On Tue, May 14, 2019 at 07:24:38AM -0700, Randy Dunlap wrote: > On 5/14/19 7:01 AM, Ricardo Neri wrote: > > Instead of setting the timer period directly in hpet_set_periodic(), add a > > new helper function hpet_set_comparator() that only sets the accumulator > > and comparator. hpet_set_periodic() will only prepare the timer for > > periodic mode and leave the expiration programming to > > hpet_set_comparator(). > > > > This new function can also be used by other components (e.g., the HPET- > > based hardlockup detector) which also need to configure HPET timers. Thus, > > add its declaration into the hpet header file. > > > > Cc: "H. Peter Anvin" <[email protected]> > > Cc: Ashok Raj <[email protected]> > > Cc: Andi Kleen <[email protected]> > > Cc: Tony Luck <[email protected]> > > Cc: Philippe Ombredanne <[email protected]> > > Cc: Kate Stewart <[email protected]> > > Cc: "Rafael J. Wysocki" <[email protected]> > > Cc: Stephane Eranian <[email protected]> > > Cc: Suravee Suthikulpanit <[email protected]> > > Cc: "Ravi V. Shankar" <[email protected]> > > Cc: [email protected] > > Originally-by: Suravee Suthikulpanit <[email protected]> > > Signed-off-by: Ricardo Neri <[email protected]> > > --- > > arch/x86/include/asm/hpet.h | 1 + > > arch/x86/kernel/hpet.c | 57 ++++++++++++++++++++++++++++--------- > > 2 files changed, 45 insertions(+), 13 deletions(-) > > > > diff --git a/arch/x86/include/asm/hpet.h b/arch/x86/include/asm/hpet.h > > index f132fbf984d4..e7098740f5ee 100644 > > --- a/arch/x86/include/asm/hpet.h > > +++ b/arch/x86/include/asm/hpet.h > > @@ -102,6 +102,7 @@ extern int hpet_rtc_timer_init(void); > > extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id); > > extern int hpet_register_irq_handler(rtc_irq_handler handler); > > extern void hpet_unregister_irq_handler(rtc_irq_handler handler); > > +extern void hpet_set_comparator(int num, unsigned int cmp, unsigned int > > period); > > > > #endif /* CONFIG_HPET_EMULATE_RTC */ > > > > diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c > > index 560fc28e1d13..c5c5fc150193 100644 > > --- a/arch/x86/kernel/hpet.c > > +++ b/arch/x86/kernel/hpet.c > > @@ -289,6 +289,46 @@ static void hpet_legacy_clockevent_register(void) > > printk(KERN_DEBUG "hpet clockevent registered\n"); > > } > > > > +/** > > + * hpet_set_comparator() - Helper function for setting comparator register > > + * @num: The timer ID > > + * @cmp: The value to be written to the comparator/accumulator > > + * @period: The value to be written to the period (0 = oneshot mode) > > + * > > + * Helper function for updating comparator, accumulator and period values. > > + * > > + * In periodic mode, HPET needs HPET_TN_SETVAL to be set before writing > > + * to the Tn_CMP to update the accumulator. Then, HPET needs a second > > + * write (with HPET_TN_SETVAL cleared) to Tn_CMP to set the period. > > + * The HPET_TN_SETVAL bit is automatically cleared after the first write. > > + * > > + * For one-shot mode, HPET_TN_SETVAL does not need to be set. > > + * > > + * See the following documents: > > + * - Intel IA-PC HPET (High Precision Event Timers) Specification > > + * - AMD-8111 HyperTransport I/O Hub Data Sheet, Publication # 24674 > > + */ > > +void hpet_set_comparator(int num, unsigned int cmp, unsigned int period) > > +{ > > + if (period) { > > + unsigned int v = hpet_readl(HPET_Tn_CFG(num)); > > + > > + hpet_writel(v | HPET_TN_SETVAL, HPET_Tn_CFG(num)); > > + } > > + > > + hpet_writel(cmp, HPET_Tn_CMP(num)); > > + > > + if (!period) > > + return; > > + > > + /* This delay is seldom used: never in one-shot mode and in periodic > > + * only when reprogramming the timer. > > + */ > > comment style warning ;) >
Uh! I'll correct this. Strangely, I reran checkpatch and it didn't catch it. Thanks and BR, Ricardo
