[PATCH] arch_timer: Move delay timer to drivers clocksource
Rob Herring
robherring2 at gmail.com
Wed Jan 15 10:41:48 EST 2014
On Wed, Jan 15, 2014 at 7:07 AM, Prashant Gaikwad <pgaikwad at nvidia.com> wrote:
> Now arch timer is registerd using generic sched timer, delay
> timer registration is the only part remaining in arch ports.
> Move this part to drivers clocksource and remove arch timer
> from arch ports.
>
> Signed-off-by: Prashant Gaikwad <pgaikwad at nvidia.com>
> ---
> arch/arm/include/asm/arch_timer.h | 1 -
> arch/arm/kernel/Makefile | 1 -
> arch/arm/kernel/arch_timer.c | 44 ----------------------------------
> arch/arm64/include/asm/arch_timer.h | 5 ----
> arch/arm64/include/asm/delay.h | 32 ++++++++++++++++++++++++
> arch/arm64/include/asm/timex.h | 5 +--
> arch/arm64/kernel/time.c | 9 -------
> arch/arm64/lib/delay.c | 26 ++++++++++++++++++++
> drivers/clocksource/arm_arch_timer.c | 12 ++++++++-
> 9 files changed, 71 insertions(+), 64 deletions(-)
> delete mode 100644 arch/arm/kernel/arch_timer.c
> create mode 100644 arch/arm64/include/asm/delay.h
>
> diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h
> index 0704e0c..61ad692 100644
> --- a/arch/arm/include/asm/arch_timer.h
> +++ b/arch/arm/include/asm/arch_timer.h
> @@ -10,7 +10,6 @@
> #include <clocksource/arm_arch_timer.h>
>
> #ifdef CONFIG_ARM_ARCH_TIMER
> -int arch_timer_arch_init(void);
>
> /*
> * These register accessors are marked inline so the compiler can
> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index a30fc9b..6b51cf9 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -45,7 +45,6 @@ obj-$(CONFIG_SMP) += smp_tlb.o
> endif
> obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o
> obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o
> -obj-$(CONFIG_ARM_ARCH_TIMER) += arch_timer.o
> obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o
> obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o
> obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o
> diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
> deleted file mode 100644
> index 1791f12..0000000
> --- a/arch/arm/kernel/arch_timer.c
> +++ /dev/null
> @@ -1,44 +0,0 @@
> -/*
> - * linux/arch/arm/kernel/arch_timer.c
> - *
> - * Copyright (C) 2011 ARM Ltd.
> - * All Rights Reserved
> - *
> - * 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.
> - */
> -#include <linux/init.h>
> -#include <linux/types.h>
> -#include <linux/errno.h>
> -
> -#include <asm/delay.h>
> -
> -#include <clocksource/arm_arch_timer.h>
> -
> -static unsigned long arch_timer_read_counter_long(void)
> -{
> - return arch_timer_read_counter();
> -}
> -
> -static struct delay_timer arch_delay_timer;
> -
> -static void __init arch_timer_delay_timer_register(void)
> -{
> - /* Use the architected timer for the delay loop. */
> - arch_delay_timer.read_current_timer = arch_timer_read_counter_long;
> - arch_delay_timer.freq = arch_timer_get_rate();
> - register_current_timer_delay(&arch_delay_timer);
> -}
> -
> -int __init arch_timer_arch_init(void)
> -{
> - u32 arch_timer_rate = arch_timer_get_rate();
> -
> - if (arch_timer_rate == 0)
> - return -ENXIO;
> -
> - arch_timer_delay_timer_register();
> -
> - return 0;
> -}
> diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
> index 9400596..48e06bd 100644
> --- a/arch/arm64/include/asm/arch_timer.h
> +++ b/arch/arm64/include/asm/arch_timer.h
> @@ -145,9 +145,4 @@ static inline u64 arch_counter_get_cntvct(void)
> return cval;
> }
>
> -static inline int arch_timer_arch_init(void)
> -{
> - return 0;
> -}
> -
> #endif
> diff --git a/arch/arm64/include/asm/delay.h b/arch/arm64/include/asm/delay.h
> new file mode 100644
> index 0000000..ea90d99
> --- /dev/null
> +++ b/arch/arm64/include/asm/delay.h
> @@ -0,0 +1,32 @@
> +
> +/*
> + * Copyright (c) 2014, NVIDIA Corporation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef __ASM_ARM64_DELAY_H
> +#define __ASM_ARM64_DELAY_H
> +
> +#include <asm-generic/delay.h>
> +
> +struct delay_timer {
> + unsigned long (*read_current_timer)(void);
> + unsigned long freq;
> +};
> +
> +/* Delay-loop timer registration. */
> +#define ARCH_HAS_READ_CURRENT_TIMER
> +extern void register_current_timer_delay(const struct delay_timer *timer);
Can't all but the define be moved to a common location?
