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- Cleanup x86/rtc.c and delete duplicated functionality in favor of

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using the respective functionality from the RTC library
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Merge tag 'x86_timers_for_v6.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 RTC cleanups from Borislav Petkov:

 - Cleanup x86/rtc.c and delete duplicated functionality in favor of
   using the respective functionality from the RTC library

* tag 'x86_timers_for_v6.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/rtc: Rename mach_set_rtc_mmss() to mach_set_cmos_time()
  x86/rtc: Rewrite & simplify mach_get_cmos_time() by deleting duplicated functionality
This commit is contained in:
Linus Torvalds 2022-10-04 09:13:21 -07:00
commit f8475a6749
3 changed files with 11 additions and 56 deletions
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2
arch/x86/include/asm/mc146818rtc.h
View File

@ -95,7 +95,7 @@ static inline unsigned char current_lock_cmos_reg(void)
unsigned char rtc_cmos_read(unsigned char addr);
void rtc_cmos_write(unsigned char val, unsigned char addr);
extern int mach_set_rtc_mmss(const struct timespec64 *now);
extern int mach_set_cmos_time(const struct timespec64 *now);
extern void mach_get_cmos_time(struct timespec64 *now);
#define RTC_IRQ 8

63
arch/x86/kernel/rtc.c
View File

@ -4,11 +4,8 @@
*/
#include <linux/platform_device.h>
#include <linux/mc146818rtc.h>
#include <linux/acpi.h>
#include <linux/bcd.h>
#include <linux/export.h>
#include <linux/pnp.h>
#include <linux/of.h>
#include <asm/vsyscall.h>
#include <asm/x86_init.h>
@ -20,26 +17,23 @@
/*
* This is a special lock that is owned by the CPU and holds the index
* register we are working with. It is required for NMI access to the
* CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
* CMOS/RTC registers. See arch/x86/include/asm/mc146818rtc.h for details.
*/
volatile unsigned long cmos_lock;
EXPORT_SYMBOL(cmos_lock);
#endif /* CONFIG_X86_32 */
/* For two digit years assume time is always after that */
#define CMOS_YEARS_OFFS 2000
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
/*
* In order to set the CMOS clock precisely, set_rtc_mmss has to be
* In order to set the CMOS clock precisely, mach_set_cmos_time has to be
* called 500 ms after the second nowtime has started, because when
* nowtime is written into the registers of the CMOS clock, it will
* jump to the next second precisely 500 ms later. Check the Motorola
* MC146818A or Dallas DS12887 data sheet for details.
*/
int mach_set_rtc_mmss(const struct timespec64 *now)
int mach_set_cmos_time(const struct timespec64 *now)
{
unsigned long long nowtime = now->tv_sec;
struct rtc_time tm;
@ -62,8 +56,7 @@ int mach_set_rtc_mmss(const struct timespec64 *now)
void mach_get_cmos_time(struct timespec64 *now)
{
unsigned int status, year, mon, day, hour, min, sec, century = 0;
unsigned long flags;
struct rtc_time tm;
/*
* If pm_trace abused the RTC as storage, set the timespec to 0,
@ -74,51 +67,13 @@ void mach_get_cmos_time(struct timespec64 *now)
return;
}
spin_lock_irqsave(&rtc_lock, flags);
/*
* If UIP is clear, then we have >= 244 microseconds before
* RTC registers will be updated. Spec sheet says that this
* is the reliable way to read RTC - registers. If UIP is set
* then the register access might be invalid.
*/
while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
cpu_relax();
sec = CMOS_READ(RTC_SECONDS);
min = CMOS_READ(RTC_MINUTES);
hour = CMOS_READ(RTC_HOURS);
day = CMOS_READ(RTC_DAY_OF_MONTH);
mon = CMOS_READ(RTC_MONTH);
year = CMOS_READ(RTC_YEAR);
#ifdef CONFIG_ACPI
if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
acpi_gbl_FADT.century)
century = CMOS_READ(acpi_gbl_FADT.century);
#endif
status = CMOS_READ(RTC_CONTROL);
WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY));
spin_unlock_irqrestore(&rtc_lock, flags);
if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) {
sec = bcd2bin(sec);
min = bcd2bin(min);
hour = bcd2bin(hour);
day = bcd2bin(day);
mon = bcd2bin(mon);
year = bcd2bin(year);
if (mc146818_get_time(&tm)) {
pr_err("Unable to read current time from RTC\n");
now->tv_sec = now->tv_nsec = 0;
return;
}
if (century) {
century = bcd2bin(century);
year += century * 100;
} else
year += CMOS_YEARS_OFFS;
now->tv_sec = mktime64(year, mon, day, hour, min, sec);
now->tv_sec = rtc_tm_to_time64(&tm);
now->tv_nsec = 0;
}

2
arch/x86/kernel/x86_init.c
View File

@ -138,7 +138,7 @@ struct x86_platform_ops x86_platform __ro_after_init = {
.calibrate_cpu = native_calibrate_cpu_early,
.calibrate_tsc = native_calibrate_tsc,
.get_wallclock = mach_get_cmos_time,
.set_wallclock = mach_set_rtc_mmss,
.set_wallclock = mach_set_cmos_time,
.iommu_shutdown = iommu_shutdown_noop,
.is_untracked_pat_range = is_ISA_range,
.nmi_init = default_nmi_init,