1// SPDX-License-Identifier: GPL-2.0
2/*
3 * From Coreboot file device/oprom/realmode/x86.c
4 *
5 * Copyright (C) 2007 Advanced Micro Devices, Inc.
6 * Copyright (C) 2009-2010 coresystems GmbH
7 */
8#include <common.h>
9#include <compiler.h>
10#include <bios_emul.h>
11#include <irq_func.h>
12#include <log.h>
13#include <vesa.h>
14#include <linux/linkage.h>
15#include <asm/cache.h>
16#include <asm/processor.h>
17#include <asm/i8259.h>
18#include <asm/io.h>
19#include <asm/post.h>
20#include "bios.h"
21
22/* Interrupt handlers for each interrupt the ROM can call */
23static int (*int_handler[256])(void);
24
25/* to have a common register file for interrupt handlers */
26#if !CONFIG_IS_ENABLED(BIOSEMU)
27X86EMU_sysEnv _X86EMU_env;
28#endif
29
30asmlinkage void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx,
31				 u32 esi, u32 edi);
32
33asmlinkage void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx,
34				      u32 edx, u32 esi, u32 edi);
35
36static void setup_realmode_code(void)
37{
38	memcpy((void *)REALMODE_BASE, &asm_realmode_code,
39	       asm_realmode_code_size);
40
41	/* Ensure the global pointers are relocated properly. */
42	realmode_call = PTR_TO_REAL_MODE(asm_realmode_call);
43	realmode_interrupt = PTR_TO_REAL_MODE(__realmode_interrupt);
44
45	debug("Real mode stub @%x: %d bytes\n", REALMODE_BASE,
46	      asm_realmode_code_size);
47}
48
49static void setup_rombios(void)
50{
51	const char date[] = "06/11/99";
52	memcpy((void *)0xffff5, &date, 8);
53
54	const char ident[] = "PCI_ISA";
55	memcpy((void *)0xfffd9, &ident, 7);
56
57	/* system model: IBM-AT */
58	writeb(0xfc, 0xffffe);
59}
60
61static int int_exception_handler(void)
62{
63	/* compatibility shim */
64	struct eregs reg_info = {
65		.eax = M.x86.R_EAX,
66		.ecx = M.x86.R_ECX,
67		.edx = M.x86.R_EDX,
68		.ebx = M.x86.R_EBX,
69		.esp = M.x86.R_ESP,
70		.ebp = M.x86.R_EBP,
71		.esi = M.x86.R_ESI,
72		.edi = M.x86.R_EDI,
73		.vector = M.x86.intno,
74		.error_code = 0,
75		.eip = M.x86.R_EIP,
76		.cs = M.x86.R_CS,
77		.eflags = M.x86.R_EFLG
78	};
79	struct eregs *regs = &reg_info;
80
81	log_err("Exception %d while executing option rom\n", regs->vector);
82	cpu_hlt();
83
84	return 0;
85}
86
87static int int_unknown_handler(void)
88{
89	debug("Unsupported software interrupt #0x%x eax 0x%x\n",
90	      M.x86.intno, M.x86.R_EAX);
91
92	return -1;
93}
94
95/* setup interrupt handlers for mainboard */
96void bios_set_interrupt_handler(int intnum, int (*int_func)(void))
97{
98	int_handler[intnum] = int_func;
99}
100
101static void setup_interrupt_handlers(void)
102{
103	int i;
104
105	/*
106	 * The first 16 int_handler functions are not BIOS services,
107	 * but the CPU-generated exceptions ("hardware interrupts")
108	 */
109	for (i = 0; i < 0x10; i++)
110		int_handler[i] = &int_exception_handler;
111
112	/* Mark all other int_handler calls as unknown first */
113	for (i = 0x10; i < 0x100; i++) {
114		/* Skip if bios_set_interrupt_handler() isn't called first */
115		if (int_handler[i])
116			continue;
117
118		 /*
119		  * Now set the default functions that are actually needed
120		  * to initialize the option roms. The board may override
121		  * these with bios_set_interrupt_handler()
122		 */
123		switch (i) {
124		case 0x10:
125			int_handler[0x10] = &int10_handler;
126			break;
127		case 0x12:
128			int_handler[0x12] = &int12_handler;
129			break;
130		case 0x16:
131			int_handler[0x16] = &int16_handler;
132			break;
133		case 0x1a:
134			int_handler[0x1a] = &int1a_handler;
135			break;
136		default:
137			int_handler[i] = &int_unknown_handler;
138			break;
139		}
140	}
141}
142
143static void write_idt_stub(void *target, u8 intnum)
144{
145	unsigned char *codeptr;
146
147	codeptr = (unsigned char *)target;
148	memcpy(codeptr, &__idt_handler, __idt_handler_size);
149	codeptr[3] = intnum; /* modify int# in the code stub. */
150}
151
152static void setup_realmode_idt(void)
153{
154	struct realmode_idt *idts = NULL;
155	int i;
156
157	/*
158	 * Copy IDT stub code for each interrupt. This might seem wasteful
159	 * but it is really simple
160	 */
161	 for (i = 0; i < 256; i++) {
162		idts[i].cs = 0;
163		idts[i].offset = 0x1000 + (i * __idt_handler_size);
164		write_idt_stub((void *)((ulong)idts[i].offset), i);
165	}
166
167	/*
168	 * Many option ROMs use the hard coded interrupt entry points in the
169	 * system bios. So install them at the known locations.
