Commit Graph

126 Commits (ebdddcc402cc9a15499876c4a43fd1f559be56b4)

Author SHA1 Message Date
Benjamin Herrenschmidt 097d19fd32 Makefile: Improve unisim library generation
The rewrite of the Makefile to use "ghdl -c" somewhat broke building
the unisim library as ghdl doesn't yet support putting files in
separate libraries from a single command line invocation.

The workaround at the time was to put the entire project in "unisim"
which is ... weird and will break if we try to add another library
such as fmf.

This fixes it by generating the library separately using "ghdl -i"

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Michael Neuling 6323f27423 Add unit tests to check and check_light
Signed-off-by: Michael Neuling <mikey@neuling.org>
4 years ago
Michael Neuling 809933a567 Add unit tests make target
We don't run these but we should.

The SOC tests have bit rotted. We need to fix them but leave them out
for now.

Signed-off-by: Michael Neuling <mikey@neuling.org>
4 years ago
Michael Neuling 560a6f6b18 Add tests_console make target
Will use when splitting out Travis tests later

Signed-off-by: Michael Neuling <mikey@neuling.org>
4 years ago
Benjamin Herrenschmidt 599fad117b litedram: Remove old "VexRiscV" based initializations
Support for this has bitrotted and would require refactoring of L2 to
be brought back. It's also not really needed anymore now that we ship
pre-generated litedram and that LiteX supports what we do.

So take it out, which simplifies some of the scripts as well. This also
fixes up CSR alignment the sim model.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 6828e93113 litedram: Test bench
The test bench test simple access forms for now, it's a starting point
but it already helped find/fix a bug.

Includes a litedram update to be able to operate the sim model without
inits.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt a3857aac94 litedram: Add an L2 cache with store queue
This adds a cache between the wishbone and litedram with the following
features (at this point, it's still evolving)

  - 128 bytes line width in order to have a reasonable amount of
litedram pipelining on the 128-bit wide data port.

  - Configurable geometry otherwise

  - Stores are acked immediately on wishbone whether hit or miss
(minus a 2 cycles delay if there's a previous load response in the
way) and sent to LiteDRAM via 8 entries (configurable) store queue

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 6fe077910b litedram: Add simulation support
This adds a simulated litedram model along with the necessary
Makefile gunk to verilate it and wrap it for use by ghdl.

The core_dram_tb test bench is a variant of core_tb with
LiteDRAM simulated. It's not built by default, an explicit

make core_dram_tb

is necessary as to not require verilator to be installed for
the normal build process (also it's slow'ish).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Anton Blanchard 04c56a0c52 Pass clock frequency to UART sim wrapper
The UART sim wrapper is currently hard wired to 50 MHz.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 7b14819dbb A little less shouting in the Makefile
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 01da807476 Fix the simulated DMI
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard a9e7194de5 Merge Makefile and Makefile.synth
We still need to a way to our FPGA target on the command line, but this
at least gets us down to a common Makefile.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 6326efaca4 Add Makefile command line variables to enable docker and podman
Instead of having to edit the Makefile, we can now do:

make DOCKER=1
make PODMAN=1

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 224e7734a8 Rework Makefile
Instead of building each file one by one (and having to track all
the dependencies manually), use the ghdl -c command that does
analysis and elaboration in one go.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 4e78b8078e
Merge branch 'master' into litedram 4 years ago
Benjamin Herrenschmidt 803ee9ef35 Makefile: Improve clean a bit
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Paul Mackerras c164a2f4ea Merge branch 'mmu'
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Benjamin Herrenschmidt 025cf5efe8 syscon: Add syscon registers
These provides some info about the SoC (though it's still somewhat
incomplete and needs more work, see comments).

There's also a control register for selecting DRAM vs. BRAM at 0
(and for soft-resetting the SoC but that isn't wired up yet).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Paul Mackerras 8160f4f821 Add framework for implementing an MMU
This adds a new module to implement an MMU.  At the moment it doesn't
do very much.  Tlbie instructions now get sent by loadstore1 to mmu,
which sends them to dcache, rather than loadstore1 sending them
directly to dcache.  TLB misses from dcache now get sent by loadstore1
to mmu, which currently just returns an error.  Loadstore1 then
generates a DSI in response to the error return from mmu.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Benjamin Herrenschmidt 982cf166dd litedram: Add basic support for LiteX LiteDRAM
This comes in two parts:

 - A generator script which uses LiteX to generate litedram cores
along with their init files for various boards (currently Arty and
Nexys-video). This comes with configs for arty and nexys_video.

 - A fusesoc "generator" which uses pre-generated litedram cores

The generation process is manual on purpose. This include pre-generated
cores for the two above boards.

