• Ohad Ben-Cohen's avatar
    hwspinlock/core/omap: fix id issues on multiple hwspinlock devices · c3c1250e
    Ohad Ben-Cohen authored
    hwspinlock devices provide system-wide hardware locks that are used
    by remote processors that have no other way to achieve synchronization.
    
    To achieve that, each physical lock must have a system-wide id number
    that is agreed upon, otherwise remote processors can't possibly assume
    they're using the same hardware lock.
    
    Usually boards 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, 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.
    
    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: 's avatarArnd Bergmann <arnd@arndb.de>
    Signed-off-by: 's avatarOhad Ben-Cohen <ohad@wizery.com>
    Acked-by: 's avatarTony Lindgren <tony@atomide.com>
    c3c1250e
Name
Last commit
Last update
Documentation Loading commit data...
arch Loading commit data...
block Loading commit data...
crypto Loading commit data...
drivers Loading commit data...
firmware Loading commit data...
fs Loading commit data...
include Loading commit data...
init Loading commit data...
ipc Loading commit data...
kernel Loading commit data...
lib Loading commit data...
mm Loading commit data...
net Loading commit data...
samples Loading commit data...
scripts Loading commit data...
security Loading commit data...
sound Loading commit data...
tools Loading commit data...
usr Loading commit data...
virt/kvm Loading commit data...
.gitignore Loading commit data...
.mailmap Loading commit data...
COPYING Loading commit data...
CREDITS Loading commit data...
Kbuild Loading commit data...
Kconfig Loading commit data...
MAINTAINERS Loading commit data...
Makefile Loading commit data...
README Loading commit data...
REPORTING-BUGS Loading commit data...