From: Terrence McGuckin <[email protected]> Reply-To: <[email protected]> Date: Thursday, December 12, 2013 at 5:31 PM To: <[email protected]> Cc: <[email protected]>, Andrew D Righter <[email protected]> Subject: [beagleboard] Re: Edma 2channel transfer loop
> I am working on EDMA ATM as well. I was curious if you could write a little > bit about how you are initializing the channels and setting up the transfers. > Are you writing a kernel module for this and interfacing to it in user-space? > > Appreciate any insight, having a hard time digging up info on using EDMA on > the Beaglebone Hi Terrence, Best place to understand how to work with EDMA is this link: http://processors.wiki.ti.com/index.php/EricScottVideos Under C6000, look at the videos on EDMA3. Clearly this is working under SysBIOS, but the concepts are the same. Once you understand these concepts, it will be easier for you to understand how the Linux drivers use EDMA. Regards, John > > > On Thursday, November 7, 2013 10:06:53 AM UTC-5, [email protected] wrote: >> Greeting again everyone!. >> >> I am using beaglebone with angstrom. >> >> I am trying( by writing a kernel module ) to loop two dma channels together >> but i cant figure out how.... >> >> Here is what i want. i want the completion of the 1st channel to trigger the >> final interrupt(callback1) and also channel 2. >> and at the completion of channel 2 to trigger the final interrupt (callback2) >> and also channel 1. etc... creating a loop between ch1 and ch2. >> >> By linking the channels it seems that i cant link channel 2 back to channel >> 1. ( >> >> edma_link(ch1, ch2); >> edma_link(ch2, ch1); system fail. >> >> i can only link ch2 on its self >> >> edma_link(ch1, ch2); >> edma_link(ch2, ch2); >> >> but i dont want that. >> >> By chaining the final interrupt is not going off. so i dont want that either. >> >> I tried to link edma_link(ch1, ch2) then chain ch2 with a ch3 and have >> edma_link(ch3, ch1); >> >> but then ch1 callback1 returns DMA_CC_ERROR with its paramset being NULL (so >> the error is from that). >> >> Any suggestions ? > > -- > 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/groups/opt_out. -- 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/groups/opt_out.
