Commit a2c5d4ed authored by James Hogan's avatar James Hogan

metag: Time keeping

Add time keeping code for metag. Meta hardware threads have 2 timers.
The background timer (TXTIMER) is used as a free-running time base, and
the interrupt timer (TXTIMERI) is used for the timer interrupt. Both
counters traditionally count at approximately 1MHz.
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
parent bc3966bf
......@@ -5039,6 +5039,7 @@ S: Supported
F: arch/metag/
F: Documentation/metag/
F: Documentation/devicetree/bindings/metag/
F: drivers/clocksource/metag_generic.c
MICROBLAZE ARCHITECTURE
M: Michal Simek <monstr@monstr.eu>
......
/*
* arch/metag/include/asm/clock.h
*
* Copyright (C) 2012 Imagination Technologies Ltd.
*
* 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.
*/
#ifndef _METAG_CLOCK_H_
#define _METAG_CLOCK_H_
#include <asm/mach/arch.h>
/**
* struct meta_clock_desc - Meta Core clock callbacks.
* @get_core_freq: Get the frequency of the Meta core. If this is NULL, the
* core frequency will be determined like this:
* Meta 1: based on loops_per_jiffy.
* Meta 2: (EXPAND_TIMER_DIV + 1) MHz.
*/
struct meta_clock_desc {
unsigned long (*get_core_freq)(void);
};
extern struct meta_clock_desc _meta_clock;
/*
* Set up the default clock, ensuring all callbacks are valid - only accessible
* during boot.
*/
void setup_meta_clocks(struct meta_clock_desc *desc);
/**
* get_coreclock() - Get the frequency of the Meta core clock.
*
* Returns: The Meta core clock frequency in Hz.
*/
static inline unsigned long get_coreclock(void)
{
/*
* Use the current clock callback. If set correctly this will provide
* the most accurate frequency as it can be calculated directly from the
* PLL configuration. otherwise a default callback will have been set
* instead.
*/
return _meta_clock.get_core_freq();
}
#endif /* _METAG_CLOCK_H_ */
#ifndef _METAG_DELAY_H
#define _METAG_DELAY_H
/*
* Copyright (C) 1993 Linus Torvalds
*
* Delay routines calling functions in arch/metag/lib/delay.c
*/
/* Undefined functions to get compile-time errors */
extern void __bad_udelay(void);
extern void __bad_ndelay(void);
extern void __udelay(unsigned long usecs);
extern void __ndelay(unsigned long nsecs);
extern void __const_udelay(unsigned long xloops);
extern void __delay(unsigned long loops);
/* 0x10c7 is 2**32 / 1000000 (rounded up) */
#define udelay(n) (__builtin_constant_p(n) ? \
((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
__udelay(n))
/* 0x5 is 2**32 / 1000000000 (rounded up) */
#define ndelay(n) (__builtin_constant_p(n) ? \
((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
__ndelay(n))
#endif /* _METAG_DELAY_H */
......@@ -16,10 +16,13 @@
#include <linux/stddef.h>
#include <asm/clock.h>
/**
* struct machine_desc - Describes a board controlled by a Meta.
* @name: Board/SoC name.
* @dt_compat: Array of device tree 'compatible' strings.
* @clocks: Clock callbacks.
*
* @nr_irqs: Maximum number of IRQs.
* If 0, defaults to NR_IRQS in asm-generic/irq.h.
......@@ -37,6 +40,7 @@
struct machine_desc {
const char *name;
const char **dt_compat;
struct meta_clock_desc *clocks;
unsigned int nr_irqs;
......
/*
* arch/metag/kernel/clock.c
*
* Copyright (C) 2012 Imagination Technologies Ltd.
*
* 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/delay.h>
#include <linux/io.h>
#include <asm/param.h>
#include <asm/clock.h>
struct meta_clock_desc _meta_clock;
/* Default machine get_core_freq callback. */
static unsigned long get_core_freq_default(void)
{
#ifdef CONFIG_METAG_META21
/*
* Meta 2 cores divide down the core clock for the Meta timers, so we
* can estimate the core clock from the divider.
*/
return (metag_in32(EXPAND_TIMER_DIV) + 1) * 1000000;
#else
/*
* On Meta 1 we don't know the core clock, but assuming the Meta timer
* is correct it can be estimated based on loops_per_jiffy.
*/
return (loops_per_jiffy * HZ * 5) >> 1;
#endif
}
/**
* setup_meta_clocks() - Set up the Meta clock.
* @desc: Clock descriptor usually provided by machine description
*
* Ensures all callbacks are valid.
*/
void __init setup_meta_clocks(struct meta_clock_desc *desc)
{
/* copy callbacks */
if (desc)
_meta_clock = *desc;
/* set fallback functions */
if (!_meta_clock.get_core_freq)
_meta_clock.get_core_freq = get_core_freq_default;
}
/*
* Copyright (C) 2005-2013 Imagination Technologies Ltd.
*
* This file contains the Meta-specific time handling details.
*
*/
#include <linux/init.h>
#include <clocksource/metag_generic.h>
void __init time_init(void)
{
metag_generic_timer_init();
}
......@@ -58,3 +58,8 @@ config CLKSRC_ARM_GENERIC
def_bool y if ARM64
help
This option enables support for the ARM generic timer.
config CLKSRC_METAG_GENERIC
def_bool y if METAG
help
This option enables support for the Meta per-thread timers.
