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    Subject[PATCH 20/28] nios2: Time keeping
    Date
    Add time keeping code for nios2.

    Signed-off-by: Ley Foon Tan <lftan@altera.com>
    ---
    arch/nios2/include/asm/delay.h | 92 +++++++++++++++++++++++++
    arch/nios2/include/asm/timex.h | 27 ++++++++
    arch/nios2/kernel/time.c | 150 +++++++++++++++++++++++++++++++++++++++++
    3 files changed, 269 insertions(+)
    create mode 100644 arch/nios2/include/asm/delay.h
    create mode 100644 arch/nios2/include/asm/timex.h
    create mode 100644 arch/nios2/kernel/time.c

    diff --git a/arch/nios2/include/asm/delay.h b/arch/nios2/include/asm/delay.h
    new file mode 100644
    index 0000000..8070a09
    --- /dev/null
    +++ b/arch/nios2/include/asm/delay.h
    @@ -0,0 +1,92 @@
    +/*
    + * Copyright (C) 2004 Microtronix Datacom Ltd
    + *
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + */
    +
    +#ifndef _ASM_NIOS2_DELAY_H
    +#define _ASM_NIOS2_DELAY_H
    +
    +#include <asm/param.h>
    +
    +static inline void __delay(unsigned long loops)
    +{
    + int dummy;
    +
    + __asm__ __volatile__(
    + "1:\n\t"
    + " beq %0,zero,2f\n\t"
    + " addi %0, %0, -1\n\t"
    + " br 1b\n\t"
    + "2:\n\t"
    + : "=r" (dummy) /* Need output for optimizer */
    + : "0" (loops)); /* %0 Input */
    +}
    +
    +/*
    + * Note that 19 * 226 == 4294 ==~ 2^32 / 10^6, so
    + * loops = (4294 * usecs * loops_per_jiffy * HZ) / 2^32.
    + *
    + * The mul instruction gives us loops = (a * b) / 2^32.
    + * We choose a = usecs * 19 * HZ and b = loops_per_jiffy * 226
    + * because this lets us support a wide range of HZ and
    + * loops_per_jiffy values without either a or b overflowing 2^32.
    + * Thus we need usecs * HZ <= (2^32 - 1) / 19 = 226050910 and
    + * loops_per_jiffy <= (2^32 - 1) / 226 = 19004280
    + * (which corresponds to ~3800 bogomips at HZ = 100).
    + * -- paulus
    + */
    +#define __MAX_UDELAY (226050910UL/HZ) /* maximum udelay argument */
    +#define __MAX_NDELAY (4294967295UL/HZ) /* maximum ndelay argument */
    +
    +extern unsigned long loops_per_jiffy;
    +
    +static inline void __udelay(unsigned int x)
    +{
    + unsigned int loops;
    +
    + /*
    + * Note, if this is compiled with -mhw-mulx it will produce a "mulxuu"
    + * (at least in toolchain 145) so there is no need for inline
    + * assembly here anymore, which might in turn be emulated if unsupported
    + * by the design.
    + */
    + loops = (unsigned int)((((unsigned long long)(x) *
    + (unsigned long long)(loops_per_jiffy * 226))) >> 32);
    +
    +/*
    + __asm__("mulxuu %0,%1,%2" : "=r" (loops) :
    + "r" (x), "r" (loops_per_jiffy * 226));
    +*/
    + __delay(loops);
    +}
    +
    +static inline void __ndelay(unsigned int x)
    +{
    + unsigned int loops;
    +
    + /* see comment in __udelay */
    + loops = (unsigned int)((((unsigned long long)(x) *
    + (unsigned long long)(loops_per_jiffy * 5))) >> 32);
    +
    +/*
    + __asm__("mulxuu %0,%1,%2" : "=r" (loops) :
    + "r" (x), "r" (loops_per_jiffy * 5));
    +*/
    + __delay(loops);
    +}
    +
    +extern void __bad_udelay(void); /* deliberately undefined */
    +extern void __bad_ndelay(void); /* deliberately undefined */
    +
    +#define udelay(n) (__builtin_constant_p(n) ? \
    + ((n) > __MAX_UDELAY ? __bad_udelay() : __udelay((n) * (19 * HZ))) : \
    + __udelay((n) * (19 * HZ)))
    +
    +#define ndelay(n) (__builtin_constant_p(n) ? \
    + ((n) > __MAX_NDELAY ? __bad_ndelay() : __ndelay((n) * HZ)) : \
    + __ndelay((n) * HZ))
    +
    +#endif /* _ASM_NIOS2_DELAY_H */
    diff --git a/arch/nios2/include/asm/timex.h b/arch/nios2/include/asm/timex.h
    new file mode 100644
    index 0000000..524b47d79d3dad53b98713f31517e28ac0c99d98
    --- /dev/null
    +++ b/arch/nios2/include/asm/timex.h
    @@ -0,0 +1,27 @@
    +/*
    + * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * 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 _ASM_NIOS2_TIMEX_H
    +#define _ASM_NIOS2_TIMEX_H
    +
    +/* Supply dummy tick-rate. Real value will be read from devicetree */
    +#define CLOCK_TICK_RATE (HZ * 100000UL)
    +
    +#include <asm-generic/timex.h>
    +
    +#endif
    diff --git a/arch/nios2/kernel/time.c b/arch/nios2/kernel/time.c
    new file mode 100644
    index 0000000..0677ebaa1dffd8213f52a704c6a8366d34c05ca2
    --- /dev/null
    +++ b/arch/nios2/kernel/time.c
