Commit Graph

71 Commits (4eae29801b823fde65df38576a90be0abb89e782)

Author SHA1 Message Date
Benjamin Herrenschmidt 7575b1e0c2 uart: Import and hook up opencore 16550 compatible UART
This imports via fusesoc a 16550 compatible (ie "standard") UART,
and wires it up optionally in the SoC instead of the potato one.

This also adds support for a second UART (which is always a
16550) to Arty, wired to JC "bottom" port.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 8366710217 liteeth: Hook up LiteX LiteEth ethernet controller
Currently only generated for Arty.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Joel Stanley 60e5f7b958 spi: Fix dat_i_l constraints
No cells matched 'get_cells -hierarchical -filter {NAME =~*/spi_rxtx/dat_i_l*}'. [build/microwatt_0/src/microwatt_0/fpga/arty_a7.xdc:42]

The signal is in it's own process so the net name ends up being
spi_rxtx/input_delay_1.dat_i_l_reg.

After this change the log shows:

Applied set_property IOB = TRUE for soc0/\spiflash_gen.spiflash /spi_rxtx/\input_delay_1.dat_i_l_reg . (constraint file  fpga/arty_a7.xdc, line 42).
Applied set_property IOB = TRUE for soc0/\spiflash_gen.spiflash /spi_rxtx/\input_delay_1.dat_i_l_reg . (constraint file  fpga/arty_a7.xdc, line 42).
Applied set_property IOB = TRUE for soc0/\spiflash_gen.spiflash /spi_rxtx/\input_delay_1.dat_i_l_reg . (constraint file  fpga/arty_a7.xdc, line 42).
Applied set_property IOB = TRUE for soc0/\spiflash_gen.spiflash /spi_rxtx/\input_delay_1.dat_i_l_reg . (constraint file  fpga/arty_a7.xdc, line 42).

Signed-off-by: Joel Stanley <joel@jms.id.au>
4 years ago
Michael Neuling b90a0a2139
Merge pull request #208 from paulusmack/faster
Make the core go faster

Several major improvements in here:
- Simple branch predictor
- Reduced latency for mispredicted branches and interrupts by removing fetch2 stage
- Cache improvements
  o Request critical dword first on refill
  o Handle hits while refilling, including on line being refilled
  o Sizes doubled for both D and I
- Loadstore improvements: can now do one load or store every two cycles in most cases
- Optimized 2-cycle multiplier for Xilinx 7-series parts using DSP slices
- Timing improvements, including:
  o Stash buffer in decode1
  o Reduced width of execute1 result mux
  o Improved SPR decode in decode1
  o Some non-critical operation take a cycle longer so we can break some long combinatorial chains
- Core logging: logs 256 bits of info every cycle into a ring buffer, to help with debugging and performance analysis

This increases the LUT usage for the "synth" + A35 target from 9182 to 10297 = 12%.
4 years ago
Paul Mackerras 78de4fef72 Make LOG_LENGTH configurable per FPGA variant
This plumbs the LOG_LENGTH parameter (which controls how many entries
the core log RAM has) up to the top level so that it can be set on
the fusesoc command line and have different default values on
different FPGAs.

It now defaults to 512 entries generally and on the Artix-7 35 parts,
and 2048 on the larger Artix-7 FPGAs.  It can be set to 0 if desired.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
4 years ago
Benjamin Herrenschmidt f9f18906a3 soc: Rename wb_dram_ctrl to wb_ext_io and rework decoding
This makes the control bus currently going out of "soc" towards
litedram more generic for external IO devices added by the
top-level rather than inside the SoC proper.

This is mostly renaming of signals and a small change on how the
address decoder operates, using a separate "cascaded" decode for
the external IOs.

We make the region 0xc8nn_nnnn be the "external IO" region for
now.

This will make it easier / cleaner to add more external devices.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt bf7def5503 soc: Don't require dram wishbones signals to be wired by toplevel
Currently, when not using litedram, the top level still has to hook
up "dummy" wishbones to the main dram and control dram busses coming
out of the SoC and provide ack signals.

