We need to expose all the input, output and output enable SPI lines
in order to use QSPI.
Remove the reset controller and PLL, since we are driving these
directly from caravel.
Make a few changes to match what mw_debug expects:
- 6 byte instructions
- IDCODE at 001001
- microwatt debug at 000011
Also change IDCODE to be an IBM ID.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
The verilator simulation interface uses the remote_bitbang
protocol from openocd. I have a simple implementation for
urjtag too.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
This makes it easier to parse the records in verilog because they
are getting flattened into an array of bits by ghdl/yosys.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
The ability to stop the core using the debug interface has been broken
since commit bb4332b7e6b5 ("Remove fetch2 pipeline stage"), which
removed a statement that cleared the valid bit on instructions when
their stop_mark was 1.
Fix this by clearing r.req coming out of fetch1 when r.stop_mark = 1.
This has the effect of making i_out.valid be 0 from the icache. We
also fix a bug in icache.vhdl where it was not honouring i_in.req when
use_previous = 1.
It turns out that the logic in fetch1.vhdl to handle stopping and
restarting was not correct, with the effect that stopping the core
would leave NIA pointing to the last instruction executed, not the
next instruction to be executed. In fact the state machine is
unnecessary and the whole thing can be simplified enormously - we
need to increment NIA whenever stop_in = 0 in the previous cycle.
Fixes: bb4332b7e6b5 ("Remove fetch2 pipeline stage")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The tools complain about uart1_irq not being driven and not having a
default when HAS_UART1 is false. This sets it to 0 in that case.
Fixes: 7575b1e0c2 ("uart: Import and hook up opencore 16550 compatible UART")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
If BOOT_CLOCKS is false we currently get stuck in the flash
state machine. This patch from Ben fixes it.
Also fix an x state issue I see in icarus verilog where we need
to reset auto_state.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Some of the bits in the FPU buses end up as z state. Yosys
flags them, so we may as well clean it up.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Our flash controller fails when simulating with iverilog. Looking
closer, both wb_stash and auto_last_addr are X state, and things
fall apart after they get used.
Initialise them both fixes the iverilog issue.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Our Makefiles need some work, but for now create an FPGA target:
make FPGA_TARGET=verilator microwatt-verilator
ghdl and yosys can use containers using PODMAN=1 or DOCKER=1
options.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
yosys and verilator did not like us passing in the verilog and
exporting it again. Pass the source directly to verilator instead.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
When building with yosys we assume hello_world fits in 8kB. There's
enough free space that we can adjust the linker script to make it fit.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
This adds a test with a bdnzl followed immediately by a bdnz, to check
that CTR and LR both get evaluated and written back correctly in this
situation.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>