On Fri, Dec 30, 2016 at 12:18:27PM +0100, Hauke Mehrtens wrote: > The DMA controller channel and port configuration is changed by > selecting the port or channel in one register and then update the > configuration in other registers. This has to be done in an atomic > operation. Previously only the local interrupts were deactivated which > works for single CPU systems. If the system supports SMP a better > locking is needed, use spinlocks instead. > On more recent SoCs (at least xrx200 and later) there are two memory > regions to change the configuration, there we could use one area for > each CPU and do not have to synchronize between the CPUs and more. You should always use proper locking, not interrupt fiddlery for proper serialization. On UP kernels the spinlocks will expand to call just the local_irq_* so no overhead. Applied, Ralf
