/* -*- 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.
 *
 * ----------------------------------------------------------------------- */

/*
 * 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;

#ifndef _WAKEUP
static void vesa_store_mode_params_graphics(void);
#else /* _WAKEUP */
static inline void vesa_store_mode_params_graphics(void) {}
#endif /* _WAKEUP */

static int vesa_probe(void)
{
#if defined(CONFIG_VIDEO_VESA) || defined(CONFIG_FIRMWARE_EDID)
        u16 ax, cx, di;
        u16 mode;
        addr_t mode_ptr;
        struct mode_info *mi;
        int nmodes = 0;

        video_vesa.modes = GET_HEAP(struct mode_info, 0);

        ax = 0x4f00;
        di = (size_t)&vginfo;
        asm(INT10
            : "+a" (ax), "+D" (di), "=m" (vginfo)
            : : "ebx", "ecx", "edx", "esi");

        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;
                cx = mode;
                di = (size_t)&vminfo;
                asm(INT10
                    : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
                    : : "ebx", "edx", "esi");

                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->depth = 0; /* text */
                        mi->x     = vminfo.h_res;
                        mi->y     = vminfo.v_res;
                        nmodes++;
                } else if ((vminfo.mode_attr & 0x99) == 0x99 &&
                           (vminfo.memory_layout == 4 ||
                            vminfo.memory_layout == 6) &&
                           vminfo.memory_planes == 1) {
#ifdef CONFIG_FB
                        /* Graphics mode, color, linear frame buffer
                           supported.  Only register the mode if
                           if framebuffer is configured, however,
                           otherwise the user will be left without a screen.
                           We don't require CONFIG_FB_VESA, however, since
                           some of the other framebuffer drivers can use
                           this mode-setting, too. */
                        mi = GET_HEAP(struct mode_info, 1);
                        mi->mode = mode + VIDEO_FIRST_VESA;
                        mi->depth = vminfo.bpp;
                        mi->x = vminfo.h_res;
                        mi->y = vminfo.v_res;
                        nmodes++;
#endif
                }
        }

        return nmodes;
#else
        return 0;
#endif /* CONFIG_VIDEO_VESA */
}

static int vesa_set_mode(struct mode_info *mode)
{
        u16 ax, bx, cx, di;
        int is_graphic;
        u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;

        memset(&vminfo, 0, sizeof vminfo); /* Just in case... */

        ax = 0x4f01;
        cx = vesa_mode;
        di = (size_t)&vminfo;
        asm(INT10
            : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
            : : "ebx", "edx", "esi");

        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;
        bx = vesa_mode;
        di = 0;
        asm volatile(INT10
                     : "+a" (ax), "+b" (bx), "+D" (di)
                     : : "ecx", "edx", "esi");

        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;
}


#ifndef _WAKEUP

/* 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), "=m" (boot_params.edid_info)
            : "c" (cx), "D" (di)
            : "esi");
#endif /* CONFIG_FIRMWARE_EDID */
}

#endif /* not _WAKEUP */

__videocard video_vesa =
{
        .card_name      = "VESA",
        .probe          = vesa_probe,
        .set_mode       = vesa_set_mode,
        .xmode_first    = VIDEO_FIRST_VESA,
        .xmode_n        = 0x200,
};