aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/char/hvc_xen.c
blob: d5fe0a8952faeb52f5f0acf5daf40eba0fa1632f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
/*
 * xen console driver interface to hvc_console.c
 *
 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/console.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/types.h>

#include <asm/xen/hypervisor.h>
#include <xen/page.h>
#include <xen/events.h>
#include <xen/interface/io/console.h>
#include <xen/hvc-console.h>

#include "hvc_console.h"

#define HVC_COOKIE   0x58656e /* "Xen" in hex */

static struct hvc_struct *hvc;
static int xencons_irq;

/* ------------------------------------------------------------------ */

static inline struct xencons_interface *xencons_interface(void)
{
	return mfn_to_virt(xen_start_info->console.domU.mfn);
}

static inline void notify_daemon(void)
{
	/* Use evtchn: this is called early, before irq is set up. */
	notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
}

static int write_console(uint32_t vtermno, const char *data, int len)
{
	struct xencons_interface *intf = xencons_interface();
	XENCONS_RING_IDX cons, prod;
	int sent = 0;

	cons = intf->out_cons;
	prod = intf->out_prod;
	mb();			/* update queue values before going on */
	BUG_ON((prod - cons) > sizeof(intf->out));

	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];

	wmb();			/* write ring before updating pointer */
	intf->out_prod = prod;

	notify_daemon();
	return sent;
}

static int read_console(uint32_t vtermno, char *buf, int len)
{
	struct xencons_interface *intf = xencons_interface();
	XENCONS_RING_IDX cons, prod;
	int recv = 0;

	cons = intf->in_cons;
	prod = intf->in_prod;
	mb();			/* get pointers before reading ring */
	BUG_ON((prod - cons) > sizeof(intf->in));

	while (cons != prod && recv < len)
		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];

	mb();			/* read ring before consuming */
	intf->in_cons = cons;

	notify_daemon();
	return recv;
}

static struct hv_ops hvc_ops = {
	.get_chars = read_console,
	.put_chars = write_console,
};

static int __init xen_init(void)
{
	struct hvc_struct *hp;

	if (!is_running_on_xen())
		return 0;

	xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
	if (xencons_irq < 0)
		xencons_irq = 0 /* NO_IRQ */;
	hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
	if (IS_ERR(hp))
		return PTR_ERR(hp);

	hvc = hp;
	return 0;
}

static void __exit xen_fini(void)
{
	if (hvc)
		hvc_remove(hvc);
}

static int xen_cons_init(void)
{
	if (!is_running_on_xen())
		return 0;

	hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
	return 0;
}

module_init(xen_init);
module_exit(xen_fini);
console_initcall(xen_cons_init);

static void raw_console_write(const char *str, int len)
{
	while(len > 0) {
		int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
		if (rc <= 0)
			break;

		str += rc;
		len -= rc;
	}
}

#ifdef CONFIG_EARLY_PRINTK
static void xenboot_write_console(struct console *console, const char *string,
				  unsigned len)
{
	unsigned int linelen, off = 0;
	const char *pos;

	raw_console_write(string, len);

	write_console(0, "(early) ", 8);
	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
		linelen = pos-string+off;
		if (off + linelen > len)
			break;
		write_console(0, string+off, linelen);
		write_console(0, "\r\n", 2);
		off += linelen + 1;
	}
	if (off < len)
		write_console(0, string+off, len-off);
}

struct console xenboot_console = {
	.name		= "xenboot",
	.write		= xenboot_write_console,
	.flags		= CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
};
#endif	/* CONFIG_EARLY_PRINTK */

void xen_raw_console_write(const char *str)
{
	raw_console_write(str, strlen(str));
}

void xen_raw_printk(const char *fmt, ...)
{
	static char buf[512];
	va_list ap;

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);

	xen_raw_console_write(buf);
}