Video mode probing support for the new x86 setup code

Video mode probing for the new x86 setup code.  This code breaks down
different drivers into modules.  This code deliberately drops support
for a lot of the vendor-specific mode probing present in the assembly
version, since a lot of those probes have been found to be stale in
current versions of those chips -- frequently, support for those modes
have been dropped from recent video BIOSes due to space constraints,
but the video BIOS signatures are still the same.

However, additional drivers should be extremely straightforward to plug
in, if desirable.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 284 insertions, 0 deletions

diff --git a/arch/i386/boot/video-vesa.c b/arch/i386/boot/video-vesa.c
new file mode 100644
index 000000000000..e6aa9eb8d93a
--- /dev/null
+++ b/arch/i386/boot/video-vesa.c
@@ -0,0 +1,284 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/video-vesa.c
+ *
+ * VESA text modes
+ */
+
+#include "boot.h"
+#include "video.h"
+#include "vesa.h"
+
+/* VESA information */
+static struct vesa_general_info vginfo;
+static struct vesa_mode_info vminfo;
+
+__videocard video_vesa;
+
+static void vesa_store_mode_params_graphics(void);
+
+static int vesa_probe(void)
+{
+#if defined(CONFIG_VIDEO_VESA) || defined(CONFIG_FIRMWARE_EDID)
+        u16 ax;
+        u16 mode;
+        addr_t mode_ptr;
+        struct mode_info *mi;
+        int nmodes = 0;
+
+        video_vesa.modes = GET_HEAP(struct mode_info, 0);
+
+        vginfo.signature = VBE2_MAGIC;
+
+        /* Optimistically assume a VESA BIOS is register-clean... */
+        ax = 0x4f00;
+        asm("int $0x10" : "+a" (ax), "=m" (vginfo) : "D" (&vginfo));
+
+        if (ax != 0x004f ||
+            vginfo.signature != VESA_MAGIC ||
+            vginfo.version < 0x0102)
+                return 0;       /* Not present */
+#endif /* CONFIG_VIDEO_VESA || CONFIG_FIRMWARE_EDID */
+#ifdef CONFIG_VIDEO_VESA
+        set_fs(vginfo.video_mode_ptr.seg);
+        mode_ptr = vginfo.video_mode_ptr.off;
+
+        while ((mode = rdfs16(mode_ptr)) != 0xffff) {
+                mode_ptr += 2;
+
+                if (heap_free() < sizeof(struct mode_info))
+                        break;  /* Heap full, can't save mode info */
+
+                if (mode & ~0x1ff)
+                        continue;
+
+                memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
+
+                ax = 0x4f01;
+                asm("int $0x10"
+                    : "+a" (ax), "=m" (vminfo)
+                    : "c" (mode), "D" (&vminfo));
+
+                if (ax != 0x004f)
+                        continue;
+
+                if ((vminfo.mode_attr & 0x15) == 0x05) {
+                        /* Text Mode, TTY BIOS supported,
+                           supported by hardware */
+                        mi = GET_HEAP(struct mode_info, 1);
+                        mi->mode = mode + VIDEO_FIRST_VESA;
+                        mi->x    = vminfo.h_res;
+                        mi->y    = vminfo.v_res;
+                        nmodes++;
+                } else if ((vminfo.mode_attr & 0x99) == 0x99) {
+#ifdef CONFIG_FB
+                        /* Graphics mode, color, linear frame buffer
+                           supported -- register the mode but hide from
+                           the menu.  Only do this if framebuffer is
+                           configured, however, otherwise the user will
+                           be left without a screen. */
+                        mi = GET_HEAP(struct mode_info, 1);
+                        mi->mode = mode + VIDEO_FIRST_VESA;
+                        mi->x = mi->y = 0;
+                        nmodes++;
+#endif
+                }
+        }
+
+        return nmodes;
+#else
+        return 0;
+#endif /* CONFIG_VIDEO_VESA */
+}
+
+static int vesa_set_mode(struct mode_info *mode)
+{
+        u16 ax;
+        int is_graphic;
+        u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;
+
+        memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
+
+        ax = 0x4f01;
+        asm("int $0x10"
+            : "+a" (ax), "=m" (vminfo)
+            : "c" (vesa_mode), "D" (&vminfo));
+
+        if (ax != 0x004f)
+                return -1;
+
+        if ((vminfo.mode_attr & 0x15) == 0x05) {
+                /* It's a supported text mode */
+                is_graphic = 0;
+        } else if ((vminfo.mode_attr & 0x99) == 0x99) {
+                /* It's a graphics mode with linear frame buffer */
+                is_graphic = 1;
+                vesa_mode |= 0x4000; /* Request linear frame buffer */
+        } else {
+                return -1;      /* Invalid mode */
+        }
+
+
+        ax = 0x4f02;
+        asm volatile("int $0x10"
