summaryrefslogtreecommitdiff
path: root/arch/x86/lib/bios.c
blob: 3ab432e2623c437488a8516ba06f546e134e903e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
// 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 <irq_func.h>
#include <log.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;
}