How do I set the 27th or 22th bit of register ADMA_PAGE<m>_CH<n>_CTRL_0?</n></m>

How do I set the 27th or 22th bit of register ADMA_PAGE_CH_CTRL_0?
I should choose which channel of the AHUB?
What factors influence the selection of AHUB channels?

Where did you get this REG and what your purpose.

It’s on page 3227 of the manual.
I’m debugging ADMAIF.
How do I choose the second parameter of the dma_request_slave_channel function?
I see a lot of dmas in the device tree.

The TX/RX request selects are programmed by setting the ‘slave_id’ in the dma_slave_config structure and calling dmaengine_slave_config() for the DMA channel. This will configure the ‘dma_sconfig’ structure in the Tegra ADMA driver for the DMA channel, and it will be programmed into the register by the function get_transfer_param() when a DMA transfer for the channel is setup. See drivers/dma/tegra210-adma.c for more details.

I originally wanted to ask how I should configure 27th or 22th bit of register ADMA_PAGE_CH_CTRL_0,which is slave_id.After all,there are 20 AHUB channels to choose from.