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linux-stable/arch/sparc64/kernel/time.c
Richard Mortimer 9eb3394bf2 [SPARC64]: Eliminate race condition reading Hummingbird STICK register 
Ensure a consistent value is read from the STICK register by ensuring
that both high and low are read without high changing due to a roll
over of the low register.

Various Debian/SPARC users (myself include) have noticed problems with
Hummingbird based systems. The symptoms are that the system time is
seen to jump forward 3 days, 6 hours, 11 minutes give or take a few
seconds. In many cases the system then hangs some time afterwards.

I've spotted a race condition in the code to read the STICK register.
I could not work out why 3d, 6h, 11m is important but guess that it is
due to the 2^32 jump of STICK (forwards on one read and then the next
read will seem to be backwards) during a timer interrupt. I'm guessing
that a change of -2^32 will get converted to a large unsigned
increment after the arithmetic manipulation between STICK,
nanoseconds, jiffies etc.

I did a test where I modified __hbird_read_stick to artificially
inject rollover faults forcefully every few seconds. With this I saw
the clock jump over 6 times in 12 hours compared to once every month
or so.

Signed-off-by: Richard Mortimer <richm@oldelvet.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-17 15:21:01 -08:00

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/* $Id: time.c,v 1.42 2002/01/23 14:33:55 davem Exp $
* time.c: UltraSparc timer and TOD clock support.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1998 Eddie C. Dost (ecd@skynet.be)
*
* Based largely on code which is:
*
* Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
*/
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/mc146818rtc.h>
#include <linux/delay.h>
#include <linux/profile.h>
#include <linux/bcd.h>
#include <linux/jiffies.h>
#include <linux/cpufreq.h>
#include <linux/percpu.h>
#include <linux/profile.h>
#include <asm/oplib.h>
#include <asm/mostek.h>
#include <asm/timer.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/sbus.h>
#include <asm/fhc.h>
#include <asm/pbm.h>
#include <asm/ebus.h>
#include <asm/isa.h>
#include <asm/starfire.h>
#include <asm/smp.h>
#include <asm/sections.h>
#include <asm/cpudata.h>
DEFINE_SPINLOCK(mostek_lock);
DEFINE_SPINLOCK(rtc_lock);
void __iomem *mstk48t02_regs = NULL;
#ifdef CONFIG_PCI
unsigned long ds1287_regs = 0UL;
#endif
extern unsigned long wall_jiffies;
static void __iomem *mstk48t08_regs;
static void __iomem *mstk48t59_regs;
static int set_rtc_mmss(unsigned long);
#define TICK_PRIV_BIT (1UL << 63)
#ifdef CONFIG_SMP
unsigned long profile_pc(struct pt_regs *regs)
{
unsigned long pc = instruction_pointer(regs);
if (in_lock_functions(pc))
return regs->u_regs[UREG_RETPC];
return pc;
}
EXPORT_SYMBOL(profile_pc);
#endif
static void tick_disable_protection(void)
{
/* Set things up so user can access tick register for profiling
* purposes. Also workaround BB_ERRATA_1 by doing a dummy
* read back of %tick after writing it.
*/
__asm__ __volatile__(
" ba,pt %%xcc, 1f\n"
" nop\n"
" .align 64\n"
"1: rd %%tick, %%g2\n"
" add %%g2, 6, %%g2\n"
" andn %%g2, %0, %%g2\n"
" wrpr %%g2, 0, %%tick\n"
" rdpr %%tick, %%g0"
: /* no outputs */
: "r" (TICK_PRIV_BIT)
: "g2");
}
static void tick_init_tick(unsigned long offset)
{
tick_disable_protection();
__asm__ __volatile__(
" rd %%tick, %%g1\n"
" andn %%g1, %1, %%g1\n"
" ba,pt %%xcc, 1f\n"
" add %%g1, %0, %%g1\n"
" .align 64\n"
"1: wr %%g1, 0x0, %%tick_cmpr\n"
" rd %%tick_cmpr, %%g0"
: /* no outputs */
: "r" (offset), "r" (TICK_PRIV_BIT)
: "g1");
}
static unsigned long tick_get_tick(void)
{
unsigned long ret;
__asm__ __volatile__("rd %%tick, %0\n\t"
"mov %0, %0"
: "=r" (ret));
return ret & ~TICK_PRIV_BIT;
}
static unsigned long tick_get_compare(void)
{
unsigned long ret;
__asm__ __volatile__("rd %%tick_cmpr, %0\n\t"
"mov %0, %0"
: "=r" (ret));
return ret;
}
static unsigned long tick_add_compare(unsigned long adj)
{
unsigned long new_compare;
/* Workaround for Spitfire Errata (#54 I think??), I discovered
* this via Sun BugID 4008234, mentioned in Solaris-2.5.1 patch
* number 103640.
