Patch to enable ASRC_P2P support for SSI based on Kernel 3.0.35 for I.MX6DL/DQ SebreSD boards

[#1]

i.MX6 4.0.0 BSP release doesn't support ASRC_P2P function. This patch provides the reference codes to enable ASRC_P2P function for SSI. It can convert input sample rate to 44.1K_16bit/44.1K_24bit and 48K_16bit/48K_24bit. You can modify the configurations in the Board file.

By the way, the SSI controler works at slave mode.

Known limitations for the patch:

-- The SDMA doesn't support SSI Dual FIFO when using ASRC_P2P function.

-- From the waveform, the converted 24bit data have some abnormal data(values between 0 and 1) , but can't hear any abnormal sound from headphone. One suggestion is given under https://community.freescale.com/docs/DOC-95340

[saurabh206]

Hi,

Lei Ge / Xiaoli Zhang

We have implemented P2P ASRC for recording using your attached patch.

ASRC is working perfectly but it stops working after 8 to 10 hours of Recording.

We are getting Overflow error in SDMA_MODE_P2P mode.

How to fix this issue?

Saurabh