CSND Registers

0x1EC03000

NAME	PHYSICAL ADDRESS	WIDTH	DESCRIPTION
REG_DSP_FIFO	0x1ED03000	2
REG_DSP_??	0x1ED03004	2	???
REG_DSP_FIFO_CNT	0x1ED03008	2
REG_DSP_??	0x1ED03010	2	???
REG_DSP_STATUS	0x1ED0300C	2
REG_DSP_??	0x1ED03014	2	???
REG_DSP_??	0x1ED03018	2	???
REG_DSP_??	0x1ED0301C	2	???
REG_DSP_PORT<0-2>	0x1ED03020	3*8=0x18

REG_DSP_STATUS

bit1,8: FIFO WRITE ERRORS?

bit6: FIFO_READ_READY

bit7: FIFO_WRITE_READY

bit9: ???

bit10-12: PORT<0-2>_RECV_READY

bit13-15: PORT<0-2>_SEND_READY

0x1EC03400

The channel registers are based at 0x1EC03400(process virtual address). There's 0x20-bytes total for each channel slot, thus the base-address for a channel's slot is determined with: 0x1EC03400 + (channel_index*0x20). The below offsets are relative to these channel register slots.

Relative offset	Size	Description
0x0	2	REG_CSNDCHANX_CNT. For Type0 Cmd 0xE, CSND module basically writes this value here: u16 (cmdword[2] & 0xFFFF).
0x2	2	For Type0 Cmd 0xE, CSND module writes this value here: 0 - (cmdword[2]>>16).
0x4	2	For Type0 Cmd 0xE, CSND module writes value 0 here.
0x6	2	For Type0 Cmd 0xE, CSND module writes value 0 here.
0x8	2	For Type0 Cmd 0xE, CSND module writes this value here: (u16)cmdword[4].
0xA	2	For Type0 Cmd 0xE, CSND module writes this value here: cmdword[4]>>16.
0xC	4	This is the audio data physical address, for the main channel.
0x10	4	This is the audio data total byte-size. The CSND module masks the size loaded from the Type0 command-data with value 0x7FFFFFF, which is then used when writing these registers.
0x14	4	This is the audio data physical address, for the second channel. When this is not 0x0 stereo audio is used, otherwise mono audio is used.
0x18	4	When CSND module handles type0 Cmd 0xE with encoding!=IMA-ADPCM, CSND module sets this to zero. This register can be initialized via CSND module type0 Cmd 0xB.
0x1C	4	CSND module writes value zero here immediately after it writes to chanslotreg+0x18.