Commit b536b4b9 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Jeremy Fitzhardinge
Browse files

xen: use the hvc console infrastructure for Xen console



Implement a Xen back-end for hvc console.

* * *
Add early printk support via hvc console, enable using
"earlyprintk=xen" on the kernel command line.

From: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Acked-by: default avatarOlof Johansson <olof@lixom.net>
parent 8b84ad94
......@@ -244,7 +244,7 @@ static int find_unbound_irq(void)
return irq;
}
static int bind_evtchn_to_irq(unsigned int evtchn)
int bind_evtchn_to_irq(unsigned int evtchn)
{
int irq;
......@@ -269,6 +269,7 @@ static int bind_evtchn_to_irq(unsigned int evtchn)
return irq;
}
EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
{
......
......@@ -6,6 +6,7 @@
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/fcntl.h>
#include <xen/hvc-console.h>
/* Simple VGA output */
......@@ -242,6 +243,10 @@ static int __init setup_early_printk(char *buf)
simnow_init(buf + 6);
early_console = &simnow_console;
keep_early = 1;
#ifdef CONFIG_HVC_XEN
} else if (!strncmp(buf, "xen", 3)) {
early_console = &xenboot_console;
#endif
}
if (keep_early)
......
......@@ -604,6 +604,14 @@ config HVC_BEAT
help
Toshiba's Cell Reference Set Beat Console device driver
config HVC_XEN
bool "Xen Hypervisor Console support"
depends on XEN
select HVC_DRIVER
default y
help
Xen virtual console device driver
config HVCS
tristate "IBM Hypervisor Virtual Console Server support"
depends on PPC_PSERIES
......
......@@ -48,6 +48,7 @@ obj-$(CONFIG_HVC_ISERIES) += hvc_iseries.o
obj-$(CONFIG_HVC_RTAS) += hvc_rtas.o
obj-$(CONFIG_HVC_BEAT) += hvc_beat.o
obj-$(CONFIG_HVC_DRIVER) += hvc_console.o
obj-$(CONFIG_HVC_XEN) += hvc_xen.o
obj-$(CONFIG_RAW_DRIVER) += raw.o
obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o
obj-$(CONFIG_MSPEC) += mspec.o
......
/*
* 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 xenboot_write_console(struct console *console, const char *string,
unsigned len)
{
unsigned int linelen, off = 0;
const char *pos;
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,
};
......@@ -13,6 +13,7 @@ enum ipi_vector {
XEN_NR_IPIS,
};
int bind_evtchn_to_irq(unsigned int evtchn);
int bind_evtchn_to_irqhandler(unsigned int evtchn,
irq_handler_t handler,
unsigned long irqflags, const char *devname,
......
#ifndef XEN_HVC_CONSOLE_H
#define XEN_HVC_CONSOLE_H
extern struct console xenboot_console;
#endif /* XEN_HVC_CONSOLE_H */
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