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// SPDX-License-Identifier: GPL-2.0
/*
* From Coreboot file device/oprom/realmode/x86.c
*
* Copyright (C) 2007 Advanced Micro Devices, Inc.
* Copyright (C) 2009-2010 coresystems GmbH
*/
#include <common.h>
#include <bios_emul.h>
#include <vbe.h>
#include <linux/linkage.h>
#include <asm/cache.h>
#include <asm/processor.h>
#include <asm/i8259.h>
#include <asm/io.h>
#include <asm/post.h>
#include "bios.h"
/* Interrupt handlers for each interrupt the ROM can call */
static int (*int_handler[256])(void);
/* to have a common register file for interrupt handlers */
X86EMU_sysEnv _X86EMU_env;
asmlinkage void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx,
u32 esi, u32 edi);
asmlinkage void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx,
u32 edx, u32 esi, u32 edi);
static void setup_realmode_code(void)
{
memcpy((void *)REALMODE_BASE, &asm_realmode_code,
asm_realmode_code_size);
/* Ensure the global pointers are relocated properly. */
realmode_call = PTR_TO_REAL_MODE(asm_realmode_call);
realmode_interrupt = PTR_TO_REAL_MODE(__realmode_interrupt);
debug("Real mode stub @%x: %d bytes\n", REALMODE_BASE,
asm_realmode_code_size);
}
static void setup_rombios(void)
{
const char date[] = "06/11/99";
memcpy((void *)0xffff5, &date, 8);
const char ident[] = "PCI_ISA";
memcpy((void *)0xfffd9, &ident, 7);
/* system model: IBM-AT */
writeb(0xfc, 0xffffe);
}
static int int_exception_handler(void)
{
/* compatibility shim */
struct eregs reg_info = {
.eax = M.x86.R_EAX,
.ecx = M.x86.R_ECX,
.edx = M.x86.R_EDX,
.ebx = M.x86.R_EBX,
.esp = M.x86.R_ESP,
.ebp = M.x86.R_EBP,
.esi = M.x86.R_ESI,
.edi = M.x86.R_EDI,
.vector = M.x86.intno,
.error_code = 0,
.eip = M.x86.R_EIP,
.cs = M.x86.R_CS,
.eflags = M.x86.R_EFLG
};
struct eregs *regs = &reg_info;
debug("Oops, exception %d while executing option rom\n", regs->vector);
cpu_hlt();
return 0;
}
static int int_unknown_handler(void)
{
debug("Unsupported software interrupt #0x%x eax 0x%x\n",
M.x86.intno, M.x86.R_EAX);
return -1;
}
/* setup interrupt handlers for mainboard */
void bios_set_interrupt_handler(int intnum, int (*int_func)(void))
{
int_handler[intnum] = int_func;
}
static void setup_interrupt_handlers(void)
{
int i;
/*
* The first 16 int_handler functions are not BIOS services,
* but the CPU-generated exceptions ("hardware interrupts")
*/
for (i = 0; i < 0x10; i++)
int_handler[i] = &int_exception_handler;
/* Mark all other int_handler calls as unknown first */
for (i = 0x10; i < 0x100; i++) {
/* Skip if bios_set_interrupt_handler() isn't called first */
if (int_handler[i])
continue;
/*
* Now set the default functions that are actually needed
* to initialize the option roms. The board may override
* these with bios_set_interrupt_handler()
*/
switch (i) {
case 0x10:
int_handler[0x10] = &int10_handler;
break;
case 0x12:
int_handler[0x12] = &int12_handler;
break;
case 0x16:
int_handler[0x16] = &int16_handler;
break;
case 0x1a:
int_handler[0x1a] = &int1a_handler;
break;
default:
int_handler[i] = &int_unknown_handler;
break;
}
}
}
static void write_idt_stub(void *target, u8 intnum)
{
unsigned char *codeptr;
codeptr = (unsigned char *)target;
memcpy(codeptr, &__idt_handler, __idt_handler_size);
codeptr[3] = intnum; /* modify int# in the code stub. */
}
static void setup_realmode_idt(void)
{
struct realmode_idt *idts = NULL;
int i;
/*
* Copy IDT stub code for each interrupt. This might seem wasteful
* but it is really simple
*/
for (i = 0; i < 256; i++) {
idts[i].cs = 0;
idts[i].offset = 0x1000 + (i * __idt_handler_size);
write_idt_stub((void *)((ulong)idts[i].offset), i);
}
/*
* Many option ROMs use the hard coded interrupt entry points in the
* system bios. So install them at the known locations.
