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b536b4b9 JF |
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 inline struct xencons_interface *xencons_interface(void) | |
43 | { | |
44 | return mfn_to_virt(xen_start_info->console.domU.mfn); | |
45 | } | |
46 | ||
47 | static inline void notify_daemon(void) | |
48 | { | |
49 | /* Use evtchn: this is called early, before irq is set up. */ | |
50 | notify_remote_via_evtchn(xen_start_info->console.domU.evtchn); | |
51 | } | |
52 | ||
53 | static int write_console(uint32_t vtermno, const char *data, int len) | |
54 | { | |
55 | struct xencons_interface *intf = xencons_interface(); | |
56 | XENCONS_RING_IDX cons, prod; | |
57 | int sent = 0; | |
58 | ||
59 | cons = intf->out_cons; | |
60 | prod = intf->out_prod; | |
61 | mb(); /* update queue values before going on */ | |
62 | BUG_ON((prod - cons) > sizeof(intf->out)); | |
63 | ||
64 | while ((sent < len) && ((prod - cons) < sizeof(intf->out))) | |
65 | intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++]; | |
66 | ||
67 | wmb(); /* write ring before updating pointer */ | |
68 | intf->out_prod = prod; | |
69 | ||
70 | notify_daemon(); | |
71 | return sent; | |
72 | } | |
73 | ||
74 | static int read_console(uint32_t vtermno, char *buf, int len) | |
75 | { | |
76 | struct xencons_interface *intf = xencons_interface(); | |
77 | XENCONS_RING_IDX cons, prod; | |
78 | int recv = 0; | |
79 | ||
80 | cons = intf->in_cons; | |
81 | prod = intf->in_prod; | |
82 | mb(); /* get pointers before reading ring */ | |
83 | BUG_ON((prod - cons) > sizeof(intf->in)); | |
84 | ||
85 | while (cons != prod && recv < len) | |
86 | buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)]; | |
87 | ||
88 | mb(); /* read ring before consuming */ | |
89 | intf->in_cons = cons; | |
90 | ||
91 | notify_daemon(); | |
92 | return recv; | |
93 | } | |
94 | ||
95 | static struct hv_ops hvc_ops = { | |
96 | .get_chars = read_console, | |
97 | .put_chars = write_console, | |
98 | }; | |
99 | ||
100 | static int __init xen_init(void) | |
101 | { | |
102 | struct hvc_struct *hp; | |
103 | ||
104 | if (!is_running_on_xen()) | |
105 | return 0; | |
106 | ||
107 | xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn); | |
108 | if (xencons_irq < 0) | |
109 | xencons_irq = 0 /* NO_IRQ */; | |
110 | hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256); | |
111 | if (IS_ERR(hp)) | |
112 | return PTR_ERR(hp); | |
113 | ||
114 | hvc = hp; | |
115 | return 0; | |
116 | } | |
117 | ||
118 | static void __exit xen_fini(void) | |
119 | { | |
120 | if (hvc) | |
121 | hvc_remove(hvc); | |
122 | } | |
123 | ||
124 | static int xen_cons_init(void) | |
125 | { | |
126 | if (!is_running_on_xen()) | |
127 | return 0; | |
128 | ||
129 | hvc_instantiate(HVC_COOKIE, 0, &hvc_ops); | |
130 | return 0; | |
131 | } | |
132 | ||
133 | module_init(xen_init); | |
134 | module_exit(xen_fini); | |
135 | console_initcall(xen_cons_init); | |
136 | ||
137 | static void xenboot_write_console(struct console *console, const char *string, | |
138 | unsigned len) | |
139 | { | |
140 | unsigned int linelen, off = 0; | |
141 | const char *pos; | |
142 | ||
143 | while (off < len && NULL != (pos = strchr(string+off, '\n'))) { | |
144 | linelen = pos-string+off; | |
145 | if (off + linelen > len) | |
146 | break; | |
147 | write_console(0, string+off, linelen); | |
148 | write_console(0, "\r\n", 2); | |
149 | off += linelen + 1; | |
150 | } | |
151 | if (off < len) | |
152 | write_console(0, string+off, len-off); | |
153 | } | |
154 | ||
155 | struct console xenboot_console = { | |
156 | .name = "xenboot", | |
157 | .write = xenboot_write_console, | |
158 | .flags = CON_PRINTBUFFER | CON_BOOT, | |
159 | }; |