+                     : "+a" (ax)
+                     : "b" (vesa_mode), "D" (0));
+
+        if (ax != 0x004f)
+                return -1;
+
+        graphic_mode = is_graphic;
+        if (!is_graphic) {
+                /* Text mode */
+                force_x = mode->x;
+                force_y = mode->y;
+                do_restore = 1;
+        } else {
+                /* Graphics mode */
+                vesa_store_mode_params_graphics();
+        }
+
+        return 0;
+}
+
+
+/* Switch DAC to 8-bit mode */
+static void vesa_dac_set_8bits(void)
+{
+        u8 dac_size = 6;
+
+        /* If possible, switch the DAC to 8-bit mode */
+        if (vginfo.capabilities & 1) {
+                u16 ax, bx;
+
+                ax = 0x4f08;
+                bx = 0x0800;
+                asm volatile(INT10
+                             : "+a" (ax), "+b" (bx)
+                             : : "ecx", "edx", "esi", "edi");
+
+                if (ax == 0x004f)
+                        dac_size = bx >> 8;
+        }
+
+        /* Set the color sizes to the DAC size, and offsets to 0 */
+        boot_params.screen_info.red_size = dac_size;
+        boot_params.screen_info.green_size = dac_size;
+        boot_params.screen_info.blue_size = dac_size;
+        boot_params.screen_info.rsvd_size = dac_size;
+
+        boot_params.screen_info.red_pos = 0;
+        boot_params.screen_info.green_pos = 0;
+        boot_params.screen_info.blue_pos = 0;
+        boot_params.screen_info.rsvd_pos = 0;
+}
+
+/* Save the VESA protected mode info */
+static void vesa_store_pm_info(void)
+{
+        u16 ax, bx, di, es;
+
+        ax = 0x4f0a;
+        bx = di = 0;
+        asm("pushw %%es; "INT10"; movw %%es,%0; popw %%es"
+            : "=d" (es), "+a" (ax), "+b" (bx), "+D" (di)
+            : : "ecx", "esi");
+
+        if (ax != 0x004f)
+                return;
+
+        boot_params.screen_info.vesapm_seg = es;
+        boot_params.screen_info.vesapm_off = di;
+}
+
+/*
+ * Save video mode parameters for graphics mode
+ */
+static void vesa_store_mode_params_graphics(void)
+{
+        /* Tell the kernel we're in VESA graphics mode */
+        boot_params.screen_info.orig_video_isVGA = 0x23;
+
+        /* Mode parameters */
+        boot_params.screen_info.vesa_attributes = vminfo.mode_attr;
+        boot_params.screen_info.lfb_linelength = vminfo.logical_scan;
+        boot_params.screen_info.lfb_width = vminfo.h_res;
+        boot_params.screen_info.lfb_height = vminfo.v_res;
+        boot_params.screen_info.lfb_depth = vminfo.bpp;
+        boot_params.screen_info.pages = vminfo.image_planes;
+        boot_params.screen_info.lfb_base = vminfo.lfb_ptr;
+        memcpy(&boot_params.screen_info.red_size,
+               &vminfo.rmask, 8);
+
+        /* General parameters */
+        boot_params.screen_info.lfb_size = vginfo.total_memory;
+
+        if (vminfo.bpp <= 8)
+                vesa_dac_set_8bits();
+
+        vesa_store_pm_info();
+}
+
+/*
+ * Save EDID information for the kernel; this is invoked, separately,
+ * after mode-setting.
+ */
+void vesa_store_edid(void)
+{
+#ifdef CONFIG_FIRMWARE_EDID
+        u16 ax, bx, cx, dx, di;
+
+        /* Apparently used as a nonsense token... */
+        memset(&boot_params.edid_info, 0x13, sizeof boot_params.edid_info);
+
+        if (vginfo.version < 0x0200)
+                return;         /* EDID requires VBE 2.0+ */
+
+        ax = 0x4f15;            /* VBE DDC */
+        bx = 0x0000;            /* Report DDC capabilities */
+        cx = 0;                 /* Controller 0 */
+        di = 0;                 /* ES:DI must be 0 by spec */
+
+        /* Note: The VBE DDC spec is different from the main VESA spec;
+           we genuinely have to assume all registers are destroyed here. */
+
+        asm("pushw %%es; movw %2,%%es; "INT10"; popw %%es"
+            : "+a" (ax), "+b" (bx)
+            :  "c" (cx), "D" (di)
+            : "esi");
+
+        if (ax != 0x004f)
+                return;         /* No EDID */
+
+        /* BH = time in seconds to transfer EDD information */
+        /* BL = DDC level supported */
+
+        ax = 0x4f15;            /* VBE DDC */
+        bx = 0x0001;            /* Read EDID */
+        cx = 0;                 /* Controller 0 */
+        dx = 0;                 /* EDID block number */
+        di =(size_t) &boot_params.edid_info; /* (ES:)Pointer to block */
+        asm(INT10
+            : "+a" (ax), "+b" (bx), "+d" (dx)
+            : "c" (cx), "D" (di)
+            : "esi");
+#endif /* CONFIG_FIRMWARE_EDID */
+}
+
+__videocard video_vesa =
+{
+        .card_name      = "VESA",
+        .probe          = vesa_probe,
+        .set_mode       = vesa_set_mode,
+        .xmode_first    = VIDEO_FIRST_VESA,
+        .xmode_n        = 0x200,
+};