Instead, make the SoC generate the acks internally when not using
litedram and use defaults to make the wiring entirely optional.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 1ffc89e58b soc: Add defaults for some input signals
That way the top-level's don't need to assign them

Also remove generics that are set to the default anyways

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 4244b54984 soc: Remove unused RESET_LOW generic
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt e5aa0e9dc9 uart: Remove combinational loops on ack and stall signal
They hurt timing forcing signals to come from the master and back
again in one cycle. Stall isn't sampled by the master unless there
is an active cycle so masking it with cyc is pointless. Masking acks
is somewhat pointless too as we don't handle early dropping of cyc
in any of our slaves properly anyways.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt cc4dcb3597 spi: Add SPI Flash controller
This adds an SPI flash controller which supports direct
memory-mapped access to the flash along with a manual
mode to send commands.

The direct mode can be set via generic to default to single
wire or quad mode. The controller supports normal, dual and quad
accesses with configurable commands, clock divider, dummy clocks
etc...

The SPI clock can be an even divider of sys_clk starting at 2
(so max 50Mhz with our typical Arty designs).

A flash offset is carried via generics to syscon to tell SW about
which portion of the flash is reserved for the FPGA bitfile. There
is currently no plumbing to make the CPU reset past that address (TBD).

Note: Operating at 50Mhz has proven unreliable without adding some
delay to the sampling of the input data. I'm working in improving
this, in the meantime, I'm leaving the default set at 25 Mhz.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 5ae5f76558 arty/nexys-video: Update XDC
The DRAM related pins have some small changes in LiteX, so resync
and add the false path information as well.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt a93d9e77c9 litedram: Remove remnants of riscv-inits
We still had some wires bringing an extra serial port out of
litedram for the built-in riscv processor. This is all gone now
so take them out.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt bf1b98b958 litedram: Add support for booting without BRAM
This adds an option to disable the main BRAM and instead copy a
payload stashed along with the init code in the secondary BRAM
into DRAM and boot from there

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 573b6b4bc4 soc: Rework interconnect
This changes the SoC interconnect such that the main 64-bit wishbone out
of the processor is first split between only 3 slaves (BRAM, DRAM and a
general "IO" bus) instead of all the slaves in the SoC.

The IO bus leg is then latched and down-converted to 32 bits data width,
before going through a second address decoder for the various IO devices.

This significantly reduces routing and timing pressure on the main bus,
allowing to get rid of frequent timing violations when synthetizing on
small'ish FPGAs such as the Artix-7 35T found on the original Arty board.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Anton Blanchard ab86b58d95 Exit cleanly from testbench on success
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 4e78b8078e
Merge branch 'master' into litedram 4 years ago
Anton Blanchard f96d179f66 Some yosys fixes
This gets the yosys build further along, but I'm now chasing what looks
like a yosys bug.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Benjamin Herrenschmidt 7560e8f2ff arty/nexys: Rework reset with litedram
When using litedram, request a much longer PLL reset. This seems to
help get rid of all the grabled output after config.

Also use the clean system_rst out of litedram as our source of reset
for the rest of the SoC (it is synchronized with system_clk and takes
pll_locked into account already)
4 years ago
Benjamin Herrenschmidt 3b603402d2 soc_reset: Use counters, add synchronizers
In some cases we need to keep the reset held for much longer,
so use counters rather than shift registers.

Additionally, some signals such as ext_rst and pll_locked
or signals going from the ext_clk domain to the pll_clk
domain need to be treated as async, and testing them without
synchronizers is asking for trouble.

Finally, make the external reset also reset the PLL.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt c19b5b8cc7 litedram: Update to new LiteX/LiteDRAM version
Things have changed a bit in upstream LiteX. LiteDRAM now exposes a
wishbone for the CSRs for example.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 13e84b0bbb pp_soc_uart: Fix rx synchronizers and ensure stable tx init state
The rx synchronizers were ... non existent. Someone forgot to add
a if rising_edge(clk) to the process.

For tx, ensure that we have a default value so that TX stays high
from TPGA configuration to the reset being sampled on the first clock
cycle.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt bd42580a42 pp_fifo: Fix full fifo losing all data on simultaneous push & pop
The pp_fifo decides whether top = bottom means empty or full based
on whether the previous operation was a push or a pop.

