forked from Minki/linux
2f0778afac
sched_clock() is yet another blocker on the road to the single image. This patch implements an idea by Russell King: http://www.spinics.net/lists/linux-omap/msg49561.html Instead of asking the platform to implement both sched_clock() itself and the rollover callback, simply register a read() function, and let the ARM code care about sched_clock() itself, the conversion to ns and the rollover. sched_clock() uses this read() function as an indirection to the platform code. If the platform doesn't provide a read(), the code falls back to the jiffy counter (just like the default sched_clock). This allow some simplifications and possibly some footprint gain when multiple platforms are compiled in. Among the drawbacks, the removal of the *_fixed_sched_clock optimization which could negatively impact some platforms (sa1100, tegra, versatile and omap). Tested on 11MPCore, OMAP4 and Tegra. Cc: Imre Kaloz <kaloz@openwrt.org> Cc: Eric Miao <eric.y.miao@gmail.com> Cc: Colin Cross <ccross@android.com> Cc: Erik Gilling <konkers@android.com> Cc: Olof Johansson <olof@lixom.net> Cc: Sascha Hauer <kernel@pengutronix.de> Cc: Alessandro Rubini <rubini@unipv.it> Cc: STEricsson <STEricsson_nomadik_linux@list.st.com> Cc: Lennert Buytenhek <kernel@wantstofly.org> Cc: Ben Dooks <ben-linux@fluff.org> Tested-by: Jamie Iles <jamie@jamieiles.com> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Krzysztof Halasa <khc@pm.waw.pl> Acked-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
122 lines
2.9 KiB
C
122 lines
2.9 KiB
C
/*
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* Copyright (c) 2011 Picochip Ltd., Jamie Iles
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* All enquiries to support@picochip.com
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*/
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#include <linux/dw_apb_timer.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <asm/mach/time.h>
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#include <asm/sched_clock.h>
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#include "common.h"
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static void timer_get_base_and_rate(struct device_node *np,
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void __iomem **base, u32 *rate)
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{
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*base = of_iomap(np, 0);
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if (!*base)
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panic("Unable to map regs for %s", np->name);
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if (of_property_read_u32(np, "clock-freq", rate))
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panic("No clock-freq property for %s", np->name);
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}
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static void picoxcell_add_clockevent(struct device_node *event_timer)
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{
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void __iomem *iobase;
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struct dw_apb_clock_event_device *ced;
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u32 irq, rate;
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irq = irq_of_parse_and_map(event_timer, 0);
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if (irq == NO_IRQ)
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panic("No IRQ for clock event timer");
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timer_get_base_and_rate(event_timer, &iobase, &rate);
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ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq,
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rate);
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if (!ced)
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panic("Unable to initialise clockevent device");
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dw_apb_clockevent_register(ced);
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}
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static void picoxcell_add_clocksource(struct device_node *source_timer)
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{
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void __iomem *iobase;
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struct dw_apb_clocksource *cs;
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u32 rate;
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timer_get_base_and_rate(source_timer, &iobase, &rate);
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cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate);
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if (!cs)
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panic("Unable to initialise clocksource device");
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dw_apb_clocksource_start(cs);
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dw_apb_clocksource_register(cs);
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}
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static void __iomem *sched_io_base;
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unsigned u32 notrace picoxcell_read_sched_clock(void)
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{
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return __raw_readl(sched_io_base);
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}
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static const struct of_device_id picoxcell_rtc_ids[] __initconst = {
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{ .compatible = "picochip,pc3x2-rtc" },
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{ /* Sentinel */ },
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};
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static void picoxcell_init_sched_clock(void)
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{
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struct device_node *sched_timer;
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u32 rate;
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sched_timer = of_find_matching_node(NULL, picoxcell_rtc_ids);
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if (!sched_timer)
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panic("No RTC for sched clock to use");
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timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
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of_node_put(sched_timer);
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setup_sched_clock(picoxcell_read_sched_clock, 32, rate);
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}
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static const struct of_device_id picoxcell_timer_ids[] __initconst = {
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{ .compatible = "picochip,pc3x2-timer" },
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{},
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};
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static void __init picoxcell_timer_init(void)
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{
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struct device_node *event_timer, *source_timer;
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event_timer = of_find_matching_node(NULL, picoxcell_timer_ids);
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if (!event_timer)
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panic("No timer for clockevent");
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picoxcell_add_clockevent(event_timer);
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source_timer = of_find_matching_node(event_timer, picoxcell_timer_ids);
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if (!source_timer)
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panic("No timer for clocksource");
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picoxcell_add_clocksource(source_timer);
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of_node_put(source_timer);
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picoxcell_init_sched_clock();
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}
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struct sys_timer picoxcell_timer = {
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.init = picoxcell_timer_init,
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};
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