Re: [PATCH 1/3] ia64: convert to use clocksource code

[Chris Wright <chrisw@sous-sol.org>]

* Peter Keilty (peter.keilty@hp.com) wrote:
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 6077300..35ad71f 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -480,10 +480,12 @@ #endif
>  		/* Get end time (ticks) */
>  		t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
>  
> +#ifndef CONFIG_IA64
>  #ifdef CONFIG_GENERIC_TIME
>  		/* TSC halts in C2, so notify users */
>  		mark_tsc_unstable();
>  #endif
> +#endif

Is this a better description of the dependency?

  #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)

>  		/* Re-enable interrupts */
>  		local_irq_enable();
>  		current_thread_info()->status |= TS_POLLING;
> @@ -522,10 +524,12 @@ #endif
>  			acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
>  		}
>  
> +#ifndef CONFIG_IA64
>  #ifdef CONFIG_GENERIC_TIME
>  		/* TSC halts in C3, so notify users */
>  		mark_tsc_unstable();
>  #endif
> +#endif

ditto

>  		/* Re-enable interrupts */
>  		local_irq_enable();
>  		current_thread_info()->status |= TS_POLLING;
> diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
> index 0be700f..5ea7d3e 100644
> --- a/drivers/char/hpet.c
> +++ b/drivers/char/hpet.c
> @@ -29,6 +29,7 @@ #include <linux/wait.h>
>  #include <linux/bcd.h>
>  #include <linux/seq_file.h>
>  #include <linux/bitops.h>
> +#include <linux/clocksource.h>
>  
>  #include <asm/current.h>
>  #include <asm/uaccess.h>
> @@ -51,8 +52,34 @@ #define	HPET_DRIFT	(500)
>  
>  #define HPET_RANGE_SIZE		1024	/* from HPET spec */
>  
> +#if BITS_PER_LONG == 64
> +#define	write_counter(V, MC)	writeq(V, MC)
> +#define	read_counter(MC)	readq(MC)
> +#else
> +#define	write_counter(V, MC) 	writel(V, MC)
> +#define	read_counter(MC)	readl(MC)
> +#endif
> +
>  static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
>  
> +static void __iomem *hpet_mc_ptr;

CodingStyle nit: we don't need all this _ptr...

> +static cycle_t read_hpet(void)
> +{
> +	return (cycle_t)read_counter((void __iomem *)hpet_mc_ptr);
> +}
> +
> +static struct clocksource clocksource_hpet = {
> +        .name           = "hpet",
> +        .rating         = 300,
> +        .read           = read_hpet,
> +        .mask           = 0xffffffffffffffffLL,
> +        .mult           = 0, /*to be caluclated*/
> +        .shift          = 10,
> +        .is_continuous  = 1,
> +};
> +static struct clocksource *hpet_clocksource_p;

and _p naming.

> +
>  /* A lock for concurrent access by app and isr hpet activity. */
>  static DEFINE_SPINLOCK(hpet_lock);
>  /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
> @@ -79,7 +106,7 @@ struct hpets {
>  	struct hpets *hp_next;
>  	struct hpet __iomem *hp_hpet;
>  	unsigned long hp_hpet_phys;
> -	struct time_interpolator *hp_interpolator;
> +	struct clocksource *hp_clocksource;
>  	unsigned long long hp_tick_freq;
>  	unsigned long hp_delta;
>  	unsigned int hp_ntimer;
> @@ -94,13 +121,6 @@ #define	HPET_IE			0x0002	/* interrupt en
>  #define	HPET_PERIODIC		0x0004
>  #define	HPET_SHARED_IRQ		0x0008
>  
> -#if BITS_PER_LONG == 64
> -#define	write_counter(V, MC)	writeq(V, MC)
> -#define	read_counter(MC)	readq(MC)
> -#else
> -#define	write_counter(V, MC) 	writel(V, MC)
> -#define	read_counter(MC)	readl(MC)
> -#endif
>  
>  #ifndef readq
>  static inline unsigned long long readq(void __iomem *addr)
> @@ -737,27 +757,6 @@ static ctl_table dev_root[] = {
>  
>  static struct ctl_table_header *sysctl_header;
>  
> -static void hpet_register_interpolator(struct hpets *hpetp)
> -{
> -#ifdef	CONFIG_TIME_INTERPOLATION
> -	struct time_interpolator *ti;
> -
> -	ti = kzalloc(sizeof(*ti), GFP_KERNEL);
> -	if (!ti)
> -		return;
> -
> -	ti->source = TIME_SOURCE_MMIO64;
> -	ti->shift = 10;
> -	ti->addr = &hpetp->hp_hpet->hpet_mc;
> -	ti->frequency = hpetp->hp_tick_freq;
> -	ti->drift = HPET_DRIFT;
> -	ti->mask = -1;
> -
> -	hpetp->hp_interpolator = ti;
> -	register_time_interpolator(ti);
> -#endif
> -}
> -
>  /*
>   * Adjustment for when arming the timer with
>   * initial conditions.  That is, main counter
> @@ -909,7 +908,14 @@ int hpet_alloc(struct hpet_data *hdp)
>  	}
>  
>  	hpetp->hp_delta = hpet_calibrate(hpetp);
> -	hpet_register_interpolator(hpetp);
> +
> +	if (!hpet_clocksource_p) {
> +        	clocksource_hpet.fsys_mmio_ptr = hpet_mc_ptr = &hpetp->hp_hpet->hpet_mc;
> +        	clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
> +						clocksource_hpet.shift);
> +        	clocksource_register(&clocksource_hpet);
> +		hpet_clocksource_p = hpetp->hp_clocksource = &clocksource_hpet;
> +	}

This looks like a change in behaviour for non-ia64.  Now i386 and x86_64
will get this clocksource twice (and this one has a higher rating).
Doesn't look like this will even compile since fsys_mmio_ptr (more
extraneous _ptr suffix) is ia64 only?  And sparc64 is left out in
the cold.

>  	return 0;
>  }
> @@ -995,7 +1001,7 @@ static int hpet_acpi_add(struct acpi_dev
>  
>  static int hpet_acpi_remove(struct acpi_device *device, int type)
>  {
> -	/* XXX need to unregister interpolator, dealloc mem, etc */
> +	/* XXX need to unregister clocksource, dealloc mem, etc */
>  	return -EINVAL;
>  }
>  
> diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
> index daa4940..a20b4d6 100644
> --- a/include/linux/clocksource.h
> +++ b/include/linux/clocksource.h
> @@ -61,6 +61,9 @@ struct clocksource {
>  	u32 shift;
>  	unsigned long flags;
>  	cycle_t (*vread)(void);
> +#ifdef CONFIG_IA64
> +	void *fsys_mmio_ptr;	/* used by fsyscall asm code */
> +#endif
>  
>  	/* timekeeping specific data, ignore */
>  	cycle_t cycle_last, cycle_interval;
-
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