| Message ID | 20190403124019.8947-3-wsa+renesas@sang-engineering.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i2c: core: introduce atomic transfers | expand |
On Wed, Apr 3, 2019 at 3:43 PM Wolfram Sang <wsa+renesas@sang-engineering.com> wrote: > > If I2C transfers are executed in atomic contexts, trylock is used > instead of lock. This behaviour was missing for SMBUS, although a lot of > transfers are of SMBUS type, either emulated or direct. So, factor out > the locking routine into a helper and use it for I2C and SMBUS. > Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> > --- > drivers/i2c/i2c-core-base.c | 11 +++-------- > drivers/i2c/i2c-core-smbus.c | 7 ++++++- > drivers/i2c/i2c-core.h | 12 ++++++++++++ > 3 files changed, 21 insertions(+), 9 deletions(-) > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index f8502064cd6b..ad14f38a67e4 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -1946,14 +1946,9 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) > * one (discarding status on the second message) or errno > * (discarding status on the first one). > */ > - if (i2c_in_atomic_xfer_mode()) { > - ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT); > - if (!ret) > - /* I2C activity is ongoing. */ > - return -EAGAIN; > - } else { > - i2c_lock_bus(adap, I2C_LOCK_SEGMENT); > - } > + ret = __i2c_lock_bus_helper(adap); > + if (ret) > + return ret; > > ret = __i2c_transfer(adap, msgs, num); > i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); > diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c > index 132119112596..357e083e8f45 100644 > --- a/drivers/i2c/i2c-core-smbus.c > +++ b/drivers/i2c/i2c-core-smbus.c > @@ -20,6 +20,8 @@ > #include <linux/i2c-smbus.h> > #include <linux/slab.h> > > +#include "i2c-core.h" > + > #define CREATE_TRACE_POINTS > #include <trace/events/smbus.h> > > @@ -530,7 +532,10 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, > { > s32 res; > > - i2c_lock_bus(adapter, I2C_LOCK_SEGMENT); > + res = __i2c_lock_bus_helper(adapter); > + if (res) > + return res; > + > res = __i2c_smbus_xfer(adapter, addr, flags, read_write, > command, protocol, data); > i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT); > diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h > index 9d8526415b26..deea47c576e5 100644 > --- a/drivers/i2c/i2c-core.h > +++ b/drivers/i2c/i2c-core.h > @@ -39,6 +39,18 @@ static inline bool i2c_in_atomic_xfer_mode(void) > return system_state > SYSTEM_RUNNING && irqs_disabled(); > } > > +static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap) > +{ > + int ret = 0; > + > + if (i2c_in_atomic_xfer_mode()) > + ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN; > + else > + i2c_lock_bus(adap, I2C_LOCK_SEGMENT); > + > + return ret; > +} > + > #ifdef CONFIG_ACPI > const struct acpi_device_id * > i2c_acpi_match_device(const struct acpi_device_id *matches, > -- > 2.11.0 >
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index f8502064cd6b..ad14f38a67e4 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1946,14 +1946,9 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) * one (discarding status on the second message) or errno * (discarding status on the first one). */ - if (i2c_in_atomic_xfer_mode()) { - ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT); - if (!ret) - /* I2C activity is ongoing. */ - return -EAGAIN; - } else { - i2c_lock_bus(adap, I2C_LOCK_SEGMENT); - } + ret = __i2c_lock_bus_helper(adap); + if (ret) + return ret; ret = __i2c_transfer(adap, msgs, num); i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index 132119112596..357e083e8f45 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -20,6 +20,8 @@ #include <linux/i2c-smbus.h> #include <linux/slab.h> +#include "i2c-core.h" + #define CREATE_TRACE_POINTS #include <trace/events/smbus.h> @@ -530,7 +532,10 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, { s32 res; - i2c_lock_bus(adapter, I2C_LOCK_SEGMENT); + res = __i2c_lock_bus_helper(adapter); + if (res) + return res; + res = __i2c_smbus_xfer(adapter, addr, flags, read_write, command, protocol, data); i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT); diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h index 9d8526415b26..deea47c576e5 100644 --- a/drivers/i2c/i2c-core.h +++ b/drivers/i2c/i2c-core.h @@ -39,6 +39,18 @@ static inline bool i2c_in_atomic_xfer_mode(void) return system_state > SYSTEM_RUNNING && irqs_disabled(); } +static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap) +{ + int ret = 0; + + if (i2c_in_atomic_xfer_mode()) + ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN; + else + i2c_lock_bus(adap, I2C_LOCK_SEGMENT); + + return ret; +} + #ifdef CONFIG_ACPI const struct acpi_device_id * i2c_acpi_match_device(const struct acpi_device_id *matches,
If I2C transfers are executed in atomic contexts, trylock is used instead of lock. This behaviour was missing for SMBUS, although a lot of transfers are of SMBUS type, either emulated or direct. So, factor out the locking routine into a helper and use it for I2C and SMBUS. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> --- drivers/i2c/i2c-core-base.c | 11 +++-------- drivers/i2c/i2c-core-smbus.c | 7 ++++++- drivers/i2c/i2c-core.h | 12 ++++++++++++ 3 files changed, 21 insertions(+), 9 deletions(-)