> +
> +#endif /* defined(_ARM64_DELAY_H) */
> diff --git a/arch/arm64/include/asm/timex.h b/arch/arm64/include/asm/timex.h
> index 81a076e..ca4bdfb 100644
> --- a/arch/arm64/include/asm/timex.h
> +++ b/arch/arm64/include/asm/timex.h
> @@ -16,13 +16,12 @@
> #ifndef __ASM_TIMEX_H
> #define __ASM_TIMEX_H
>
> -#include <asm/arch_timer.h>
> -
> /*
> * Use the current timer as a cycle counter since this is what we use for
> * the delay loop.
> */
> -#define get_cycles() arch_counter_get_cntvct()
> +typedef unsigned long cycles_t;
> +#define get_cycles() ({ cycles_t c; read_current_timer(&c) ? 0 : c; })
Could be in a common location conditional on ARCH_HAS_READ_CURRENT_TIMER.
> #include <asm-generic/timex.h>
>
> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
> index 29c39d5..213d1a3 100644
> --- a/arch/arm64/kernel/time.c
> +++ b/arch/arm64/kernel/time.c
> @@ -63,14 +63,5 @@ EXPORT_SYMBOL(profile_pc);
>
> void __init time_init(void)
> {
> - u32 arch_timer_rate;
> -
> clocksource_of_init();
> -
> - arch_timer_rate = arch_timer_get_rate();
> - if (!arch_timer_rate)
> - panic("Unable to initialise architected timer.\n");
> -
> - /* Calibrate the delay loop directly */
> - lpj_fine = arch_timer_rate / HZ;
> }
> diff --git a/arch/arm64/lib/delay.c b/arch/arm64/lib/delay.c
> index dad4ec9..cde0a28 100644
> --- a/arch/arm64/lib/delay.c
> +++ b/arch/arm64/lib/delay.c
> @@ -24,6 +24,19 @@
> #include <linux/module.h>
> #include <linux/timex.h>
>
> +static const struct delay_timer *delay_timer;
> +static bool delay_calibrated;
> +
> +int read_current_timer(unsigned long *timer_val)
> +{
> + if (!delay_timer)
> + return -ENXIO;
> +
> + *timer_val = delay_timer->read_current_timer();
> + return 0;
> +}
> +EXPORT_SYMBOL(read_current_timer);
> +
This too could be common.
> void __delay(unsigned long cycles)
> {
> cycles_t start = get_cycles();
> @@ -53,3 +66,16 @@ void __ndelay(unsigned long nsecs)
> __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
> }
> EXPORT_SYMBOL(__ndelay);
> +
> +void register_current_timer_delay(const struct delay_timer *timer)
> +{
> + if (!delay_calibrated) {
> + pr_info("Switching to timer-based delay loop\n");
> + delay_timer = timer;
> + lpj_fine = timer->freq / HZ;
> +
> + delay_calibrated = true;
> + } else {
> + pr_info("Ignoring duplicate/late registration of read_current_timer delay\n");
> + }
> +}
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 57e823c..8ee9918 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -422,6 +422,16 @@ struct timecounter *arch_timer_get_timecounter(void)
> return &timecounter;
> }
>
> +static struct delay_timer arch_delay_timer;
> +
> +static void __init arch_delay_timer_register(void)
> +{
> + /* Use the architected timer for the delay loop. */
> + arch_delay_timer.read_current_timer = arch_timer_read_counter();
> + arch_delay_timer.freq = arch_timer_rate;
> + register_current_timer_delay(&arch_delay_timer);
> +}
> +
> static void __init arch_counter_register(unsigned type)
> {
> u64 start_count;
> @@ -630,7 +640,7 @@ static void __init arch_timer_common_init(void)
>
> arch_timer_banner(arch_timers_present);
> arch_counter_register(arch_timers_present);
> - arch_timer_arch_init();
> + arch_delay_timer_register();
> }
>
> static void __init arch_timer_init(struct device_node *np)
> --
> 1.7.4.1
>
>
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