diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-17 16:38:06 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-17 16:38:06 -0800 |
commit | dbfc985195410dad803c845743c63cd73bd1fe32 (patch) | |
tree | 6bf6dbecb92539285ebb89948e63e691a0947941 /arch/mips/loongson/common/cs5536/cs5536_mfgpt.c | |
parent | 7c508e50be47737b9a72d0f15c3ef1146925e2d2 (diff) | |
parent | 606d62fa02cf1da43c6e21521650fff07a2e56d1 (diff) |
Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (71 commits)
MIPS: Lasat: Fix botched changes to sysctl code.
RTC: rtc-cmos.c: Fix warning on MIPS
MIPS: Cleanup random differences beween lmo and Linus' kernel.
MIPS: No longer hardwire CONFIG_EMBEDDED to y
MIPS: Fix and enhance built-in kernel command line
MIPS: eXcite: Remove platform.
MIPS: Loongson: Cleanups of serial port support
MIPS: Lemote 2F: Suspend CS5536 MFGPT Timer
MIPS: Excite: move iodev_remove to .devexit.text
MIPS: Lasat: Convert to proc_fops / seq_file
MIPS: Cleanup signal code initialization
MIPS: Modularize COP2 handling
MIPS: Move EARLY_PRINTK to Kconfig.debug
MIPS: Yeeloong 2F: Cleanup reset logic using the new ec_write function
MIPS: Yeeloong 2F: Add LID open event as the wakeup event
MIPS: Yeeloong 2F: Add basic EC operations
MIPS: Move several variables from .bss to .init.data
MIPS: Tracing: Make function graph tracer work with -mmcount-ra-address
MIPS: Tracing: Reserve $12(t0) for mcount-ra-address of gcc 4.5
MIPS: Tracing: Make ftrace for MIPS work without -fno-omit-frame-pointer
...
Diffstat (limited to 'arch/mips/loongson/common/cs5536/cs5536_mfgpt.c')
-rw-r--r-- | arch/mips/loongson/common/cs5536/cs5536_mfgpt.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/arch/mips/loongson/common/cs5536/cs5536_mfgpt.c b/arch/mips/loongson/common/cs5536/cs5536_mfgpt.c new file mode 100644 index 00000000000..6cb44dbaeec --- /dev/null +++ b/arch/mips/loongson/common/cs5536/cs5536_mfgpt.c @@ -0,0 +1,217 @@ +/* + * CS5536 General timer functions + * + * Copyright (C) 2007 Lemote Inc. & Insititute of Computing Technology + * Author: Yanhua, yanh@lemote.com + * + * Copyright (C) 2009 Lemote Inc. + * Author: Wu zhangjin, wuzj@lemote.com + * + * Reference: AMD Geode(TM) CS5536 Companion Device Data Book + * + * 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. + */ + +#include <linux/io.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/jiffies.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/clockchips.h> + +#include <asm/time.h> + +#include <cs5536/cs5536_mfgpt.h> + +DEFINE_SPINLOCK(mfgpt_lock); +EXPORT_SYMBOL(mfgpt_lock); + +static u32 mfgpt_base; + +/* + * Initialize the MFGPT timer. + * + * This is also called after resume to bring the MFGPT into operation again. + */ + +/* disable counter */ +void disable_mfgpt0_counter(void) +{ + outw(inw(MFGPT0_SETUP) & 0x7fff, MFGPT0_SETUP); +} +EXPORT_SYMBOL(disable_mfgpt0_counter); + +/* enable counter, comparator2 to event mode, 14.318MHz clock */ +void enable_mfgpt0_counter(void) +{ + outw(0xe310, MFGPT0_SETUP); +} +EXPORT_SYMBOL(enable_mfgpt0_counter); + +static void init_mfgpt_timer(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + spin_lock(&mfgpt_lock); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + outw(COMPARE, MFGPT0_CMP2); /* set comparator2 */ + outw(0, MFGPT0_CNT); /* set counter to 0 */ + enable_mfgpt0_counter(); + break; + + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + if (evt->mode == CLOCK_EVT_MODE_PERIODIC || + evt->mode == CLOCK_EVT_MODE_ONESHOT) + disable_mfgpt0_counter(); + break; + + case CLOCK_EVT_MODE_ONESHOT: + /* The oneshot mode have very high deviation, Not use it! */ + break; + + case CLOCK_EVT_MODE_RESUME: + /* Nothing to do here */ + break; + } + spin_unlock(&mfgpt_lock); +} + +static