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| author | Hans de Goede <hdegoede@redhat.com> | 2017-02-10 11:27:51 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-02-26 21:13:24 +0100 |
| commit | 9260a0409794a59079393e843511414d5f08c14b (patch) | |
| tree | b892381ffa8e9df787d0b9d8150bd7bb5db99444 /arch/x86/platform | |
| parent | 64a577196d66b44e37384bc5c4d78c61f59d5b2a (diff) | |
| download | linux-9260a0409794a59079393e843511414d5f08c14b.tar.bz2 | |
x86/platform/intel/iosf_mbi: Add a mutex for P-Unit access
One some systems the P-Unit accesses the PMIC to change various voltages
through the same bus as other kernel drivers use for e.g. battery
monitoring.
If a driver sends requests to the P-Unit which require the P-Unit to access
the PMIC bus while another driver is also accessing the PMIC bus various
bad things happen.
This commit adds a mutex to protect the P-Unit against simultaneous
accesses and 2 functions to lock / unlock this mutex.
Note on these systems the i2c-bus driver will request a sempahore from the
P-Unit for exclusive access to the PMIC bus when i2c drivers are accessing
it, but this does not appear to be sufficient, we still need to avoid
making certain P-Unit requests during the access window to avoid problems.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170210102802.20898-2-hdegoede@redhat.com
Diffstat (limited to 'arch/x86/platform')
| -rw-r--r-- | arch/x86/platform/intel/iosf_mbi.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/platform/intel/iosf_mbi.c b/arch/x86/platform/intel/iosf_mbi.c index edf2c54bf131..ed24fa9fb65d 100644 --- a/arch/x86/platform/intel/iosf_mbi.c +++ b/arch/x86/platform/intel/iosf_mbi.c @@ -34,6 +34,7 @@ static struct pci_dev *mbi_pdev; static DEFINE_SPINLOCK(iosf_mbi_lock); +static DEFINE_MUTEX(iosf_mbi_punit_mutex); static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset) { @@ -190,6 +191,18 @@ bool iosf_mbi_available(void) } EXPORT_SYMBOL(iosf_mbi_available); +void iosf_mbi_punit_acquire(void) +{ + mutex_lock(&iosf_mbi_punit_mutex); +} +EXPORT_SYMBOL(iosf_mbi_punit_acquire); + +void iosf_mbi_punit_release(void) +{ + mutex_unlock(&iosf_mbi_punit_mutex); +} +EXPORT_SYMBOL(iosf_mbi_punit_release); + #ifdef CONFIG_IOSF_MBI_DEBUG static u32 dbg_mdr; static u32 dbg_mcr; |