summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/early_printk.c
blob: 93fbdff2974f9194766429d83830cf24d62751ad (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
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
// SPDX-License-Identifier: GPL-2.0
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/screen_info.h>
#include <linux/usb/ch9.h>
#include <linux/pci_regs.h>
#include <linux/pci_ids.h>
#include <linux/errno.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/fcntl.h>
#include <asm/setup.h>
#include <xen/hvc-console.h>
#include <asm/pci-direct.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
#include <linux/usb/ehci_def.h>
#include <linux/usb/xhci-dbgp.h>
#include <asm/pci_x86.h>

/* Simple VGA output */
#define VGABASE		(__ISA_IO_base + 0xb8000)

static int max_ypos = 25, max_xpos = 80;
static int current_ypos = 25, current_xpos;

static void early_vga_write(struct console *con, const char *str, unsigned n)
{
	char c;
	int  i, k, j;

	while ((c = *str++) != '\0' && n-- > 0) {
		if (current_ypos >= max_ypos) {
			/* scroll 1 line up */
			for (k = 1, j = 0; k < max_ypos; k++, j++) {
				for (i = 0; i < max_xpos; i++) {
					writew(readw(VGABASE+2*(max_xpos*k+i)),
					       VGABASE + 2*(max_xpos*j + i));
				}
			}
			for (i = 0; i < max_xpos; i++)
				writew(0x720, VGABASE + 2*(max_xpos*j + i));
			current_ypos = max_ypos-1;
		}
#ifdef CONFIG_KGDB_KDB
		if (c == '\b') {
			if (current_xpos > 0)
				current_xpos--;
		} else if (c == '\r') {
			current_xpos = 0;
		} else
#endif
		if (c == '\n') {
			current_xpos = 0;
			current_ypos++;
		} else if (c != '\r')  {
			writew(((0x7 << 8) | (unsigned short) c),
			       VGABASE + 2*(max_xpos*current_ypos +
						current_xpos++));
			if (current_xpos >= max_xpos) {
				current_xpos = 0;
				current_ypos++;
			}
		}
	}
}

static struct console early_vga_console = {
	.name =		"earlyvga",
	.write =	early_vga_write,
	.flags =	CON_PRINTBUFFER,
	.index =	-1,
};

/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */

static unsigned long early_serial_base = 0x3f8;  /* ttyS0 */

#define XMTRDY          0x20

#define DLAB		0x80

#define TXR             0       /*  Transmit register (WRITE) */
#define RXR             0       /*  Receive register  (READ)  */
#define IER             1       /*  Interrupt Enable          */
#define IIR             2       /*  Interrupt ID              */
#define FCR             2       /*  FIFO control              */
#define LCR             3       /*  Line control              */
#define MCR             4       /*  Modem control             */
#define LSR             5       /*  Line Status               */
#define MSR             6       /*  Modem Status              */
#define DLL             0       /*  Divisor Latch Low         */
#define DLH             1       /*  Divisor latch High        */

static unsigned int io_serial_in(unsigned long addr, int offset)
{
	return inb(addr + offset);
}

static void io_serial_out(unsigned long addr, int offset, int value)
{
	outb(value, addr + offset);
}

static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;

static int early_serial_putc(unsigned char ch)
{
	unsigned timeout = 0xffff;

	while ((serial_in(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
		cpu_relax();
	serial_out(early_serial_base, TXR, ch);
	return timeout ? 0 : -1;
}

static void early_serial_write(struct console *con, const char *s, unsigned n)
{
	while (*s && n-- > 0) {
		if (*s == '\n')
			early_serial_putc('\r');
		early_serial_putc(*s);
		s++;
	}
}

static __init void early_serial_hw_init(unsigned divisor)
{
	unsigned char c;

	serial_out(early_serial_base, LCR, 0x3);	/* 8n1 */
	serial_out(early_serial_base, IER, 0);	/* no interrupt */
	serial_out(early_serial_base, FCR, 0);	/* no fifo */
	serial_out(early_serial_base, MCR, 0x3);	/* DTR + RTS */

	c = serial_in(early_serial_base, LCR);
	serial_out(early_serial_base, LCR, c | DLAB);
	serial_out(early_serial_base, DLL, divisor & 0xff);
	serial_out(early_serial_base, DLH, (divisor >> 8) & 0xff);
	serial_out(early_serial_base, LCR, c & ~DLAB);
}

#define DEFAULT_BAUD 9600

static __init void early_serial_init(char *s)
{
	unsigned divisor;
	unsigned long baud = DEFAULT_BAUD;
	char *e;

	if (*s == ',')
		++s;

	if (*s) {
		unsigned port;
		if (!strncmp(s, "0x", 2)) {
			early_serial_base = simple_strtoul(s, &e, 16);
		} else {
			static const int __initconst bases[] = { 0x3f8, 0x2f8 };

			if (!strncmp(s, "ttyS", 4))
				s += 4;
			port = simple_strtoul(s, &e, 10);
			if (port > 1 || s == e)
				port = 0;
			early_serial_base = bases[port];
		}
		s += strcspn(s, ",");
		if (*s == ',')
			s++;
	}

	if (*s) {
		baud = simple_strtoull(s, &e, 0);

		if (baud == 0 || s == e)
			baud = DEFAULT_BAUD;
	}

	/* Convert from baud to divisor value */
	divisor = 115200 / baud;

	/* These will always be IO based ports */
	serial_in = io_serial_in;
	serial_out = io_serial_out;

