x86: Constify a few items
[linux-3.10.git] / arch / x86 / kernel / early_printk.c
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/mrst.h>
18 #include <asm/pgtable.h>
19 #include <linux/usb/ehci_def.h>
20
21 /* Simple VGA output */
22 #define VGABASE         (__ISA_IO_base + 0xb8000)
23
24 static int max_ypos = 25, max_xpos = 80;
25 static int current_ypos = 25, current_xpos;
26
27 static void early_vga_write(struct console *con, const char *str, unsigned n)
28 {
29         char c;
30         int  i, k, j;
31
32         while ((c = *str++) != '\0' && n-- > 0) {
33                 if (current_ypos >= max_ypos) {
34                         /* scroll 1 line up */
35                         for (k = 1, j = 0; k < max_ypos; k++, j++) {
36                                 for (i = 0; i < max_xpos; i++) {
37                                         writew(readw(VGABASE+2*(max_xpos*k+i)),
38                                                VGABASE + 2*(max_xpos*j + i));
39                                 }
40                         }
41                         for (i = 0; i < max_xpos; i++)
42                                 writew(0x720, VGABASE + 2*(max_xpos*j + i));
43                         current_ypos = max_ypos-1;
44                 }
45 #ifdef CONFIG_KGDB_KDB
46                 if (c == '\b') {
47                         if (current_xpos > 0)
48                                 current_xpos--;
49                 } else if (c == '\r') {
50                         current_xpos = 0;
51                 } else
52 #endif
53                 if (c == '\n') {
54                         current_xpos = 0;
55                         current_ypos++;
56                 } else if (c != '\r')  {
57                         writew(((0x7 << 8) | (unsigned short) c),
58                                VGABASE + 2*(max_xpos*current_ypos +
59                                                 current_xpos++));
60                         if (current_xpos >= max_xpos) {
61                                 current_xpos = 0;
62                                 current_ypos++;
63                         }
64                 }
65         }
66 }
67
68 static struct console early_vga_console = {
69         .name =         "earlyvga",
70         .write =        early_vga_write,
71         .flags =        CON_PRINTBUFFER,
72         .index =        -1,
73 };
74
75 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
76
77 static int early_serial_base = 0x3f8;  /* ttyS0 */
78
79 #define XMTRDY          0x20
80
81 #define DLAB            0x80
82
83 #define TXR             0       /*  Transmit register (WRITE) */
84 #define RXR             0       /*  Receive register  (READ)  */
85 #define IER             1       /*  Interrupt Enable          */
86 #define IIR             2       /*  Interrupt ID              */
87 #define FCR             2       /*  FIFO control              */
88 #define LCR             3       /*  Line control              */
89 #define MCR             4       /*  Modem control             */
90 #define LSR             5       /*  Line Status               */
91 #define MSR             6       /*  Modem Status              */
92 #define DLL             0       /*  Divisor Latch Low         */
93 #define DLH             1       /*  Divisor latch High        */
94
95 static int early_serial_putc(unsigned char ch)
96 {
97         unsigned timeout = 0xffff;
98
99         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
100                 cpu_relax();
101         outb(ch, early_serial_base + TXR);
102         return timeout ? 0 : -1;
103 }
104
105 static void early_serial_write(struct console *con, const char *s, unsigned n)
106 {
107         while (*s && n-- > 0) {
108                 if (*s == '\n')
109                         early_serial_putc('\r');
110                 early_serial_putc(*s);
111                 s++;
112         }
113 }
114
115 #define DEFAULT_BAUD 9600
116
117 static __init void early_serial_init(char *s)
118 {
119         unsigned char c;
120         unsigned divisor;
121         unsigned baud = DEFAULT_BAUD;
122         char *e;
123
124         if (*s == ',')
125                 ++s;
126
127         if (*s) {
128                 unsigned port;
129                 if (!strncmp(s, "0x", 2)) {
130                         early_serial_base = simple_strtoul(s, &e, 16);
131                 } else {
132                         static const int __initconst bases[] = { 0x3f8, 0x2f8 };
133
134                         if (!strncmp(s, "ttyS", 4))
135                                 s += 4;
136                         port = simple_strtoul(s, &e, 10);
