From 3876b531222c53124b0eb154fb331c0c662f5e09 Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Tue, 24 Jan 2012 00:07:44 -0500
Subject: [PATCH] vgabios: Add support for vbe get/set line length function.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
 vgasrc/bochsvga.c | 15 ++++++++++++++
 vgasrc/bochsvga.h |  2 ++
 vgasrc/clext.c    | 51 +++++++++++++++++++----------------------------
 vgasrc/clext.h    |  2 ++
 vgasrc/stdvga.c   | 31 ++++++++++++++++++++++++++++
 vgasrc/stdvga.h   |  3 +++
 vgasrc/vbe.c      | 29 +++++++++++++++++++++++++--
 vgasrc/vgabios.c  | 16 +++++++++++++++
 vgasrc/vgabios.h  |  1 +
 vgasrc/vgahw.h    | 16 +++++++++++++++
 10 files changed, 133 insertions(+), 33 deletions(-)

diff --git a/vgasrc/bochsvga.c b/vgasrc/bochsvga.c
index 74da887..2a4b0d5 100644
--- a/vgasrc/bochsvga.c
+++ b/vgasrc/bochsvga.c
@@ -217,6 +217,21 @@ bochsvga_set_window(struct vgamode_s *vmode_g, int window, int val)
     return 0;
 }
 
+int
+bochsvga_get_linelength(struct vgamode_s *vmode_g)
+{
+    return dispi_read(VBE_DISPI_INDEX_VIRT_WIDTH) * vga_bpp(vmode_g) / 8;
+}
+
+int
+bochsvga_set_linelength(struct vgamode_s *vmode_g, int val)
+{
+    stdvga_set_linelength(vmode_g, val);
+    int pixels = (val * 8) / vga_bpp(vmode_g);
+    dispi_write(VBE_DISPI_INDEX_VIRT_WIDTH, pixels);
+    return 0;
+}
+
 static void
 bochsvga_clear_scr(void)
 {
diff --git a/vgasrc/bochsvga.h b/vgasrc/bochsvga.h
index 26a82e0..b6abf0a 100644
--- a/vgasrc/bochsvga.h
+++ b/vgasrc/bochsvga.h
@@ -57,6 +57,8 @@ void bochsvga_list_modes(u16 seg, u16 *dest, u16 *last);
 struct vgamode_s *bochsvga_find_mode(int mode);
 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_set_mode(struct vgamode_s *vmode_g, int flags);
 
 #endif // bochsvga.h
diff --git a/vgasrc/clext.c b/vgasrc/clext.c
index ee39c5e..27af810 100644
--- a/vgasrc/clext.c
+++ b/vgasrc/clext.c
@@ -415,6 +415,26 @@ clext_set_window(struct vgamode_s *vmode_g, int window, int val)
     return 0;
 }
 
+int
+clext_get_linelength(struct vgamode_s *vmode_g)
+{
+    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) * stdvga_bpp_factor(vmode_g) * 2;
+}
+
+int
+clext_set_linelength(struct vgamode_s *vmode_g, int val)
+{
+    u16 crtc_addr = stdvga_get_crtc();
+    int factor = stdvga_bpp_factor(vmode_g) * 2;
+    int new_line_offset = DIV_ROUND_UP(val, factor);
+    stdvga_crtc_write(crtc_addr, 0x13, new_line_offset);
+    stdvga_crtc_mask(crtc_addr, 0x1b, 0x10, (new_line_offset & 0x100) >> 4);
+    return 0;
+}
+
 static void
 cirrus_enable_16k_granularity(void)
 {
@@ -593,15 +613,6 @@ cirrus_get_bpp_bytes(void)
     return v;
 }
 
