McASP DMA Address Map

Atmaram K R

Hi,

We would like to know the DMA memory offset details of McASP in Netra.

In the linux driver file, address of McASP2 is mentioned as 0x46800000, sample code below:

static struct snd_platform_data ti8168_evm_snd_data = {
        .tx_dma_offset = 0x46800000,
        .rx_dma_offset = 0x46800000,
        .op_mode        = DAVINCI_MCASP_IIS_MODE,
        .num_serializer = ARRAY_SIZE(ti8168_iis_serializer_direction),
        .tdm_slots      = 2,
        .serial_dir     = ti8168_iis_serializer_direction,
        .asp_chan_q     = EVENTQ_2,
        .version        = MCASP_VERSION_2,
        .txnumevt       = 1,
        .rxnumevt       = 1,
};

Similarly what are the corresponding addresses for McASP0 and McASP1?

We went through the datasheet (SPRUGX8.pdf) but couldn't find any of these addresses.

Thanks,

Atmaram

over 13 years ago

0 Vaibhav Bedia over 13 years ago

TI__Expert 5290 points

This information is part of the system memory map which is given in http://www.ti.com/lit/ds/symlink/tms320dm8168.pdf

The L3 address for the McASPs is the DMA address.

Regards,

Vaibhav

0 Atmaram K R over 13 years ago in reply to Vaibhav Bedia

Prodigy 100 points

Hi Vaibhav,

Thanks for pointing us to the right document.

We are making modifications to use McASP0 for input (I2S Rx) and McASP2 for output (I2S Tx), both w.r.t. Netra. We have followed the steps mentioned in TI81xx PSP Porting Guide and also, changed the DMA address of McASP0. McASP2 is running as I2S Master whereas McASP0 as I2S Slave. With these changes when we check /proc/asound/devices, we see both playback and capture devices listed. However, only playback is working fine but capture seems to have hung at poll_wait(...) call. We have probed the data and clock lines of both Tx and Rx, and we see valid signals.

Any pointers to debug this further?

Thanks,

Atmaram

0 Vaibhav Bedia over 13 years ago in reply to Atmaram K R

TI__Expert 5290 points

If you don't mind, can you create a new post for this. Multiple queries in the same thread make it hard to search for similar posts.

Regards,

Vaibhav

0 Atmaram K R over 13 years ago in reply to Vaibhav Bedia

Prodigy 100 points

Hi Vaibhav,

Sorry for the same. I've created a new post as per your suggestion.

Thanks,

Atmaram

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McASP DMA Address Map