	/* Set up the HW */
	early_serial_hw_init(divisor);
}

#ifdef CONFIG_PCI
static void mem32_serial_out(unsigned long addr, int offset, int value)
{
	u32 __iomem *vaddr = (u32 __iomem *)addr;
	/* shift implied by pointer type */
	writel(value, vaddr + offset);
}

static unsigned int mem32_serial_in(unsigned long addr, int offset)
{
	u32 __iomem *vaddr = (u32 __iomem *)addr;
	/* shift implied by pointer type */
	return readl(vaddr + offset);
}

/*
 * early_pci_serial_init()
 *
 * This function is invoked when the early_printk param starts with "pciserial"
 * The rest of the param should be "[force],B:D.F,baud", where B, D & F describe
 * the location of a PCI device that must be a UART device. "force" is optional
 * and overrides the use of an UART device with a wrong PCI class code.
 */
static __init void early_pci_serial_init(char *s)
{
	unsigned divisor;
	unsigned long baud = DEFAULT_BAUD;
	u8 bus, slot, func;
	u32 classcode, bar0;
	u16 cmdreg;
	char *e;
	int force = 0;

	if (*s == ',')
		++s;

	if (*s == 0)
		return;

	/* Force the use of an UART device with wrong class code */
	if (!strncmp(s, "force,", 6)) {
		force = 1;
		s += 6;
	}

	/*
	 * Part the param to get the BDF values
	 */
	bus = (u8)simple_strtoul(s, &e, 16);
	s = e;
	if (*s != ':')
		return;
	++s;
	slot = (u8)simple_strtoul(s, &e, 16);
	s = e;
	if (*s != '.')
		return;
	++s;
	func = (u8)simple_strtoul(s, &e, 16);
	s = e;

	/* A baud might be following */
	if (*s == ',')
		s++;

	/*
	 * Find the device from the BDF
	 */
	cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
	classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
	bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);

	/*
	 * Verify it is a UART type device
	 */
	if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
	     (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
	   (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */ {
		if (!force)
			return;
	}

	/*
	 * Determine if it is IO or memory mapped
	 */
	if (bar0 & 0x01) {
		/* it is IO mapped */
		serial_in = io_serial_in;
		serial_out = io_serial_out;
		early_serial_base = bar0&0xfffffffc;
		write_pci_config(bus, slot, func, PCI_COMMAND,
						cmdreg|PCI_COMMAND_IO);
	} else {
		/* It is memory mapped - assume 32-bit alignment */
		serial_in = mem32_serial_in;
		serial_out = mem32_serial_out;
		/* WARNING! assuming the address is always in the first 4G */
		early_serial_base =
			(unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
		write_pci_config(bus, slot, func, PCI_COMMAND,
						cmdreg|PCI_COMMAND_MEMORY);
	}

	/*
	 * Initialize the hardware
	 */
	if (*s) {
		if (strcmp(s, "nocfg") == 0)
			/* Sometimes, we want to leave the UART alone
			 * and assume the BIOS has set it up correctly.
			 * "nocfg" tells us this is the case, and we
			 * should do no more setup.
			 */
			return;
		if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
			baud = DEFAULT_BAUD;
	}

	/* Convert from baud to divisor value */
	divisor = 115200 / baud;

	/* Set up the HW */
	early_serial_hw_init(divisor);
}
#endif

static struct console early_serial_console = {
	.name =		"earlyser",
	.write =	early_serial_write,
	.flags =	CON_PRINTBUFFER,
	.index =	-1,
};

static void early_console_register(struct console *con, int keep_early)
{
	if (con->index != -1) {
		printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
		       con->name);
		return;
	}
	early_console = con;
	if (keep_early)
		early_console->flags &= ~CON_BOOT;
	else
		early_console->flags |= CON_BOOT;
	register_console(early_console);
}

static int __init setup_early_printk(char *buf)
{
	int keep;

	if (!buf)
		return 0;

	if (early_console)
		return 0;

	keep = (strstr(buf, "keep") != NULL);

	while (*buf != '\0') {
		if (!strncmp(buf, "serial", 6)) {
			buf += 6;
			early_serial_init(buf);
			early_console_register(&early_serial_console, keep);
			if (!strncmp(buf, ",ttyS", 5))
				buf += 5;
		}
		if (!strncmp(buf, "ttyS", 4)) {
			early_serial_init(buf + 4);
			early_console_register(&early_serial_console, keep);
		}
#ifdef CONFIG_PCI
		if (!strncmp(buf, "pciserial", 9)) {
			early_pci_serial_init(buf + 9);
			early_console_register(&early_serial_console, keep);
			buf += 9; /* Keep from match the above "serial" */
		}
#endif
		if (!strncmp(buf, "vga", 3) &&
		    boot_params.screen_info.orig_video_isVGA == 1) {
			max_xpos = boot_params.screen_info.orig_video_cols;
			max_ypos = boot_params.screen_info.orig_video_lines;
			current_ypos = boot_params.screen_info.orig_y;
			early_console_register(&early_vga_console, keep);
		}
#ifdef CONFIG_EARLY_PRINTK_DBGP
		if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
			early_console_register(&early_dbgp_console, keep);
#endif
#ifdef CONFIG_HVC_XEN
		if (!strncmp(buf, "xen", 3))
			early_console_register(&xenboot_console, keep);
#endif
#ifdef CONFIG_EARLY_PRINTK_USB_XDBC
		if (!strncmp(buf, "xdbc", 4))
			early_xdbc_parse_parameter(buf + 4);
#endif

		buf++;
	}
	return 0;
}

early_param("earlyprintk", setup_early_printk);