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 <[email protected]> Signed-off-by: Sascha Hauer <[email protected]> Reported-by: Alexander Aring <[email protected]> Reported-by: Alexander Shiyan <[email protected]> --- 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 <[email protected]> + * + * 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 <common.h> +#include <init.h> +#include <clock.h> + +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 _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
