tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
37static struct hvc_struct *hvc;
38static int xencons_irq;
39
40/* ------------------------------------------------------------------ */
41
42static unsigned long console_pfn = ~0ul;
43
44static 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
52static 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
58static int write_console(uint32_t vtermno, 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
79static int read_console(uint32_t vtermno, char *buf, int len)
80{
81 struct xencons_interface *intf = xencons_interface();
82 XENCONS_RING_IDX cons, prod;
83 int recv = 0;
84
85 cons = intf->in_cons;
86 prod = intf->in_prod;
87 mb(); /* get pointers before reading ring */
88 BUG_ON((prod - cons) > sizeof(intf->in));
89
90 while (cons != prod && recv < len)
91 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
92
93 mb(); /* read ring before consuming */
94 intf->in_cons = cons;
95
96 notify_daemon();
97 return recv;
98}
99
100static struct hv_ops hvc_ops = {
101 .get_chars = read_console,
102 .put_chars = write_console,
103 .notifier_add = notifier_add_irq,
104 .notifier_del = notifier_del_irq,
105 .notifier_hangup = notifier_hangup_irq,
106};
107
108static int __init xen_init(void)
109{
110 struct hvc_struct *hp;
111
112 if (!xen_pv_domain() ||
113 xen_initial_domain() ||
114 !xen_start_info->console.domU.evtchn)
115 return -ENODEV;
116
117 xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
118 if (xencons_irq < 0)
119 xencons_irq = 0; /* NO_IRQ */
120
121 hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
122 if (IS_ERR(hp))
123 return PTR_ERR(hp);
124
125 hvc = hp;
126
127 console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
128
129 return 0;
130}
131
132void xen_console_resume(void)
133{
134 if (xencons_irq)
135 rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq);
136}
137
138static void __exit xen_fini(void)
139{
140 if (hvc)
141 hvc_remove(hvc);
142}
143
144static int xen_cons_init(void)
145{
146 if (!xen_pv_domain())
147 return 0;
148
149 hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
150 return 0;
151}
152
153module_init(xen_init);
154module_exit(xen_fini);
155console_initcall(xen_cons_init);
156
157static void raw_console_write(const char *str, int len)
158{
159 while(len > 0) {
160 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
161 if (rc <= 0)
162 break;
163
164 str += rc;
165 len -= rc;
166 }
167}
168
169#ifdef CONFIG_EARLY_PRINTK
170static void xenboot_write_console(struct console *console, const char *string,
171 unsigned len)
172{
173 unsigned int linelen, off = 0;
174 const char *pos;
175
176 raw_console_write(string, len);
177
178 write_console(0, "(early) ", 8);
179 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
180 linelen = pos-string+off;
181 if (off + linelen > len)
182 break;
183 write_console(0, string+off, linelen);
184 write_console(0, "\r\n", 2);
185 off += linelen + 1;
186 }
187 if (off < len)
188 write_console(0, string+off, len-off);
189}
190
191struct console xenboot_console = {
192 .name = "xenboot",
193 .write = xenboot_write_console,
194 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
195};
196#endif /* CONFIG_EARLY_PRINTK */
197
198void xen_raw_console_write(const char *str)
199{
200 raw_console_write(str, strlen(str));
201}
202
203void xen_raw_printk(const char *fmt, ...)
204{
205 static char buf[512];
206 va_list ap;
207
208 va_start(ap, fmt);
209 vsnprintf(buf, sizeof(buf), fmt, ap);
210 va_end(ap);
211
212 xen_raw_console_write(buf);
213}