xref: /openbmc/linux/arch/x86/kernel/early_printk.c (revision 79f08d9e)
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 
23 /* Simple VGA output */
24 #define VGABASE		(__ISA_IO_base + 0xb8000)
25 
26 static int max_ypos = 25, max_xpos = 80;
27 static int current_ypos = 25, current_xpos;
28 
29 static void early_vga_write(struct console *con, const char *str, unsigned n)
30 {
31 	char c;
32 	int  i, k, j;
33 
34 	while ((c = *str++) != '\0' && n-- > 0) {
35 		if (current_ypos >= max_ypos) {
36 			/* scroll 1 line up */
37 			for (k = 1, j = 0; k < max_ypos; k++, j++) {
38 				for (i = 0; i < max_xpos; i++) {
39 					writew(readw(VGABASE+2*(max_xpos*k+i)),
40 					       VGABASE + 2*(max_xpos*j + i));
41 				}
42 			}
43 			for (i = 0; i < max_xpos; i++)
44 				writew(0x720, VGABASE + 2*(max_xpos*j + i));
45 			current_ypos = max_ypos-1;
46 		}
47 #ifdef CONFIG_KGDB_KDB
48 		if (c == '\b') {
49 			if (current_xpos > 0)
50 				current_xpos--;
51 		} else if (c == '\r') {
52 			current_xpos = 0;
53 		} else
54 #endif
55 		if (c == '\n') {
56 			current_xpos = 0;
57 			current_ypos++;
58 		} else if (c != '\r')  {
59 			writew(((0x7 << 8) | (unsigned short) c),
60 			       VGABASE + 2*(max_xpos*current_ypos +
61 						current_xpos++));
62 			if (current_xpos >= max_xpos) {
63 				current_xpos = 0;
64 				current_ypos++;
65 			}
66 		}
67 	}
68 }
69 
70 static struct console early_vga_console = {
71 	.name =		"earlyvga",
72 	.write =	early_vga_write,
73 	.flags =	CON_PRINTBUFFER,
74 	.index =	-1,
75 };
76 
77 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
78 
79 static int early_serial_base = 0x3f8;  /* ttyS0 */
80 
81 #define XMTRDY          0x20
82 
83 #define DLAB		0x80
84 
85 #define TXR             0       /*  Transmit register (WRITE) */
86 #define RXR             0       /*  Receive register  (READ)  */
87 #define IER             1       /*  Interrupt Enable          */
88 #define IIR             2       /*  Interrupt ID              */
89 #define FCR             2       /*  FIFO control              */
90 #define LCR             3       /*  Line control              */
91 #define MCR             4       /*  Modem control             */
92 #define LSR             5       /*  Line Status               */
93 #define MSR             6       /*  Modem Status              */
94 #define DLL             0       /*  Divisor Latch Low         */
95 #define DLH             1       /*  Divisor latch High        */
96 
97 static int early_serial_putc(unsigned char ch)
98 {
99 	unsigned timeout = 0xffff;
100 
101 	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
102 		cpu_relax();
103 	outb(ch, early_serial_base + TXR);
104 	return timeout ? 0 : -1;
105 }
106 
107 static void early_serial_write(struct console *con, const char *s, unsigned n)
108 {
109 	while (*s && n-- > 0) {
110 		if (*s == '\n')
111 			early_serial_putc('\r');
112 		early_serial_putc(*s);
113 		s++;
114 	}
115 }
116 
117 #define DEFAULT_BAUD 9600
118 
119 static __init void early_serial_init(char *s)
120 {
121 	unsigned char c;
122 	unsigned divisor;
123 	unsigned baud = DEFAULT_BAUD;
124 	char *e;
125 
126 	if (*s == ',')
127 		++s;
128 
129 	if (*s) {
130 		unsigned port;
131 		if (!strncmp(s, "0x", 2)) {
132 			early_serial_base = simple_strtoul(s, &e, 16);
133 		} else {
