xref: /linux/arch/x86/kernel/early_printk.c (revision a8b70ccf10e38775785d9cb12ead916474549f99)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/console.h>
3 #include <linux/kernel.h>
4 #include <linux/init.h>
5 #include <linux/string.h>
6 #include <linux/screen_info.h>
7 #include <linux/usb/ch9.h>
8 #include <linux/pci_regs.h>
9 #include <linux/pci_ids.h>
10 #include <linux/errno.h>
11 #include <asm/io.h>
12 #include <asm/processor.h>
13 #include <asm/fcntl.h>
14 #include <asm/setup.h>
15 #include <xen/hvc-console.h>
16 #include <asm/pci-direct.h>
17 #include <asm/fixmap.h>
18 #include <asm/intel-mid.h>
19 #include <asm/pgtable.h>
20 #include <linux/usb/ehci_def.h>
21 #include <linux/usb/xhci-dbgp.h>
22 #include <linux/efi.h>
23 #include <asm/efi.h>
24 #include <asm/pci_x86.h>
25 
26 /* Simple VGA output */
27 #define VGABASE		(__ISA_IO_base + 0xb8000)
28 
29 static int max_ypos = 25, max_xpos = 80;
30 static int current_ypos = 25, current_xpos;
31 
32 static void early_vga_write(struct console *con, const char *str, unsigned n)
33 {
34 	char c;
35 	int  i, k, j;
36 
37 	while ((c = *str++) != '\0' && n-- > 0) {
38 		if (current_ypos >= max_ypos) {
39 			/* scroll 1 line up */
40 			for (k = 1, j = 0; k < max_ypos; k++, j++) {
41 				for (i = 0; i < max_xpos; i++) {
42 					writew(readw(VGABASE+2*(max_xpos*k+i)),
43 					       VGABASE + 2*(max_xpos*j + i));
44 				}
45 			}
46 			for (i = 0; i < max_xpos; i++)
47 				writew(0x720, VGABASE + 2*(max_xpos*j + i));
48 			current_ypos = max_ypos-1;
49 		}
50 #ifdef CONFIG_KGDB_KDB
51 		if (c == '\b') {
52 			if (current_xpos > 0)
53 				current_xpos--;
54 		} else if (c == '\r') {
55 			current_xpos = 0;
56 		} else
57 #endif
58 		if (c == '\n') {
59 			current_xpos = 0;
60 			current_ypos++;
61 		} else if (c != '\r')  {
62 			writew(((0x7 << 8) | (unsigned short) c),
63 			       VGABASE + 2*(max_xpos*current_ypos +
64 						current_xpos++));
65 			if (current_xpos >= max_xpos) {
66 				current_xpos = 0;
67 				current_ypos++;
68 			}
69 		}
70 	}
71 }
72 
73 static struct console early_vga_console = {
74 	.name =		"earlyvga",
75 	.write =	early_vga_write,
76 	.flags =	CON_PRINTBUFFER,
77 	.index =	-1,
78 };
79 
80 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
81 
82 static unsigned long early_serial_base = 0x3f8;  /* ttyS0 */
83 
84 #define XMTRDY          0x20
85 
86 #define DLAB		0x80
87 
88 #define TXR             0       /*  Transmit register (WRITE) */
89 #define RXR             0       /*  Receive register  (READ)  */
90 #define IER             1       /*  Interrupt Enable          */
91 #define IIR             2       /*  Interrupt ID              */
92 #define FCR             2       /*  FIFO control              */
93 #define LCR             3       /*  Line control              */
94 #define MCR             4       /*  Modem control             */
95 #define LSR             5       /*  Line Status               */
96 #define MSR             6       /*  Modem Status              */
97 #define DLL             0       /*  Divisor Latch Low         */
98 #define DLH             1       /*  Divisor latch High        */
99 
100 static unsigned int io_serial_in(unsigned long addr, int offset)
101 {
102 	return inb(addr + offset);
103 }
104 
105 static void io_serial_out(unsigned long addr, int offset, int value)
106 {
107 	outb(value, addr + offset);
108 }
109 
110 static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
111 static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;