170	 */
171
172	/* int42 is the relocated int10 */
173	write_idt_stub((void *)0xff065, 0x42);
174	/* BIOS Int 11 Handler F000:F84D */
175	write_idt_stub((void *)0xff84d, 0x11);
176	/* BIOS Int 12 Handler F000:F841 */
177	write_idt_stub((void *)0xff841, 0x12);
178	/* BIOS Int 13 Handler F000:EC59 */
179	write_idt_stub((void *)0xfec59, 0x13);
180	/* BIOS Int 14 Handler F000:E739 */
181	write_idt_stub((void *)0xfe739, 0x14);
182	/* BIOS Int 15 Handler F000:F859 */
183	write_idt_stub((void *)0xff859, 0x15);
184	/* BIOS Int 16 Handler F000:E82E */
185	write_idt_stub((void *)0xfe82e, 0x16);
186	/* BIOS Int 17 Handler F000:EFD2 */
187	write_idt_stub((void *)0xfefd2, 0x17);
188	/* ROM BIOS Int 1A Handler F000:FE6E */
189	write_idt_stub((void *)0xffe6e, 0x1a);
190}
191
192#ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE
193static u8 vbe_get_mode_info(struct vesa_state *mi)
194{
195	u16 buffer_seg;
196	u16 buffer_adr;
197	char *buffer;
198
199	debug("VBE: Getting information about VESA mode %04x\n",
200	      mi->video_mode);
201	buffer = PTR_TO_REAL_MODE(asm_realmode_buffer);
202	buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00;
203	buffer_adr = ((unsigned long)buffer) & 0xffff;
204
205	realmode_interrupt(0x10, VESA_GET_MODE_INFO, 0x0000, mi->video_mode,
206			   0x0000, buffer_seg, buffer_adr);
207	memcpy(mi->mode_info_block, buffer, sizeof(struct vesa_mode_info));
208	mi->valid = true;
209
210	return 0;
211}
212
213static u8 vbe_set_mode(struct vesa_state *mi)
214{
215	int video_mode = mi->video_mode;
216
217	debug("VBE: Setting VESA mode %#04x\n", video_mode);
218	/* request linear framebuffer mode */
219	video_mode |= (1 << 14);
220	/* don't clear the framebuffer, we do that later */
221	video_mode |= (1 << 15);
222	realmode_interrupt(0x10, VESA_SET_MODE, video_mode,
223			   0x0000, 0x0000, 0x0000, 0x0000);
224
225	return 0;
226}
227
228static void vbe_set_graphics(int vesa_mode, struct vesa_state *mode_info)
229{
230	unsigned char *framebuffer;
231
232	mode_info->video_mode = (1 << 14) | vesa_mode;
233	vbe_get_mode_info(mode_info);
234
235	framebuffer = (unsigned char *)(ulong)mode_info->vesa.phys_base_ptr;
236	debug("VBE: resolution:  %dx%d@%d\n",
237	      le16_to_cpu(mode_info->vesa.x_resolution),
238	      le16_to_cpu(mode_info->vesa.y_resolution),
239	      mode_info->vesa.bits_per_pixel);
240	debug("VBE: framebuffer: %p\n", framebuffer);
241	if (!framebuffer) {
242		debug("VBE: Mode does not support linear framebuffer\n");
243		return;
244	}
245
246	mode_info->video_mode &= 0x3ff;
247	vbe_set_mode(mode_info);
248}
249#endif /* CONFIG_FRAMEBUFFER_SET_VESA_MODE */
250
251void bios_run_on_x86(struct udevice *dev, unsigned long addr, int vesa_mode,
252		     struct vesa_state *mode_info)
253{
254	pci_dev_t pcidev = dm_pci_get_bdf(dev);
255	u32 num_dev;
256
257	num_dev = PCI_BUS(pcidev) << 8 | PCI_DEV(pcidev) << 3 |
258			PCI_FUNC(pcidev);
259
