diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-08 10:10:11 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-08 10:10:11 -0700 |
commit | 45d7f32c7a43cbb9592886d38190e379e2eb2226 (patch) | |
tree | ea68b67b1d2127527d856248c0485f2ed7e50088 /arch/tile/kernel/time.c | |
parent | 53bcef60633086ad73683d01a4ef9ca678484d2d (diff) | |
parent | ab11b487402f97975f3ac1eeea09c82f4431481e (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
arch/tile: check kmalloc() result
arch/tile: catch up on various minor cleanups.
arch/tile: avoid erroneous error return for PTRACE_POKEUSR.
tile: set ARCH_KMALLOC_MINALIGN
tile: remove homegrown L1_CACHE_ALIGN macro
arch/tile: Miscellaneous cleanup changes.
arch/tile: Split the icache flush code off to a generic <arch> header.
arch/tile: Fix bug in support for atomic64_xx() ops.
arch/tile: Shrink the tile-opcode files considerably.
arch/tile: Add driver to enable access to the user dynamic network.
arch/tile: Enable more sophisticated IRQ model for 32-bit chips.
Move list types from <linux/list.h> to <linux/types.h>.
Add wait4() back to the set of <asm-generic/unistd.h> syscalls.
Revert adding some arch-specific signal syscalls to <linux/syscalls.h>.
arch/tile: Do not use GFP_KERNEL for dma_alloc_coherent(). Feedback from fujita.tomonori@lab.ntt.co.jp.
arch/tile: core support for Tilera 32-bit chips.
Fix up the "generic" unistd.h ABI to be more useful.
Diffstat (limited to 'arch/tile/kernel/time.c')
-rw-r--r-- | arch/tile/kernel/time.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/tile/kernel/time.c b/arch/tile/kernel/time.c new file mode 100644 index 00000000000..b9ab25a889b --- /dev/null +++ b/arch/tile/kernel/time.c @@ -0,0 +1,221 @@ +/* + * Copyright 2010 Tilera Corporation. 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 + * as published by the Free Software Foundation, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + * + * Support the cycle counter clocksource and tile timer clock event device. + */ + +#include <linux/time.h> +#include <linux/timex.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/hardirq.h> +#include <linux/sched.h> +#include <linux/smp.h> +#include <linux/delay.h> +#include <asm/irq_regs.h> +#include <asm/traps.h> +#include <hv/hypervisor.h> +#include <arch/interrupts.h> +#include <arch/spr_def.h> + + +/* + * Define the cycle counter clock source. + */ + +/* How many cycles per second we are running at. */ +static cycles_t cycles_per_sec __write_once; + +/* + * We set up shift and multiply values with a minsec of five seconds, + * since our timer counter counts down 31 bits at a frequency of + * no less than 500 MHz. See @minsec for clocks_calc_mult_shift(). + * We could use a different value for the 64-bit free-running + * cycle counter, but we use the same one for consistency, and since + * we will be reasonably precise with this value anyway. + */ +#define TILE_MINSEC 5 + +cycles_t get_clock_rate(void) +{ + return cycles_per_sec; +} + +#if CHIP_HAS_SPLIT_CYCLE() +cycles_t get_cycles(void) +{ + unsigned int high = __insn_mfspr(SPR_CYCLE_HIGH); + unsigned int low = __insn_mfspr(SPR_CYCLE_LOW); + unsigned int high2 = __insn_mfspr(SPR_CYCLE_HIGH); + + while (unlikely(high != high2)) { + low = __insn_mfspr(SPR_CYCLE_LOW); + high = high2; + high2 = __insn_mfspr(SPR_CYCLE_HIGH); + } + + return (((cycles_t)high) << 32) | low; +} +#endif + +static cycles_t clocksource_get_cycles(struct clocksource *cs) +{ + return get_cycles(); +} + +static struct clocksource cycle_counter_cs = { + .name = "cycle counter", + .rating = 300, + .read = clocksource_get_cycles, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +/* + * Called very early from setup_arch() to set cycles_per_sec. + * We initialize it early so we can use it to set up loops_per_jiffy. + */ +void __init setup_clock(void) +{ + cycles_per_sec = hv_sysconf(HV_SYSCONF_CPU_SPEED); + clocksource_calc_mult_shift(&cycle_counter_cs, cycles_per_sec, + TILE_MINSEC); +} + +void __init calibrate_delay(void) +{ + loops_per_jiffy = get_clock_rate() / HZ; + pr_info("Clock rate yields %lu.