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x86: share rtc code
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Remove the rtc code from time_64.c and add the extra bits to the
i386 path. The ACPI century check is probably valid for i386 as
well, but this is material for a separate patch.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Thomas Gleixner authored and Ingo Molnar committed Jan 30, 2008
1 parent fe599f9 commit 1122b13
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Showing 3 changed files with 64 additions and 191 deletions.
2 changes: 1 addition & 1 deletion arch/x86/kernel/Makefile_64
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ obj-y := process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \
x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \
setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \
pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \
i8253.o io_delay.o
i8253.o io_delay.o rtc.o

obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += cpu/
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96 changes: 63 additions & 33 deletions arch/x86/kernel/rtc.c
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Original file line number Diff line number Diff line change
@@ -1,11 +1,32 @@
/*
* RTC related functions
*/
#include <linux/acpi.h>
#include <linux/bcd.h>
#include <linux/mc146818rtc.h>

#include <asm/time.h>

#ifdef CONFIG_X86_32
# define CMOS_YEARS_OFFS 1900
/*
* 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.
*/
volatile unsigned long cmos_lock = 0;
EXPORT_SYMBOL(cmos_lock);
#else
/*
* x86-64 systems only exists since 2002.
* This will work up to Dec 31, 2100
*/
# define CMOS_YEARS_OFFS 2000
#endif

DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);

/*
* In order to set the CMOS clock precisely, set_rtc_mmss has to be
* called 500 ms after the second nowtime has started, because when
Expand All @@ -22,10 +43,12 @@ int mach_set_rtc_mmss(unsigned long nowtime)
int real_seconds, real_minutes, cmos_minutes;
unsigned char save_control, save_freq_select;

save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
/* tell the clock it's being set */
save_control = CMOS_READ(RTC_CONTROL);
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);

save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
/* stop and reset prescaler */
save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

cmos_minutes = CMOS_READ(RTC_MINUTES);
Expand All @@ -40,8 +63,9 @@ int mach_set_rtc_mmss(unsigned long nowtime)
*/
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
/* correct for half hour time zone */
if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
real_minutes += 30; /* correct for half hour time zone */
real_minutes += 30;
real_minutes %= 60;

if (abs(real_minutes - cmos_minutes) < 30) {
Expand Down Expand Up @@ -73,18 +97,32 @@ int mach_set_rtc_mmss(unsigned long nowtime)

unsigned long mach_get_cmos_time(void)
{
unsigned int year, mon, day, hour, min, sec;

do {
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);
} while (sec != CMOS_READ(RTC_SECONDS));

if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
unsigned int year, mon, day, hour, min, sec, century = 0;

/*
* 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);

#if defined(CONFIG_ACPI) && defined(CONFIG_X86_64)
/* CHECKME: Is this really 64bit only ??? */
if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
acpi_gbl_FADT.century)
century = CMOS_READ(acpi_gbl_FADT.century);
#endif

if (RTC_ALWAYS_BCD || !(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)) {
BCD_TO_BIN(sec);
BCD_TO_BIN(min);
BCD_TO_BIN(hour);
Expand All @@ -93,24 +131,19 @@ unsigned long mach_get_cmos_time(void)
BCD_TO_BIN(year);
}

year += 1900;
if (year < 1970)
year += 100;
if (century) {
BCD_TO_BIN(century);
year += century * 100;
printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
} else {
year += CMOS_YEARS_OFFS;
if (year < 1970)
year += 100;
}

return mktime(year, mon, day, hour, min, sec);
}

DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);

/*
* 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.
*/
volatile unsigned long cmos_lock = 0;
EXPORT_SYMBOL(cmos_lock);

/* Routines for accessing the CMOS RAM/RTC. */
unsigned char rtc_cmos_read(unsigned char addr)
{
Expand Down Expand Up @@ -138,8 +171,6 @@ static int set_rtc_mmss(unsigned long nowtime)
int retval;
unsigned long flags;

/* gets recalled with irq locally disabled */
/* XXX - does irqsave resolve this? -johnstul */
spin_lock_irqsave(&rtc_lock, flags);
retval = set_wallclock(nowtime);
spin_unlock_irqrestore(&rtc_lock, flags);
Expand All @@ -150,8 +181,7 @@ static int set_rtc_mmss(unsigned long nowtime)
/* not static: needed by APM */
unsigned long read_persistent_clock(void)
{
unsigned long retval;
unsigned long flags;
unsigned long retval, flags;

spin_lock_irqsave(&rtc_lock, flags);
retval = get_wallclock();
Expand Down
157 changes: 0 additions & 157 deletions arch/x86/kernel/time_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -46,9 +46,6 @@
#include <asm/nmi.h>
#include <asm/vgtod.h>

DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);

volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;

unsigned long profile_pc(struct pt_regs *regs)
Expand All @@ -69,103 +66,6 @@ unsigned long profile_pc(struct pt_regs *regs)
}
EXPORT_SYMBOL(profile_pc);

/* Routines for accessing the CMOS RAM/RTC. */
unsigned char rtc_cmos_read(unsigned char addr)
{
unsigned char val;
lock_cmos_prefix(addr);
outb_p(addr, RTC_PORT(0));
val = inb_p(RTC_PORT(1));
lock_cmos_suffix(addr);
return val;
}
EXPORT_SYMBOL(rtc_cmos_read);

void rtc_cmos_write(unsigned char val, unsigned char addr)
{
lock_cmos_prefix(addr);
outb_p(addr, RTC_PORT(0));
outb_p(val, RTC_PORT(1));
lock_cmos_suffix(addr);
}
EXPORT_SYMBOL(rtc_cmos_write);

/*
* In order to set the CMOS clock precisely, set_rtc_mmss 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.
*/

static int set_rtc_mmss(unsigned long nowtime)
{
int retval = 0;
int real_seconds, real_minutes, cmos_minutes;
unsigned char control, freq_select;
unsigned long flags;

/*
* set_rtc_mmss is called when irqs are enabled, so disable irqs here
*/
spin_lock_irqsave(&rtc_lock, flags);
/*
* Tell the clock it's being set and stop it.
*/
control = CMOS_READ(RTC_CONTROL);
CMOS_WRITE(control | RTC_SET, RTC_CONTROL);

freq_select = CMOS_READ(RTC_FREQ_SELECT);
CMOS_WRITE(freq_select | RTC_DIV_RESET2, RTC_FREQ_SELECT);

cmos_minutes = CMOS_READ(RTC_MINUTES);
BCD_TO_BIN(cmos_minutes);

/*
* since we're only adjusting minutes and seconds, don't interfere with hour
* overflow. This avoids messing with unknown time zones but requires your RTC
* not to be off by more than 15 minutes. Since we're calling it only when
* our clock is externally synchronized using NTP, this shouldn't be a problem.
*/

real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
real_minutes += 30; /* correct for half hour time zone */
real_minutes %= 60;

if (abs(real_minutes - cmos_minutes) >= 30) {
printk(KERN_WARNING "time.c: can't update CMOS clock "
"from %d to %d\n", cmos_minutes, real_minutes);
retval = -1;
} else {
BIN_TO_BCD(real_seconds);
BIN_TO_BCD(real_minutes);
CMOS_WRITE(real_seconds, RTC_SECONDS);
CMOS_WRITE(real_minutes, RTC_MINUTES);
}

/*
* The following flags have to be released exactly in this order, otherwise the
* DS12887 (popular MC146818A clone with integrated battery and quartz) will
* not reset the oscillator and will not update precisely 500 ms later. You
* won't find this mentioned in the Dallas Semiconductor data sheets, but who
* believes data sheets anyway ... -- Markus Kuhn
*/

CMOS_WRITE(control, RTC_CONTROL);
CMOS_WRITE(freq_select, RTC_FREQ_SELECT);

spin_unlock_irqrestore(&rtc_lock, flags);

return retval;
}

int update_persistent_clock(struct timespec now)
{
return set_rtc_mmss(now.tv_sec);
}

static irqreturn_t timer_event_interrupt(int irq, void *dev_id)
{
add_pda(irq0_irqs, 1);
Expand All @@ -175,63 +75,6 @@ static irqreturn_t timer_event_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}

unsigned long read_persistent_clock(void)
{
unsigned int year, mon, day, hour, min, sec;
unsigned long flags;
unsigned century = 0;

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 invalid (off bus) during update
*/
while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
cpu_relax();


/* now read all RTC registers while stable with interrupts disabled */
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
spin_unlock_irqrestore(&rtc_lock, flags);

/*
* We know that x86-64 always uses BCD format, no need to check the
* config register.
*/

BCD_TO_BIN(sec);
BCD_TO_BIN(min);
BCD_TO_BIN(hour);
BCD_TO_BIN(day);
BCD_TO_BIN(mon);
BCD_TO_BIN(year);

if (century) {
BCD_TO_BIN(century);
year += century * 100;
printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
} else {
/*
* x86-64 systems only exists since 2002.
* This will work up to Dec 31, 2100
*/
year += 2000;
}

return mktime(year, mon, day, hour, min, sec);
}

/* calibrate_cpu is used on systems with fixed rate TSCs to determine
* processor frequency */
#define TICK_COUNT 100000000
Expand Down

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