AMD SB600 - Manual (Page 239)

©2008 Advanced Micro Devices, Inc. HD Audio Controllers Registers
AMD SB600 Register Reference Manual Proprietary Page 239
CORB Upper Base Address – RW – 32 bits – [Mem_Reg: Base + 44h]
Field Name Bits Default Description
CORB Upper Base
Address 31:0 00000000
h
Upper 32 bits address of the CORB. This register must not
be written when the DMA engine is running or the DMA
transfer may be corrupted.
CORB Write Pointer – RW – 16 bits – [Mem_Reg: Base + 48h]
Field Name Bits Default Description
CORB Write Pointer 7:0 00h Software writes the last valid CORB entry offset into this
field in dword granularity. The DMA engine fetches
commands from the CORB until the Read Pointer matches
the Write Pointer. This supports up to 256 CORB entries.
This field may not be written while the DMA engine is
running.
Reserved 15:8 00h Reserved. Software must do a read-modify-write to
preserve the value of these bits.
CORB Read Pointer – RW – 16 bits – [Mem_Reg: Base + 4Ah]
Field Name Bits Default Description
CORB Read Pointer 7:0 00h Software reads this field to determine how many
commands it can write to the CORB without over-running.
The value read indicates the CORB Read Pointer offset in
dword granularity. The offset entry read from this field has
been successfully fetched by the DMA controller and may
be over-written by software. This field may be read while
the DMA engine is running.
Reserved 14:8 00h Reserved. Software must do a read-modify-write to
preserve the value of these bits.
CORB Read Pointer
Reset 15 0b Software writes a 1 to this bit to reset the CORB Read
Pointer to 0 and clear any residual prefetched commands
in the CORB hardware buffer within the controller. The
hardware will physically update this bit to 1 when the
CORB pointer reset is complete. Software must read a 1 to
verify that the reset completed correctly. Software must
clear this bit back to 0, by writing a 0, and then read back
the 0 to verify that the clear completed correctly. The
CORB DMA engine must be stopped prior to resetting the
Read Pointer or else DMA transfer may be corrupted.
CORB Control – RW – 8 bits – [Mem_Reg: Base + 4Ch]
Field Name Bits Default Description
CORB Memory Error
Interrupt Enable 0 0b If this bit is set, the controller will generate an interrupt if
the Memory Error Interrupt bit is set.
Enable CORB DMA
Engine 1 0b 0: DMA Stop
1: DMA Run
After software writes a “0” to this bit, the hardware may not
stop immediately. The hardware will physically update the
bit to “0” when the DMA engine is truly stopped. Software
must read a “0” from this bit to verify that the DMA engine
is truly stopped.
Reserved 7:2 00h Reserved. Software must do a read-modify-write to
preserve the value of these bits.