The host can issue the following commands with descriptors:
• Data DMA
• Erase
• Copyback
• Lock
• Lock-tight
• Unlock
Command DMA Operation
Command DMA operation is initiated by a MAP10 command containing the descriptor chain start address
and the channel number associated with the descriptor chain.
The flash controller fetches the complete descriptor with a burst transaction. The addresses must be aligned
to 32 bits in the host memory. When the flash controller fetches a descriptor, the flash controller extracts
the flash pointer to construct the MAP10 command address to be issued to the flash controller. A complete
MAP10 command is structured from the information decoded from the descriptor and the flash controller
executes this MAP10 command. The flash controller can retrieve the next descriptor immediately after
processing the command in the current descriptor without waiting for host instructions.
When the flash controller completes the command operation, it writes the status back into the descriptor
placeholder in the system memory. Command DMA issues an interrupt,
desc_comp_channel<x>
for
channel
<x>
, if the
Int
bit is set in the command flags field. After issuing the interrupt, the next descriptor
is fetched if the
Cont
bit is set in the command flags field.
This descriptor processing happens in parallel for all channels that have been enabled by a MAP10 command-
DMA command.
The MAP10 command can be sent as four separate single-beat transactions (multitransaction DMA command)
or a single transaction consisting of four data beats (burst DMA command).
Multitransaction DMA Commands
The flash controller processes multi-transaction DMA commands only if it receives all four transactions in
order. The flash controller responds with an
unsup_cmd
interrupt if there are any out-of-order commands
or the sequenced commands are interleaved with other flash controller MAP commands.
Related Information
Multitransaction Command-DMA Command Format
on page 10-17
Multitransaction Command-DMA Command Format
The following tables show the format of each command-data pair for multi-transaction DMA commands.
Table 10-9: Transaction 1 Address Encoding
23:0
25:24
27:26
31:28
Reserved
Res.
0x2
0x0
Altera Corporation
NAND Flash Controller
10-17
Command DMA Operation
cv_54010
2013.12.30