112 
113 static int early_serial_putc(unsigned char ch)
114 {
115 	unsigned timeout = 0xffff;
116 
117 	while ((serial_in(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
118 		cpu_relax();
119 	serial_out(early_serial_base, TXR, ch);
120 	return timeout ? 0 : -1;
121 }
122 
123 static void early_serial_write(struct console *con, const char *s, unsigned n)
124 {
125 	while (*s && n-- > 0) {
126 		if (*s == '\n')
127 			early_serial_putc('\r');
128 		early_serial_putc(*s);
129 		s++;
130 	}
131 }
132 
133 static __init void early_serial_hw_init(unsigned divisor)
134 {
135 	unsigned char c;
136 
137 	serial_out(early_serial_base, LCR, 0x3);	/* 8n1 */
138 	serial_out(early_serial_base, IER, 0);	/* no interrupt */
139 	serial_out(early_serial_base, FCR, 0);	/* no fifo */
140 	serial_out(early_serial_base, MCR, 0x3);	/* DTR + RTS */
141 
142 	c = serial_in(early_serial_base, LCR);
143 	serial_out(early_serial_base, LCR, c | DLAB);
144 	serial_out(early_serial_base, DLL, divisor & 0xff);
145 	serial_out(early_serial_base, DLH, (divisor >> 8) & 0xff);
146 	serial_out(early_serial_base, LCR, c & ~DLAB);
147 }
148 
149 #define DEFAULT_BAUD 9600
150 
151 static __init void early_serial_init(char *s)
152 {
153 	unsigned divisor;
154 	unsigned long baud = DEFAULT_BAUD;
155 	char *e;
156 
157 	if (*s == ',')
158 		++s;
159 
160 	if (*s) {
161 		unsigned port;
162 		if (!strncmp(s, "0x", 2)) {
163 			early_serial_base = simple_strtoul(s, &e, 16);
164 		} else {
165 			static const int __initconst bases[] = { 0x3f8, 0x2f8 };
166 
167 			if (!strncmp(s, "ttyS", 4))
168 				s += 4;
169 			port = simple_strtoul(s, &e, 10);
170 			if (port > 1 || s == e)
171 				port = 0;
172 			early_serial_base = bases[port];
173 		}
174 		s += strcspn(s, ",");
175 		if (*s == ',')
176 			s++;
177 	}
178 
179 	if (*s) {
180 		baud = simple_strtoull(s, &e, 0);
181 
182 		if (baud == 0 || s == e)
183 			baud = DEFAULT_BAUD;
184 	}
185 
186 	/* Convert from baud to divisor value */
187 	divisor = 115200 / baud;
188 
189 	/* These will always be IO based ports */
190 	serial_in = io_serial_in;
191 	serial_out = io_serial_out;
192 
193 	/* Set up the HW */
194 	early_serial_hw_init(divisor);
195 }
196 
197 #ifdef CONFIG_PCI
198 static void mem32_serial_out(unsigned long addr, int offset, int value)
199 {
200 	u32 __iomem *vaddr = (u32 __iomem *)addr;
201 	/* shift implied by pointer type */
202 	writel(value, vaddr + offset);
203 }
204 
205 static unsigned int mem32_serial_in(unsigned long addr, int offset)
206 {
207 	u32 __iomem *vaddr = (u32 __iomem *)addr;
208 	/* shift implied by pointer type */
209 	return readl(vaddr + offset);
210 }
211 
212 /*
213  * early_pci_serial_init()
214  *
215  * This function is invoked when the early_printk param starts with "pciserial"
216  * The rest of the param should be ",B:D.F,baud" where B, D & F describe the
217  * location of a PCI device that must be a UART device.
218  */
219 static __init void early_pci_serial_init(char *s)
220 {
221 	unsigned divisor;
222 	unsigned long baud = DEFAULT_BAUD;
223 	u8 bus, slot, func;
224 	u32 classcode, bar0;
225 	u16 cmdreg;
226 	char *e;
227 
228 
229 	/*
230 	 * First, part the param to get the BDF values
231 	 */
232 	if (*s == ',')
233 		++s;
234 
235 	if (*s == 0)
236 		return;
237 
238 	bus = (u8)simple_strtoul(s, &e, 16);
239 	s = e;
240 	if (*s != ':')
241 		return;
242 	++s;
243 	slot = (u8)simple_strtoul(s, &e, 16);
244 	s = e;
245 	if (*s != '.')