This is done so that one doesn't have to install LiteX to build
microwatt. In addition, the generator script or wrapper vhdl tend to
break when LiteX changes significantly which happens.

This is still rather standalone and hasn't been plumbed into the SoC
or the FPGA toplevel files yet.

At this point LiteDRAM self-initializes using a built-in VexRiscv
"Minimum" core obtained from LiteX and included in this commit. There
is some plumbing to generate and cores that are initialized by Microwatt
directly but this isn't working yet and so isn't enabled yet.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Paul Mackerras 102b304db7 Merge remote-tracking branch 'remotes/origin/master' 4 years ago
Anton Blanchard 4160f2138d
Merge pull request #165 from mikey/xics
Implement XICS compliant interrupt controller
4 years ago
Paul Mackerras a05ee9fc7f Makefile: fix typo
Fix a typo which meant that the console tests weren't getting
executed by 'make check'.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Paul Mackerras 167e37d667 Plumb insn_type through to loadstore1
In preparation for adding a TLB to the dcache, this plumbs the
insn_type from execute1 through to loadstore1, so that we can have
other operations besides loads and stores (e.g. tlbie) going to
loadstore1 and thence to the dcache.  This also plumbs the unit field
of the decode ROM from decode2 through to execute1 to simplify the
logic around which ops need to go to loadstore1.

The load and store data formatting are now not conditional on the
op being OP_LOAD or OP_STORE.  This eliminates the inferred latches
clocked by each of the bits of r.op that we were getting previously.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Michael Neuling b4f20c20b9 XICS interrupt controller
New unified ICP and ICS XICS compliant interrupt controller.
Configurable number of hardware sources.

Fixed hardware source number based on hardware line taken. All
hardware interrupts are a fixed priority. Level interrupts supported
only.

Hardwired to 0xc0004000 in SOC (UART is kept at 0xc0002000).

Signed-off-by: Michael Neuling <mikey@neuling.org>
4 years ago
Michael Neuling ff162e42eb Add VHDL TAGS
Adds `make TAGS`

Signed-off-by: Michael Neuling <mikey@neuling.org>
4 years ago
Michael Neuling 9d7df2d507 Add test cases for new exceptions and supervisor state
This adds test cases for:
- sc, illegals and decrementer exceptions
- decrementer overflow
- rfid
- mt/mf sprg0/1 srr0/1
- mtdec
- mtmsrd
- sc

It also adds these test cases to make check/check_light

Signed-off-by: Michael Neuling <mikey@neuling.org>
4 years ago
Dan Horák ab50c7710d make the sources volume mount SELinux friendly
Signed-off-by: Dan Horák <dan@danny.cz>
4 years ago
Anton Blanchard 471c7e2197 Consolidate VHPI code
We had many copies of the VHPI marshalling/unmarshalling code.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard f77b31a552
Merge pull request #134 from paulusmack/master
Add bypass from execute1 output to input
4 years ago
Anton Blanchard c18830a5e5 Add an option to use Docker
Some distros don't have a version of ghdl with the  LLVM or GCC backend,
so add a Docker image as an alternative.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard a4dbbfda4a Fix Makefile dependency issue with files in vhdl/*
GHDL doesn't seem to have a way to specify the location of the object
file it writes, so right now they are all ending up in the root
directory. The Makefile rules did not reflect that, so make would
continually the files in fpga/*

Fix the rules to match what GHDL is doing.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Paul Mackerras 39d18d2738 Make divider hang off the side of execute1
With this, the divider is a unit that execute1 sends operands to and
which sends its results back to execute1, which then send them to
writeback.  Execute1 now sends a stall signal when it gets a divide
or modulus instruction until it gets a valid signal back from the
divider.  Divide and modulus instructions are no longer marked as
single-issue.

The data formatting step that used to be done in decode2 for div
and mod instructions is now done in execute1.  We also do the
absolute value operation in that same cycle instead of taking an
extra cycle inside the divider for signed operations with a
negative operand.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Paul Mackerras 2167186b5f Make multiplier hang off the side of execute1
With this, the multiplier isn't a separate pipe that decode2 issues
instructions to, but rather is a unit that execute1 sends operands
to and which sends the result back to execute1, which then sends it
to writeback.  Execute1 now sends a stall signal when it gets a
multiply instruction until it gets a valid signal back from the
multiplier.

This all means that we no longer need to mark the multiply
instructions as single-issue.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Benjamin Herrenschmidt e4f475e17f sprs: Store common SPRs in register file
This stores the most common SPRs in the register file.

This includes CTR and LR and a not yet final list of others.

