From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WPwrd-00084w-Ky for barebox@lists.infradead.org; Tue, 18 Mar 2014 16:27:42 +0000 Date: Tue, 18 Mar 2014 17:27:19 +0100 From: Sascha Hauer Message-ID: <20140318162719.GY17250@pengutronix.de> References: <1395049022-13693-1-git-send-email-antonynpavlov@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1395049022-13693-1-git-send-email-antonynpavlov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH v2] clocksource: add dummy software-only clocksource To: Antony Pavlov Cc: barebox@lists.infradead.org On Mon, Mar 17, 2014 at 01:37:02PM +0400, Antony Pavlov wrote: > This driver is very handy for initial barebox porting. > It was used for running barebox on DiGiC2-based camera > and initial porting barebox to Loongson-1 and ar9331. > > Signed-off-by: Antony Pavlov > Signed-off-by: Sascha Hauer > Reported-by: Alexander Aring > Reported-by: Alexander Shiyan Applied, thanks Sascha > --- > drivers/clocksource/Kconfig | 22 +++++++++++++++++ > drivers/clocksource/Makefile | 1 + > drivers/clocksource/dummy.c | 56 ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 79 insertions(+) > create mode 100644 drivers/clocksource/dummy.c > > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index 4ef25ec..f53c933 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -14,6 +14,28 @@ config CLOCKSOURCE_CLPS711X > bool > depends on ARCH_CLPS711X > > +config CLOCKSOURCE_DUMMY > + bool "Enable dummy software-only clocksource" > + help > + When porting barebox to a new SoC there might be a case > + of broken or absent clocksource. This causes barebox serial > + console to be non functional. > + To solve the problem this software-only clocksource driver is used. > + WARNING!!! This clocksource doesn't provide correct timing. > + To adjust this clocksource please use CONFIG_CLOCKSOURCE_DUMMY_RATE. > + The bigger rate valuest makes clocksource "faster". > + It's possible to add this clocksource unconditionally. > + This clocksource starts very early (pure_initcall) so > + real clocksource will take over. > + This can help if initialization order is wrong so that > + the time functions are used before the real clocksource > + was initialized. > + > +config CLOCKSOURCE_DUMMY_RATE > + int " dummy clocksource rate" > + depends on CLOCKSOURCE_DUMMY > + default 1000 > + > config CLOCKSOURCE_MVEBU > bool > depends on ARCH_MVEBU > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > index 25b7f46..834a15d 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -2,6 +2,7 @@ obj-$(CONFIG_AMBA_SP804) += amba-sp804.o > obj-$(CONFIG_ARM_SMP_TWD) += arm_smp_twd.o > obj-$(CONFIG_CLOCKSOURCE_BCM2835) += bcm2835.o > obj-$(CONFIG_CLOCKSOURCE_CLPS711X) += clps711x.o > +obj-$(CONFIG_CLOCKSOURCE_DUMMY) += dummy.o > obj-$(CONFIG_CLOCKSOURCE_MVEBU) += mvebu.o > obj-$(CONFIG_CLOCKSOURCE_NOMADIK) += nomadik.o > obj-$(CONFIG_CLOCKSOURCE_ORION) += orion.o > diff --git a/drivers/clocksource/dummy.c b/drivers/clocksource/dummy.c > new file mode 100644 > index 0000000..154a8cd > --- /dev/null > +++ b/drivers/clocksource/dummy.c > @@ -0,0 +1,56 @@ > +/* > + * Copyright (C) 2013 Antony Pavlov > + * > + * This file is part of barebox. > + * See file CREDITS for list of people who contributed to this project. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 > + * as published by the Free Software Foundation. > + * > + * 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. > + * > + */ > + > +#include > +#include > +#include > + > +static uint64_t dummy_counter; > + > +static uint64_t dummy_cs_read(void) > +{ > + static int first; > + > + if (!first) { > + pr_warn("Warning: Using dummy clocksource\n"); > + first = 1; > + } > + > + dummy_counter += CONFIG_CLOCKSOURCE_DUMMY_RATE; > + > + return dummy_counter; > +} > + > +static struct clocksource dummy_cs = { > + .read = dummy_cs_read, > + .mask = CLOCKSOURCE_MASK(32), > +}; > + > +static int clocksource_init(void) > +{ > + dummy_counter = 0; > + > + clocks_calc_mult_shift(&dummy_cs.mult, &dummy_cs.shift, > + 100000000, NSEC_PER_SEC, 10); > + > + pr_debug("clocksource_init: mult=%08x, shift=%08x\n", > + dummy_cs.mult, dummy_cs.shift); > + init_clock(&dummy_cs); > + > + return 0; > +} > +pure_initcall(clocksource_init); > -- > 1.9.0 > > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox