xref: /openbmc/linux/arch/x86/kernel/early_printk.c (revision 8c749ce9)
1 #include <linux/console.h>
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/string.h>
5 #include <linux/screen_info.h>
6 #include <linux/usb/ch9.h>
7 #include <linux/pci_regs.h>
8 #include <linux/pci_ids.h>
9 #include <linux/errno.h>
10 #include <asm/io.h>
11 #include <asm/processor.h>
12 #include <asm/fcntl.h>
13 #include <asm/setup.h>
14 #include <xen/hvc-console.h>
15 #include <asm/pci-direct.h>
16 #include <asm/fixmap.h>
17 #include <asm/intel-mid.h>
18 #include <asm/pgtable.h>
19 #include <linux/usb/ehci_def.h>
20 #include <linux/efi.h>
21 #include <asm/efi.h>
22 #include <asm/pci_x86.h>
23 
24 /* Simple VGA output */
25 #define VGABASE		(__ISA_IO_base + 0xb8000)
26 
27 static int max_ypos = 25, max_xpos = 80;
28 static int current_ypos = 25, current_xpos;
29 
30 static void early_vga_write(struct console *con, const char *str, unsigned n)
31 {
32 	char c;
33 	int  i, k, j;
34 
35 	while ((c = *str++) != '\0' && n-- > 0) {
36 		if (current_ypos >= max_ypos) {
37 			/* scroll 1 line up */
38 			for (k = 1, j = 0; k < max_ypos; k++, j++) {
39 				for (i = 0; i < max_xpos; i++) {
40 					writew(readw(VGABASE+2*(max_xpos*k+i)),
41 					       VGABASE + 2*(max_xpos*j + i));
42 				}
43 			}
44 			for (i = 0; i < max_xpos; i++)
45 				writew(0x720, VGABASE + 2*(max_xpos*j + i));
46 			current_ypos = max_ypos-1;
47 		}
48 #ifdef CONFIG_KGDB_KDB
49 		if (c == '\b') {
50 			if (current_xpos > 0)
51 				current_xpos--;
52 		} else if (c == '\r') {
53 			current_xpos = 0;
54 		} else
55 #endif
56 		if (c == '\n') {
57 			current_xpos = 0;
58 			current_ypos++;
59 		} else if (c != '\r')  {
60 			writew(((0x7 << 8) | (unsigned short) c),
61 			       VGABASE + 2*(max_xpos*current_ypos +
62 						current_xpos++));
63 			if (current_xpos >= max_xpos) {
64 				current_xpos = 0;
65 				current_ypos++;
66 			}
67 		}
68 	}
69 }
70 
71 static struct console early_vga_console = {
72 	.name =		"earlyvga",
73 	.write =	early_vga_write,
74 	.flags =	CON_PRINTBUFFER,
75 	.index =	-1,
76 };
77 
78 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
79 
80 static unsigned long early_serial_base = 0x3f8;  /* ttyS0 */
81 
82 #define XMTRDY          0x20
83 
84 #define DLAB		0x80
85 
86 #define TXR             0       /*  Transmit register (WRITE) */
87 #define RXR             0       /*  Receive register  (READ)  */
88 #define IER             1       /*  Interrupt Enable          */
89 #define IIR             2       /*  Interrupt ID              */
90 #define FCR             2       /*  FIFO control              */
91 #define LCR             3       /*  Line control              */
92 #define MCR             4       /*  Modem control             */
93 #define LSR             5       /*  Line Status               */
94 #define MSR             6       /*  Modem Status              */
95 #define DLL             0       /*  Divisor Latch Low         */
96 #define DLH             1       /*  Divisor latch High        */
97 
98 static unsigned int io_serial_in(unsigned long addr, int offset)
99 {
100 	return inb(addr + offset);
101 }
102 
103 static void io_serial_out(unsigned long addr, int offset, int value)
104 {
105 	outb(value, addr + offset);
106 }
107 
108 static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
109 static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;
110 
111 static int early_serial_putc(unsigned char ch)
