> On Dec 17, 2015, at 1:59 PM, Charles Steinkuehler <[email protected]> > wrote: > > On 12/17/2015 2:04 PM, [email protected] wrote: >> I am trying to access the McASP control registers. Reading from the first >> one fails with the kernel oops stating "external abort on non-linefetch >> (0x1028)". I dont know what that means. A minimum failing example of the >> code is below: > > <snip> > >> I have also tried request_mem_region around it, but that changes nothing. >> The sound drivers are not loaded, and the devicetree entry for the McASP is >> disabled, so there shouldn't be any problems with conflicts. > > One way to get this error is if the hardware you are talking to is > disabled. You need to either enable the hardware via the device tree, > or otherwise manage to setup the low-level SoC registers so the McASP > is provided a clock, power, and is taken out of reset. > > Most of the hardware blocks on the AM335x series can be individually > enabled or shut-down to save power. That is a good point. To understand how to enable the power and clock for McASP, look at the Starterware examples for McASP as they do everything you need to make this work.
Regards, John > > -- > Charles Steinkuehler > [email protected] > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