260	/* Needed to avoid exceptions in some ROMs */
261	interrupt_init();
262
263	/* Set up some legacy information in the F segment */
264	setup_rombios();
265
266	/* Set up C interrupt handlers */
267	setup_interrupt_handlers();
268
269	/* Set up real-mode IDT */
270	setup_realmode_idt();
271
272	/* Make sure the code is placed. */
273	setup_realmode_code();
274
275	debug("Calling Option ROM at %lx, pci device %#x...", addr, num_dev);
276
277	/* Option ROM entry point is at OPROM start + 3 */
278	realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0,
279		      0x0);
280	debug("done\n");
281
282#ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE
283	if (vesa_mode != -1)
284		vbe_set_graphics(vesa_mode, mode_info);
285#endif
286}
287
288asmlinkage int interrupt_handler(u32 intnumber, u32 gsfs, u32 dses,
289				 u32 edi, u32 esi, u32 ebp, u32 esp,
290				 u32 ebx, u32 edx, u32 ecx, u32 eax,
291				 u32 cs_ip, u16 stackflags)
292{
293	u32 ip;
294	u32 cs;
295	u32 flags;
296	int ret = 0;
297
298	ip = cs_ip & 0xffff;
299	cs = cs_ip >> 16;
300	flags = stackflags;
301
302#ifdef CONFIG_REALMODE_DEBUG
303	debug("oprom: INT# 0x%x\n", intnumber);
304	debug("oprom: eax: %08x ebx: %08x ecx: %08x edx: %08x\n",
305	      eax, ebx, ecx, edx);
306	debug("oprom: ebp: %08x esp: %08x edi: %08x esi: %08x\n",
307	      ebp, esp, edi, esi);
308	debug("oprom:  ip: %04x      cs: %04x   flags: %08x\n",
309	      ip, cs, flags);
310	debug("oprom: stackflags = %04x\n", stackflags);
311#endif
312
313	/*
314	 * Fetch arguments from the stack and put them to a place
315	 * suitable for the interrupt handlers
316	 */
317	M.x86.R_EAX = eax;
318	M.x86.R_ECX = ecx;
319	M.x86.R_EDX = edx;
320	M.x86.R_EBX = ebx;
321	M.x86.R_ESP = esp;
322	M.x86.R_EBP = ebp;
323	M.x86.R_ESI = esi;
324	M.x86.R_EDI = edi;
325	M.x86.intno = intnumber;
326	M.x86.R_EIP = ip;
327	M.x86.R_CS = cs;
328	M.x86.R_EFLG = flags;
329
330	/* Call the interrupt handler for this interrupt number */
331	ret = int_handler[intnumber]();
332
333	/*
334	 * This code is quite strange...
335	 *
336	 * Put registers back on the stack. The assembler code will pop them
337	 * later. We force (volatile!) changing the values of the parameters
338	 * of this function. We know that they stay alive on the stack after
339	 * we leave this function.
340	 */
341	*(volatile u32 *)&eax = M.x86.R_EAX;
342	*(volatile u32 *)&ecx = M.x86.R_ECX;
343	*(volatile u32 *)&edx = M.x86.R_EDX;
344	*(volatile u32 *)&ebx = M.x86.R_EBX;
345	*(volatile u32 *)&esi = M.x86.R_ESI;
346	*(volatile u32 *)&edi = M.x86.R_EDI;
347	flags = M.x86.R_EFLG;
348
349	/* Pass success or error back to our caller via the CARRY flag */
350	if (ret) {
351		flags &= ~1; /* no error: clear carry */
352	} else {
353		debug("int%02x call returned error\n", intnumber);
354		flags |= 1;  /* error: set carry */
355	}
356	*(volatile u16 *)&stackflags = flags;
357
358	return ret;
359}
360