Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 220e2a8d authored by Pawel Moll's avatar Pawel Moll
Browse files

clocksource: Sched clock source for Versatile Express 



This patch adds a trival sched clock source using free
running, 24MHz clocked counter present in the ARM Ltd.
reference platforms (Versatile, RealView, Versatile
Express) System Registers block.

This code replaces the call in the VE machine code.

Signed-off-by: default avatarPawel Moll <pawel.moll@arm.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 5ee2b877

arch/arm/mach-vexpress/v2m.c

+0 −2
Original line number Diff line number Diff line
@@ -418,8 +418,6 @@ void __init v2m_dt_init_early(void) 
			pr_warning("vexpress: DT HBI (%x) is not matching "

					"hardware (%x)!\n", dt_hbi, hbi);

	}



	versatile_sched_clock_init(vexpress_get_24mhz_clock_base(), 24000000);

}

drivers/clocksource/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -191,3 +191,14 @@ config EM_TIMER_STI 


config CLKSRC_QCOM

	bool



config CLKSRC_VERSATILE

	bool "ARM Versatile (Express) reference platforms clock source"

	depends on GENERIC_SCHED_CLOCK

	select CLKSRC_OF

	default y if MFD_VEXPRESS_SYSREG

	help

	  This option enables clock source based on free running

	  counter available in the "System Registers" block of

	  ARM Versatile, RealView and Versatile Express reference

	  platforms.

drivers/clocksource/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -39,3 +39,4 @@ obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o 
obj-$(CONFIG_CLKSRC_METAG_GENERIC)	+= metag_generic.o

obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST)	+= dummy_timer.o

obj-$(CONFIG_ARCH_KEYSTONE)		+= timer-keystone.o

obj-$(CONFIG_CLKSRC_VERSATILE)		+= versatile.o

drivers/clocksource/versatile.c

0 → 100644
+40 −0
Original line number Diff line number Diff line 
/*

 * 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.

 *

 * Copyright (C) 2014 ARM Limited

 */



#include <linux/clocksource.h>

#include <linux/io.h>

#include <linux/of_address.h>

#include <linux/sched_clock.h>



#define SYS_24MHZ 0x05c



static void __iomem *versatile_sys_24mhz;



static u32 notrace versatile_sys_24mhz_read(void)

{

	return readl(versatile_sys_24mhz);

}



static void __init versatile_sched_clock_init(struct device_node *node)

{

	void __iomem *base = of_iomap(node, 0);



	if (!base)

		return;



	versatile_sys_24mhz = base + SYS_24MHZ;



	setup_sched_clock(versatile_sys_24mhz_read, 32, 24000000);

}

CLOCKSOURCE_OF_DECLARE(versatile, "arm,vexpress-sysreg",

		versatile_sched_clock_init);