
69rlq62d-f714peg4 * Memec (Headquar
ter
s) - Unique
Tec
h,
Insight,
Impact
MAR
VELL CONFIDENTIAL,
UNDER ND
A# 12101050
69rlq62d-f714peg4 * Memec (Headquar
ter
s) - Unique
Tec
h,
Insight,
Impact
MAR
VELL CONFIDENTIAL,
UNDER ND
A# 12101050
69r
lq62d-f714peg4 * Memec (Headquar
ters) - Unique
T
ech, Insight, Impact * UNDER ND
A# 12101050
MAR
VELL CONFIDENTIAL - UNA
UTHORIZED DISTRIB
UTION OR USE STRICTL
Y PR
OHIBITED
DMA Controller
Copyright © 12/13/06 Marvell
CONFIDENTIAL
Doc. No. MV-TBD-00 Rev. A
December 13, 2006
Document Classification: Proprietary Information
Page 299
Not approved by Document Control. For review only.
11.3.2.1.1
Descriptor Branching
If DDADRx[BREN] and DCSRx[CMPST] are set, the DMAC fetches the next descriptor from (the address in
the DDADRx re 32 bytes). If either of the bits is cleared, DMAC fetches the next descriptor from the
address in the DDADRx register.
DDADRx[BREN] is relevant only for descriptor-fetch transfers (DCSRx[NODESCFETCH] is cleared).
Figure 11-3. Descriptor-Fetch Transfer Channel State Diagram
Uninitialized
Valid
Descriptor-
Reset (hardware or sleep)
not running
(running)
Wait
for
request
Transferring
data
Stopped
descriptor
fetch
error
Channel
DCSRx[RUN]=1
DCMDx[LEN]
≠
0 &
DCMDx[FLOWS RC] = 0 &
DCMDx[FLOWTRG ] = 0
DDADRx[STOP] = 1
DDADRx[ STOP] = 1
DCMDx[FLO WSRC] X OR
DCMDx[FLO WTRG] = 1
DCMDx[FLOWSRC] &
DCMDx[FLOWTRG] = 0
Request asserted
DDA DRx[ STOP] = 0
DCMDx[FLOWSRC] X OR
DCMDx[FLOWTRG] = 1
DCSRx[RUN]=0
DCSRx[RUN]=0,
DCSRx[NODESCFETCH]=0,
DDADRx points to a
valid descriptor
DCSRx[BUSERRINTR]