*
* On Blackbird writes to %tick_cmpr can fail, the
* workaround seems to be to execute the wr instruction
* at the start of an I-cache line, and perform a dummy
* read back from %tick_cmpr right after writing to it. -DaveM
*/
__asm__ __volatile__("rd %%tick_cmpr, %0\n\t"
"ba,pt %%xcc, 1f\n\t"
" add %0, %1, %0\n\t"
".align 64\n"
"1:\n\t"
"wr %0, 0, %%tick_cmpr\n\t"
"rd %%tick_cmpr, %%g0"
: "=&r" (new_compare)
: "r" (adj));
return new_compare;
}
static unsigned long tick_add_tick(unsigned long adj, unsigned long offset)
{
unsigned long new_tick, tmp;
/* Also need to handle Blackbird bug here too. */
__asm__ __volatile__("rd %%tick, %0\n\t"
"add %0, %2, %0\n\t"
"wrpr %0, 0, %%tick\n\t"
"andn %0, %4, %1\n\t"
"ba,pt %%xcc, 1f\n\t"
" add %1, %3, %1\n\t"
".align 64\n"
"1:\n\t"
"wr %1, 0, %%tick_cmpr\n\t"
"rd %%tick_cmpr, %%g0"
: "=&r" (new_tick), "=&r" (tmp)
: "r" (adj), "r" (offset), "r" (TICK_PRIV_BIT));
return new_tick;
}
static struct sparc64_tick_ops tick_operations __read_mostly = {
.init_tick = tick_init_tick,
.get_tick = tick_get_tick,
.get_compare = tick_get_compare,
.add_tick = tick_add_tick,
.add_compare = tick_add_compare,
.softint_mask = 1UL << 0,
};
struct sparc64_tick_ops *tick_ops __read_mostly = &tick_operations;
static void stick_init_tick(unsigned long offset)
{
tick_disable_protection();
/* Let the user get at STICK too. */
__asm__ __volatile__(
" rd %%asr24, %%g2\n"
" andn %%g2, %0, %%g2\n"
" wr %%g2, 0, %%asr24"
: /* no outputs */
: "r" (TICK_PRIV_BIT)
: "g1", "g2");
__asm__ __volatile__(
" rd %%asr24, %%g1\n"
" andn %%g1, %1, %%g1\n"
" add %%g1, %0, %%g1\n"
" wr %%g1, 0x0, %%asr25"
: /* no outputs */
: "r" (offset), "r" (TICK_PRIV_BIT)
: "g1");
}
static unsigned long stick_get_tick(void)
{
unsigned long ret;
__asm__ __volatile__("rd %%asr24, %0"
: "=r" (ret));
return ret & ~TICK_PRIV_BIT;
}
static unsigned long stick_get_compare(void)
{
unsigned long ret;
__asm__ __volatile__("rd %%asr25, %0"
: "=r" (ret));
return ret;
}
static unsigned long stick_add_tick(unsigned long adj, unsigned long offset)
{
unsigned long new_tick, tmp;
__asm__ __volatile__("rd %%asr24, %0\n\t"
"add %0, %2, %0\n\t"
"wr %0, 0, %%asr24\n\t"
"andn %0, %4, %1\n\t"
"add %1, %3, %1\n\t"
"wr %1, 0, %%asr25"
: "=&r" (new_tick), "=&r" (tmp)
: "r" (adj), "r" (offset), "r" (TICK_PRIV_BIT));
return new_tick;
}
static unsigned long stick_add_compare(unsigned long adj)
{
unsigned long new_compare;
__asm__ __volatile__("rd %%asr25, %0\n\t"
"add %0, %1, %0\n\t"
"wr %0, 0, %%asr25"
: "=&r" (new_compare)
: "r" (adj));
return new_compare;
}
static struct sparc64_tick_ops stick_operations __read_mostly = {
.init_tick = stick_init_tick,
.get_tick = stick_get_tick,
.get_compare = stick_get_compare,
.add_tick = stick_add_tick,
.add_compare = stick_add_compare,
.softint_mask = 1UL << 16,
};
/* On Hummingbird the STICK/STICK_CMPR register is implemented
* in I/O space. There are two 64-bit registers each, the
* first holds the low 32-bits of the value and the second holds
* the high 32-bits.
