From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-la0-x231.google.com ([2a00:1450:4010:c03::231]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xvav5-00044F-A7 for barebox@lists.infradead.org; Tue, 02 Dec 2014 00:02:20 +0000 Received: by mail-la0-f49.google.com with SMTP id hs14so9562763lab.22 for ; Mon, 01 Dec 2014 16:01:56 -0800 (PST) From: Antony Pavlov Date: Tue, 2 Dec 2014 03:03:28 +0300 Message-Id: <1417478608-11670-1-git-send-email-antonynpavlov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 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: [RFC] clock: incorporate dummy clocksource into core clock code To: barebox@lists.infradead.org Signed-off-by: Antony Pavlov --- common/clock.c | 20 ++++++++++++++-- drivers/clocksource/Kconfig | 27 ++++++++-------------- drivers/clocksource/Makefile | 1 - drivers/clocksource/dummy.c | 55 -------------------------------------------- 4 files changed, 28 insertions(+), 75 deletions(-) diff --git a/common/clock.c b/common/clock.c index 2ee81da..35c9e6c 100644 --- a/common/clock.c +++ b/common/clock.c @@ -22,6 +22,7 @@ */ #include +#include #include #include #include @@ -35,6 +36,16 @@ static uint64_t time_ns; */ uint64_t time_beginning; +static int dummy_csrc_warn(void) +{ + if (!current_clock) { + pr_warn("Warning: Using dummy clocksource\n"); + } + + return 0; +} +late_initcall(dummy_csrc_warn); + /** * get_time_ns - get current timestamp in nanoseconds */ @@ -44,8 +55,13 @@ uint64_t get_time_ns(void) uint64_t cycle_now, cycle_delta; uint64_t ns_offset; - if (!cs) - return 0; + if (!cs) { + static uint64_t dummy_counter; + + dummy_counter += CONFIG_CLOCKSOURCE_DUMMY_RATE; + + return dummy_counter; + } /* read clocksource: */ cycle_now = cs->read() & cs->mask; diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index fc5a389..598edc9 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -18,28 +18,21 @@ config CLOCKSOURCE_DIGIC bool depends on ARCH_DIGIC -config CLOCKSOURCE_DUMMY - bool "Enable dummy software-only clocksource" +config CLOCKSOURCE_DUMMY_RATE + int + prompt "dummy clocksource rate" + default 1000 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. + To solve the problem barebox has built-in software-only clocksource. + The software-only clocksource is used only if no hardware clocksource + is registered. This can help if initialization order is wrong so that + the time functions are used before the real clocksource was initialized. + WARNING!!! Built-in software-only clocksource doesn't provide correct timing. + The option CONFIG_CLOCKSOURCE_DUMMY_RATE is used to adjust this clocksource. 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 - prompt "dummy clocksource rate" - depends on CLOCKSOURCE_DUMMY - default 1000 config CLOCKSOURCE_MVEBU bool diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index b80df6b..f5f5141 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -3,7 +3,6 @@ obj-$(CONFIG_ARM_SMP_TWD) += arm_smp_twd.o obj-$(CONFIG_CLOCKSOURCE_BCM2835) += bcm2835.o obj-$(CONFIG_CLOCKSOURCE_CLPS711X) += clps711x.o obj-$(CONFIG_CLOCKSOURCE_DIGIC) += digic.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 deleted file mode 100644 index 96f9b6e..0000000 --- a/drivers/clocksource/dummy.c +++ /dev/null @@ -1,55 +0,0 @@ -/* - * 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); - - return init_clock(&dummy_cs); -} -pure_initcall(clocksource_init); -- 2.1.3 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox