At present the logic prevents any interrupts from being handled while
there is a load/store instruction (one that has unit=LDST) being
executed. However, load/store instructions can still get sent to
loadstore1. Thus an instruction which should generate an interrupt
such as a floating-point unavailable interrupt will instead get
executed.
To fix this, when we detect that an interrupt should be generated but
loadstore1 is still executing a previous instruction, we don't execute
any new instructions, and set a new r.intr_pending flag. That results
in busy_out being asserted (meaning that no further instructions will
come in from decode2). When loadstore1 has finished the instructions
it has, the interrupt gets sent to writeback. If one of the
instructions in loadstore1 generates an interrupt in the meantime, the
l_in.interrupt signal gets asserted and that clears r.intr_pending, so
the interrupt we detected gets discarded.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
litesdcard provides a macro per vendor (eg xilinx, lattice) and not per
board, so modify the fusesoc generator to take a vendor. This will make
it easier to add litesdcard to more boards.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Unfortunately the CSR layout has shifted on upstream litex, so this
is built with the following litex patch backed out:
aad56a047a33 ("integration/soc: Use CSR automatic allocation.")
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
csr_data_width is no longer required. Add ntxslots and nrxslots
parameters but set them to the default value.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
This option was added in the commit but is no longer needed for github
CI to work.
commit ef0dcf3bc6
Author: Michael Neuling <mikey@neuling.org>
Date: Thu Jul 2 14:36:14 2020 +1000
Add SYNTH_ECP5_FLAGS option for building
Removing noflatten has the added advantage that it gets our builds
from 75% down to 59% usage on ECP5 85K.
Signed-off-by: Michael Neuling <mikey@neuling.org>
The icache RAM is currently LUT ram not block ram. This massively
bloats the icache size. We think this is due to yosys not inferencing
the RAM correctly but that's yet to be confirmed.
Work around this for now by reducing the default size of the icache
RAM for the ECP5 builds.
On the ECP5 85K builts, this gets us from 95% down to 76% and helps
our CI to pass.
Signed-off-by: Michael Neuling <mikey@neuling.org>
This implements a 1-entry partition table, so that instead of getting
the process table base address from the PRTBL SPR, the MMU now reads
the doubleword pointed to by the PTCR register plus 8 to get the
process table base address. The partition table entry is cached.
Having the PTCR and the vestigial partition table reduces the amount
of software change required in Linux for Microwatt support.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The VUnit log package is a SW style logging framework in VHDL and the check package is an assertion library doing its error reporting with VUnit logging.
These testbenches don't use, and do not need, very advanced logging/checking features but the following was possible to improve
- Checking equality in VHDL can be quite tedious with a lot of type conversions and long message strings to explain the data received and what was expected.
VUnit's check_equal procedure allow comparison between same or similar types and automatically create the error message for you.
- The code has report statements used for testbench progress reporting and debugging. These were replaced with the info and debug procedures.
info logs are visible by default while debug is not. This means that debug logs don't have to be commented, which they are now, when not used.
Instead there is a show procedure making debug messages visible. The show procedure has been commented to hide the debug messages but a more elegant
solution is to control visibility from a generic and then set that generic from the command line. I've left this as a TODO but the run script allow you to
extend the standard CLI of VUnit to add new options and you can also set generics from the run script.
- VUnit log messages are color coded if color codes are supported by the terminal. It makes it quicker to spot messages of different types when there are many log messages.
Error messages will always be made visible on the terminal but you must use the -v (verbose) to see other logs.
- Some tests have a lot of "metvalue detected" warning messages from the numeric_std package and these clutter the logs when using the -v option. VUnit has a simulator independent
option allowing you to suppress those messages. That option has been enabled.
Signed-off-by: Lars Asplund <lars.anders.asplund@gmail.com>
Several of the testbenches have stimuli code divided into sections preceded with a header comment explaining
what is being tested. These sections have been made into VUnit test cases. The default behavior of VUnit is
to run each test case in a separate simulation which comes with a number of benefits:
* A failing test case doesn't prevent other test cases to be executed
* Test cases are independent. A test case cannot fail as a side-effect to a problem with another test case
* Test execution can be more parallelized and the overall test execution time reduced
Signed-off-by: Lars Asplund <lars.anders.asplund@gmail.com>
This commit also removes the dependencies these testbenches have on VHPIDIRECT.
The use of VHPIDIRECT limits the number of available simulators for the project. Rather than using
foreign functions the testbenches can be implemented entirely in VHDL where equivalent functionality exists.
For these testbenches the VHPIDIRECT-based randomization functions were replaced with VHDL-based functions.
The testbenches recognized by VUnit can be executed in parallel threads for better simulation performance using
the -p option to the run.py script
Signed-off-by: Lars Asplund <lars.anders.asplund@gmail.com>
The VUnit run script will find all VHDL files based on given search patterns, figure out their dependencies, and support incremental compile based on the dependencies.
The same script is used for all VUnit supported simulators. Supporting several simulators simplifies the adoption of this project.
At this point only compilation is performed. Coming commits will enable simulation of VHDL testbenches.
Signed-off-by: Lars Asplund <lars.anders.asplund@gmail.com>
This adds litesdcard.v generated from the litex/litesdcard project,
along with logic in top-arty.vhdl to connect it into the system.
There is now a DMA wishbone coming in to soc.vhdl which is narrower
than the other wishbone masters (it has 32-bit data rather than
64-bit) so there is a widening/narrowing adapter between it and the
main wishbone master arbiter.
Also, litesdcard generates a non-pipelined wishbone for its DMA
connection, which needs to be converted to a pipelined wishbone. We
have a latch on both the incoming and outgoing sides of the wishbone
in order to help make timing (at the cost of two extra cycles of
latency).
litesdcard generates an interrupt signal which is wired up to input 3
of the ICS (IRQ 19).
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This makes the icache snoop writes to memory in the same way that the
dcache does, thus making DMA cache-coherent for the icache as well as
the dcache.
This also simplifies the logic for the WAIT_ACK state by removing the
stbs_done variable, since is_last_row(r.store_row, r.end_row_ix) can
only be true when stbs_done is true.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Since the expression is_last_row(r1.store_row, r1.end_row_ix) can only
be true when stbs_done is true, there is no need to include stbs_done
in the expression for the reload being completed, and hence no need to
compute stbs_done in the RELOAD_WAIT_ACK state.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This adds a path where the wishbone that goes out to memory and I/O
also gets fed back to the dcache, which looks for writes that it
didn't initiate, and invalidates any cache line that gets written to.
This involves a second read port on the cache tag RAM for looking up
the snooped writes, and effectively a second write port on the cache
valid bit array to clear bits corresponding to snoop hits.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Update documentation to reference fusesoc init for Xilinx boards, for
those like me who have never used fusesoc before. Add a reference to the
board files for Digilent boards and comment on perhaps installing them
for other boards as appropriate.
Signed-off-by: Antony Vennard <antony@vennard.ch>
Paul Mackerras
Anton Blanchard
Michael Neuling