*
* Since STICK is constantly updating, we have to access it carefully.
*
* The sequence we use to read is:
* 1) read high
* 2) read low
* 3) read high again, if it rolled re-read both low and high again.
*
* Writing STICK safely is also tricky:
* 1) write low to zero
* 2) write high
* 3) write low
*/
#define HBIRD_STICKCMP_ADDR 0x1fe0000f060UL
#define HBIRD_STICK_ADDR 0x1fe0000f070UL
static unsigned long __hbird_read_stick(void)
{
unsigned long ret, tmp1, tmp2, tmp3;
unsigned long addr = HBIRD_STICK_ADDR+8;
__asm__ __volatile__("ldxa [%1] %5, %2\n"
"1:\n\t"
"sub %1, 0x8, %1\n\t"
"ldxa [%1] %5, %3\n\t"
"add %1, 0x8, %1\n\t"
"ldxa [%1] %5, %4\n\t"
"cmp %4, %2\n\t"
"bne,a,pn %%xcc, 1b\n\t"
" mov %4, %2\n\t"
"sllx %4, 32, %4\n\t"
"or %3, %4, %0\n\t"
: "=&r" (ret), "=&r" (addr),
"=&r" (tmp1), "=&r" (tmp2), "=&r" (tmp3)
: "i" (ASI_PHYS_BYPASS_EC_E), "1" (addr));
return ret;
}
static unsigned long __hbird_read_compare(void)
{
unsigned long low, high;
unsigned long addr = HBIRD_STICKCMP_ADDR;
__asm__ __volatile__("ldxa [%2] %3, %0\n\t"
"add %2, 0x8, %2\n\t"
"ldxa [%2] %3, %1"
: "=&r" (low), "=&r" (high), "=&r" (addr)
: "i" (ASI_PHYS_BYPASS_EC_E), "2" (addr));
return (high << 32UL) | low;
}
static void __hbird_write_stick(unsigned long val)
{
unsigned long low = (val & 0xffffffffUL);
unsigned long high = (val >> 32UL);
unsigned long addr = HBIRD_STICK_ADDR;
__asm__ __volatile__("stxa %%g0, [%0] %4\n\t"
"add %0, 0x8, %0\n\t"
"stxa %3, [%0] %4\n\t"
"sub %0, 0x8, %0\n\t"
"stxa %2, [%0] %4"
: "=&r" (addr)
: "0" (addr), "r" (low), "r" (high),
"i" (ASI_PHYS_BYPASS_EC_E));
}
static void __hbird_write_compare(unsigned long val)
{
unsigned long low = (val & 0xffffffffUL);
unsigned long high = (val >> 32UL);
unsigned long addr = HBIRD_STICKCMP_ADDR + 0x8UL;
__asm__ __volatile__("stxa %3, [%0] %4\n\t"
"sub %0, 0x8, %0\n\t"
"stxa %2, [%0] %4"
: "=&r" (addr)
: "0" (addr), "r" (low), "r" (high),
"i" (ASI_PHYS_BYPASS_EC_E));
}
static void hbtick_init_tick(unsigned long offset)
{
unsigned long val;
tick_disable_protection();
/* XXX This seems to be necessary to 'jumpstart' Hummingbird
* XXX into actually sending STICK interrupts. I think because
* XXX of how we store %tick_cmpr in head.S this somehow resets the
* XXX {TICK + STICK} interrupt mux. -DaveM
*/
__hbird_write_stick(__hbird_read_stick());
val = __hbird_read_stick() & ~TICK_PRIV_BIT;
__hbird_write_compare(val + offset);
}
static unsigned long hbtick_get_tick(void)
{
return __hbird_read_stick() & ~TICK_PRIV_BIT;
}
static unsigned long hbtick_get_compare(void)
{
return __hbird_read_compare();
}
static unsigned long hbtick_add_tick(unsigned long adj, unsigned long offset)
{
unsigned long val;
val = __hbird_read_stick() + adj;
__hbird_write_stick(val);
val &= ~TICK_PRIV_BIT;
__hbird_write_compare(val + offset);
return val;
}
static unsigned long hbtick_add_compare(unsigned long adj)
{
unsigned long val = __hbird_read_compare() + adj;
val &= ~TICK_PRIV_BIT;
__hbird_write_compare(val);
return val;
}
static struct sparc64_tick_ops hbtick_operations __read_mostly = {
.init_tick = hbtick_init_tick,
.get_tick = hbtick_get_tick,
.get_compare = hbtick_get_compare,
.add_tick = hbtick_add_tick,
.add_compare = hbtick_add_compare,
.softint_mask = 1UL << 0,
};
/* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*
* NOTE: On SUN5 systems the ticker interrupt comes in using 2
* interrupts, one at level14 and one with softint bit 0.
*/
unsigned long timer_tick_offset __read_mostly;
static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
#define TICK_SIZE (tick_nsec / 1000)
static inline void timer_check_rtc(void)
{
/* last time the cmos clock got updated */
static long last_rtc_update;
/* Determine when to update the Mostek clock. */
if (ntp_synced() &&
xtime.tv_sec > last_rtc_update + 660 &&
(xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
(xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
if (set_rtc_mmss(xtime.tv_sec) == 0)
last_rtc_update = xtime.tv_sec;
else
last_rtc_update = xtime.tv_sec - 600;
/* do it again in 60 s */
}
}
static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
unsigned long ticks, compare, pstate;
write_seqlock(&xtime_lock);
do {
#ifndef CONFIG_SMP
profile_tick(CPU_PROFILING, regs);
update_process_times(user_mode(regs));
#endif
do_timer(regs);
/* Guarantee that the following sequences execute
* uninterrupted.
*/
__asm__ __volatile__("rdpr %%pstate, %0\n\t"
"wrpr %0, %1, %%pstate"
: "=r" (pstate)
: "i" (PSTATE_IE));
compare = tick_ops->add_compare(timer_tick_offset);
ticks = tick_ops->get_tick();
/* Restore PSTATE_IE. */
__asm__ __volatile__("wrpr %0, 0x0, %%pstate"
: /* no outputs */
: "r" (pstate));
} while (time_after_eq(ticks, compare));
timer_check_rtc();
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
#ifdef CONFIG_SMP
void timer_tick_interrupt(struct pt_regs *regs)
{
write_seqlock(&xtime_lock);
do_timer(regs);
timer_check_rtc();
write_sequnlock(&xtime_lock);
}
#endif
/* Kick start a stopped clock (procedure from the Sun NVRAM/hostid FAQ). */
static void __init kick_start_clock(void)
{
void __iomem *regs = mstk48t02_regs;
u8 sec, tmp;
int i, count;
prom_printf("CLOCK: Clock was stopped. Kick start ");
spin_lock_irq(&mostek_lock);
/* Turn on the kick start bit to start the oscillator. */
tmp = mostek_read(regs + MOSTEK_CREG);
tmp |= MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
tmp = mostek_read(regs + MOSTEK_SEC);
tmp &= ~MSTK_STOP;
mostek_write(regs + MOSTEK_SEC, tmp);
tmp = mostek_read(regs + MOSTEK_HOUR);
tmp |= MSTK_KICK_START;
mostek_write(regs + MOSTEK_HOUR, tmp);
tmp = mostek_read(regs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
spin_unlock_irq(&mostek_lock);
/* Delay to allow the clock oscillator to start. */
sec = MSTK_REG_SEC(regs);
for (i = 0; i < 3; i++) {
while (sec == MSTK_REG_SEC(regs))
for (count = 0; count < 100000; count++)
/* nothing */ ;
prom_printf(".");
sec = MSTK_REG_SEC(regs);
}
prom_printf("\n");
spin_lock_irq(&mostek_lock);
/* Turn off kick start and set a "valid" time and date. */
tmp = mostek_read(regs + MOSTEK_CREG);
tmp |= MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
tmp = mostek_read(regs + MOSTEK_HOUR);
tmp &= ~MSTK_KICK_START;
mostek_write(regs + MOSTEK_HOUR, tmp);
MSTK_SET_REG_SEC(regs,0);
MSTK_SET_REG_MIN(regs,0);
MSTK_SET_REG_HOUR(regs,0);
MSTK_SET_REG_DOW(regs,5);
MSTK_SET_REG_DOM(regs,1);
MSTK_SET_REG_MONTH(regs,8);
MSTK_SET_REG_YEAR(regs,1996 - MSTK_YEAR_ZERO);
tmp = mostek_read(regs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
spin_unlock_irq(&mostek_lock);
/* Ensure the kick start bit is off. If it isn't, turn it off. */
while (mostek_read(regs + MOSTEK_HOUR) & MSTK_KICK_START) {
