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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 | |
29 | #include <xen/xen.h> |
30 | #include <xen/page.h> |
31 | #include <xen/events.h> |
32 | #include <xen/interface/io/console.h> |
33 | #include <xen/hvc-console.h> |
34 | |
35 | #include "hvc_console.h" |
36 | |
37 | #define HVC_COOKIE 0x58656e /* "Xen" in hex */ |
38 | |
39 | static struct hvc_struct *hvc; |
40 | static int xencons_irq; |
41 | |
42 | /* ------------------------------------------------------------------ */ |
43 | |
44 | static unsigned long console_pfn = ~0ul; |
45 | |
46 | static inline struct xencons_interface *xencons_interface(void) |
47 | { |
48 | if (console_pfn == ~0ul) |
49 | return mfn_to_virt(xen_start_info->console.domU.mfn); |
50 | else |
51 | return __va(console_pfn << PAGE_SHIFT); |
52 | } |
53 | |
54 | static inline void notify_daemon(void) |
55 | { |
56 | /* Use evtchn: this is called early, before irq is set up. */ |
57 | notify_remote_via_evtchn(xen_start_info->console.domU.evtchn); |
58 | } |
59 | |
60 | static int __write_console(const char *data, int len) |
61 | { |
62 | struct xencons_interface *intf = xencons_interface(); |
63 | XENCONS_RING_IDX cons, prod; |
64 | int sent = 0; |
65 | |
66 | cons = intf->out_cons; |
67 | prod = intf->out_prod; |
68 | mb(); /* update queue values before going on */ |
69 | BUG_ON((prod - cons) > sizeof(intf->out)); |
70 | |
71 | while ((sent < len) && ((prod - cons) < sizeof(intf->out))) |
72 | intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++]; |
73 | |
74 | wmb(); /* write ring before updating pointer */ |
75 | intf->out_prod = prod; |
76 | |
77 | notify_daemon(); |
78 | return sent; |
79 | } |
80 | |
81 | static int write_console(uint32_t vtermno, const char *data, int len) |
82 | { |
83 | int ret = len; |
84 | |
85 | /* |
86 | * Make sure the whole buffer is emitted, polling if |
87 | * necessary. We don't ever want to rely on the hvc daemon |
88 | * because the most interesting console output is when the |
89 | * kernel is crippled. |
90 | */ |
91 | while (len) { |
92 | int sent = __write_console(data, len); |
93 | |
94 | data += sent; |
95 | len -= sent; |
96 | |
97 | if (unlikely(len)) |
98 | HYPERVISOR_sched_op(SCHEDOP_yield, NULL); |
99 | } |
100 | |
101 | return ret; |
102 | } |
103 | |
104 | static int read_console(uint32_t vtermno, char *buf, int len) |
105 | { |
106 | struct xencons_interface *intf = xencons_interface(); |
107 | XENCONS_RING_IDX cons, prod; |
108 | int recv = 0; |
109 | |
110 | cons = intf->in_cons; |
111 | prod = intf->in_prod; |
112 | mb(); /* get pointers before reading ring */ |
113 | BUG_ON((prod - cons) > sizeof(intf->in)); |
114 | |
115 | while (cons != prod && recv < len) |
116 | buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)]; |
117 | |
118 | mb(); /* read ring before consuming */ |
119 | intf->in_cons = cons; |
120 | |
121 | notify_daemon(); |
122 | return recv; |
123 | } |
124 | |
125 | static const struct hv_ops hvc_ops = { |
126 | .get_chars = read_console, |
127 | .put_chars = write_console, |
128 | .notifier_add = notifier_add_irq, |
129 | .notifier_del = notifier_del_irq, |
130 | .notifier_hangup = notifier_hangup_irq, |
131 | }; |
132 | |
133 | static int __init xen_init(void) |
134 | { |
135 | struct hvc_struct *hp; |
136 | |
137 | if (!xen_pv_domain() || |
138 | xen_initial_domain() || |
139 | !xen_start_info->console.domU.evtchn) |
140 | return -ENODEV; |
141 | |
142 | xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn); |
143 | if (xencons_irq < 0) |
144 | xencons_irq = 0; /* NO_IRQ */ |
145 | |
146 | hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256); |
147 | if (IS_ERR(hp)) |
148 | return PTR_ERR(hp); |
149 | |
150 | hvc = hp; |
151 | |
152 | console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn); |
153 | |
154 | return 0; |
155 | } |
156 | |
157 | void xen_console_resume(void) |
158 | { |
159 | if (xencons_irq) |
160 | rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq); |
161 | } |
162 | |
163 | static void __exit xen_fini(void) |
164 | { |
165 | if (hvc) |
166 | hvc_remove(hvc); |
167 | } |
168 | |
169 | static int xen_cons_init(void) |
170 | { |
171 | if (!xen_pv_domain()) |
172 | return 0; |
173 | |
174 | hvc_instantiate(HVC_COOKIE, 0, &hvc_ops); |
175 | return 0; |
176 | } |
177 | |
178 | module_init(xen_init); |
179 | module_exit(xen_fini); |
180 | console_initcall(xen_cons_init); |
181 | |
182 | static void raw_console_write(const char *str, int len) |
183 | { |
184 | while(len > 0) { |
185 | int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str); |
186 | if (rc <= 0) |
187 | break; |
188 | |
189 | str += rc; |
190 | len -= rc; |
191 | } |
192 | } |
193 | |
194 | #ifdef CONFIG_EARLY_PRINTK |
195 | static void xenboot_write_console(struct console *console, const char *string, |
196 | unsigned len) |
197 | { |
198 | unsigned int linelen, off = 0; |
199 | const char *pos; |
200 | |
201 | raw_console_write(string, len); |
202 | |
203 | write_console(0, "(early) ", 8); |
204 | while (off < len && NULL != (pos = strchr(string+off, '\n'))) { |
205 | linelen = pos-string+off; |
206 | if (off + linelen > len) |
207 | break; |
208 | write_console(0, string+off, linelen); |
209 | write_console(0, "\r\n", 2); |
210 | off += linelen + 1; |
211 | } |
212 | if (off < len) |
213 | write_console(0, string+off, len-off); |
214 | } |
215 | |
216 | struct console xenboot_console = { |
217 | .name = "xenboot", |
218 | .write = xenboot_write_console, |
219 | .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME, |
220 | }; |
221 | #endif /* CONFIG_EARLY_PRINTK */ |
222 | |
223 | void xen_raw_console_write(const char *str) |
224 | { |
225 | raw_console_write(str, strlen(str)); |
226 | } |
227 | |
228 | void xen_raw_printk(const char *fmt, ...) |
229 | { |
230 | static char buf[512]; |
231 | va_list ap; |
232 | |
233 | va_start(ap, fmt); |
234 | vsnprintf(buf, sizeof(buf), fmt, ap); |
235 | va_end(ap); |
236 | |
237 | xen_raw_console_write(buf); |
238 | } |
239 |
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