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clear wakeup enable bit upon resuming from suspend

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The FVP specific code that gets called after a cpu has been physically
powered on after having been turned off or suspended earlier does not
clear the PWRC.PWKUPR.WEN bit. Not doing so causes problems if: a cpu
is suspended, woken from suspend, powered down through a cpu_off call
& receives a spurious interrupt. Since the WEN bit is not cleared
after the cpu woke up from suspend, the spurious wakeup will power the
cpu on. Since the cpu_off call clears the jump address in the mailbox
this spurious wakeup will cause the cpu to crash.

This patch fixes this issue by clearing the WEN bit whenever a cpu is
powered up.

Change-Id: Ic91f5dffe1ed01d76bc7fc807acf0ecd3e38ce5b
This commit is contained in:
Achin Gupta 2013-11-12 16:40:00 +00:00 • committed by Dan Handley
parent 4a826ddad8
commit b127cdb879
4 changed files with 21 additions and 3 deletions
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3
docs/change-log.md
View file

@ -45,6 +45,9 @@ Detailed changes since last release
instructions for how to contribute and update copyright text in all files to
acknowledge contributors.
* The wake up enable bit in the FVP power controller is cleared when a cpu is
physically powered up to prevent a spurious wake up from a subsequent cpu
off state.
ARM Trusted Firmware - version 0.2
==================================

10
drivers/power/fvp_pwrc.c
View file

@ -77,7 +77,7 @@ void fvp_pwrc_write_ppoffr(unsigned long mpidr)
bakery_lock_release(mpidr, &pwrc_lock);
}
void fvp_pwrc_write_pwkupr(unsigned long mpidr)
void fvp_pwrc_set_wen(unsigned long mpidr)
{
bakery_lock_get(mpidr, &pwrc_lock);
mmio_write_32(PWRC_BASE + PWKUPR_OFF,
@ -85,6 +85,14 @@ void fvp_pwrc_write_pwkupr(unsigned long mpidr)
bakery_lock_release(mpidr, &pwrc_lock);
}
void fvp_pwrc_clr_wen(unsigned long mpidr)
{
bakery_lock_get(mpidr, &pwrc_lock);
mmio_write_32(PWRC_BASE + PWKUPR_OFF,
(unsigned int) mpidr);
bakery_lock_release(mpidr, &pwrc_lock);
}
void fvp_pwrc_write_pcoffr(unsigned long mpidr)
{
bakery_lock_get(mpidr, &pwrc_lock);

3
drivers/power/fvp_pwrc.h
View file

@ -67,7 +67,8 @@ extern int fvp_pwrc_setup(void);
extern void fvp_pwrc_write_pcoffr(unsigned long);
extern void fvp_pwrc_write_ppoffr(unsigned long);
extern void fvp_pwrc_write_pponr(unsigned long);
extern void fvp_pwrc_write_pwkupr(unsigned long);
extern void fvp_pwrc_set_wen(unsigned long);
extern void fvp_pwrc_clr_wen(unsigned long);
extern unsigned int fvp_pwrc_read_psysr(unsigned long);
extern unsigned int fvp_pwrc_get_cpu_wkr(unsigned long);

8
plat/fvp/fvp_pm.c
View file

@ -251,7 +251,7 @@ int fvp_affinst_suspend(unsigned long mpidr,
* Program the power controller to power this
* cpu off and enable wakeup interrupts.
*/
fvp_pwrc_write_pwkupr(mpidr);
fvp_pwrc_set_wen(mpidr);
fvp_pwrc_write_ppoffr(mpidr);
}
break;
@ -309,6 +309,12 @@ int fvp_affinst_on_finish(unsigned long mpidr,
write_cpuectlr(ectlr);
}
/*
* Clear PWKUPR.WEN bit to ensure interrupts do not interfere
* with a cpu power down unless the bit is set again
*/
fvp_pwrc_clr_wen(mpidr);
/* Zero the jump address in the mailbox for this cpu */
fvp_mboxes = (mailbox *) (TZDRAM_BASE + MBOX_OFF);
linear_id = platform_get_core_pos(mpidr);