prom_printf("CLOCK: Kick start still on!\n");
spin_lock_irq(&mostek_lock);
tmp = mostek_read(regs + MOSTEK_CREG);
tmp |= MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
tmp = mostek_read(regs + MOSTEK_HOUR);
tmp &= ~MSTK_KICK_START;
mostek_write(regs + MOSTEK_HOUR, tmp);
tmp = mostek_read(regs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
spin_unlock_irq(&mostek_lock);
}
prom_printf("CLOCK: Kick start procedure successful.\n");
}
/* Return nonzero if the clock chip battery is low. */
static int __init has_low_battery(void)
{
void __iomem *regs = mstk48t02_regs;
u8 data1, data2;
spin_lock_irq(&mostek_lock);
data1 = mostek_read(regs + MOSTEK_EEPROM); /* Read some data. */
mostek_write(regs + MOSTEK_EEPROM, ~data1); /* Write back the complement. */
data2 = mostek_read(regs + MOSTEK_EEPROM); /* Read back the complement. */
mostek_write(regs + MOSTEK_EEPROM, data1); /* Restore original value. */
spin_unlock_irq(&mostek_lock);
return (data1 == data2); /* Was the write blocked? */
}
/* Probe for the real time clock chip. */
static void __init set_system_time(void)
{
unsigned int year, mon, day, hour, min, sec;
void __iomem *mregs = mstk48t02_regs;
#ifdef CONFIG_PCI
unsigned long dregs = ds1287_regs;
#else
unsigned long dregs = 0UL;
#endif
u8 tmp;
if (!mregs && !dregs) {
prom_printf("Something wrong, clock regs not mapped yet.\n");
prom_halt();
}
if (mregs) {
spin_lock_irq(&mostek_lock);
/* Traditional Mostek chip. */
tmp = mostek_read(mregs + MOSTEK_CREG);
tmp |= MSTK_CREG_READ;
mostek_write(mregs + MOSTEK_CREG, tmp);
sec = MSTK_REG_SEC(mregs);
min = MSTK_REG_MIN(mregs);
hour = MSTK_REG_HOUR(mregs);
day = MSTK_REG_DOM(mregs);
mon = MSTK_REG_MONTH(mregs);
year = MSTK_CVT_YEAR( MSTK_REG_YEAR(mregs) );
} else {
int i;
/* Dallas 12887 RTC chip. */
/* Stolen from arch/i386/kernel/time.c, see there for
* credits and descriptive comments.
*/
for (i = 0; i < 1000000; i++) {
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
break;
udelay(10);
}
for (i = 0; i < 1000000; i++) {
if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
break;
udelay(10);
}
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) {
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 ((year += 1900) < 1970)
year += 100;
}
xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
if (mregs) {
tmp = mostek_read(mregs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_READ;
mostek_write(mregs + MOSTEK_CREG, tmp);
spin_unlock_irq(&mostek_lock);
}
}
void __init clock_probe(void)
{
struct linux_prom_registers clk_reg[2];
char model[128];
int node, busnd = -1, err;
unsigned long flags;
struct linux_central *cbus;
#ifdef CONFIG_PCI
struct linux_ebus *ebus = NULL;
struct sparc_isa_bridge *isa_br = NULL;
#endif
static int invoked;
if (invoked)
return;
invoked = 1;
if (this_is_starfire) {
/* davem suggests we keep this within the 4M locked kernel image */
static char obp_gettod[256];
static u32 unix_tod;
sprintf(obp_gettod, "h# %08x unix-gettod",
(unsigned int) (long) &unix_tod);
prom_feval(obp_gettod);
xtime.tv_sec = unix_tod;
xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
return;
}
local_irq_save(flags);
cbus = central_bus;
if (cbus != NULL)
busnd = central_bus->child->prom_node;
/* Check FHC Central then EBUSs then ISA bridges then SBUSs.