The register file is set to 64 entries for now. Specific types
are defined that can represent a GPR index (gpr_index_t) or
a GPR/SPR index (gspr_index_t) along with conversion functions
between the two.

On order to deal with some forms of branch updating both LR and
CTR, we introduced a delayed update of LR after a branch link.

Note: We currently stall the pipeline on such a delayed branch,
but we could avoid stalling fetch in that specific case as we
know we have a branch delay. We could also limit that to the
specific case where we need to update both CTR and LR.

This allows us to make bcreg, mtspr and mfspr pipelined. decode1
will automatically force the single issue flag on mfspr/mtspr to
a "slow" SPR.

[paulus@ozlabs.org - fix direction of decode2.stall_in]

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Benjamin Herrenschmidt 8e0389b973 ram: Rework main RAM interface
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>
5 years ago
Benjamin Herrenschmidt 9a63c098a5 Move log2/ispow2 to a utils package
(Out of icache and dcache)


Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Benjamin Herrenschmidt cb4451498f dcache: Add testbench
A very simple one for now...

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Benjamin Herrenschmidt b513f0fb48 dcache: Add a dcache
This replaces loadstore2 with a dcache

The dcache unit is losely based on the icache one (same basic cache
layout), but has some significant logic additions to deal with stores,
loads with update, non-cachable accesses and other differences due to
operating in the execution part of the pipeline rather than the fetch
part.

The cache is store-through, though a hit with an existing line will
update the line rather than invalidate it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Paul Mackerras f49a5a99a5 Remove execute2 stage
Since the condition setting got moved to writeback, execute2 does
nothing aside from wasting a cycle.  This removes it.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Paul Mackerras 374f4c536d writeback: Do data formatting and condition recording in writeback
This adds code to writeback to format data and test the result
against zero for the purpose of setting CR0.  The data formatter
is able to shift and mask by bytes and do byte reversal and sign
extension.  It can also put together bytes from two input
doublewords to support unaligned loads (including unaligned
byte-reversed loads).

The data formatter starts with an 8:1 multiplexer that is able
to direct any byte of the input to any byte of the output.  This
lets us rotate the data and simultaneously byte-reverse it.
The rotated/reversed data goes to a register for the unaligned
cases that overlap two doublewords.  Then there is per-byte logic
that does trimming, sign extension, and splicing together bytes
from a previous input doubleword (stored in data_latched) and the
current doubleword.  Finally the 64-bit result is tested to set
CR0 if rc = 1.

This removes the RC logic from the execute2, multiply and divide
units, and the shift/mask/byte-reverse/sign-extend logic from
loadstore2.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Anton Blanchard 813f834012 Add CR hazard detection
To keep things simple we treat the CR as a single entity.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard bdc26b7527 Add GPR hazard detection
Check GPRs against any writers in the pipeline.

All instructions are still marked single in pipeline at
this stage.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard e4c98dce36
Merge pull request #100 from antonblanchard/gpr-hazard-5-a
Separate issue control into its own unit
5 years ago
Anton Blanchard d5346d0abf Separate issue control into its own unit
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Paul Mackerras 4396eddc31 countzero: Add a testbench
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Anton Blanchard 3c6e66dc96
Merge pull request #83 from paulusmack/logical
execute: Consolidate count-leading/trailing-zeroes implementations
5 years ago
Anton Blanchard 4b7b702e01
Merge pull request #81 from antonblanchard/logical
Consolidate logical instructions
5 years ago
Paul Mackerras 24a4a796ce execute: Consolidate count-leading/trailing-zeroes implementations
This adds combinatorial logic that does 32-bit and 64-bit count
leading and trailing zeroes in one unit, and consolidates the
four instructions under a single OP_CNTZ opcode.

This saves 84 slice LUTs on the Arty A7-100.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Anton Blanchard b8fb721b81 Consolidate logical instructions
Consolidate and/andc/nand, or/orc/nor and xor/eqv, using a common
invert on the input and output. This saves us about 200 LUTs.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Benjamin Herrenschmidt b56b46b7d1 icache: Set associative icache
This adds support for set associativity to the icache. It can still
be direct mapped by setting NUM_WAYS to 1.

The replacement policy uses a simple tree-PLRU for each set.

This is only lightly tested, tests pass but I have to double check
that we are using the ways effectively and not creating duplicates.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Benjamin Herrenschmidt 004eb074c9 plru: Add a simple PLRU module
Tested in sim only for now

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Paul Mackerras f7c393ba7e Add a rotate/mask/shift unit and use it in execute1
This adds a new entity 'rotator' which contains combinatorial logic
for rotating and masking 64-bit values.  It implements the operations
of the rlwinm, rlwnm, rlwimi, rldicl, rldicr, rldic, rldimi, rldcl,
rldcr, sld, slw, srd, srw, srad, sradi, sraw and srawi instructions.
It consists of a 3-stage 64-bit rotator using 4:1 multiplexors at
each stage, two mask generators, output logic and control logic.