%02lu BogoMIPS (lpj=%lu)\n", + loops_per_jiffy/(500000/HZ), + (loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy); +} + +/* Called fairly late in init/main.c, but before we go smp. */ +void __init time_init(void) +{ + /* Initialize and register the clock source. */ + clocksource_register(&cycle_counter_cs); + + /* Start up the tile-timer interrupt source on the boot cpu. */ + setup_tile_timer(); +} + + +/* + * Define the tile timer clock event device. The timer is driven by + * the TILE_TIMER_CONTROL register, which consists of a 31-bit down + * counter, plus bit 31, which signifies that the counter has wrapped + * from zero to (2**31) - 1. The INT_TILE_TIMER interrupt will be + * raised as long as bit 31 is set. + */ + +#define MAX_TICK 0x7fffffff /* we have 31 bits of countdown timer */ + +static int tile_timer_set_next_event(unsigned long ticks, + struct clock_event_device *evt) +{ + BUG_ON(ticks > MAX_TICK); + __insn_mtspr(SPR_TILE_TIMER_CONTROL, ticks); + raw_local_irq_unmask_now(INT_TILE_TIMER); + return 0; +} + +/* + * Whenever anyone tries to change modes, we just mask interrupts + * and wait for the next event to get set. + */ +static void tile_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + raw_local_irq_mask_now(INT_TILE_TIMER); +} + +/* + * Set min_delta_ns to 1 microsecond, since it takes about + * that long to fire the interrupt. + */ +static DEFINE_PER_CPU(struct clock_event_device, tile_timer) = { + .name = "tile timer", + .features = CLOCK_EVT_FEAT_ONESHOT, + .min_delta_ns = 1000, + .rating = 100, + .irq = -1, + .set_next_event = tile_timer_set_next_event, + .set_mode = tile_timer_set_mode, +}; + +void __cpuinit setup_tile_timer(void) +{ + struct clock_event_device *evt = &__get_cpu_var(tile_timer); + + /* Fill in fields that are speed-specific. */ + clockevents_calc_mult_shift(evt, cycles_per_sec, TILE_MINSEC); + evt->max_delta_ns = clockevent_delta2ns(MAX_TICK, evt); + + /* Mark as being for this cpu only. */ + evt->cpumask = cpumask_of(smp_processor_id()); + + /* Start out with timer not firing. */ + raw_local_irq_mask_now(INT_TILE_TIMER); + + /* Register tile timer. */ + clockevents_register_device(evt); +} + +/* Called from the interrupt vector. */ +void do_timer_interrupt(struct pt_regs *regs, int fault_num) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + struct clock_event_device *evt = &__get_cpu_var(tile_timer); + + /* + * Mask the timer interrupt here, since we are a oneshot timer + * and there are now by definition no events pending. + */ + raw_local_irq_mask(INT_TILE_TIMER); + + /* Track time spent here in an interrupt context */ + irq_enter(); + + /* Track interrupt count. */ + __get_cpu_var(irq_stat).irq_timer_count++; + + /* Call the generic timer handler */ + evt->event_handler(evt); + + /* + * Track time spent against the current process again and + * process any softirqs if they are waiting. + */ + irq_exit(); + + set_irq_regs(old_regs); +} + +/* + * Scheduler clock - returns current time in nanosec units. + * Note that with LOCKDEP, this is called during lockdep_init(), and + * we will claim that sched_clock() is zero for a little while, until + * we run setup_clock(), above. + */ +unsigned long long sched_clock(void) +{ + return clocksource_cyc2ns(get_cycles(), + cycle_counter_cs.mult, + cycle_counter_cs.shift); +} + +int setup_profiling_timer(unsigned int multiplier) +{ + return -EINVAL; +} |