Commit 31e5e646 authored by Michael Kelley's avatar Michael Kelley Committed by Wei Liu
Browse files

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: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626220906-22629-1-git-send-email-mikelley@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 5f92b45c

drivers/clocksource/hyperv_timer.c

+0 −3
Original line number Diff line number Diff line
@@ -361,9 +361,6 @@ EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup); 
 * Hyper-V and 32-bit x86.  The TSC reference page version is preferred.

 */



u64 (*hv_read_reference_counter)(void);

EXPORT_SYMBOL_GPL(hv_read_reference_counter);



static union {

	struct ms_hyperv_tsc_page page;

	u8 reserved[PAGE_SIZE];

drivers/hv/hv_common.c

+14 −0
Original line number Diff line number Diff line
@@ -222,6 +222,20 @@ bool hv_is_hibernation_supported(void) 
}

EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);



/*

 * Default function to read the Hyper-V reference counter, independent

 * of whether Hyper-V enlightened clocks/timers are being used. But on

 * architectures where it is used, Hyper-V enlightenment code in

 * hyperv_timer.c may override this function.

 */

static u64 __hv_read_ref_counter(void)

{

	return hv_get_register(HV_REGISTER_TIME_REF_COUNT);

}



u64 (*hv_read_reference_counter)(void) = __hv_read_ref_counter;

EXPORT_SYMBOL_GPL(hv_read_reference_counter);



/* These __weak functions provide default "no-op" behavior and

 * may be overridden by architecture specific versions. Architectures

 * for which the default "no-op" behavior is sufficient can leave

drivers/hv/hv_util.c

+0 −5
Original line number Diff line number Diff line
@@ -17,7 +17,6 @@ 
#include <linux/hyperv.h>

#include <linux/clockchips.h>

#include <linux/ptp_clock_kernel.h>

#include <clocksource/hyperv_timer.h>

#include <asm/mshyperv.h>



#include "hyperv_vmbus.h"
@@ -735,10 +734,6 @@ static struct ptp_clock *hv_ptp_clock; 


static int hv_timesync_init(struct hv_util_service *srv)

{

	/* TimeSync requires Hyper-V clocksource. */

	if (!hv_read_reference_counter)

		return -ENODEV;



	spin_lock_init(&host_ts.lock);



	INIT_WORK(&adj_time_work, hv_set_host_time);

include/asm-generic/mshyperv.h

+2 −0
Original line number Diff line number Diff line
@@ -167,6 +167,8 @@ extern bool hv_root_partition; 
extern u32 *hv_vp_index;

extern u32 hv_max_vp_index;



extern u64 (*hv_read_reference_counter)(void);



/* Sentinel value for an uninitialized entry in hv_vp_index array */

#define VP_INVAL	U32_MAX

include/clocksource/hyperv_timer.h

+9 −2
Original line number Diff line number Diff line
@@ -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