-static void
-cirrus_set_line_offset(u16 new_line_offset)
-{
-    new_line_offset /= 8;
-    u16 crtc_addr = stdvga_get_crtc();
-    stdvga_crtc_write(crtc_addr, 0x13, new_line_offset);
-    stdvga_crtc_mask(crtc_addr, 0x1b, 0x10, (new_line_offset & 0x100) >> 4);
-}
-
 static u16
 cirrus_get_line_offset(void)
 {
@@ -634,27 +645,6 @@ cirrus_get_start_addr(void)
             | ((b4 & 0x80) << 12));
 }
 
-static void
-cirrus_vesa_06h(struct bregs *regs)
-{
-    if (regs->bl > 2) {
-        regs->ax = 0x0100;
-        return;
-    }
-
-    if (regs->bl == 0x00) {
-        cirrus_set_line_offset(cirrus_get_bpp_bytes() * regs->cx);
-    } else if (regs->bl == 0x02) {
-        cirrus_set_line_offset(regs->cx);
-    }
-
-    u32 v = cirrus_get_line_offset();
-    regs->cx = v / cirrus_get_bpp_bytes();
-    regs->bx = v;
-    regs->dx = GET_GLOBAL(VBE_total_memory) / v;
-    regs->ax = 0x004f;
-}
-
 static void
 cirrus_vesa_07h(struct bregs *regs)
 {
@@ -707,7 +697,6 @@ void
 cirrus_vesa(struct bregs *regs)
 {
     switch (regs->al) {
-    case 0x06: cirrus_vesa_06h(regs); break;
     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 b300cf4..55476a0 100644
--- a/vgasrc/clext.h
+++ b/vgasrc/clext.h
@@ -6,6 +6,8 @@
 struct vgamode_s *clext_find_mode(int mode);
 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_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 9c0cba9..a310167 100644
--- a/vgasrc/stdvga.c
+++ b/vgasrc/stdvga.c
@@ -229,6 +229,22 @@ stdvga_get_crtc(void)
     return VGAREG_MDA_CRTC_ADDRESS;
 }
 
+// Return the multiplication factor needed for the vga offset register.
+int
+stdvga_bpp_factor(struct vgamode_s *vmode_g)
+{
+    switch (GET_GLOBAL(vmode_g->memmodel)) {
+    case MM_TEXT:
+        return 2;
+    case MM_CGA:
+        return GET_GLOBAL(vmode_g->depth);
+    case MM_PLANAR:
+        return 1;
+    default:
+        return 4;
+    }
+}
+
 void
 stdvga_set_cursor_shape(u8 start, u8 end)
 {
@@ -282,6 +298,21 @@ stdvga_set_window(struct vgamode_s *vmode_g, int window, int val)
     return -1;
 }
 
+int
+stdvga_get_linelength(struct vgamode_s *vmode_g)
+{
+    u8 val = stdvga_crtc_read(stdvga_get_crtc(), 0x13);
+    return val * stdvga_bpp_factor(vmode_g) * 2;
+}
+
+int
+stdvga_set_linelength(struct vgamode_s *vmode_g, int val)
+{
+    int factor = stdvga_bpp_factor(vmode_g) * 2;
+    stdvga_crtc_write(stdvga_get_crtc(), 0x13, DIV_ROUND_UP(val, factor));
+    return 0;
+}
+
 
