AMD SB600 - page 226

©2008 Advanced Micro Devices, Inc. AC ’97 Controller Functional Descriptions
AMD SB600 Register Reference Manual Proprietary Page 226
Modem Fifo Flush– W - 32 bits - [MEM_Reg: 88h]
Field Name Bits Default Description
Output DMA3 Fifo Flush 2 0b Writing to this bit flushes modem output DMA3 fifo,
i.e., the indexes and Used/Free counts are reset.
Reading this bit returns 0.
Input DMA Fifo Flush 3 0b Writing to this bit flushes modem input DMA fifo, i.e.,
the indexes and Used/Free counts are reset. Reading
this bit returns 0.
Reserved 31:4 0000000h
Modem Fifo Flush Register.
Modem Phy Semaphore Reg- RW - 8 bits - [MEM_Reg: A8h]
Field Name Bits Default Description
Modem Phy
semaphore
0 0b PHY is ready for Modem to access.
0 = PHY is not ready for Modem to access.
1 = PHY is ready for Modem to access.
Modem driver can only accesses PHY register when the read back
value of this bit is ‘1’ after write a ‘1’ to this bit. It is possible the read
back value is ‘0’ after write ‘1’ which mean PHY is not ready for
Modem to access. Since PHY can be accessed by both audio &
modem controllers, the bit is used by modem driver to establish
semaphore handshake with audio driver.
Driver is also responsible to clear the bit after its PHY read/write
access.
Note: The driver can check Mem_reg 0x10[8] which indicates a PHY
read access completion. For writing to PHY, the driver can clear the
semaphore bit after the write command.
Reserved 7:1 00h