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authorDavid Gibson <david@gibson.dropbear.id.au>2008-11-05 09:20:17 -0500
committerPaul Mackerras <paulus@samba.org>2008-11-19 00:04:25 -0500
commitd5e54913433fff89609adfc4b96fefcf807a9030 (patch)
tree6ab66827c98837a86a2b4f0e77732c43238db5a0 /drivers/char/hvc_udbg.c
parent8c6531868d4917adbd363030f28a734b76c7471a (diff)
powerpc: udbg-based backend for hvc_console
This adds a new backend for the hvc console based on the low-level udbg callbacks. This effectively implements a working runtime console in terms of the simple udbg primitives. This is kind of a hack - since udbg isn't something you really want to be using routinely - but it's really useful during bringup. This can be used to quickly implement a userspace-usable console while you're working on a proper driver for whatever console I/O device the hardware has. Or, it can be used to avoid writing a full blown tty/console driver entirely for quick-and-dirty I/O hardware that will later be replaced by something else. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'drivers/char/hvc_udbg.c')
-rw-r--r--drivers/char/hvc_udbg.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/drivers/char/hvc_udbg.c b/drivers/char/hvc_udbg.c
new file mode 100644
index 000000000000..bd63ba878a56
--- /dev/null
+++ b/drivers/char/hvc_udbg.c
@@ -0,0 +1,96 @@
1/*
2 * udbg interface to hvc_console.c
3 *
4 * (C) Copyright David Gibson, IBM Corporation 2008.
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/moduleparam.h>
26#include <linux/types.h>
27#include <linux/irq.h>
28
29#include <asm/udbg.h>
30
31#include "hvc_console.h"
32
33struct hvc_struct *hvc_udbg_dev;
34
35static int hvc_udbg_put(uint32_t vtermno, const char *buf, int count)
36{
37 int i;
38
39 for (i = 0; i < count; i++)
40 udbg_putc(buf[i]);
41
42 return i;
43}
44
45static int hvc_udbg_get(uint32_t vtermno, char *buf, int count)
46{
47 int i, c;
48
49 if (!udbg_getc_poll)
50 return 0;
51
52 for (i = 0; i < count; i++) {
53 if ((c = udbg_getc_poll()) == -1)
54 break;
55 buf[i] = c;
56 }
57
58 return i;
59}
60
61static struct hv_ops hvc_udbg_ops = {
62 .get_chars = hvc_udbg_get,
63 .put_chars = hvc_udbg_put,
64};
65
66static int __init hvc_udbg_init(void)
67{
68 struct hvc_struct *hp;
69
70 BUG_ON(hvc_udbg_dev);
71
72 hp = hvc_alloc(0, NO_IRQ, &hvc_udbg_ops, 16);
73 if (IS_ERR(hp))
74 return PTR_ERR(hp);
75
76 hvc_udbg_dev = hp;
77
78 return 0;
79}
80module_init(hvc_udbg_init);
81
82static void __exit hvc_udbg_exit(void)
83{
84 if (hvc_udbg_dev)
85 hvc_remove(hvc_udbg_dev);
86}
87module_exit(hvc_udbg_exit);
88
89static int __init hvc_udbg_console_init(void)
90{
91 hvc_instantiate(0, 0, &hvc_udbg_ops);
92 add_preferred_console("hvc", 0, NULL);
93
94 return 0;
95}
96console_initcall(hvc_udbg_console_init);