From patchwork Thu Nov 6 00:20:17 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 7445 X-Patchwork-Delegate: paulus@samba.org Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id 7FE18DDED8 for ; Thu, 6 Nov 2008 11:20:35 +1100 (EST) X-Original-To: linuxppc-dev@ozlabs.org Delivered-To: linuxppc-dev@ozlabs.org Received: by ozlabs.org (Postfix, from userid 1007) id 28C77DDE9F; Thu, 6 Nov 2008 11:20:23 +1100 (EST) Date: Thu, 6 Nov 2008 11:20:17 +1100 From: David Gibson To: Paul Mackerras Subject: Re: powerpc: udbg based backend for hvc_console Message-ID: <20081106002017.GE28465@yookeroo.seuss> Mail-Followup-To: Paul Mackerras , benh@yookeroo.seuss, linuxppc-dev@ozlabs.org References: <20081024035434.GF4267@yookeroo.seuss> <18705.9955.2582.373653@cargo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <18705.9955.2582.373653@cargo.ozlabs.ibm.com> User-Agent: Mutt/1.5.18 (2008-05-17) Cc: benh@yookeroo.seuss, linuxppc-dev@ozlabs.org X-BeenThere: linuxppc-dev@ozlabs.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org On Wed, Nov 05, 2008 at 03:53:55PM +1100, Paul Mackerras wrote: > David Gibson writes: > > > This patch 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. > > Since only powerpc has udbg, shouldn't the Kconfig option depend on > PPC? Ah.. yes, yes it should. Forgot that hvconsole was used on non-powerpc as well. Corrected patch below. powerpc: udbg based backend for hvc_console This patch 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 Index: working-2.6/drivers/char/Kconfig =================================================================== --- working-2.6.orig/drivers/char/Kconfig 2008-10-31 13:31:49.000000000 +1100 +++ working-2.6/drivers/char/Kconfig 2008-11-06 11:18:22.000000000 +1100 @@ -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 Index: working-2.6/drivers/char/Makefile =================================================================== --- working-2.6.orig/drivers/char/Makefile 2008-10-31 13:31:49.000000000 +1100 +++ working-2.6/drivers/char/Makefile 2008-11-06 11:17:31.000000000 +1100 @@ -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 Index: working-2.6/drivers/char/hvc_udbg.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ working-2.6/drivers/char/hvc_udbg.c 2008-11-06 11:17:31.000000000 +1100 @@ -0,0 +1,96 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include + +#include + +#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);