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Commit af0ab55f authored by Hans de Goede's avatar Hans de Goede Committed by Hans de Goede
Browse files

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: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171019111620.26761-2-hdegoede@redhat.com
parent c16c4ba7

arch/x86/include/asm/iosf_mbi.h

+25 −0
Original line number Diff line number Diff line
@@ -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 */

arch/x86/platform/intel/iosf_mbi.c

+17 −2
Original line number Diff line number Diff line
@@ -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;