112 {
113 	unsigned timeout = 0xffff;
114 
115 	while ((serial_in(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
116 		cpu_relax();
117 	serial_out(early_serial_base, TXR, ch);
118 	return timeout ? 0 : -1;
119 }
120 
121 static void early_serial_write(struct console *con, const char *s, unsigned n)
122 {
123 	while (*s && n-- > 0) {
124 		if (*s == '\n')
125 			early_serial_putc('\r');
126 		early_serial_putc(*s);
127 		s++;
128 	}
129 }
130 
131 static __init void early_serial_hw_init(unsigned divisor)
132 {
133 	unsigned char c;
134 
135 	serial_out(early_serial_base, LCR, 0x3);	/* 8n1 */
136 	serial_out(early_serial_base, IER, 0);	/* no interrupt */
137 	serial_out(early_serial_base, FCR, 0);	/* no fifo */
138 	serial_out(early_serial_base, MCR, 0x3);	/* DTR + RTS */
139 
140 	c = serial_in(early_serial_base, LCR);
141 	serial_out(early_serial_base, LCR, c | DLAB);
142 	serial_out(early_serial_base, DLL, divisor & 0xff);
143 	serial_out(early_serial_base, DLH, (divisor >> 8) & 0xff);
144 	serial_out(early_serial_base, LCR, c & ~DLAB);
145 }
146 
147 #define DEFAULT_BAUD 9600
148 
149 static __init void early_serial_init(char *s)
150 {
151 	unsigned divisor;
152 	unsigned long baud = DEFAULT_BAUD;
153 	char *e;
154 
155 	if (*s == ',')
156 		++s;
157 
158 	if (*s) {
159 		unsigned port;
160 		if (!strncmp(s, "0x", 2)) {
161 			early_serial_base = simple_strtoul(s, &e, 16);
162 		} else {
163 			static const int __initconst bases[] = { 0x3f8, 0x2f8 };
164 
165 			if (!strncmp(s, "ttyS", 4))
166 				s += 4;
167 			port = simple_strtoul(s, &e, 10);
168 			if (port > 1 || s == e)
169 				port = 0;
170 			early_serial_base = bases[port];
171 		}
172 		s += strcspn(s, ",");
173 		if (*s == ',')
174 			s++;
175 	}
176 
177 	if (*s) {
178 		baud = simple_strtoull(s, &e, 0);
179 
180 		if (baud == 0 || s == e)
181 			baud = DEFAULT_BAUD;
182 	}
183 
184 	/* Convert from baud to divisor value */
185 	divisor = 115200 / baud;
186 
187 	/* These will always be IO based ports */
188 	serial_in = io_serial_in;
189 	serial_out = io_serial_out;
190 
191 	/* Set up the HW */
192 	early_serial_hw_init(divisor);
193 }
194 
195 #ifdef CONFIG_PCI
196 static void mem32_serial_out(unsigned long addr, int offset, int value)
197 {
198 	u32 __iomem *vaddr = (u32 __iomem *)addr;
199 	/* shift implied by pointer type */
200 	writel(value, vaddr + offset);
201 }
202 
203 static unsigned int mem32_serial_in(unsigned long addr, int offset)
204 {
205 	u32 __iomem *vaddr = (u32 __iomem *)addr;
206 	/* shift implied by pointer type */
207 	return readl(vaddr + offset);
208 }
209 
210 /*
211  * early_pci_serial_init()
212  *
213  * This function is invoked when the early_printk param starts with "pciserial"
214  * The rest of the param should be ",B:D.F,baud" where B, D & F describe the
215  * location of a PCI device that must be a UART device.
216  */
217 static __init void early_pci_serial_init(char *s)
218 {
219 	unsigned divisor;
220 	unsigned long baud = DEFAULT_BAUD;
221 	u8 bus, slot, func;
222 	u32 classcode, bar0;
223 	u16 cmdreg;
224 	char *e;
225 
226 
227 	/*
228 	 * First, part the param to get the BDF values
229 	 */
230 	if (*s == ',')
231 		++s;
232 
233 	if (*s == 0)
234 		return;
235 
236 	bus = (u8)simple_strtoul(s, &e, 16);
237 	s = e;
238 	if (*s != ':')
239 		return;
240 	++s;
241 	slot = (u8)simple_strtoul(s, &e, 16);
242 	s = e;
243 	if (*s != '.')
