From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Hogan Subject: [PATCH v2 22/44] metag: Time keeping Date: Wed, 5 Dec 2012 16:08:40 +0000 Message-ID: <1354723742-6195-23-git-send-email-james.hogan@imgtec.com> References: <1354723742-6195-1-git-send-email-james.hogan@imgtec.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from multi.imgtec.com ([194.200.65.239]:51616 "EHLO multi.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753292Ab2LEQJf (ORCPT ); Wed, 5 Dec 2012 11:09:35 -0500 In-Reply-To: <1354723742-6195-1-git-send-email-james.hogan@imgtec.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Arnd Bergmann , James Hogan 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: James Hogan --- arch/metag/include/asm/clock.h | 51 +++++++++++ arch/metag/include/asm/delay.h | 29 +++++++ arch/metag/include/asm/mach/arch.h | 4 + arch/metag/kernel/clock.c | 53 ++++++++++++ arch/metag/kernel/time.c | 163 ++++++++++++++++++++++++++++++++++++ 5 files changed, 300 insertions(+), 0 deletions(-) create mode 100644 arch/metag/include/asm/clock.h create mode 100644 arch/metag/include/asm/delay.h create mode 100644 arch/metag/kernel/clock.c create mode 100644 arch/metag/kernel/time.c diff --git a/arch/metag/include/asm/clock.h b/arch/metag/include/asm/clock.h new file mode 100644 index 0000000..3e2915a --- /dev/null +++ b/arch/metag/include/asm/clock.h @@ -0,0 +1,51 @@ +/* + * 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 + +/** + * 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_ */ diff --git a/arch/metag/include/asm/delay.h b/arch/metag/include/asm/delay.h new file mode 100644 index 0000000..9c92f99 --- /dev/null +++ b/arch/metag/include/asm/delay.h @@ -0,0 +1,29 @@ +#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 */ diff --git a/arch/metag/include/asm/mach/arch.h b/arch/metag/include/asm/mach/arch.h index 8429c76..230d896 100644 --- a/arch/metag/include/asm/mach/arch.h +++ b/arch/metag/include/asm/mach/arch.h @@ -16,10 +16,13 @@ #include +#include + /** * 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. * * @init_early: Early init callback. * @init_irq: IRQ init callback for setting up IRQ controllers. @@ -34,6 +37,7 @@ struct machine_desc { const char *name; const char **dt_compat; + struct meta_clock_desc *clocks; void (*init_early)(void); void (*init_irq)(void); diff --git a/arch/metag/kernel/clock.c b/arch/metag/kernel/clock.c new file mode 100644 index 0000000..defc840 --- /dev/null +++ b/arch/metag/kernel/clock.c @@ -0,0 +1,53 @@ +/* + * 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 +#include + +#include +#include + +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; +} + diff --git a/arch/metag/kernel/time.c b/arch/metag/kernel/time.c new file mode 100644 index 0000000..6df41b8 --- /dev/null +++ b/arch/metag/kernel/time.c @@ -0,0 +1,163 @@ +/* + * Copyright (C) 2005,2006,2007,2008 Imagination Technologies Ltd. + * + * This file contains the Meta-specific time handling details. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#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) +{ + TBI_SETREG(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 inline cycle_t txtimer_read(void) +{ + unsigned int ret; + + __asm__ volatile ("MOV %0, TXTIMER\n" : "=r" (ret)); + return ret; +} + +static cycle_t metag_clocksource_read(struct clocksource *cs) +{ + return txtimer_read(); +} + +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 = txtimer_read(); + return ticks << HARDWARE_TO_NS_SHIFT; +} + +void __cpuinit local_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 = TBI_GETREG(TXDIVTIME); + + txdivtime &= ~TXDIVTIME_DIV_BITS; + txdivtime |= (HARDWARE_DIV & TXDIVTIME_DIV_BITS); + + TBI_SETREG(TXDIVTIME, txdivtime); + + sprintf(name, "META %d", cpu); + clk->name = name; + clk->features = CLOCK_EVT_FEAT_ONESHOT, + + clk->rating = 200, + clk->shift = 12, + clk->irq = 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); + + asm volatile("MOV TXTIMER, %0\n" : : "r" (val)); + } +} + +void __init time_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(TBID_SIGNUM_TRT, &metag_timer_irq); + + local_timer_setup(smp_processor_id()); +} -- 1.7.7.6