On Sun, 2017-01-08 at 14:44 +0100, Hans de Goede wrote: > Some drivers may need to acquire punit managed resources from > interrupt > context, where they cannot call iosf_mbi_punit_lock(). > > This commit adds a notifier chain which allows a driver to get > notified > (in a process context) before other drivers start accessing the pmic > bus, > so that the driver can acquire any resources, which it may need during > the window the other driver is accessing the pmic, before hand. > Same comments as per patch 1. I'm okay with the patch, but I would hear from other stakeholders that's _the_ way we are going. So, FWIW: Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241 > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > Tested-by: tagorereddy <tagore.chandan@xxxxxxxxx> > --- > arch/x86/include/asm/iosf_mbi.h | 54 > ++++++++++++++++++++++++++++++++++++++ > arch/x86/platform/intel/iosf_mbi.c | 36 +++++++++++++++++++++++++ > 2 files changed, 90 insertions(+) > > diff --git a/arch/x86/include/asm/iosf_mbi.h > b/arch/x86/include/asm/iosf_mbi.h > index 91f5d16..b8733bb 100644 > --- a/arch/x86/include/asm/iosf_mbi.h > +++ b/arch/x86/include/asm/iosf_mbi.h > @@ -47,6 +47,10 @@ > #define QRK_MBI_UNIT_MM 0x05 > #define QRK_MBI_UNIT_SOC 0x31 > > +/* Action values for the pmic_bus_access_notifier functions */ > +#define MBI_PMIC_BUS_ACCESS_BEGIN 1 > +#define MBI_PMIC_BUS_ACCESS_END 2 > + > #if IS_ENABLED(CONFIG_IOSF_MBI) > > bool iosf_mbi_available(void); > @@ -115,6 +119,38 @@ void iosf_mbi_punit_lock(void); > */ > void iosf_mbi_punit_unlock(void); > > +/** > + * iosf_mbi_register_pmic_bus_access_notifier - Register pmic bus > notifier > + * > + * This function can be used by drivers which may need to acquire > punit > + * managed resources from interrupt context, where > iosf_mbi_punit_lock() > + * can not be used. > + * > + * This function allows a driver to register a notifier to get > notified (in a > + * process context) before other drivers start accessing the pmic > bus. > + * > + * This allows the driver to acquire any resources, which it may need > during > + * the window the other driver is accessing the pmic, before hand. > + * > + * @nb: notifier_block to register > + */ > +int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block > *nb); > + > +/** > + * iosf_mbi_register_pmic_bus_access_notifier - Unregister pmic bus > notifier > + * > + * @nb: notifier_block to unregister > + */ > +int iosf_mbi_unregister_pmic_bus_access_notifier(struct > notifier_block *nb); > + > +/** > + * iosf_mbi_call_pmic_bus_access_notifier_chain - Call pmic bus > notifier chain > + * > + * @val: action to pass into listener's notifier_call function > + * @v: data pointer to pass into listener's notifier_call function > + */ > +int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, > void *v); > + > #else /* CONFIG_IOSF_MBI is not enabled */ > static inline > bool iosf_mbi_available(void) > @@ -146,6 +182,24 @@ int iosf_mbi_modify(u8 port, u8 opcode, u32 > offset, u32 mdr, u32 mask) > static inline void iosf_mbi_punit_lock(void) {} > static inline void iosf_mbi_punit_unlock(void) {} > > +static inline > +int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block > *nb) > +{ > + return 0; > +} > + > +static inline > +int iosf_mbi_unregister_pmic_bus_access_notifier(struct > notifier_block *nb) > +{ > + return 0; > +} > + > +static inline > +int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, > void *v) > +{ > + return 0; > +} > + > #endif /* CONFIG_IOSF_MBI */ > > #endif /* IOSF_MBI_SYMS_H */ > diff --git a/arch/x86/platform/intel/iosf_mbi.c > b/arch/x86/platform/intel/iosf_mbi.c > index 75d8135..a995789 100644 > --- a/arch/x86/platform/intel/iosf_mbi.c > +++ b/arch/x86/platform/intel/iosf_mbi.c > @@ -35,6 +35,7 @@ > static struct pci_dev *mbi_pdev; > static DEFINE_SPINLOCK(iosf_mbi_lock); > static DEFINE_MUTEX(iosf_mbi_punit_mutex); > +static BLOCKING_NOTIFIER_HEAD(iosf_mbi_pmic_bus_access_notifier); > > static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset) > { > @@ -203,6 +204,41 @@ void iosf_mbi_punit_unlock(void) > } > EXPORT_SYMBOL(iosf_mbi_punit_unlock); > > +int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block > *nb) > +{ > + int ret; > + > + /* Wait for the bus to go inactive before registering */ > + mutex_lock(&iosf_mbi_punit_mutex); > + ret = blocking_notifier_chain_register( > + &iosf_mbi_pmic_bus_access_notifier, > nb); > + mutex_unlock(&iosf_mbi_punit_mutex); > + > + return ret; > +} > +EXPORT_SYMBOL(iosf_mbi_register_pmic_bus_access_notifier); > + > +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); > + mutex_unlock(&iosf_mbi_punit_mutex); > + > + return ret; > +} > +EXPORT_SYMBOL(iosf_mbi_unregister_pmic_bus_access_notifier); > + > +int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, > void *v) > +{ > + return blocking_notifier_call_chain( > + &iosf_mbi_pmic_bus_access_notifier, > val, v); > +} > +EXPORT_SYMBOL(iosf_mbi_call_pmic_bus_access_notifier_chain); > + > #ifdef CONFIG_IOSF_MBI_DEBUG > static u32 dbg_mdr; > static u32 dbg_mcr; -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
