Commit d5e54913 authored by David Gibson's avatar David Gibson Committed by Paul Mackerras
Browse files

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: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 8c653186

drivers/char/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -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

drivers/char/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/char/hvc_udbg.c

0 → 100644
+96 −0
Original line number Diff line number Diff line 
/*

 * 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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