 /****************************************************************
  * Save/Restore/Set state
diff --git a/vgasrc/stdvga.h b/vgasrc/stdvga.h
index 05f2bf5..ad496b5 100644
--- a/vgasrc/stdvga.h
+++ b/vgasrc/stdvga.h
@@ -129,6 +129,7 @@ void stdvga_planar4_plane(int plane);
 void stdvga_load_font(u16 seg, void *src_far, u16 count
                       , u16 start, u8 destflags, u8 fontsize);
 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);
@@ -136,6 +137,8 @@ void stdvga_set_scan_lines(u8 lines);
 u16 stdvga_get_vde(void);
 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);
 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 7e84794..68d2025 100644
--- a/vgasrc/vbe.c
+++ b/vgasrc/vbe.c
@@ -241,8 +241,33 @@ fail:
 static void
 vbe_104f06(struct bregs *regs)
 {
-    debug_stub(regs);
-    regs->ax = 0x0100;
+    if (regs->bl > 0x02)
+        goto fail;
+    struct vgamode_s *vmode_g = get_current_mode();
+    if (! vmode_g)
+        goto fail;
+    int bpp = vga_bpp(vmode_g);
+
+    if (regs->bl == 0x00) {
+        int ret = vgahw_set_linelength(vmode_g, DIV_ROUND_UP(regs->cx * bpp, 8));
+        if (ret)
+            goto fail;
+    } else if (regs->bl == 0x02) {
+        int ret = vgahw_set_linelength(vmode_g, regs->cx);
+        if (ret)
+            goto fail;
+    }
+    int linelength = vgahw_get_linelength(vmode_g);
+    if (linelength < 0)
+        goto fail;
+
+    regs->bx = linelength;
+    regs->cx = (linelength * 8) / bpp;
+    regs->dx = GET_GLOBAL(VBE_total_memory) / linelength;
+    regs->ax = 0x004f;
+    return;
+fail:
+    regs->ax = 0x014f;
 }
 
 static void
diff --git a/vgasrc/vgabios.c b/vgasrc/vgabios.c
index d35cb02..d000166 100644
--- a/vgasrc/vgabios.c
+++ b/vgasrc/vgabios.c
@@ -63,6 +63,22 @@ struct pci_data rom_pci_data VAR16VISIBLE = {
  * Helper functions
  ****************************************************************/
 
+// Return the bits per pixel in system memory for a given mode.
+int
+vga_bpp(struct vgamode_s *vmode_g)
+{
+    switch (GET_GLOBAL(vmode_g->memmodel)) {
+    case MM_TEXT:
+        return 16;
+    case MM_PLANAR:
+        return 1;
+    }
+    u8 depth = GET_GLOBAL(vmode_g->depth);
+    if (depth > 8)
+        return ALIGN(depth, 8);
+    return depth;
+}
+
 u16
 calc_page_size(u8 memmodel, u16 width, u16 height)
 {
diff --git a/vgasrc/vgabios.h b/vgasrc/vgabios.h
index 23d234a..aca95be 100644
--- a/vgasrc/vgabios.h
+++ b/vgasrc/vgabios.h
@@ -82,6 +82,7 @@ struct carattr {
 struct cursorpos {
     u8 x, y, page;
 };
+int vga_bpp(struct vgamode_s *vmode_g);
 u16 calc_page_size(u8 memmodel, u16 width, u16 height);
 struct vgamode_s *get_current_mode(void);
 int vga_set_mode(int mode, int flags);
diff --git a/vgasrc/vgahw.h b/vgasrc/vgahw.h
index ca8798c..494309b 100644
--- a/vgasrc/vgahw.h
+++ b/vgasrc/vgahw.h
@@ -61,4 +61,20 @@ static inline int vgahw_set_window(struct vgamode_s *vmode_g, int window
     return stdvga_set_window(vmode_g, window, val);
 }
 
+static inline int vgahw_get_linelength(struct vgamode_s *vmode_g) {
+    if (CONFIG_VGA_CIRRUS)
+        return clext_get_linelength(vmode_g);
+    if (CONFIG_VGA_BOCHS)
+        return bochsvga_get_linelength(vmode_g);
+    return stdvga_get_linelength(vmode_g);
+}
+
+static inline int vgahw_set_linelength(struct vgamode_s *vmode_g, int val) {
+    if (CONFIG_VGA_CIRRUS)
+        return clext_set_linelength(vmode_g, val);
+    if (CONFIG_VGA_BOCHS)
+        return bochsvga_set_linelength(vmode_g, val);
+    return stdvga_set_linelength(vmode_g, val);
+}
+
 #endif // vgahw.h
-- 
2.25.1