This will be useful when we start needing different toplevels for
different boards.
We keep the reset and clock generators in the toplevel as they will
eventually be taken over by litedram when we integrate it, and they
are more likely to change on different system types.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We no longer gate multiply with the valid signal, so it's complaining
a lot. Comment out the warning.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
We weren't actually forwarding writes in the same cycle. Not a
problem right now, but noticed when testing the pipelining series.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
We want to make sure we never complete more than one
instruction per cycle, or write back more than one GPR
or CR per cycle.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
We only need two write ports for load with update instructions.
Having two write ports just for this instruction is expensive.
For now we will force them to be the only instruction in the
pipeline, and take two cycles of writeback.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
It simulated fine, but didn't synthesize. Fix some obvious issues
to get us going again.
Fixes: 9fbaea6f08 ("Rework CR file and add forwarding")
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Right now we continually print all 3 possible GPRs an instruction
may be using. Add signals so we only print GPRs when they are
actually read. This should hopefully optimise away when synthesized.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Handle the CR as a single field with per nibble enables. Forward any
writes in the same cycle.
If this proves to be an issue for timing, we may want to revisit
this in the future. For now, it keeps things simple.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
This adds support for the Digilane Cmod A7-35.
I had to use the MMCM because the clock (12 MHz) is below the PLL
minimum of 19 MHz.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
I wasn't waiting to get a wishbone ack back on stores before continuing.
This creates all sorts of problems when we add pipelining and send
loads and stores down the pipe faster.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
The old reset code was overly complicated and never worked properly.
Replace it with a simpler sequence that uses a couple of shift registers
to assert resets:
- Wait a number of external clock cycles before removing reset from
the PLL.
- After the PLL locks and the external reset button isn't pressed,
wait a number of PLL clock cycles before removing reset from the SOC.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Benjamin Herrenschmidt
Michael Neuling