244 		return;
245 	++s;
246 	func = (u8)simple_strtoul(s, &e, 16);
247 	s = e;
248 
249 	/* A baud might be following */
250 	if (*s == ',')
251 		s++;
252 
253 	/*
254 	 * Second, find the device from the BDF
255 	 */
256 	cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
257 	classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
258 	bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
259 
260 	/*
261 	 * Verify it is a UART type device
262 	 */
263 	if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
264 	     (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
265 	   (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */
266 		return;
267 
268 	/*
269 	 * Determine if it is IO or memory mapped
270 	 */
271 	if (bar0 & 0x01) {
272 		/* it is IO mapped */
273 		serial_in = io_serial_in;
274 		serial_out = io_serial_out;
275 		early_serial_base = bar0&0xfffffffc;
276 		write_pci_config(bus, slot, func, PCI_COMMAND,
277 						cmdreg|PCI_COMMAND_IO);
278 	} else {
279 		/* It is memory mapped - assume 32-bit alignment */
280 		serial_in = mem32_serial_in;
281 		serial_out = mem32_serial_out;
282 		/* WARNING! assuming the address is always in the first 4G */
283 		early_serial_base =
284 			(unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
285 		write_pci_config(bus, slot, func, PCI_COMMAND,
286 						cmdreg|PCI_COMMAND_MEMORY);
287 	}
288 
289 	/*
290 	 * Lastly, initalize the hardware
291 	 */
292 	if (*s) {
293 		if (strcmp(s, "nocfg") == 0)
294 			/* Sometimes, we want to leave the UART alone
295 			 * and assume the BIOS has set it up correctly.
296 			 * "nocfg" tells us this is the case, and we
297 			 * should do no more setup.
298 			 */
299 			return;
300 		if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
301 			baud = DEFAULT_BAUD;
302 	}
303 
304 	/* Convert from baud to divisor value */
305 	divisor = 115200 / baud;
306 
307 	/* Set up the HW */
308 	early_serial_hw_init(divisor);
309 }
310 #endif
311 
312 static struct console early_serial_console = {
313 	.name =		"earlyser",
314 	.write =	early_serial_write,
315 	.flags =	CON_PRINTBUFFER,
316 	.index =	-1,
317 };
318 
319 static void early_console_register(struct console *con, int keep_early)
320 {
321 	if (con->index != -1) {
322 		printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
323 		       con->name);
324 		return;
325 	}
326 	early_console = con;
327 	if (keep_early)
328 		early_console->flags &= ~CON_BOOT;
329 	else
330 		early_console->flags |= CON_BOOT;
331 	register_console(early_console);
332 }
333 
334 static int __init setup_early_printk(char *buf)
335 {
336 	int keep;
337 
338 	if (!buf)
339 		return 0;
340 
341 	if (early_console)
342 		return 0;
343 
344 	keep = (strstr(buf, "keep") != NULL);
345 
346 	while (*buf != '\0') {
347 		if (!strncmp(buf, "serial", 6)) {
348 			buf += 6;
349 			early_serial_init(buf);
350 			early_console_register(&early_serial_console, keep);
351 			if (!strncmp(buf, ",ttyS", 5))
352 				buf += 5;
353 		}
354 		if (!strncmp(buf, "ttyS", 4)) {
355 			early_serial_init(buf + 4);
356 			early_console_register(&early_serial_console, keep);
357 		}
358 #ifdef CONFIG_PCI
359 		if (!strncmp(buf, "pciserial", 9)) {
360 			early_pci_serial_init(buf + 9);
361 			early_console_register(&early_serial_console, keep);
362 			buf += 9; /* Keep from match the above "serial" */
363 		}
364 #endif
365 		if (!strncmp(buf, "vga", 3) &&
366 		    boot_params.screen_info.orig_video_isVGA == 1) {
367 			max_xpos = boot_params.screen_info.orig_video_cols;
368 			max_ypos = boot_params.screen_info.orig_video_lines;
369 			current_ypos = boot_params.screen_info.orig_y;
370 			early_console_register(&early_vga_console, keep);
371 		}
372 #ifdef CONFIG_EARLY_PRINTK_DBGP
373 		if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
374 			early_console_register(&early_dbgp_console, keep);
375 #endif
376 #ifdef CONFIG_HVC_XEN
377 		if (!strncmp(buf, "xen", 3))
378 			early_console_register(&xenboot_console, keep);
379 #endif
380 #ifdef CONFIG_EARLY_PRINTK_EFI
381 		if (!strncmp(buf, "efi", 3))
382 			early_console_register(&early_efi_console, keep);
383 #endif
384 
385 		buf++;
386 	}
387 	return 0;
388 }
389 
390 early_param("earlyprintk", setup_early_printk);
391