......@@ -18,3 +18,4 @@ obj-$(CONFIG_ARCH_BCM2835) += bcm2835_timer.o
obj-$(CONFIG_SUNXI_TIMER) += sunxi_timer.o
obj-$(CONFIG_CLKSRC_ARM_GENERIC) += arm_generic.o
obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o
/*
* Copyright (C) 2005-2013 Imagination Technologies Ltd.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* Support for Meta per-thread timers.
*
* Meta hardware threads have 2 timers. The background timer (TXTIMER) is used
* as a free-running time base (hz clocksource), and the interrupt timer
* (TXTIMERI) is used for the timer interrupt (clock event). Both counters
* traditionally count at approximately 1MHz.
*/
#include <clocksource/metag_generic.h>
#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <asm/clock.h>
#include <asm/hwthread.h>
#include <asm/core_reg.h>
#include <asm/metag_mem.h>
#include <asm/tbx.h>
#define HARDWARE_FREQ 1000000 /* 1MHz */
#define HARDWARE_DIV 1 /* divide by 1 = 1MHz clock */
#define HARDWARE_TO_NS_SHIFT 10 /* convert ticks to ns */
static unsigned int hwtimer_freq = HARDWARE_FREQ;
static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);
static DEFINE_PER_CPU(char [11], local_clockevent_name);
static int metag_timer_set_next_event(unsigned long delta,
struct clock_event_device *dev)
{
__core_reg_set(TXTIMERI, -delta);
return 0;
}
static void metag_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_RESUME:
break;
case CLOCK_EVT_MODE_SHUTDOWN:
/* We should disable the IRQ here */
break;
case CLOCK_EVT_MODE_PERIODIC:
case CLOCK_EVT_MODE_UNUSED:
WARN_ON(1);
break;
};
}
static cycle_t metag_clocksource_read(struct clocksource *cs)
{
return __core_reg_get(TXTIMER);
}
static struct clocksource clocksource_metag = {
.name = "META",
.rating = 200,
.mask = CLOCKSOURCE_MASK(32),
.read = metag_clocksource_read,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static irqreturn_t metag_timer_interrupt(int irq, void *dummy)
{
struct clock_event_device *evt = &__get_cpu_var(local_clockevent);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction metag_timer_irq = {
.name = "META core timer",
.handler = metag_timer_interrupt,
.flags = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU,
};
unsigned long long sched_clock(void)
{
unsigned long long ticks = __core_reg_get(TXTIMER);
return ticks << HARDWARE_TO_NS_SHIFT;
}
static void __cpuinit arch_timer_setup(unsigned int cpu)
{
unsigned int txdivtime;
struct clock_event_device *clk = &per_cpu(local_clockevent, cpu);
char *name = per_cpu(local_clockevent_name, cpu);
txdivtime = __core_reg_get(TXDIVTIME);
txdivtime &= ~TXDIVTIME_DIV_BITS;
txdivtime |= (HARDWARE_DIV & TXDIVTIME_DIV_BITS);
__core_reg_set(TXDIVTIME, txdivtime);
sprintf(name, "META %d", cpu);
clk->name = name;
clk->features = CLOCK_EVT_FEAT_ONESHOT,
clk->rating = 200,
clk->shift = 12,
clk->irq = tbisig_map(TBID_SIGNUM_TRT),
clk->set_mode = metag_timer_set_mode,
clk->set_next_event = metag_timer_set_next_event,
clk->mult = div_sc(hwtimer_freq, NSEC_PER_SEC, clk->shift);
clk->max_delta_ns = clockevent_delta2ns(0x7fffffff, clk);
clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
clk->cpumask = cpumask_of(cpu);
clockevents_register_device(clk);
/*
* For all non-boot CPUs we need to synchronize our free
* running clock (TXTIMER) with the boot CPU's clock.
*
* While this won't be accurate, it should be close enough.
*/
if (cpu) {
unsigned int thread0 = cpu_2_hwthread_id[0];
unsigned long val;
val = core_reg_read(TXUCT_ID, TXTIMER_REGNUM, thread0);
__core_reg_set(TXTIMER, val);
}
}
static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
int cpu = (long)hcpu;
switch (action) {
case CPU_STARTING:
case CPU_STARTING_FROZEN:
arch_timer_setup(cpu);
break;
}
return NOTIFY_OK;
}
static struct notifier_block __cpuinitdata arch_timer_cpu_nb = {
.notifier_call = arch_timer_cpu_notify,
};
int __init metag_generic_timer_init(void)
{
/*
* On Meta 2 SoCs, the actual frequency of the timer is based on the
* Meta core clock speed divided by an integer, so it is only
* approximately 1MHz. Calculating the real frequency here drastically
* reduces clock skew on these SoCs.
*/
#ifdef CONFIG_METAG_META21
hwtimer_freq = get_coreclock() / (metag_in32(EXPAND_TIMER_DIV) + 1);
#endif
clocksource_register_hz(&clocksource_metag, hwtimer_freq);
setup_irq(tbisig_map(TBID_SIGNUM_TRT), &metag_timer_irq);
/* Configure timer on boot CPU */
arch_timer_setup(smp_processor_id());
/* Hook cpu boot to configure other CPU's timers */
register_cpu_notifier(&arch_timer_cpu_nb);
return 0;
}
/*
* Copyright (C) 2013 Imaginaton Technologies Ltd.
*
* 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.
*
* 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 __CLKSOURCE_METAG_GENERIC_H
#define __CLKSOURCE_METAG_GENERIC_H
extern int metag_generic_timer_init(void);
#endif /* __CLKSOURCE_METAG_GENERIC_H */
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