* That way we handle the presence of multiple properly.
*
* As a special case, machines with Central must provide the
* timer chip there.
*/
#ifdef CONFIG_PCI
if (ebus_chain != NULL) {
ebus = ebus_chain;
if (busnd == -1)
busnd = ebus->prom_node;
}
if (isa_chain != NULL) {
isa_br = isa_chain;
if (busnd == -1)
busnd = isa_br->prom_node;
}
#endif
if (sbus_root != NULL && busnd == -1)
busnd = sbus_root->prom_node;
if (busnd == -1) {
prom_printf("clock_probe: problem, cannot find bus to search.\n");
prom_halt();
}
node = prom_getchild(busnd);
while (1) {
if (!node)
model[0] = 0;
else
prom_getstring(node, "model", model, sizeof(model));
if (strcmp(model, "mk48t02") &&
strcmp(model, "mk48t08") &&
strcmp(model, "mk48t59") &&
strcmp(model, "m5819") &&
strcmp(model, "m5819p") &&
strcmp(model, "m5823") &&
strcmp(model, "ds1287")) {
if (cbus != NULL) {
prom_printf("clock_probe: Central bus lacks timer chip.\n");
prom_halt();
}
if (node != 0)
node = prom_getsibling(node);
#ifdef CONFIG_PCI
while ((node == 0) && ebus != NULL) {
ebus = ebus->next;
if (ebus != NULL) {
busnd = ebus->prom_node;
node = prom_getchild(busnd);
}
}
while ((node == 0) && isa_br != NULL) {
isa_br = isa_br->next;
if (isa_br != NULL) {
busnd = isa_br->prom_node;
node = prom_getchild(busnd);
}
}
#endif
if (node == 0) {
prom_printf("clock_probe: Cannot find timer chip\n");
prom_halt();
}
continue;
}
err = prom_getproperty(node, "reg", (char *)clk_reg,
sizeof(clk_reg));
if(err == -1) {
prom_printf("clock_probe: Cannot get Mostek reg property\n");
prom_halt();
}
if (cbus != NULL) {
apply_fhc_ranges(central_bus->child, clk_reg, 1);
apply_central_ranges(central_bus, clk_reg, 1);
}
#ifdef CONFIG_PCI
else if (ebus != NULL) {
struct linux_ebus_device *edev;
for_each_ebusdev(edev, ebus)
if (edev->prom_node == node)
break;
if (edev == NULL) {
if (isa_chain != NULL)
goto try_isa_clock;
prom_printf("%s: Mostek not probed by EBUS\n",
__FUNCTION__);
prom_halt();
}
if (!strcmp(model, "ds1287") ||
!strcmp(model, "m5819") ||
!strcmp(model, "m5819p") ||
!strcmp(model, "m5823")) {
ds1287_regs = edev->resource[0].start;
} else {
mstk48t59_regs = (void __iomem *)
edev->resource[0].start;
mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
}
break;
}
else if (isa_br != NULL) {
struct sparc_isa_device *isadev;
try_isa_clock:
for_each_isadev(isadev, isa_br)
if (isadev->prom_node == node)
break;
if (isadev == NULL) {
prom_printf("%s: Mostek not probed by ISA\n");
prom_halt();
}
if (!strcmp(model, "ds1287") ||
!strcmp(model, "m5819") ||
!strcmp(model, "m5819p") ||
!strcmp(model, "m5823")) {
ds1287_regs = isadev->resource.start;
} else {
mstk48t59_regs = (void __iomem *)
isadev->resource.start;
mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
}
break;
}
#endif
else {
if (sbus_root->num_sbus_ranges) {
int nranges = sbus_root->num_sbus_ranges;
int rngc;
for (rngc = 0; rngc < nranges; rngc++)
if (clk_reg[0].which_io ==
sbus_root->sbus_ranges[rngc].ot_child_space)
break;
if (rngc == nranges) {
prom_printf("clock_probe: Cannot find ranges for "
"clock regs.\n");
prom_halt();
}
clk_reg[0].which_io =
sbus_root->sbus_ranges[rngc].ot_parent_space;
clk_reg[0].phys_addr +=
sbus_root->sbus_ranges[rngc].ot_parent_base;
}
}
if(model[5] == '0' && model[6] == '2') {
mstk48t02_regs = (void __iomem *)
(((u64)clk_reg[0].phys_addr) |
(((u64)clk_reg[0].which_io)<<32UL));
} else if(model[5] == '0' && model[6] == '8') {
mstk48t08_regs = (void __iomem *)
(((u64)clk_reg[0].phys_addr) |
(((u64)clk_reg[0].which_io)<<32UL));
mstk48t02_regs = mstk48t08_regs + MOSTEK_48T08_48T02;
} else {
mstk48t59_regs = (void __iomem *)
(((u64)clk_reg[0].phys_addr) |
