
+    return addr * stdvga_bpp_factor(vmode_g);
+}
+
+int
+stdvga_set_displaystart(struct vgamode_s *vmode_g, int val)
+{
+    u16 crtc_addr = stdvga_get_crtc();
+    val /= stdvga_bpp_factor(vmode_g);
+    stdvga_crtc_write(crtc_addr, 0x0c, val >> 8);
+    stdvga_crtc_write(crtc_addr, 0x0d, val);
+    return 0;
+}
+
 
 /****************************************************************
  * Save/Restore/Set state
diff --git a/vgasrc/stdvga.h b/vgasrc/stdvga.h
index ad496b5d..f6fda000 100644
--- a/vgasrc/stdvga.h
+++ b/vgasrc/stdvga.h
@@ -131,7 +131,6 @@ void stdvga_load_font(u16 seg, void *src_far, u16 count
 u16 stdvga_get_crtc(void);
 int stdvga_bpp_factor(struct vgamode_s *vmode_g);
 void stdvga_set_cursor_shape(u8 start, u8 end);
-void stdvga_set_active_page(u16 address);
 void stdvga_set_cursor_pos(u16 address);
 void stdvga_set_scan_lines(u8 lines);
 u16 stdvga_get_vde(void);
@@ -139,6 +138,8 @@ int stdvga_get_window(struct vgamode_s *vmode_g, int window);
 int stdvga_set_window(struct vgamode_s *vmode_g, int window, int val);
 int stdvga_get_linelength(struct vgamode_s *vmode_g);
 int stdvga_set_linelength(struct vgamode_s *vmode_g, int val);
+int stdvga_get_displaystart(struct vgamode_s *vmode_g);
+int stdvga_set_displaystart(struct vgamode_s *vmode_g, int val);
 void stdvga_save_state(u16 seg, struct saveVideoHardware *info);
 void stdvga_restore_state(u16 seg, struct saveVideoHardware *info);
 int stdvga_set_mode(struct vgamode_s *vmode_g, int flags);
diff --git a/vgasrc/vbe.c b/vgasrc/vbe.c
index 68d20259..9e1fe1c2 100644
--- a/vgasrc/vbe.c
+++ b/vgasrc/vbe.c
@@ -273,8 +273,37 @@ fail:
 static void
 vbe_104f07(struct bregs *regs)
 {
-    debug_stub(regs);
-    regs->ax = 0x0100;
+    struct vgamode_s *vmode_g = get_current_mode();
+    if (! vmode_g)
+        goto fail;
+    int bpp = vga_bpp(vmode_g);
+    int linelength = vgahw_get_linelength(vmode_g);
+    if (linelength < 0)
+        goto fail;
+
+    int ret;
+    switch (regs->bl) {
+    case 0x80:
+    case 0x00:
+        ret = vgahw_set_displaystart(
+            vmode_g, DIV_ROUND_UP(regs->cx * bpp, 8) + linelength * regs->dx);
+        if (ret)
+            goto fail;
+        break;
+    case 0x01:
+        ret = vgahw_get_displaystart(vmode_g);
+        if (ret < 0)
+            goto fail;
+        regs->dx = ret / linelength;
+        regs->cx = (ret % linelength) * 8 / bpp;
+        break;
+    default:
+        goto fail;
+    }
+    regs->ax = 0x004f;
+    return;
+fail:
+    regs->ax = 0x014f;
 }
 
 static void
diff --git a/vgasrc/vgabios.c b/vgasrc/vgabios.c
index d0001668..25d97294 100644
--- a/vgasrc/vgabios.c
+++ b/vgasrc/vgabios.c
@@ -176,9 +176,8 @@ set_active_page(u8 page)
     struct cursorpos cp = get_cursor_pos(page);
 
     // Calculate memory address of start of page
-    u8 memmodel = GET_GLOBAL(vmode_g->memmodel);
-    u16 address = GET_BDA(video_pagesize) * page;
-    stdvga_set_active_page(memmodel == MM_TEXT ? address / 2 : address);
+    int address = GET_BDA(video_pagesize) * page;
+    vgahw_set_displaystart(vmode_g, address);
 
     // And change the BIOS page
     SET_BDA(video_pagestart, address);
diff --git a/vgasrc/vgahw.h b/vgasrc/vgahw.h
index 494309b3..af6b0689 100644
--- a/vgasrc/vgahw.h
+++ b/vgasrc/vgahw.h
@@ -77,4 +77,20 @@ static inline int vgahw_set_linelength(struct vgamode_s *vmode_g, int val) {
     return stdvga_set_linelength(vmode_g, val);
 }
 
+static inline int vgahw_get_displaystart(struct vgamode_s *vmode_g) {
+    if (CONFIG_VGA_CIRRUS)
+        return clext_get_displaystart(vmode_g);
+    if (CONFIG_VGA_BOCHS)
+        return bochsvga_get_displaystart(vmode_g);
+    return stdvga_get_displaystart(vmode_g);
+}
+
+static inline int vgahw_set_displaystart(struct vgamode_s *vmode_g, int val) {
+    if (CONFIG_VGA_CIRRUS)
+        return clext_set_displaystart(vmode_g, val);
+    if (CONFIG_VGA_BOCHS)
+        return bochsvga_set_displaystart(vmode_g, val);
+    return stdvga_set_displaystart(vmode_g, val);
+}
+
 #endif // vgahw.h