提交 d5e54913 编写于 作者: D David Gibson 提交者: Paul Mackerras

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: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
上级 8c653186
......@@ -631,6 +631,12 @@ config HVC_XEN
help
Xen virtual console device driver
config HVC_UDBG
bool "udbg based fake hypervisor console"
depends on PPC && EXPERIMENTAL
select HVC_DRIVER
default n
config VIRTIO_CONSOLE
tristate "Virtio console"
depends on VIRTIO
......
......@@ -50,6 +50,7 @@ obj-$(CONFIG_HVC_BEAT) += hvc_beat.o
obj-$(CONFIG_HVC_DRIVER) += hvc_console.o
obj-$(CONFIG_HVC_IRQ) += hvc_irq.o
obj-$(CONFIG_HVC_XEN) += hvc_xen.o
obj-$(CONFIG_HVC_UDBG) += hvc_udbg.o
obj-$(CONFIG_VIRTIO_CONSOLE) += virtio_console.o
obj-$(CONFIG_RAW_DRIVER) += raw.o
obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o
......
/*
* udbg interface to hvc_console.c
*
* (C) Copyright David Gibson, IBM Corporation 2008.
*
* 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/moduleparam.h>
#include <linux/types.h>
#include <linux/irq.h>
#include <asm/udbg.h>
#include "hvc_console.h"
struct hvc_struct *hvc_udbg_dev;
static int hvc_udbg_put(uint32_t vtermno, const char *buf, int count)
{
int i;
for (i = 0; i < count; i++)
udbg_putc(buf[i]);
return i;
}
static int hvc_udbg_get(uint32_t vtermno, char *buf, int count)
{
int i, c;
if (!udbg_getc_poll)
return 0;
for (i = 0; i < count; i++) {
if ((c = udbg_getc_poll()) == -1)
break;
buf[i] = c;
}
return i;
}
static struct hv_ops hvc_udbg_ops = {
.get_chars = hvc_udbg_get,
.put_chars = hvc_udbg_put,
};
static int __init hvc_udbg_init(void)
{
struct hvc_struct *hp;
BUG_ON(hvc_udbg_dev);
hp = hvc_alloc(0, NO_IRQ, &hvc_udbg_ops, 16);
if (IS_ERR(hp))
return PTR_ERR(hp);
hvc_udbg_dev = hp;
return 0;
}
module_init(hvc_udbg_init);
static void __exit hvc_udbg_exit(void)
{
if (hvc_udbg_dev)
hvc_remove(hvc_udbg_dev);
}
module_exit(hvc_udbg_exit);
static int __init hvc_udbg_console_init(void)
{
hvc_instantiate(0, 0, &hvc_udbg_ops);
add_preferred_console("hvc", 0, NULL);
return 0;
}
console_initcall(hvc_udbg_console_init);
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