1 /*
2 * xen console driver interface to hvc_console.c
3 *
4 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21 #include <linux/console.h>
22 #include <linux/delay.h>
23 #include <linux/err.h>
24 #include <linux/init.h>
25 #include <linux/types.h>
26
27 #include <asm/xen/hypervisor.h>
28 #include <xen/page.h>
29 #include <xen/events.h>
30 #include <xen/interface/io/console.h>
31 #include <xen/hvc-console.h>
32
33 #include "hvc_console.h"
34
35 #define HVC_COOKIE 0x58656e /* "Xen" in hex */
36
37 static struct hvc_struct *hvc;
38 static int xencons_irq;
39
40 /* ------------------------------------------------------------------ */
41
42 static unsigned long console_pfn = ~0ul;
43
44 static inline struct xencons_interface *xencons_interface(void)
45 {
46 if (console_pfn == ~0ul)
47 return mfn_to_virt(xen_start_info->console.domU.mfn);
48 else
49 return __va(console_pfn << PAGE_SHIFT);
50 }
51
52 static inline void notify_daemon(void)
53 {
54 /* Use evtchn: this is called early, before irq is set up. */
55 notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
56 }
57
58 static int __write_console(const char *data, int len)
59 {
60 struct xencons_interface *intf = xencons_interface();
61 XENCONS_RING_IDX cons, prod;
62 int sent = 0;
63
64 cons = intf->out_cons;
65 prod = intf->out_prod;
66 mb(); /* update queue values before going on */
67 BUG_ON((prod - cons) > sizeof(intf->out));
68
69 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
70 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
71
72 wmb(); /* write ring before updating pointer */
73 intf->out_prod = prod;
74
75 notify_daemon();
76 return sent;
77 }
78
79 static int write_console(uint32_t vtermno, const char *data, int len)
80 {
81 int ret = len;
82
83 /*
84 * Make sure the whole buffer is emitted, polling if
85 * necessary. We don't ever want to rely on the hvc daemon
86 * because the most interesting console output is when the
87 * kernel is crippled.
88 */
89 while (len) {
90 int sent = __write_console(data, len);
91
92 data += sent;
93 len -= sent;
94
95 if (unlikely(len))
96 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
97 }
98
99 return ret;
100 }
101
102 static int read_console(uint32_t vtermno, char *buf, int len)
103 {
104 struct xencons_interface *intf = xencons_interface();
105 XENCONS_RING_IDX cons, prod;
106 int recv = 0;
107
108 cons = intf->in_cons;
109 prod = intf->in_prod;
110 mb(); /* get pointers before reading ring */
111 BUG_ON((prod - cons) > sizeof(intf->in));
112
113 while (cons != prod && recv < len)
114 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
115
116 mb(); /* read ring before consuming */
117 intf->in_cons = cons;
118
119 notify_daemon();
120 return recv;
121 }
122
123 static struct hv_ops hvc_ops = {
124 .get_chars = read_console,
125 .put_chars = write_console,
126 .notifier_add = notifier_add_irq,
127 .notifier_del = notifier_del_irq,
128 .notifier_hangup = notifier_hangup_irq,
129 };
130
131 static int __init xen_init(void)
132 {
133 struct hvc_struct *hp;
134
135 if (!xen_pv_domain() ||
136 xen_initial_domain() ||
137 !xen_start_info->console.domU.evtchn)
138 return -ENODEV;
139
140 xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
141 if (xencons_irq < 0)
142 xencons_irq = 0; /* NO_IRQ */
143
144 hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
145 if (IS_ERR(hp))
146 return PTR_ERR(hp);
147
148 hvc = hp;
149
150 console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
151
152 return 0;
153 }
154
155 void xen_console_resume(void)
156 {
157 if (xencons_irq)
158 rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq);
159 }
160
161 static void __exit xen_fini(void)
162 {
163 if (hvc)
164 hvc_remove(hvc);
165 }
166
167 static int xen_cons_init(void)
168 {
169 if (!xen_pv_domain())
170 return 0;
171
172 hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
173 return 0;
174 }
175
176 module_init(xen_init);
177 module_exit(xen_fini);
178 console_initcall(xen_cons_init);
179
180 static void raw_console_write(const char *str, int len)
181 {
182 while(len > 0) {
183 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
184 if (rc <= 0)
185 break;
186
187 str += rc;
188 len -= rc;
189 }
190 }
191
192 #ifdef CONFIG_EARLY_PRINTK
193 static void xenboot_write_console(struct console *console, const char *string,
194 unsigned len)
195 {
196 unsigned int linelen, off = 0;
197 const char *pos;
198
199 raw_console_write(string, len);
200
201 write_console(0, "(early) ", 8);
202 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
203 linelen = pos-string+off;
204 if (off + linelen > len)
205 break;
206 write_console(0, string+off, linelen);
207 write_console(0, "\r\n", 2);
208 off += linelen + 1;
209 }
210 if (off < len)
211 write_console(0, string+off, len-off);
212 }
213
214 struct console xenboot_console = {
215 .name = "xenboot",
216 .write = xenboot_write_console,
217 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
218 };
219 #endif /* CONFIG_EARLY_PRINTK */
220
221 void xen_raw_console_write(const char *str)
222 {
223 raw_console_write(str, strlen(str));
224 }
225
226 void xen_raw_printk(const char *fmt, ...)
227 {
228 static char buf[512];
229 va_list ap;
230
231 va_start(ap, fmt);
232 vsnprintf(buf, sizeof(buf), fmt, ap);
233 va_end(ap);
234
235 xen_raw_console_write(buf);
236 }
237
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