At Wed, 14 Nov 2007 00:12:07 +0530, Pharaoh . wrote:
Hi,
I am trying to use snd_pcm_lib_preallocate_pages_for_all() on an arm based platform for preallocating the DMA buffer. I am using it as
snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV, NULL, 64 * 1024, 64 * 1024);
since I dont know what should be passed as the 3'rd param. I tried passing my device pointer i.e. card->dev after correctly populating it but I get an error as 'DMA coherent mask in not set' and buffer is not allocated.
For ARM, avoid the present buffer-preallocation and mmap functions in ALSA core. Instead you can allocate the buffers directly via normal dma_alloc_coherent() in your driver. And, mmap it via dma_mmap_coherent() by defining the own mmap callback for PCM ops.
See other arm/* drivers for rerecence.
Takashi