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[POWERPC] Implement arch disable/enable irq hooks.
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These hooks ensure that a decrementer interrupt is not pending when
suspending; otherwise, problems may occur on 6xx/7xx/7xxx-based
systems (except for powermacs, which use a separate suspend path).
For example, with deep sleep on the 831x, a pending decrementer will
cause a system freeze because the SoC thinks the decrementer interrupt
would have woken the system, but the core must have interrupts
disabled due to the setup required for deep sleep.

Changed via-pmu.c to use the new ppc_md hooks, and made the arch_*
functions call the generic_* functions unconditionally.  -- paulus

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Scott Wood authored and Paul Mackerras committed Dec 21, 2007
1 parent cbea923 commit 7ac5dde
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Showing 3 changed files with 58 additions and 42 deletions.
39 changes: 39 additions & 0 deletions arch/powerpc/kernel/time.c
Original file line number Diff line number Diff line change
Expand Up @@ -629,6 +629,45 @@ void wakeup_decrementer(void)
set_dec(ticks);
}

#ifdef CONFIG_SUSPEND
void generic_suspend_disable_irqs(void)
{
preempt_disable();

/* Disable the decrementer, so that it doesn't interfere
* with suspending.
*/

set_dec(0x7fffffff);
local_irq_disable();
set_dec(0x7fffffff);
}

void generic_suspend_enable_irqs(void)
{
wakeup_decrementer();

local_irq_enable();
preempt_enable();
}

/* Overrides the weak version in kernel/power/main.c */
void arch_suspend_disable_irqs(void)
{
if (ppc_md.suspend_disable_irqs)
ppc_md.suspend_disable_irqs();
generic_suspend_disable_irqs();
}

/* Overrides the weak version in kernel/power/main.c */
void arch_suspend_enable_irqs(void)
{
generic_suspend_enable_irqs();
if (ppc_md.suspend_enable_irqs)
ppc_md.suspend_enable_irqs();
}
#endif

#ifdef CONFIG_SMP
void __init smp_space_timers(unsigned int max_cpus)
{
Expand Down
48 changes: 6 additions & 42 deletions drivers/macintosh/via-pmu.c
Original file line number Diff line number Diff line change
Expand Up @@ -197,12 +197,6 @@ static int proc_read_options(char *page, char **start, off_t off,
static int proc_write_options(struct file *file, const char __user *buffer,
unsigned long count, void *data);

#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PPC32)
static void powerbook_sleep_init_3400(void);
#else
#define powerbook_sleep_init_3400() do { } while (0)
#endif

#ifdef CONFIG_ADB
struct adb_driver via_pmu_driver = {
"PMU",
Expand Down Expand Up @@ -450,10 +444,6 @@ static int __init via_pmu_start(void)
pmu_poll();
} while (pmu_state != idle);

/* Do allocations and ioremaps that will be needed for sleep */
if (pmu_kind == PMU_OHARE_BASED)
powerbook_sleep_init_3400();

return 0;
}

Expand Down Expand Up @@ -2168,13 +2158,7 @@ pmu_release(struct inode *inode, struct file *file)
}

#if defined(CONFIG_SUSPEND) && defined(CONFIG_PPC32)
/*
* overrides the weak arch_suspend_disable_irqs in kernel/power/main.c
*
* XXX: Once Scott Wood's patch is merged, this needs to use the ppc_md
* hooks that patch adds!
*/
void arch_suspend_disable_irqs(void)
static void pmac_suspend_disable_irqs(void)
{
#ifdef CONFIG_PMAC_BACKLIGHT
/* Tell backlight code not to muck around with the chip anymore */
Expand All @@ -2184,18 +2168,6 @@ void arch_suspend_disable_irqs(void)
/* Call platform functions marked "on sleep" */
pmac_pfunc_i2c_suspend();
pmac_pfunc_base_suspend();

/* Stop preemption */
preempt_disable();

/* Make sure the decrementer won't interrupt us */
asm volatile("mtdec %0" : : "r" (0x7fffffff));
/* Make sure any pending DEC interrupt occurring while we did
* the above didn't re-enable the DEC */
mb();
asm volatile("mtdec %0" : : "r" (0x7fffffff));

local_irq_disable();
}

static int powerbook_sleep(suspend_state_t state)
Expand Down Expand Up @@ -2244,25 +2216,13 @@ static int powerbook_sleep(suspend_state_t state)
return 0;
}

/*
* overrides the weak arch_suspend_enable_irqs in kernel/power/main.c
*
* XXX: Once Scott Wood's patch is merged, this needs to use the ppc_md
* hooks that patch adds!
*/
void arch_suspend_enable_irqs(void)
static void pmac_suspend_enable_irqs(void)
{
/* Force a poll of ADB interrupts */
adb_int_pending = 1;
via_pmu_interrupt(0, NULL);

/* Restart jiffies & scheduling */
wakeup_decrementer();

/* Re-enable local CPU interrupts */
local_irq_enable();
mdelay(10);
preempt_enable();

/* Call platform functions marked "on wake" */
pmac_pfunc_base_resume();
Expand All @@ -2282,6 +2242,10 @@ static struct platform_suspend_ops pmu_pm_ops = {

static int register_pmu_pm_ops(void)
{
if (pmu_kind == PMU_OHARE_BASED)
powerbook_sleep_init_3400();
ppc_md.suspend_disable_irqs = pmac_suspend_disable_irqs;
ppc_md.suspend_enable_irqs = pmac_suspend_enable_irqs;
suspend_set_ops(&pmu_pm_ops);

return 0;
Expand Down
13 changes: 13 additions & 0 deletions include/asm-powerpc/machdep.h
Original file line number Diff line number Diff line change
Expand Up @@ -251,6 +251,16 @@ struct machdep_calls {
*/
void (*machine_kexec)(struct kimage *image);
#endif /* CONFIG_KEXEC */

#ifdef CONFIG_SUSPEND
/* These are called to disable and enable, respectively, IRQs when
* entering a suspend state. If NULL, then the generic versions
* will be called. The generic versions disable/enable the
* decrementer along with interrupts.
*/
void (*suspend_disable_irqs)(void);
void (*suspend_enable_irqs)(void);
#endif
};

extern void power4_idle(void);
Expand Down Expand Up @@ -347,5 +357,8 @@ static inline void log_error(char *buf, unsigned int err_type, int fatal)
#define machine_late_initcall(mach,fn) __define_machine_initcall(mach,"7",fn,7)
#define machine_late_initcall_sync(mach,fn) __define_machine_initcall(mach,"7s",fn,7s)

void generic_suspend_disable_irqs(void);
void generic_suspend_enable_irqs(void);

#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_MACHDEP_H */

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