diff options
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/include/asm/arcregs.h | 11 | ||||
| -rw-r--r-- | arch/arc/include/asm/clk.h | 20 | ||||
| -rw-r--r-- | arch/arc/include/asm/delay.h | 68 | ||||
| -rw-r--r-- | arch/arc/include/asm/irq.h | 2 | ||||
| -rw-r--r-- | arch/arc/include/asm/timex.h | 18 | ||||
| -rw-r--r-- | arch/arc/kernel/clk.c | 11 | ||||
| -rw-r--r-- | arch/arc/kernel/time.c | 295 |
7 files changed, 425 insertions, 0 deletions
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h index d764118..5131bb3 100644 --- a/arch/arc/include/asm/arcregs.h +++ b/arch/arc/include/asm/arcregs.h @@ -47,6 +47,17 @@ #define AUX_ITRIGGER 0x40d #define AUX_IPULSE 0x415 +/* Timer related Aux registers */ +#define ARC_REG_TIMER0_LIMIT 0x23 /* timer 0 limit */ +#define ARC_REG_TIMER0_CTRL 0x22 /* timer 0 control */ +#define ARC_REG_TIMER0_CNT 0x21 /* timer 0 count */ +#define ARC_REG_TIMER1_LIMIT 0x102 /* timer 1 limit */ +#define ARC_REG_TIMER1_CTRL 0x101 /* timer 1 control */ +#define ARC_REG_TIMER1_CNT 0x100 /* timer 1 count */ + +#define TIMER_CTRL_IE (1 << 0) /* Interupt when Count reachs limit */ +#define TIMER_CTRL_NH (1 << 1) /* Count only when CPU NOT halted */ + /* * Floating Pt Registers * Status regs are read-only (build-time) so need not be saved/restored diff --git a/arch/arc/include/asm/clk.h b/arch/arc/include/asm/clk.h new file mode 100644 index 0000000..6195643 --- /dev/null +++ b/arch/arc/include/asm/clk.h @@ -0,0 +1,20 @@ +/* + * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com) + * + * 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 _ASM_ARC_CLK_H +#define _ASM_ARC_CLK_H + +/* Although we can't really hide core_freq, the accessor is still better way */ +extern unsigned long core_freq; + +static inline unsigned long arc_get_core_freq(void) +{ + return core_freq; +} + +#endif diff --git a/arch/arc/include/asm/delay.h b/arch/arc/include/asm/delay.h new file mode 100644 index 0000000..442ce5d --- /dev/null +++ b/arch/arc/include/asm/delay.h @@ -0,0 +1,68 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * 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. + * + * Delay routines using pre computed loops_per_jiffy value. + * + * vineetg: Feb 2012 + * -Rewrote in "C" to avoid dealing with availability of H/w MPY + * -Also reduced the num of MPY operations from 3 to 2 + * + * Amit Bhor: Codito Technologies 2004 + */ + +#ifndef __ASM_ARC_UDELAY_H +#define __ASM_ARC_UDELAY_H + +#include <asm/param.h> /* HZ */ + +static inline void __delay(unsigned long loops) +{ + __asm__ __volatile__( + "1: sub.f %0, %0, 1 \n" + " jpnz 1b \n" + : "+r"(loops) + : + : "cc"); +} + +extern void __bad_udelay(void); + +/* + * Normal Math for computing loops in "N" usecs + * -we have precomputed @loops_per_jiffy + * -1 sec has HZ jiffies + * loops per "N" usecs = ((loops_per_jiffy * HZ / 1000000) * N) + * + * Approximate Division by multiplication: + * -Mathematically if we multiply and divide a number by same value the + * result remains unchanged: In this case, we use 2^32 + * -> (loops_per_N_usec * 2^32 ) / 2^32 + * -> (((loops_per_jiffy * HZ / 1000000) * N) * 2^32) / 2^32 + * -> (loops_per_jiffy * HZ * N * 4295) / 2^32 + * + * -Divide by 2^32 is very simply right shift by 32 + * -We simply need to ensure that the multiply per above eqn happens in + * 64-bit precision (if CPU doesn't support it - gcc can emaulate it) + */ + +static inline void __udelay(unsigned long usecs) +{ + unsigned long loops; + + /* (long long) cast ensures 64 bit MPY - real or emulated + * HZ * 4295 is pre-evaluated by gcc - hence only 2 mpy ops + */ + loops = ((long long)(usecs * 4295 * HZ) * + (long long)(loops_per_jiffy)) >> 32; + + __delay(loops); +} + +#define udelay(n) (__builtin_constant_p(n) ? ((n) > 20000 ? __bad_udelay() \ + : __udelay(n)) : __udelay(n)) + +#endif /* __ASM_ARC_UDELAY_H */ diff --git a/arch/arc/include/asm/irq.h b/arch/arc/include/asm/irq.h index ca4aeba..514b302 100644 --- a/arch/arc/include/asm/irq.h +++ b/arch/arc/include/asm/irq.h @@ -19,4 +19,6 @@ extern void __init arc_init_IRQ(void); extern void __init plat_init_IRQ(void); extern int __init get_hw_config_num_irq(void); +void __cpuinit arc_local_timer_setup(unsigned int cpu); + #endif diff --git a/arch/arc/include/asm/timex.h b/arch/arc/include/asm/timex.h new file mode 100644 index 0000000..0a82960 --- /dev/null +++ b/arch/arc/include/asm/timex.h @@ -0,0 +1,18 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * 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 _ASM_ARC_TIMEX_H +#define _ASM_ARC_TIMEX_H + +#define CLOCK_TICK_RATE 80000000 /* slated to be removed */ + +#include <asm-generic/timex.h> + +/* XXX: get_cycles() to be implemented with RTSC insn */ + +#endif /* _ASM_ARC_TIMEX_H */ diff --git a/arch/arc/kernel/clk.c b/arch/arc/kernel/clk.c new file mode 100644 index 0000000..64925db --- /dev/null +++ b/arch/arc/kernel/clk.c @@ -0,0 +1,11 @@ +/* + * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com) + * + * 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 <asm/clk.h> + +unsigned long core_freq = CONFIG_ARC_PLAT_CLK; diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c new file mode 100644 index 0000000..05dba11 --- /dev/null +++ b/arch/arc/kernel/time.c @@ -0,0 +1,295 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * 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. + * + * vineetg: Jan 1011 + * -sched_clock( ) no longer jiffies based. Uses the same clocksource + * as gtod + * + * Rajeshwarr/Vineetg: Mar 2008 + * -Implemented CONFIG_GENERIC_TIME (rather deleted arch specific code) + * for arch independent gettimeofday() + * -Implemented CONFIG_GENERIC_CLOCKEVENTS as base for hrtimers + * + * Vineetg: Mar 2008: Forked off from time.c which now is time-jiff.c + */ + +/* ARC700 has two 32bit independent prog Timers: TIMER0 and TIMER1 + * Each can programmed to go from @count to @limit and optionally + * interrupt when that happens. + * A write to Control Register clears the Interrupt + * + * We've designated TIMER0 for events (clockevents) + * while TIMER1 for free running (clocksource) + * + * Newer ARC700 cores have 64bit clk fetching RTSC insn, preferred over TIMER1 + */ + +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/time.h> +#include <linux/init.h> +#include <linux/timex.h> +#include <linux/profile.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <asm/irq.h> +#include <asm/arcregs.h> +#include <asm/clk.h> + +#define ARC_TIMER_MAX 0xFFFFFFFF + +/********** Clock Source Device *********/ + +#ifdef CONFIG_ARC_HAS_RTSC + +int __cpuinit arc_counter_setup(void) +{ + /* RTSC insn taps into cpu clk, needs no setup */ + + /* For SMP, only allowed if cross-core-sync, hence usable as cs */ + return 1; +} + +static cycle_t arc_counter_read(struct clocksource *cs) +{ + unsigned long flags; + union { +#ifdef CONFIG_CPU_BIG_ENDIAN + struct { u32 high, low; }; +#else + struct { u32 low, high; }; +#endif + cycle_t full; + } stamp; + + flags = arch_local_irq_save(); + + __asm__ __volatile( + " .extCoreRegister tsch, 58, r, cannot_shortcut \n" + " rtsc %0, 0 \n" + " mov %1, tsch \n" /* TSCH is extn core reg 58 */ + : "=r" (stamp.low), "=r" (stamp.high)); + + arch_local_irq_restore(flags); + + return stamp.full; +} + +static struct clocksource arc_counter = { + .name = "ARC RTSC", + .rating = 300, + .read = arc_counter_read, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +#else /* !CONFIG_ARC_HAS_RTSC */ + +static bool is_usable_as_clocksource(void) +{ +#ifdef CONFIG_SMP + return 0; +#else + return 1; +#endif +} + +/* + * set 32bit TIMER1 to keep counting monotonically and wraparound + */ +int __cpuinit arc_counter_setup(void) +{ + write_aux_reg(ARC_REG_TIMER1_LIMIT, ARC_TIMER_MAX); + write_aux_reg(ARC_REG_TIMER1_CNT, 0); + write_aux_reg(ARC_REG_TIMER1_CTRL, TIMER_CTRL_NH); + + return is_usable_as_clocksource(); +} + +static cycle_t arc_counter_read(struct clocksource *cs) +{ + return (cycle_t) read_aux_reg(ARC_REG_TIMER1_CNT); +} + +static struct clocksource arc_counter = { + .name = "ARC Timer1", + .rating = 300, + .read = arc_counter_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +#endif + +/********** Clock Event Device *********/ + +/* + * Arm the timer to interrupt after @limit cycles + * The distinction for oneshot/periodic is done in arc_event_timer_ack() below + */ +static void arc_timer_event_setup(unsigned int limit) +{ + write_aux_reg(ARC_REG_TIMER0_LIMIT, limit); + write_aux_reg(ARC_REG_TIMER0_CNT, 0); /* start from 0 */ + + write_aux_reg(ARC_REG_TIMER0_CTRL, TIMER_CTRL_IE | TIMER_CTRL_NH); +} + +/* + * Acknowledge the interrupt (oneshot) and optionally re-arm it (periodic) + * -Any write to CTRL Reg will ack the intr (NH bit: Count