On Wed, Jan 16, 2019 at 11:40 AM Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx> wrote: > > In multi-master environment, this driver's master cannot know > exactly when a peer master sends data to this driver's slave so > cases can be happened that this master tries sending data through > the master_xfer function but slave data from a peer master is still > being processed or slave xfer is started by a peer immediately > after it queues a master command. To support multi-master use cases > properly, this H/W provides arbitration in physical level and it > provides priority based command handling too to avoid conflicts in > multi-master environment, means that if a master and a slave events > happen at the same time, H/W will handle a higher priority event > first and a pending event will be handled when bus comes back to > the idle state. > > To support this H/W feature properly, this patch adds the 'pending' > state of master and its handling code so that the pending master > xfer can be continued after slave operation properly. > > Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx> > --- > drivers/i2c/busses/i2c-aspeed.c | 118 +++++++++++++++++++++++++------- > 1 file changed, 92 insertions(+), 26 deletions(-) > Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