struct clock_event_device mfgpt_clockevent = { + .name = "mfgpt", + .features = CLOCK_EVT_FEAT_PERIODIC, + .set_mode = init_mfgpt_timer, + .irq = CS5536_MFGPT_INTR, +}; + +static irqreturn_t timer_interrupt(int irq, void *dev_id) +{ + u32 basehi; + + /* + * get MFGPT base address + * + * NOTE: do not remove me, it's need for the value of mfgpt_base is + * variable + */ + _rdmsr(DIVIL_MSR_REG(DIVIL_LBAR_MFGPT), &basehi, &mfgpt_base); + + /* ack */ + outw(inw(MFGPT0_SETUP) | 0x4000, MFGPT0_SETUP); + + mfgpt_clockevent.event_handler(&mfgpt_clockevent); + + return IRQ_HANDLED; +} + +static struct irqaction irq5 = { + .handler = timer_interrupt, + .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_TIMER, + .name = "timer" +}; + +/* + * Initialize the conversion factor and the min/max deltas of the clock event + * structure and register the clock event source with the framework. + */ +void __init setup_mfgpt0_timer(void) +{ + u32 basehi; + struct clock_event_device *cd = &mfgpt_clockevent; + unsigned int cpu = smp_processor_id(); + + cd->cpumask = cpumask_of(cpu); + clockevent_set_clock(cd, MFGPT_TICK_RATE); + cd->max_delta_ns = clockevent_delta2ns(0xffff, cd); + cd->min_delta_ns = clockevent_delta2ns(0xf, cd); + + /* Enable MFGPT0 Comparator 2 Output to the Interrupt Mapper */ + _wrmsr(DIVIL_MSR_REG(MFGPT_IRQ), 0, 0x100); + + /* Enable Interrupt Gate 5 */ + _wrmsr(DIVIL_MSR_REG(PIC_ZSEL_LOW), 0, 0x50000); + + /* get MFGPT base address */ + _rdmsr(DIVIL_MSR_REG(DIVIL_LBAR_MFGPT), &basehi, &mfgpt_base); + + clockevents_register_device(cd); + + setup_irq(CS5536_MFGPT_INTR, &irq5); +} + +/* + * Since the MFGPT overflows every tick, its not very useful + * to just read by itself. So use jiffies to emulate a free + * running counter: + */ +static cycle_t mfgpt_read(struct clocksource *cs) +{ + unsigned long flags; + int count; + u32 jifs; + static int old_count; + static u32 old_jifs; + + spin_lock_irqsave(&mfgpt_lock, flags); + /* + * Although our caller may have the read side of xtime_lock, + * this is now a seqlock, and we are cheating in this routine + * by having side effects on state that we cannot undo if + * there is a collision on the seqlock and our caller has to + * retry. (Namely, old_jifs and old_count.) So we must treat + * jiffies as volatile despite the lock. We read jiffies + * before latching the timer count to guarantee that although + * the jiffies value might be older than the count (that is, + * the counter may underflow between the last point where + * jiffies was incremented and the point where we latch the + * count), it cannot be newer. + */ + jifs = jiffies; + /* read the count */ + count = inw(MFGPT0_CNT); + + /* + * It's possible for count to appear to go the wrong way for this + * reason: + * + * The timer counter underflows, but we haven't handled the resulting + * interrupt and incremented jiffies yet. + * + * Previous attempts to handle these cases intelligently were buggy, so + * we just do the simple thing now. + */ + if (count < old_count && jifs == old_jifs) + count = old_count; + + old_count = count; + old_jifs = jifs; + + spin_unlock_irqrestore(&mfgpt_lock, flags); + + return (cycle_t) (jifs * COMPARE) + count; +} + +static struct clocksource clocksource_mfgpt = { + .name = "mfgpt", + .rating = 120, /* Functional for real use, but not desired */ + .read = mfgpt_read, + .mask = CLOCKSOURCE_MASK(32), + .mult = 0, + .shift = 22, +}; + +int __init init_mfgpt_clocksource(void) +{ + if (num_possible_cpus() > 1) /* MFGPT does not scale! */ + return 0; + + clocksource_mfgpt.mult = clocksource_hz2mult(MFGPT_TICK_RATE, 22); + return clocksource_register(&clocksource_mfgpt); +} + +arch_initcall(init_mfgpt_clocksource); |