when not halted) + * -Rearming is done by setting the IE bit + * + * Small optimisation: Normal code would have been + * if (irq_reenable) + * CTRL_REG = (IE | NH); + * else + * CTRL_REG = NH; + * However since IE is BIT0 we can fold the branch + */ +static void arc_timer_event_ack(unsigned int irq_reenable) +{ + write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | TIMER_CTRL_NH); +} + +static int arc_clkevent_set_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + arc_timer_event_setup(delta); + return 0; +} + +static void arc_clkevent_set_mode(enum clock_event_mode mode, + struct clock_event_device *dev) +{ + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + arc_timer_event_setup(arc_get_core_freq() / HZ); + break; + case CLOCK_EVT_MODE_ONESHOT: + break; + default: + break; + } + + return; +} + +static DEFINE_PER_CPU(struct clock_event_device, arc_clockevent_device) = { + .name = "ARC Timer0", + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, + .mode = CLOCK_EVT_MODE_UNUSED, + .rating = 300, + .irq = TIMER0_IRQ, /* hardwired, no need for resources */ + .set_next_event = arc_clkevent_set_next_event, + .set_mode = arc_clkevent_set_mode, +}; + +static irqreturn_t timer_irq_handler(int irq, void *dev_id) +{ + struct clock_event_device *clk = &__get_cpu_var(arc_clockevent_device); + + arc_timer_event_ack(clk->mode == CLOCK_EVT_MODE_PERIODIC); + clk->event_handler(clk); + return IRQ_HANDLED; +} + +static struct irqaction arc_timer_irq = { + .name = "Timer0 (clock-evt-dev)", + .flags = IRQF_TIMER | IRQF_PERCPU, + .handler = timer_irq_handler, +}; + +/* + * Setup the local event timer for @cpu + * N.B. weak so that some exotic ARC SoCs can completely override it + */ +void __attribute__((weak)) __cpuinit arc_local_timer_setup(unsigned int cpu) +{ + struct clock_event_device *clk = &per_cpu(arc_clockevent_device, cpu); + + clockevents_calc_mult_shift(clk, arc_get_core_freq(), 5); + + clk->max_delta_ns = clockevent_delta2ns(ARC_TIMER_MAX, clk); + clk->cpumask = cpumask_of(cpu); + + clockevents_register_device(clk); + + /* + * setup the per-cpu timer IRQ handler - for all cpus + * For non boot CPU explicitly unmask at intc + * setup_irq() -> .. -> irq_startup() already does this on boot-cpu + */ + if (!cpu) + setup_irq(TIMER0_IRQ, &arc_timer_irq); + else + arch_unmask_irq(TIMER0_IRQ); +} + +/* + * Called from start_kernel() - boot CPU only + * + * -Sets up h/w timers as applicable on boot cpu + * -Also sets up any global state needed for timer subsystem: + * - for "counting" timer, registers a clocksource, usable across CPUs + * (provided that underlying counter h/w is synchronized across cores) + * - for "event" timer, sets up TIMER0 IRQ (as that is platform agnostic) + */ +void __init time_init(void) +{ + /* + * sets up the timekeeping free-flowing counter which also returns + * whether the counter is usable as clocksource + */ + if (arc_counter_setup()) + /* + * CLK upto 4.29 GHz can be safely represented in 32 bits + * because Max 32 bit number is 4,294,967,295 + */ + clocksource_register_hz(&arc_counter, arc_get_core_freq()); + + /* sets up the periodic event timer */ + arc_local_timer_setup(smp_processor_id()); +} + +#ifdef CONFIG_ARC_HAS_RTSC +/* + * sched_clock math assist + * ns = cycles * (ns_per_sec / cpu_freq_hz) + * ns = cycles * (10^6 / cpu_freq_khz) + * ns = cycles * (10^6 * 2^SF / cpu_freq_khz) / 2^SF + * ns = cycles * cyc2ns_scale >> SF + */ +#define CYC2NS_SF 10 /* 2^10, carefully chosen */ +#define CYC2NS_SCALE ((1000000 << CYC2NS_SF) / (arc_get_core_freq() / 1000)) + +static unsigned long long cycles2ns(unsigned long long cyc) +{ + return (cyc * CYC2NS_SCALE ) >> CYC2NS_SF; +} + +/* + * Scheduler clock - a monotonically increasing clock in nanosec units. + * It's return value must NOT wrap around. + * + * - Since 32bit TIMER1 will overflow almost immediately (53sec @ 80MHz), it + * can't be used directly. + * - Using getrawmonotonic (TIMER1 based, but with state for last + current + * snapshots), is no-good either because of seqlock deadlock possibilities + * - So only with native 64bit timer we do this, otherwise fallback to generic + * jiffies based version - which despite not being fine grained gaurantees + * the monotonically increasing semantics. + */ +unsigned long long sched_clock(void) +{ + return cycles2ns(arc_counter_read(NULL)); +} +#endif |