137                         if (port > 1 || s == e)
138                                 port = 0;
139                         early_serial_base = bases[port];
140                 }
141                 s += strcspn(s, ",");
142                 if (*s == ',')
143                         s++;
144         }
145
146         outb(0x3, early_serial_base + LCR);     /* 8n1 */
147         outb(0, early_serial_base + IER);       /* no interrupt */
148         outb(0, early_serial_base + FCR);       /* no fifo */
149         outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
150
151         if (*s) {
152                 baud = simple_strtoul(s, &e, 0);
153                 if (baud == 0 || s == e)
154                         baud = DEFAULT_BAUD;
155         }
156
157         divisor = 115200 / baud;
158         c = inb(early_serial_base + LCR);
159         outb(c | DLAB, early_serial_base + LCR);
160         outb(divisor & 0xff, early_serial_base + DLL);
161         outb((divisor >> 8) & 0xff, early_serial_base + DLH);
162         outb(c & ~DLAB, early_serial_base + LCR);
163 }
164
165 static struct console early_serial_console = {
166         .name =         "earlyser",
167         .write =        early_serial_write,
168         .flags =        CON_PRINTBUFFER,
169         .index =        -1,
170 };
171
172 /* Direct interface for emergencies */
173 static struct console *early_console = &early_vga_console;
174 static int __initdata early_console_initialized;
175
176 asmlinkage void early_printk(const char *fmt, ...)
177 {
178         char buf[512];
179         int n;
180         va_list ap;
181
182         va_start(ap, fmt);
183         n = vscnprintf(buf, sizeof(buf), fmt, ap);
184         early_console->write(early_console, buf, n);
185         va_end(ap);
186 }
187
188 static inline void early_console_register(struct console *con, int keep_early)
189 {
190         if (early_console->index != -1) {
191                 printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
192                        con->name);
193                 return;
194         }
195         early_console = con;
196         if (keep_early)
197                 early_console->flags &= ~CON_BOOT;
198         else
199                 early_console->flags |= CON_BOOT;
200         register_console(early_console);
201 }
202
203 static int __init setup_early_printk(char *buf)
204 {
205         int keep;
206
207         if (!buf)
208                 return 0;
209
210         if (early_console_initialized)
211                 return 0;
212         early_console_initialized = 1;
213
214         keep = (strstr(buf, "keep") != NULL);
215
216         while (*buf != '\0') {
217                 if (!strncmp(buf, "serial", 6)) {
218                         buf += 6;
219                         early_serial_init(buf);
220                         early_console_register(&early_serial_console, keep);
221                         if (!strncmp(buf, ",ttyS", 5))
222                                 buf += 5;
223                 }
224                 if (!strncmp(buf, "ttyS", 4)) {
225                         early_serial_init(buf + 4);
226                         early_console_register(&early_serial_console, keep);
227                 }
228                 if (!strncmp(buf, "vga", 3) &&
229                     boot_params.screen_info.orig_video_isVGA == 1) {
230                         max_xpos = boot_params.screen_info.orig_video_cols;
231                         max_ypos = boot_params.screen_info.orig_video_lines;
232                         current_ypos = boot_params.screen_info.orig_y;
233                         early_console_register(&early_vga_console, keep);
234                 }
235 #ifdef CONFIG_EARLY_PRINTK_DBGP
236                 if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
237                         early_console_register(&early_dbgp_console, keep);
238 #endif
239 #ifdef CONFIG_HVC_XEN
240                 if (!strncmp(buf, "xen", 3))
241                         early_console_register(&xenboot_console, keep);
242 #endif
243 #ifdef CONFIG_EARLY_PRINTK_INTEL_MID
244                 if (!strncmp(buf, "mrst", 4)) {
245                         mrst_early_console_init();
246                         early_console_register(&early_mrst_console, keep);
247                 }
248
249                 if (!strncmp(buf, "hsu", 3)) {
250                         hsu_early_console_init(buf + 3);
251                         early_console_register(&early_hsu_console, keep);
252                 }
253 #endif
254                 buf++;
255         }
256         return 0;
257 }
258
259 early_param("earlyprintk", setup_early_printk);