246 		return;
247 	++s;
248 	func = (u8)simple_strtoul(s, &e, 16);
249 	s = e;
250 
251 	/* A baud might be following */
252 	if (*s == ',')
253 		s++;
254 
255 	/*
256 	 * Second, find the device from the BDF
257 	 */
258 	cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
259 	classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
260 	bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
261 
262 	/*
263 	 * Verify it is a UART type device
264 	 */
265 	if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
266 	     (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
267 	   (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */
268 		return;
269 
270 	/*
271 	 * Determine if it is IO or memory mapped
272 	 */
273 	if (bar0 & 0x01) {
274 		/* it is IO mapped */
275 		serial_in = io_serial_in;
276 		serial_out = io_serial_out;
277 		early_serial_base = bar0&0xfffffffc;
278 		write_pci_config(bus, slot, func, PCI_COMMAND,
279 						cmdreg|PCI_COMMAND_IO);
280 	} else {
281 		/* It is memory mapped - assume 32-bit alignment */
282 		serial_in = mem32_serial_in;
283 		serial_out = mem32_serial_out;
284 		/* WARNING! assuming the address is always in the first 4G */
285 		early_serial_base =
286 			(unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
287 		write_pci_config(bus, slot, func, PCI_COMMAND,
288 						cmdreg|PCI_COMMAND_MEMORY);
289 	}
290 
291 	/*
292 	 * Lastly, initialize the hardware
293 	 */
294 	if (*s) {
295 		if (strcmp(s, "nocfg") == 0)
296 			/* Sometimes, we want to leave the UART alone
297 			 * and assume the BIOS has set it up correctly.
298 			 * "nocfg" tells us this is the case, and we
299 			 * should do no more setup.
300 			 */
301 			return;
302 		if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
303 			baud = DEFAULT_BAUD;
304 	}
305 
306 	/* Convert from baud to divisor value */
307 	divisor = 115200 / baud;
308 
309 	/* Set up the HW */
310 	early_serial_hw_init(divisor);
311 }
312 #endif
313 
314 static struct console early_serial_console = {
315 	.name =		"earlyser",
316 	.write =	early_serial_write,
317 	.flags =	CON_PRINTBUFFER,
318 	.index =	-1,
319 };
320 
321 static void early_console_register(struct console *con, int keep_early)
322 {
323 	if (con->index != -1) {
324 		printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
325 		       con->name);
326 		return;
327 	}
328 	early_console = con;
329 	if (keep_early)
330 		early_console->flags &= ~CON_BOOT;
331 	else
332 		early_console->flags |= CON_BOOT;
333 	register_console(early_console);
334 }
335 
336 static int __init setup_early_printk(char *buf)
337 {
338 	int keep;
339 
340 	if (!buf)
341 		return 0;
342 
343 	if (early_console)
344 		return 0;
345 
346 	keep = (strstr(buf, "keep") != NULL);
347 
348 	while (*buf != '\0') {
349 		if (!strncmp(buf, "serial", 6)) {
350 			buf += 6;
351 			early_serial_init(buf);
352 			early_console_register(&early_serial_console, keep);
353 			if (!strncmp(buf, ",ttyS", 5))
354 				buf += 5;
355 		}
356 		if (!strncmp(buf, "ttyS", 4)) {
357 			early_serial_init(buf + 4);
358 			early_console_register(&early_serial_console, keep);
359 		}
360 #ifdef CONFIG_PCI
361 		if (!strncmp(buf, "pciserial", 9)) {
362 			early_pci_serial_init(buf + 9);
363 			early_console_register(&early_serial_console, keep);
364 			buf += 9; /* Keep from match the above "serial" */
365 		}
366 #endif
367 		if (!strncmp(buf, "vga", 3) &&
368 		    boot_params.screen_info.orig_video_isVGA == 1) {
369 			max_xpos = boot_params.screen_info.orig_video_cols;
370 			max_ypos = boot_params.screen_info.orig_video_lines;
371 			current_ypos = boot_params.screen_info.orig_y;
372 			early_console_register(&early_vga_console, keep);
373 		}
374 #ifdef CONFIG_EARLY_PRINTK_DBGP
375 		if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
376 			early_console_register(&early_dbgp_console, keep);
377 #endif
378 #ifdef CONFIG_HVC_XEN
379 		if (!strncmp(buf, "xen", 3))
380 			early_console_register(&xenboot_console, keep);
381 #endif
382 #ifdef CONFIG_EARLY_PRINTK_EFI
383 		if (!strncmp(buf, "efi", 3))
384 			early_console_register(&early_efi_console, keep);
385 #endif
386 #ifdef CONFIG_EARLY_PRINTK_USB_XDBC
387 		if (!strncmp(buf, "xdbc", 4))
388 			early_xdbc_parse_parameter(buf + 4);
389 #endif
390 
391 		buf++;
392 	}
393 	return 0;
394 }
395 
396 early_param("earlyprintk", setup_early_printk);
397