The insn_type_t values used for these instructions have been reduced
to just 5: OP_RLC, OP_RLCL and OP_RLCR for the rotate and mask
instructions (clear both left and right, clear left, clear right
variants), OP_SHL for left shifts, and OP_SHR for right shifts.
The control signals for the rotator are derived from the opcode
and from the is_32bit and is_signed fields of the decode_rom_t.

The rotator is instantiated as an entity in execute1 so that we can
be sure we only have one of it.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Paul Mackerras c9e92483b8 decode: Push mtspr/mfspr register decoding down into execute1
Instead of doing mfctr, mflr, mftb, mtctr, mtlr as separate ops,
just pass down mfspr and mtspr ops with the spr number and let
execute1 decode which SPR we're addressing.  This will help reduce
the number of instruction bits decode1 needs to look at.

In fact we now pass down the whole instruction from decode2 to
execute1.  We will need more bits of the instruction in future,
and the tools should just optimize away any that we don't end
up using.  Since the 'aa' bit was just a copy of an instruction
bit, we can now remove it from the record.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Benjamin Herrenschmidt 586abb70a0 Update dependency
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Anton Blanchard 26f70264b3 Update Makefile dependencies
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard b57325ce29 Merge branch 'divider' of https://github.com/paulusmack/microwatt 5 years ago
Paul Mackerras d5bc6c8824 Add a divider unit and a testbench for it
This adds a divider unit, connected to the core in much the same way
that the multiplier unit is connected.  The division algorithm is
very simple-minded, taking 64 clock cycles for any division (even
32-bit division instructions).

The decoding is simplified by making use of regularities in the
instruction encoding for div* and mod* instructions.  Instead of
having PPC_* encodings from the first-stage decoder for each of the
different div* and mod* instructions, we now just have PPC_DIV and
PPC_MOD, and the inputs to the divider that indicate what sort of
division operation to do are derived from instruction word bits.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Benjamin Herrenschmidt 42d802bed0 Add distclean to Makefile
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Benjamin Herrenschmidt 98f0994698 Add core debug module
This module adds some simple core controls:

  reset, stop, start, step

along with icache clear and reading the NIA and core
status bits

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org
5 years ago
Benjamin Herrenschmidt b46f81fae4 Wishbone debug module
This adds a debug module off the DMI (debug) bus which can act as a
wishbone master to generate read and write cycles.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Benjamin Herrenschmidt ee52fd4d80 Add a debug (DMI) bus and a JTAG interface to it on Xilinx FPGAs
This adds a simple bus that can be mastered from an external
system via JTAG, which will be used to hookup various debug
modules.

It's loosely based on the RiscV model (hence the DMI name).

The module currently only supports hooking up to a Xilinx BSCANE2
but it shouldn't be too hard to adapt it to support different TAPs
if necessary.

The JTAG protocol proper is not exactly the RiscV one at this point,
though I might still change it.

This comes with some sim variants of Xilinx BSCANE2 and BUFG and a
test bench.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Anton Blanchard 135805d2ac
Merge pull request #61 from antonblanchard/execute-cleanup
execute1 no longer needs sim_console
5 years ago
Anton Blanchard 6d85920068 execute1 no longer needs sim_console
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 1b6eef2a5d Fix multiply_tb
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 1e3e16e500 Add an icache testbench
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 89849a6856 Add a simple direct mapped icache
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard b6b2c78163 Update Makefile dependencies
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Benjamin Herrenschmidt 3ac1dbc737 Share soc.vhdl between FPGA and sim
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Benjamin Herrenschmidt 8bfd6e5eae Use simulated UART in core test bench
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago
Anton Blanchard 03fd06deaf Rework SOC reset
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>
5 years ago
Anton Blanchard 5e140298a5 Rework decode2
The decode2 stage was spaghetti code and needed cleaning up.
Create a series of functions to pull fields from a ppc instruction
and also a series of helpers to extract values for the execution
units.

As suggested by Paul, we should pass all signals to the execution
units and only set the valid signal conditionally, which should
use less resources.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard f98370f9e6
Merge pull request #5 from antonblanchard/travis-test
Add an initial travis.yml
5 years ago
Anton Blanchard 2ee269abdb Add an initial travis.yml
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 96787091a6 Add -Wall to CFLAGS
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 5a29cb4699 Initial import of microwatt
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago