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
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@ -145,6 +145,18 @@ int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb);
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*/
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int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb);
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/**
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* iosf_mbi_unregister_pmic_bus_access_notifier_unlocked - Unregister PMIC bus
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* notifier, unlocked
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*
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* Like iosf_mbi_unregister_pmic_bus_access_notifier(), but for use when the
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* caller has already called iosf_mbi_punit_acquire() itself.
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*
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* @nb: notifier_block to unregister
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*/
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int iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(
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struct notifier_block *nb);
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/**
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* iosf_mbi_call_pmic_bus_access_notifier_chain - Call PMIC bus notifier chain
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*
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@ -153,6 +165,11 @@ int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb);
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*/
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int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v);
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/**
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* iosf_mbi_assert_punit_acquired - Assert that the P-Unit has been acquired.
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*/
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void iosf_mbi_assert_punit_acquired(void);
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#else /* CONFIG_IOSF_MBI is not enabled */
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static inline
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bool iosf_mbi_available(void)
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@ -196,12 +213,20 @@ int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
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return 0;
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}
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static inline int
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iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(struct notifier_block *nb)
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{
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return 0;
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}
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static inline
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int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v)
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{
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return 0;
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}
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static inline void iosf_mbi_assert_punit_acquired(void) {}
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#endif /* CONFIG_IOSF_MBI */
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#endif /* IOSF_MBI_SYMS_H */
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@ -218,14 +218,23 @@ int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb)
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}
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EXPORT_SYMBOL(iosf_mbi_register_pmic_bus_access_notifier);
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int iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(
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struct notifier_block *nb)
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{
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iosf_mbi_assert_punit_acquired();
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return blocking_notifier_chain_unregister(
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&iosf_mbi_pmic_bus_access_notifier, nb);
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}
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EXPORT_SYMBOL(iosf_mbi_unregister_pmic_bus_access_notifier_unlocked);
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int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
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{
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int ret;
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/* Wait for the bus to go inactive before unregistering */
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mutex_lock(&iosf_mbi_punit_mutex);
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ret = blocking_notifier_chain_unregister(
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&iosf_mbi_pmic_bus_access_notifier, nb);
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ret = iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(nb);
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mutex_unlock(&iosf_mbi_punit_mutex);
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return ret;
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@ -239,6 +248,12 @@ int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v)
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}
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EXPORT_SYMBOL(iosf_mbi_call_pmic_bus_access_notifier_chain);
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void iosf_mbi_assert_punit_acquired(void)
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{
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WARN_ON(!mutex_is_locked(&iosf_mbi_punit_mutex));
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}
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EXPORT_SYMBOL(iosf_mbi_assert_punit_acquired);
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#ifdef CONFIG_IOSF_MBI_DEBUG
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static u32 dbg_mdr;
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static u32 dbg_mcr;
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