// SPDX-License-Identifier: GPL-2.0-only
/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *   Copyright 2009 Intel Corporation; author H. Peter Anvin
 *
 * ----------------------------------------------------------------------- */

/*
 * VESA text modes
 */

#include "boot.h"
#include "video.h"
#include "vesa.h"
#include "string.h"

/* VESA information */
static struct vesa_general_info vginfo;
static struct vesa_mode_info vminfo;

static __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)
{
        struct biosregs ireg, oreg;
        u16 mode;
        addr_t mode_ptr;
        struct mode_info *mi;
        int nmodes = 0;

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

        initregs(&ireg);
        ireg.ax = 0x4f00;
        ireg.di = (size_t)&vginfo;
        intcall(0x10, &ireg, &oreg);

        if (oreg.ax != 0x004f ||
            vginfo.signature != VESA_MAGIC ||
            vginfo.version < 0x0102)
                return 0;       /* Not present */

        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... */

                ireg.ax = 0x4f01;
                ireg.cx = mode;
                ireg.di = (size_t)&vminfo;
                intcall(0x10, &ireg, &oreg);

                if (oreg.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_BOOT_VESA_SUPPORT
                        /* 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. */
                        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;
}

static int vesa_set_mode(struct mode_info *mode)
{
        struct biosregs ireg, oreg;
        int is_graphic;
        u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;

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

        initregs(&ireg);
        ireg.ax = 0x4f01;
        ireg.cx = vesa_mode;
        ireg.di = (size_t)&vminfo;
        intcall(0x10, &ireg, &oreg);

        if (oreg.ax != 0x004f)
                return -1;

        if ((vminfo.mode_attr & 0x15) == 0x05) {
                /* It's a supported text mode */
                is_graphic = 0;
#ifdef CONFIG_BOOT_VESA_SUPPORT
        } 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 */
#endif
        } else {
                return -1;      /* Invalid mode */
        }


        initregs(&ireg);
        ireg.ax = 0x4f02;
        ireg.bx = vesa_mode;
        intcall(0x10, &ireg, &oreg);

        if (oreg.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)
{
        struct biosregs ireg, oreg;
        u8 dac_size = 6;

        /* If possible, switch the DAC to 8-bit mode */
        if (vginfo.capabilities & 1) {
                initregs(&ireg);
                ireg.ax = 0x4f08;
                ireg.bh = 0x08;
                intcall(0x10, &ireg, &oreg);
                if (oreg.ax == 0x004f)
                        dac_size = oreg.bh;
        }

        /* 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)
{
        struct biosregs ireg, oreg;

        initregs(&ireg);
        ireg.ax = 0x4f0a;
        intcall(0x10, &ireg, &oreg);

        if (oreg.ax != 0x004f)
                return;

        boot_params.screen_info.vesapm_seg = oreg.es;
        boot_params.screen_info.vesapm_off = oreg.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 = VIDEO_TYPE_VLFB;

        /* 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
        struct biosregs ireg, oreg;

        /* 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+ */

        initregs(&ireg);
        ireg.ax = 0x4f15;               /* VBE DDC */
        /* ireg.bx = 0x0000; */         /* Report DDC capabilities */
        /* ireg.cx = 0; */              /* Controller 0 */
        ireg.es = 0;                    /* ES:DI must be 0 by spec */
        intcall(0x10, &ireg, &oreg);

        if (oreg.ax != 0x004f)
                return;         /* No EDID */

        /* BH = time in seconds to transfer EDD information */
        /* BL = DDC level supported */

        ireg.ax = 0x4f15;               /* VBE DDC */
        ireg.bx = 0x0001;               /* Read EDID */
        /* ireg.cx = 0; */              /* Controller 0 */
        /* ireg.dx = 0; */              /* EDID block number */
        ireg.es = ds();
        ireg.di =(size_t)&boot_params.edid_info; /* (ES:)Pointer to block */
        intcall(0x10, &ireg, &oreg);
#endif /* CONFIG_FIRMWARE_EDID */
}

#endif /* not _WAKEUP */

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