    @@ -0,0 +1,150 @@
    +/*
    + * Copyright (C) 2013 Altera Corporation
    + * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
    + * Copyright (C) 2004 Microtronix Datacom Ltd.
    + *
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + */
    +
    +#include <linux/init.h>
    +#include <linux/sched.h>
    +#include <linux/interrupt.h>
    +#include <linux/time.h>
    +#include <linux/timex.h>
    +#include <linux/profile.h>
    +#include <linux/clocksource.h>
    +#include <linux/of.h>
    +#include <linux/of_address.h>
    +#include <linux/of_irq.h>
    +#include <linux/io.h>
    +
    +#define TICK_SIZE (tick_nsec / 1000)
    +#define NIOS2_TIMER_PERIOD (timer_freq / HZ)
    +
    +#define ALTERA_TIMER_STATUS_REG 0
    +#define ALTERA_TIMER_CONTROL_REG 4
    +#define ALTERA_TIMER_PERIODL_REG 8
    +#define ALTERA_TIMER_PERIODH_REG 12
    +#define ALTERA_TIMER_SNAPL_REG 16
    +#define ALTERA_TIMER_SNAPH_REG 20
    +
    +#define ALTERA_TIMER_CONTROL_ITO_MSK (0x1)
    +#define ALTERA_TIMER_CONTROL_CONT_MSK (0x2)
    +#define ALTERA_TIMER_CONTROL_START_MSK (0x4)
    +#define ALTERA_TIMER_CONTROL_STOP_MSK (0x8)
    +
    +static u32 nios2_timer_count;
    +static void __iomem *timer_membase;
    +static u32 timer_freq;
    +
    +static inline unsigned long read_timersnapshot(void)
    +{
    + unsigned long count;
    +
    + outw(0, timer_membase + ALTERA_TIMER_SNAPL_REG);
    + count =
    + inw(timer_membase + ALTERA_TIMER_SNAPH_REG) << 16 |
    + inw(timer_membase + ALTERA_TIMER_SNAPL_REG);
    +
    + return count;
    +}
    +
    +static inline void write_timerperiod(unsigned long period)
    +{
    + outw(period, timer_membase + ALTERA_TIMER_PERIODL_REG);
    + outw(period >> 16, timer_membase + ALTERA_TIMER_PERIODH_REG);
    +}
    +
    +/*
    + * timer_interrupt() needs to keep up the real-time clock,
    + * as well as call the "xtime_update()" routine every clocktick
    + */
    +irqreturn_t timer_interrupt(int irq, void *dummy)
    +{
    + /* Clear the interrupt condition */
    + outw(0, timer_membase + ALTERA_TIMER_STATUS_REG);
    + nios2_timer_count += NIOS2_TIMER_PERIOD;
    +
    + profile_tick(CPU_PROFILING);
    +
    + xtime_update(1);
    +
    + update_process_times(user_mode(get_irq_regs()));
    +
    + return IRQ_HANDLED;
    +}
    +
    +static cycle_t nios2_timer_read(struct clocksource *cs)
    +{
    + unsigned long flags;
    + u32 cycles;
    + u32 tcn;
    +
    + local_irq_save(flags);
    + tcn = NIOS2_TIMER_PERIOD - 1 - read_timersnapshot();
    + cycles = nios2_timer_count;
    + local_irq_restore(flags);
    +
    + return cycles + tcn;
    +}
    +
    +static struct clocksource nios2_timer = {
    + .name = "timer",
    + .rating = 250,
    + .read = nios2_timer_read,
    + .shift = 20,
    + .mask = CLOCKSOURCE_MASK(32),
    + .flags = CLOCK_SOURCE_IS_CONTINUOUS,
    +};
    +
    +static struct irqaction nios2_timer_irq = {
    + .name = "timer",
    + .flags = IRQF_TIMER,
    + .handler = timer_interrupt,
    +};
    +
    +static void __init nios2_time_init(struct device_node *timer)
    +{
    + int irq;
    + unsigned int ctrl;
    +
    + timer_membase = of_iomap(timer, 0);
    + if (!timer_membase)
    + panic("Unable to map timer resource\n");
    +
    + if (of_property_read_u32(timer, "clock-frequency", &timer_freq))
    + panic("Unable to get timer clock frequency\n");
    +
    + irq = irq_of_parse_and_map(timer, 0);
    + if (irq < 0)
    + panic("Unable to parse timer irq\n");
    +
    + if (setup_irq(irq, &nios2_timer_irq))
    + panic("Unable to setup timer irq\n");
    +
    + write_timerperiod(NIOS2_TIMER_PERIOD - 1);
    +
    + /* clocksource initialize */
    + nios2_timer.mult = clocksource_hz2mult(timer_freq, nios2_timer.shift);
    + clocksource_register(&nios2_timer);
    +
    + /* interrupt enable + continuous + start */
    + ctrl = ALTERA_TIMER_CONTROL_ITO_MSK | ALTERA_TIMER_CONTROL_CONT_MSK |
    + ALTERA_TIMER_CONTROL_START_MSK;
    + outw(ctrl, timer_membase + ALTERA_TIMER_CONTROL_REG);
    +}
    +
    +void read_persistent_clock(struct timespec *ts)
    +{
    + ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
    + ts->tv_nsec = 0;
    +}
    +
    +void __init time_init(void)
    +{
    + clocksource_of_init();
    +}
    +
    +CLOCKSOURCE_OF_DECLARE(nios2_timer, "ALTR,timer-1.0", nios2_time_init);
    --
    1.8.3.2


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