2009-05-15 04:59:21 BF533 Memdma doesn't transfer all the data.

zigma dsp (GERMANY)

Message: 74102

Hi,

I just wrote a driver to access memdma in BF533. The user will just open the driver and inside the driver read function, I am initiating a simple memdma. I could not see all the data in destination buffer. I am checking the data in driver itself, by printing to console. This is the result (should have printed 1,2,3,4,5,6,7,8,9,a):

kernel:-

Jan 2 03:40:15 blackfin user.debug kernel: Driver scmd_dma_basic opened..

Jan 2 03:40:15 blackfin user.debug kernel: Driver scmd_dma_basic read..

Jan 2 03:40:15 blackfin user.debug kernel: 0

Jan 2 03:40:15 blackfin user.debug kernel: 2

Jan 2 03:40:15 blackfin user.debug kernel: 3

Jan 2 03:40:15 blackfin user.debug kernel: 4

Jan 2 03:40:15 blackfin user.debug kernel: 5

Jan 2 03:40:15 blackfin user.debug kernel: 0

Jan 2 03:40:15 blackfin user.debug kernel: Driver scmd_dma_basic closed..

user:-

root:/bin> mknod /dev/scmd_dma_basic c 240 0

root:/bin> ./memdma_test_kernel

TEST DRIVER OPENED

TEST DRIVER - READ ACCESS

TEST DRIVER CLOSED

I am not using much in user space, because I am trying to learn writing drivers. Nevertheless, the DMA operation should have been alright.. If I use stream0, then it says that channel is not available (is kernel using it?).

I am using uClinux-dist-2008R1.5-RC3, with ez-kit board and the lan card.

Attached -

dma_test.c -> device driver.

memdma_test_kernel.c -> application

Thanks & Regards

JA.

memdma_test_kernel.c

dma_test.c

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2009-05-15 05:08:14 Re: BF533 Memdma doesn't transfer all the data.

Mike Frysinger (UNITED STATES)

Message: 74104