drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers

Hyper-V clock/timer code in hyperv_timer.c is mostly independent from
other VMbus drivers, but building for ARM64 without hyperv_timer.c
shows some remaining entanglements.  A default implementation of
hv_read_reference_counter can just read a Hyper-V synthetic register
and be independent of hyperv_timer.c, so move this code out and into
hv_common.c. Then it can be used by the timesync driver even if
hyperv_timer.c isn't built on a particular architecture.  If
hyperv_timer.c *is* built, it can override with a faster implementation.

Also provide stubs for stimer functions called by the VMbus driver when
hyperv_timer.c isn't built.

No functional changes.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626220906-22629-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Michael Kelley 2021-07-13 17:01:46 -07:00 committed by Wei Liu
parent 5f92b45c3b
commit 31e5e64694
5 changed files with 25 additions and 10 deletions

View file

@ -20,6 +20,8 @@
#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
#define HV_MIN_DELTA_TICKS 1
#ifdef CONFIG_HYPERV_TIMER
/* Routines called by the VMbus driver */
extern int hv_stimer_alloc(bool have_percpu_irqs);
extern int hv_stimer_cleanup(unsigned int cpu);
@ -28,8 +30,6 @@ extern void hv_stimer_legacy_cleanup(unsigned int cpu);
extern void hv_stimer_global_cleanup(void);
extern void hv_stimer0_isr(void);
#ifdef CONFIG_HYPERV_TIMER
extern u64 (*hv_read_reference_counter)(void);
extern void hv_init_clocksource(void);
extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
@ -100,6 +100,13 @@ static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
{
return U64_MAX;
}
static inline int hv_stimer_cleanup(unsigned int cpu) { return 0; }
static inline void hv_stimer_legacy_init(unsigned int cpu, int sint) {}
static inline void hv_stimer_legacy_cleanup(unsigned int cpu) {}
static inline void hv_stimer_global_cleanup(void) {}
static inline void hv_stimer0_isr(void) {}
#endif /* CONFIG_HYPERV_TIMER */
#endif