*/
/* int42 is the relocated int10 */
write_idt_stub((void *)0xff065, 0x42);
/* BIOS Int 11 Handler F000:F84D */
write_idt_stub((void *)0xff84d, 0x11);
/* BIOS Int 12 Handler F000:F841 */
write_idt_stub((void *)0xff841, 0x12);
/* BIOS Int 13 Handler F000:EC59 */
write_idt_stub((void *)0xfec59, 0x13);
/* BIOS Int 14 Handler F000:E739 */
write_idt_stub((void *)0xfe739, 0x14);
/* BIOS Int 15 Handler F000:F859 */
write_idt_stub((void *)0xff859, 0x15);
/* BIOS Int 16 Handler F000:E82E */
write_idt_stub((void *)0xfe82e, 0x16);
/* BIOS Int 17 Handler F000:EFD2 */
write_idt_stub((void *)0xfefd2, 0x17);
/* ROM BIOS Int 1A Handler F000:FE6E */
write_idt_stub((void *)0xffe6e, 0x1a);
}
#ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE
static u8 vbe_get_mode_info(struct vbe_mode_info *mi)
{
u16 buffer_seg;
u16 buffer_adr;
char *buffer;
debug("VBE: Getting information about VESA mode %04x\n",
mi->video_mode);
buffer = PTR_TO_REAL_MODE(asm_realmode_buffer);
buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00;
buffer_adr = ((unsigned long)buffer) & 0xffff;
realmode_interrupt(0x10, VESA_GET_MODE_INFO, 0x0000, mi->video_mode,
0x0000, buffer_seg, buffer_adr);
memcpy(mi->mode_info_block, buffer, sizeof(struct vbe_mode_info));
mi->valid = true;
return 0;
}
static u8 vbe_set_mode(struct vbe_mode_info *mi)
{
int video_mode = mi->video_mode;
debug("VBE: Setting VESA mode %#04x\n", video_mode);
/* request linear framebuffer mode */
video_mode |= (1 << 14);
/* don't clear the framebuffer, we do that later */
video_mode |= (1 << 15);
realmode_interrupt(0x10, VESA_SET_MODE, video_mode,
0x0000, 0x0000, 0x0000, 0x0000);
return 0;
}
static void vbe_set_graphics(int vesa_mode, struct vbe_mode_info *mode_info)
{
unsigned char *framebuffer;
mode_info->video_mode = (1 << 14) | vesa_mode;
vbe_get_mode_info(mode_info);
framebuffer = (unsigned char *)(ulong)mode_info->vesa.phys_base_ptr;
debug("VBE: resolution: %dx%d@%d\n",
le16_to_cpu(mode_info->vesa.x_resolution),
le16_to_cpu(mode_info->vesa.y_resolution),
mode_info->vesa.bits_per_pixel);
debug("VBE: framebuffer: %p\n", framebuffer);
if (!framebuffer) {
debug("VBE: Mode does not support linear framebuffer\n");
return;
}
mode_info->video_mode &= 0x3ff;
vbe_set_mode(mode_info);
}
#endif /* CONFIG_FRAMEBUFFER_SET_VESA_MODE */
void bios_run_on_x86(struct udevice *dev, unsigned long addr, int vesa_mode,
struct vbe_mode_info *mode_info)
{
pci_dev_t pcidev = dm_pci_get_bdf(dev);
u32 num_dev;
num_dev = PCI_BUS(pcidev) << 8 | PCI_DEV(pcidev) << 3 |
PCI_FUNC(pcidev);
/* Needed to avoid exceptions in some ROMs */
interrupt_init();
/* Set up some legacy information in the F segment */
setup_rombios();
/* Set up C interrupt handlers */
setup_interrupt_handlers();
/* Set up real-mode IDT */
setup_realmode_idt();
/* Make sure the code is placed. */
setup_realmode_code();
debug("Calling Option ROM at %lx, pci device %#x...", addr, num_dev);
/* Option ROM entry point is at OPROM start + 3 */
realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0,
0x0);
debug("done\n");
#ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE
if (vesa_mode != -1)
vbe_set_graphics(vesa_mode, mode_info);
#endif
}
asmlinkage int interrupt_handler(u32 intnumber, u32 gsfs, u32 dses,
u32 edi, u32 esi, u32 ebp, u32 esp,
u32 ebx, u32 edx, u32 ecx, u32 eax,
u32 cs_ip, u16 stackflags)
{
u32 ip;
u32 cs;
u32 flags;
int ret = 0;
ip = cs_ip & 0xffff;
cs = cs_ip >> 16;
flags = stackflags;
#ifdef CONFIG_REALMODE_DEBUG
debug("oprom: INT# 0x%x\n", intnumber);
debug("oprom: eax: %08x ebx: %08x ecx: %08x edx: %08x\n",
eax, ebx, ecx, edx);
debug("oprom: ebp: %08x esp: %08x edi: %08x esi: %08x\n",
ebp, esp, edi, esi);
debug("oprom: ip: %04x cs: %04x flags: %08x\n",
ip, cs, flags);
debug("oprom: stackflags = %04x\n", stackflags);
#endif
/*
* Fetch arguments from the stack and put them to a place
* suitable for the interrupt handlers
*/
M.x86.R_EAX = eax;
M.x86.R_ECX = ecx;
M.x86.R_EDX = edx;
M.x86.R_EBX = ebx;
M.x86.R_ESP = esp;
M.x86.R_EBP = ebp;
M.x86.R_ESI = esi;
M.x86.R_EDI = edi;
M.x86.intno = intnumber;
M.x86.R_EIP = ip;
M.x86.R_CS = cs;
M.x86.R_EFLG = flags;
/* Call the interrupt handler for this interrupt number */
ret = int_handler[intnumber]();
/*
* This code is quite strange...
*
* Put registers back on the stack. The assembler code will pop them
* later. We force (volatile!) changing the values of the parameters
* of this function. We know that they stay alive on the stack after
* we leave this function.
*/
*(volatile u32 *)&eax = M.x86.R_EAX;
*(volatile u32 *)&ecx = M.x86.R_ECX;
*(volatile u32 *)&edx = M.x86.R_EDX;
*(volatile u32 *)&ebx = M.x86.R_EBX;
*(volatile u32 *)&esi = M.x86.R_ESI;
*(volatile u32 *)&edi = M.x86.R_EDI;
flags = M.x86.R_EFLG;
/* Pass success or error back to our caller via the CARRY flag */
if (ret) {
flags &= ~1; /* no error: clear carry */
} else {
debug("int%02x call returned error\n", intnumber);
flags |= 1; /* error: set carry */
}
*(volatile u16 *)&stackflags = flags;
return ret;
}