134 			static const int __initconst bases[] = { 0x3f8, 0x2f8 };
135 
136 			if (!strncmp(s, "ttyS", 4))
137 				s += 4;
138 			port = simple_strtoul(s, &e, 10);
139 			if (port > 1 || s == e)
140 				port = 0;
141 			early_serial_base = bases[port];
142 		}
143 		s += strcspn(s, ",");
144 		if (*s == ',')
145 			s++;
146 	}
147 
148 	outb(0x3, early_serial_base + LCR);	/* 8n1 */
149 	outb(0, early_serial_base + IER);	/* no interrupt */
150 	outb(0, early_serial_base + FCR);	/* no fifo */
151 	outb(0x3, early_serial_base + MCR);	/* DTR + RTS */
152 
153 	if (*s) {
154 		baud = simple_strtoul(s, &e, 0);
155 		if (baud == 0 || s == e)
156 			baud = DEFAULT_BAUD;
157 	}
158 
159 	divisor = 115200 / baud;
160 	c = inb(early_serial_base + LCR);
161 	outb(c | DLAB, early_serial_base + LCR);
162 	outb(divisor & 0xff, early_serial_base + DLL);
163 	outb((divisor >> 8) & 0xff, early_serial_base + DLH);
164 	outb(c & ~DLAB, early_serial_base + LCR);
165 }
166 
167 static struct console early_serial_console = {
168 	.name =		"earlyser",
169 	.write =	early_serial_write,
170 	.flags =	CON_PRINTBUFFER,
171 	.index =	-1,
172 };
173 
174 static inline void early_console_register(struct console *con, int keep_early)
175 {
176 	if (con->index != -1) {
177 		printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
178 		       con->name);
179 		return;
180 	}
181 	early_console = con;
182 	if (keep_early)
183 		early_console->flags &= ~CON_BOOT;
184 	else
185 		early_console->flags |= CON_BOOT;
186 	register_console(early_console);
187 }
188 
189 static int __init setup_early_printk(char *buf)
190 {
191 	int keep;
192 
193 	if (!buf)
194 		return 0;
195 
196 	if (early_console)
197 		return 0;
198 
199 	keep = (strstr(buf, "keep") != NULL);
200 
201 	while (*buf != '\0') {
202 		if (!strncmp(buf, "serial", 6)) {
203 			buf += 6;
204 			early_serial_init(buf);
205 			early_console_register(&early_serial_console, keep);
206 			if (!strncmp(buf, ",ttyS", 5))
207 				buf += 5;
208 		}
209 		if (!strncmp(buf, "ttyS", 4)) {
210 			early_serial_init(buf + 4);
211 			early_console_register(&early_serial_console, keep);
212 		}
213 		if (!strncmp(buf, "vga", 3) &&
214 		    boot_params.screen_info.orig_video_isVGA == 1) {
215 			max_xpos = boot_params.screen_info.orig_video_cols;
216 			max_ypos = boot_params.screen_info.orig_video_lines;
217 			current_ypos = boot_params.screen_info.orig_y;
218 			early_console_register(&early_vga_console, keep);
219 		}
220 #ifdef CONFIG_EARLY_PRINTK_DBGP
221 		if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
222 			early_console_register(&early_dbgp_console, keep);
223 #endif
224 #ifdef CONFIG_HVC_XEN
225 		if (!strncmp(buf, "xen", 3))
226 			early_console_register(&xenboot_console, keep);
227 #endif
228 #ifdef CONFIG_EARLY_PRINTK_INTEL_MID
229 		if (!strncmp(buf, "mrst", 4)) {
230 			mrst_early_console_init();
231 			early_console_register(&early_mrst_console, keep);
232 		}
233 
234 		if (!strncmp(buf, "hsu", 3)) {
235 			hsu_early_console_init(buf + 3);
236 			early_console_register(&early_hsu_console, keep);
237 		}
238 #endif
239 #ifdef CONFIG_EARLY_PRINTK_EFI
240 		if (!strncmp(buf, "efi", 3))
241 			early_console_register(&early_efi_console, keep);
242 #endif
243 
244 		buf++;
245 	}
246 	return 0;
247 }
248 
249 early_param("earlyprintk", setup_early_printk);
250