log2ceil() returns the number of bits required to store a value, so we
need to pass in memory_size-1, not memory_size.
Every other user of log2ceil() gets this right.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
This makes the 64-bit wishbone buses have the address expressed in
units of doublewords (64 bits), and similarly for the 32-bit buses the
address is in units of words (32 bits). This is to comply with the
wishbone spec. Previously the addresses on the wishbone buses were in
units of bytes regardless of the bus data width, which is not correct
and caused problems with interfacing with externally-generated logic.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Experimenting with using ghdl to do VHDL to Verilog conversion (instead
of ghdl+yosys), verilator complains that a signal is a SystemVerilog
keyword:
%Error: microwatt.v:15013:18: Unexpected 'do': 'do' is a SystemVerilog keyword misused as an identifier.
... Suggest modify the Verilog-2001 code to avoid SV keywords, or use `begin_keywords or --language.
We could probably make this go away by disabling SystemVerilog, but
it's easy to rename the signal in question. Rename di at the same
time.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
We might want a non power of 2 amount of RAM in order to fit into an
FPGA, so create log2ceil and use it when calculating the number of
memory bits.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Stores only need a single cycle, so we can ack them early if there
isn't an older ack already in the pipeline
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This replaces the simple_ram_behavioural and mw_soc_memory modules
with a common wishbone_bram_wrapper.vhdl that interfaces the
pipelined WB with a lower-level RAM module, along with an FPGA
and a sim variants of the latter.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Anton Blanchard
Paul Mackerras