(((u64)clk_reg[0].which_io)<<32UL));
mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
}
break;
}
if (mstk48t02_regs != NULL) {
/* Report a low battery voltage condition. */
if (has_low_battery())
prom_printf("NVRAM: Low battery voltage!\n");
/* Kick start the clock if it is completely stopped. */
if (mostek_read(mstk48t02_regs + MOSTEK_SEC) & MSTK_STOP)
kick_start_clock();
}
set_system_time();
local_irq_restore(flags);
}
/* This is gets the master TICK_INT timer going. */
static unsigned long sparc64_init_timers(void)
{
unsigned long clock;
int node;
#ifdef CONFIG_SMP
extern void smp_tick_init(void);
#endif
if (tlb_type == spitfire) {
unsigned long ver, manuf, impl;
__asm__ __volatile__ ("rdpr %%ver, %0"
: "=&r" (ver));
manuf = ((ver >> 48) & 0xffff);
impl = ((ver >> 32) & 0xffff);
if (manuf == 0x17 && impl == 0x13) {
/* Hummingbird, aka Ultra-IIe */
tick_ops = &hbtick_operations;
node = prom_root_node;
clock = prom_getint(node, "stick-frequency");
} else {
tick_ops = &tick_operations;
cpu_find_by_instance(0, &node, NULL);
clock = prom_getint(node, "clock-frequency");
}
} else {
tick_ops = &stick_operations;
node = prom_root_node;
clock = prom_getint(node, "stick-frequency");
}
timer_tick_offset = clock / HZ;
#ifdef CONFIG_SMP
smp_tick_init();
#endif
return clock;
}
static void sparc64_start_timers(irqreturn_t (*cfunc)(int, void *, struct pt_regs *))
{
unsigned long pstate;
int err;
/* Register IRQ handler. */
err = request_irq(build_irq(0, 0, 0UL, 0UL), cfunc, 0,
"timer", NULL);
if (err) {
prom_printf("Serious problem, cannot register TICK_INT\n");
prom_halt();
}
/* Guarantee that the following sequences execute
* uninterrupted.
*/
__asm__ __volatile__("rdpr %%pstate, %0\n\t"
"wrpr %0, %1, %%pstate"
: "=r" (pstate)
: "i" (PSTATE_IE));
tick_ops->init_tick(timer_tick_offset);
/* Restore PSTATE_IE. */
__asm__ __volatile__("wrpr %0, 0x0, %%pstate"
: /* no outputs */
: "r" (pstate));
local_irq_enable();
}
struct freq_table {
unsigned long udelay_val_ref;
unsigned long clock_tick_ref;
unsigned int ref_freq;
};
static DEFINE_PER_CPU(struct freq_table, sparc64_freq_table) = { 0, 0, 0 };
unsigned long sparc64_get_clock_tick(unsigned int cpu)
{
struct freq_table *ft = &per_cpu(sparc64_freq_table, cpu);
if (ft->clock_tick_ref)
return ft->clock_tick_ref;
return cpu_data(cpu).clock_tick;
}
#ifdef CONFIG_CPU_FREQ
static int sparc64_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
void *data)
{
struct cpufreq_freqs *freq = data;
unsigned int cpu = freq->cpu;
struct freq_table *ft = &per_cpu(sparc64_freq_table, cpu);
if (!ft->ref_freq) {
ft->ref_freq = freq->old;
ft->udelay_val_ref = cpu_data(cpu).udelay_val;
ft->clock_tick_ref = cpu_data(cpu).clock_tick;
}
if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
(val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
(val == CPUFREQ_RESUMECHANGE)) {
cpu_data(cpu).udelay_val =
cpufreq_scale(ft->udelay_val_ref,
ft->ref_freq,
freq->new);
cpu_data(cpu).clock_tick =
cpufreq_scale(ft->clock_tick_ref,
ft->ref_freq,
freq->new);
}
return 0;
}
static struct notifier_block sparc64_cpufreq_notifier_block = {
.notifier_call = sparc64_cpufreq_notifier
};
#endif /* CONFIG_CPU_FREQ */
static struct time_interpolator sparc64_cpu_interpolator = {
.source = TIME_SOURCE_CPU,
.shift = 16,
.mask = 0xffffffffffffffffLL
};
/* The quotient formula is taken from the IA64 port. */
#define SPARC64_NSEC_PER_CYC_SHIFT 30UL
void __init time_init(void)
{
unsigned long clock = sparc64_init_timers();
sparc64_cpu_interpolator.frequency = clock;
register_time_interpolator(&sparc64_cpu_interpolator);
/* Now that the interpolator is registered, it is
* safe to start the timer ticking.
