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x86/platform/intel/iosf_mbi: Add unlocked PMIC bus access notifier unregister 

For race free unregistration drivers may need to acquire PMIC bus access
through iosf_mbi_punit_acquire() and then (un)register the notifier without
dropping the lock.

This commit adds an unlocked variant of
iosf_mbi_unregister_pmic_bus_access_notifier for this use case.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171019111620.26761-2-hdegoede@redhat.com
hifive-unleashed-5.1
Hans de Goede 2017-10-19 13:16:19 +02:00 committed by Hans de Goede
parent c16c4ba725
commit af0ab55ffe
2 changed files with 42 additions and 2 deletions
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25
arch/x86/include/asm/iosf_mbi.h
View File

@ -145,6 +145,18 @@ int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb);
*/
int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb);
/**
* iosf_mbi_unregister_pmic_bus_access_notifier_unlocked - Unregister PMIC bus
* notifier, unlocked
*
* Like iosf_mbi_unregister_pmic_bus_access_notifier(), but for use when the
* caller has already called iosf_mbi_punit_acquire() itself.
*
* @nb: notifier_block to unregister
*/
int iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(
struct notifier_block *nb);
/**
* iosf_mbi_call_pmic_bus_access_notifier_chain - Call PMIC bus notifier chain
*
@ -153,6 +165,11 @@ int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb);
*/
int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v);
/**
* iosf_mbi_assert_punit_acquired - Assert that the P-Unit has been acquired.
*/
void iosf_mbi_assert_punit_acquired(void);
#else /* CONFIG_IOSF_MBI is not enabled */
static inline
bool iosf_mbi_available(void)
@ -196,12 +213,20 @@ int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
return 0;
}
static inline int
iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(struct notifier_block *nb)
{
return 0;
}
static inline
int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v)
{
return 0;
}
static inline void iosf_mbi_assert_punit_acquired(void) {}
#endif /* CONFIG_IOSF_MBI */
#endif /* IOSF_MBI_SYMS_H */

19
arch/x86/platform/intel/iosf_mbi.c
View File

@ -218,14 +218,23 @@ int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL(iosf_mbi_register_pmic_bus_access_notifier);
int iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(
struct notifier_block *nb)
{
iosf_mbi_assert_punit_acquired();
return blocking_notifier_chain_unregister(
&iosf_mbi_pmic_bus_access_notifier, nb);
}
EXPORT_SYMBOL(iosf_mbi_unregister_pmic_bus_access_notifier_unlocked);
int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
{
int ret;
/* Wait for the bus to go inactive before unregistering */
mutex_lock(&iosf_mbi_punit_mutex);
ret = blocking_notifier_chain_unregister(
&iosf_mbi_pmic_bus_access_notifier, nb);
ret = iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(nb);
mutex_unlock(&iosf_mbi_punit_mutex);
return ret;
@ -239,6 +248,12 @@ int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v)
}
EXPORT_SYMBOL(iosf_mbi_call_pmic_bus_access_notifier_chain);
void iosf_mbi_assert_punit_acquired(void)
{
WARN_ON(!mutex_is_locked(&iosf_mbi_punit_mutex));
}
EXPORT_SYMBOL(iosf_mbi_assert_punit_acquired);
#ifdef CONFIG_IOSF_MBI_DEBUG
static u32 dbg_mdr;
static u32 dbg_mcr;