int15.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <arch/interrupt.h>
#include <console/console.h>
#include <soc/int15.h>
#include <x86emu/x86emu.h>
 
static int int15_handler(void)
{
        int res = 1;
 
        printk(BIOS_DEBUG, "%s: AX=%04x BX=%04x CX=%04x DX=%04x\n",
               __func__, X86_AX, X86_BX, X86_CX, X86_DX);
 
        switch (X86_AX) {
        case 0x5f34:
                /*
                 * Set Panel Fitting Hook:
                 *  bit 2 = Graphics Stretching
                 *  bit 1 = Text Stretching
                 *  bit 0 = Centering (do not set with bit1 or bit2)
                 *  0     = video BIOS default
                 */
                X86_AX = 0x005f;
                X86_CX = 0x0001;
                res = 1;
                break;
        case 0x5f35:
                /*
                 * Boot Display Device Hook:
                 *  bit 0 = CRT
                 *  bit 1 = TV
                 *  bit 2 = EFP (HDMI)
                 *  bit 3 = LFP (eDP)*
                 *  bit 4 = CRT2
                 *  bit 5 = TV2
                 *  bit 6 = EFP2
                 *  bit 7 = LFP2
                 */
                X86_AX = 0x005f;
                X86_CX = 0x0008;
                res = 1;
                break;
        case 0x5f51:
                /*
                 * Hook to select active LFP configuration:
                 *  00h = No LVDS, VBIOS does not enable LVDS
                 *  01h = Int-LVDS, LFP driven by integrated LVDS decoder
                 *  02h = SVDO-LVDS, LFP driven by SVDO decoder
                 *  03h = eDP, LFP Driven by Int-DisplayPort encoder
                 */
                X86_AX = 0x005f;
                X86_CX = 0x0003;
                res = 1;
                break;
        case 0x5f70:
                switch ((X86_CX >> 8) & 0xff) {
                case 0:
                        /* Get Mux */
                        X86_AX = 0x005f;
                        X86_CX = 0x0000;
                        res = 1;
                        break;
                case 1:
                        /* Set Mux */
                        X86_AX = 0x005f;
                        X86_CX = 0x0000;
                        res = 1;
                        break;
                case 2:
                        /* Get SG/Non-SG mode */
                        X86_AX = 0x005f;
                        X86_CX = 0x0000;
                        res = 1;
                        break;
                default:
                        /* Interrupt was not handled */
                        printk(BIOS_DEBUG,
                               "Unknown INT15 5f70 function: 0x%02x\n",
                                ((X86_CX >> 8) & 0xff));
                        break;
                }
                break;
 
        default:
                printk(BIOS_DEBUG, "Unknown INT15 function %04x!\n", X86_AX);
                break;
        }
        return res;
}
 
void install_baytrail_vga_int15_handler(void)
{
        mainboard_interrupt_handlers(0x15, &int15_handler);
}