*/
sparc64_start_timers(timer_interrupt);
timer_ticks_per_nsec_quotient =
(((NSEC_PER_SEC << SPARC64_NSEC_PER_CYC_SHIFT) +
(clock / 2)) / clock);
#ifdef CONFIG_CPU_FREQ
cpufreq_register_notifier(&sparc64_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
#endif
}
unsigned long long sched_clock(void)
{
unsigned long ticks = tick_ops->get_tick();
return (ticks * timer_ticks_per_nsec_quotient)
>> SPARC64_NSEC_PER_CYC_SHIFT;
}
static int set_rtc_mmss(unsigned long nowtime)
{
int real_seconds, real_minutes, chip_minutes;
void __iomem *mregs = mstk48t02_regs;
#ifdef CONFIG_PCI
unsigned long dregs = ds1287_regs;
#else
unsigned long dregs = 0UL;
#endif
unsigned long flags;
u8 tmp;
/*
* Not having a register set can lead to trouble.
* Also starfire doesn't have a tod clock.
*/
if (!mregs && !dregs)
return -1;
if (mregs) {
spin_lock_irqsave(&mostek_lock, flags);
/* Read the current RTC minutes. */
tmp = mostek_read(mregs + MOSTEK_CREG);
tmp |= MSTK_CREG_READ;
mostek_write(mregs + MOSTEK_CREG, tmp);
chip_minutes = MSTK_REG_MIN(mregs);
tmp = mostek_read(mregs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_READ;
mostek_write(mregs + MOSTEK_CREG, tmp);
/*
* 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
*/
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - chip_minutes) + 15)/30) & 1)
real_minutes += 30; /* correct for half hour time zone */
real_minutes %= 60;
if (abs(real_minutes - chip_minutes) < 30) {
tmp = mostek_read(mregs + MOSTEK_CREG);
tmp |= MSTK_CREG_WRITE;
mostek_write(mregs + MOSTEK_CREG, tmp);
MSTK_SET_REG_SEC(mregs,real_seconds);
MSTK_SET_REG_MIN(mregs,real_minutes);
tmp = mostek_read(mregs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_WRITE;
mostek_write(mregs + MOSTEK_CREG, tmp);
spin_unlock_irqrestore(&mostek_lock, flags);
return 0;
} else {
spin_unlock_irqrestore(&mostek_lock, flags);
return -1;
}
} else {
int retval = 0;
unsigned char save_control, save_freq_select;
/* Stolen from arch/i386/kernel/time.c, see there for
* credits and descriptive comments.
*/
spin_lock_irqsave(&rtc_lock, flags);
save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
chip_minutes = CMOS_READ(RTC_MINUTES);
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
BCD_TO_BIN(chip_minutes);
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - chip_minutes) + 15)/30) & 1)
real_minutes += 30;
real_minutes %= 60;
if (abs(real_minutes - chip_minutes) < 30) {
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
BIN_TO_BCD(real_seconds);
BIN_TO_BCD(real_minutes);
}
CMOS_WRITE(real_seconds,RTC_SECONDS);
CMOS_WRITE(real_minutes,RTC_MINUTES);
} else {
printk(KERN_WARNING
"set_rtc_mmss: can't update from %d to %d\n",
chip_minutes, real_minutes);
retval = -1;
}
CMOS_WRITE(save_control, RTC_CONTROL);
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
spin_unlock_irqrestore(&rtc_lock, flags);
return retval;
}
}
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