* Ohad Ben-Cohen <ohad@xxxxxxxxxx> [110912 09:14]: > hwspinlock devices provide system-wide hardware locks that are used > by remote processors that have no other way to achieve synchronization. > > For that to work, each physical lock must have a system-wide unique id > number that all processors are familiar with, otherwise they can't > possibly assume they're using the same hardware lock. > > Usually SoCs have a single hwspinlock device, which provides several > hwspinlocks, and in this case, they can be trivially numbered 0 to > (num-of-locks - 1). > > In case boards have several hwspinlocks devices (each of which > providing numerous hardware spinlocks) a different base id should be > used for each hwspinlock device (they can't all use 0 as a starting > id!). > > While this is certainly not common, it's just plain wrong to just > silently use 0 as a base id whenever the hwspinlock driver is probed. > > This patch provides a hwspinlock_pdata structure, that boards can use > to set a different base id for each of the hwspinlock devices they may > have, and demonstrates how to use it with the omap hwspinlock driver > (ultimately it will be DT which will supply this base_id information). > > While we're at it, make sure the hwspinlock core prints an explicit > error message in case an hwspinlock is registered with an id number > that already exists; this will help users catch such base id issues. > > Reported-by: Arnd Bergmann <arnd@xxxxxxxx> > Signed-off-by: Ohad Ben-Cohen <ohad@xxxxxxxxxx> Acked-by: Tony Lindgren <tony@xxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
