This commit introduces a different interface to submit transfers, using
DMA descriptors.
The structure of the DMA descriptor is as follows:
struct dma_desc {
u32 flags,
u32 id,
u64 dest_addr,
u64 src_addr,
u64 next_sg_addr,
u32 y_len,
u32 x_len,
u32 src_stride,
u32 dst_stride,
};
The 'flags' field currently offers two control bits:
- bit 0: if set, the transfer will complete after this last descriptor
is processed, and the DMA core will go back to idle state; if cleared,
the next DMA descriptor pointed to by 'next_sg_addr' will be loaded.
- bit 1: if set, an end-of-transfer interrupt will be raised after the
memory segment pointed to by this descriptor has been transferred.
The 'id' field corresponds to an identifier of the descriptor.
The 'dest_addr' and 'src_addr' contain the destination and source
addresses to use for the transfer, respectively.
The 'x_len' field contains the number of bytes to transfer,
minus one.
The 'y_len', 'src_stride' and 'dst_stride' fields are only useful for
2D transfers, and should be set to zero if 2D transfers are not
required.
To start a transfer, the address of the first DMA descriptor must be
written to register 0x47c and the HWDESC bit of CONTROL register must
be set. The Scatter-Gather transfer is queued similarly to the simple
transfers, by writing 1 in TRANSFER_SUBMIT.
The Scatter-Gather interface has a dedicated AXI-MM bus configured for
read transfers, with its own dedicated clock, which can be asynchronous.
The Scatter-Gather reset is generated by the reset manager to reset the
logic after completing any pending transactions on the bus.
When the Scatter-Gather is enabled during runtime, the legacy cyclic
functionality of the DMA is disabled.
Signed-off-by: Ionut Podgoreanu <ionut.podgoreanu@analog.com>
New improvements for the ADI DMAC IP:
1)The capability to manually overwrite the DMA_AXI_ADDR_WIDTH(from GUI or from tcl)
2)DMA_AXI_ADDR_WIDTH attribute is now visible in the Vivado GUI:
-"Auto mode": Automatically calculated by the core tcl files based on the existing attached address segments.
-"Manual mode": Specify the desired dma_width between 32-64 bits.
3)Added two new debug registers that return higher part of the current source/destination address.
Signed-off-by: Filip Gherman <Filip.Gherman@analog.com>
* Added header license for the files that didn't have
* Modified parentheses
* Removed extra spaces at the end of lines
* Fixed parameters list to be each parameter on its line
* Deleted lines after endmodule and consecutive empty lines
* Fixed indentation
Signed-off-by: Iulia Moldovan <iulia.moldovan@analog.com>
On architectures with ports that support cache coherency, the AWCACHE
signal must be set to indicate that transactions are cached. This patch
adds a parameter allowing AWCACHE to be set on an AXI4 destination port.
Adds information on:
- Log 2 of interface data widths in bits
- Interface type (0 - Axi MemoryMap, 1 - AXI Stream, 2 - FIFO ) .
Lets the driver discover interface widths and interface type settings,
this will deprecate the corresponding device tree properties.
This is useful in case of parametrized projects where the width of
the datapath is changing. This change will allow the use of a generic
device tree node.
Updated version to 4.3.a
For consistent simulation behavior it is recommended to annotate all source
files with a timescale. Add it to those where it is currently missing.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Length of partial transfers are stored in a queue for SW reads.
The presence of partial transfer is indicated by a status bit.
The reporting can be enabled by a control bit.
The progress of any transfer can be followed by a debug register.
In its current implementation the DMAC requires that the length of a
transfer is aligned to the widest interface. E.g. if the widest interface
is 128 bits wide the length of the transfer needs to be a multiple of 16
bytes.
If the requested length is not aligned to the interface width it will be
rounded up.
This works fine as long as both interfaces have the same width. If they
have different widths it is possible that the length is rounded up to
different values on the source and destination side. In that case the DMA
will deadlock because the transfer lengths don't match and either not enough
of too much data is delivered from the source to the destination side.
Currently it is up to software to make sure that such an invalid
configuration is not possible.
Also enforce this requirement in the DMAC itself by setting the LSBs of the
transfer length to a fixed 1 so that the length is always aligned to the
widest interface.
Software can also use this to discover the length alignment requirement, by
first writing a zero to the length register and then reading the register
back. The LSBs of the read back value will be non-zero indicating the
alignment requirement.
In a similar way the stride needs to be aligned to the width of its
respective interface, so the generated addresses stay aligned. Enforce this
in the same way by keeping the LSBs cleared.
Increment the minor version number to reflect these changes.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The DMAC allows a transfer to be aborted. When a transfer is aborted the
DMAC shuts down as fast as possible while still completing any pending
transactions as required by the protocol specifications of the port. E.g.
for AXI-MM this means to complete all outstanding bursts.
Once the DMAC has entered an idle state a special synchronization signal is
send to all modules. This synchronization signal instructs them to flush
the pipeline and remove any stale data and metadata associated with the
aborted transfer. Once all data has been flushed the DMAC enters the
shutdown state and is ready for the next transfer.
In addition each module has a reset that resets the modules state and is
used at system startup to bring them into a consistent state.
Re-work the shutdown process to instead of flushing the pipeline re-use the
startup reset signal also for shutdown.
To manage the reset signal generation introduce the reset manager module.
It contains a state machine that will assert the reset signals in the
correct order and for the appropriate duration in case of a transfer
shutdown.
The reset signal is asserted in all domains until it has been asserted for
at least 4 clock cycles in the slowest domain. This ensures that the reset
signal is not de-asserted in the faster domains before the slower domains
have had a chance to process the reset signal.
In addition the reset signal is de-asserted in the opposite direction of
the data flow. This ensures that the data sink is ready to receive data
before the data source can start sending data. This simplifies the internal
handshaking.
This approach has multiple advantages.
* Issuing a reset and removing all state takes less time than
explicitly flushing one sample per clock cycle at a time.
* It simplifies the logic in the faster clock domains at the expense of
more complicated logic in the slower control clock domain. This allows
for higher fMax on the data paths.
* Less signals to synchronize from the control domain to the data domains
The implementation of the pause mode has also slightly changed. Pause is
now a simple disable of the data domains. When the transfer is resumed
after a pause the data domains are re-enabled and continue at their
previous state.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Split the register map code into a separate sub-module instead of having it
as part of the top-level axi_dmac.v file.
This makes it easier to component test the register map behavior
independently from the DMA transfer logic.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Ionut Podgoreanu
Iulia Moldovan
Filip Gherman
Mathias Tausen
Laszlo Nagy
Arpadi
Lars-Peter Clausen