If the fifo performs both in one cycle, it sets the previous op to
pop. That means that a full fifo being added a character and removed
one at the same time becomes empty.

Instead, just leave the previous op alone. If the fifo was empty, it
remains so, if it was full ditto.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt c5f5f50738 hello_world: Use new headers and frequency from syscon
This uses the new header files for register definitions and
extracts the core frequency from syscon rather than hard coding it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.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
Benjamin Herrenschmidt 2cef3005cd fpga: Hookup nexys-video to litedram
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 3ac815823c fpga: Hookup Arty to litedram
The old toplevel.vhdl becomes top-generic.vhdl, which is to be used
by platforms that do not have a litedram option.

Arty has its own top-arty.vhdl which supports litedram and is now
hooked up

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 8bb3c8f8b6 soc: Add DRAM address decoding
Still not attached to any board

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 3687486d36 Update hello_world for 100Mhz clock
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Anton Blanchard 61d5e61f09 Add a few FFs on the RX input to avoid metastability issues
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard f5424f8e71 Reduce simulated and default FPGA RAM to 384kB
Micropython has been able to fit into 384kB for ages, so lets reduce our
simulated RAM. This is useful for testing if micropython will run on an
ECP5 85k, which has enough BRAM for 384kB but not enough for 512kB.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 14c5cf3b83 Fix some ghdlsynth issues with fpga_bram
Use to_integer() instead of conv_integer().

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 20674e0d65 Add SPI configuration to Xilinx constraint files
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
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>
4 years ago
Benjamin Herrenschmidt 3349bdc798 ram: Add block RAM pipelining
This adds an output buffer to help with timing and allows the BRAMs
to actually pipeline.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt d2762e70e5 Add option to not flatten hierarchy
Vivado by default tries to flatten the module hierarchy to improve
placement and timing. However this makes debugging timing issues
really hard as the net names in the timing report can be pretty
bogus.

This adds a generic that can be used to control attributes to stop
vivado from flattening the main core components. The resulting design
will have worst timing overall but it will be easier to understand
what the worst timing path are and address them.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt e638c3e8ae fpga/bram: Generate stall signal
This doesn't yet pipeline the block RAM, just generate a valid stall
signal so it's compatible with a pipelined master

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 559b3bcf2d pp_uart: reformat
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Anton Blanchard 6cdb8ca9f5 Fix clk_gen_bypass
clk_gen_bypass needed updating after the addition of CLK_INPUT_HZ and
CLK_OUTPUT_HZ.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard 7aaed5abd5 fifo: Reformat
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Anton Blanchard ad6c6790f9 fifo: Remove shared variable
The shared variable used for FIFO memory is not VHDL 2008 compliant.
I can't see why it needs to be a shared variable since reads and writes
update top and bottom synchronously, meaning they don't need same cycle
access to the FIFO memory.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago
Benjamin Herrenschmidt 9961d70dfb Improve PLL/MMCM clocks configuration
We can now pass both the input clock and target clock frequency
via generics. Add support for both 50Mhz and 100Mhz target freqs
for both cases.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt ab5c6ab9ac fpga: Arty A7's don't need multiple filesets
the XDC is identical between variants, so is the fileset

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Benjamin Herrenschmidt 79b0b9a046 Fix PLL reset signal name in toplevel
It shouldn't have a _n suffix, it's active positive.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
4 years ago
Anton Blanchard c8328cdf84 Remove gcc software divide patch
We have a divider, thanks to Paul.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 6cbf456388 SOC memory wishbone should clear ACK regardless of STB
The memory wishbone doesn't clear ACK and move the state machine on
until STB is de-asserted. This seems like it isn't compliant with
the spec and results in a maximum throughput of 1 transfer every
3 cycles.

Fixing this improves the situation to one transfer every 2 cycles.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard d89a9929fd Fix clk_gen_bypass
I broke clk_gen_bypass when updating the SOC reset code.

Fixes 03fd06deaf ("Rework SOC reset")
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 142a722ce4 Remove names from end record statements
These are optional, and vhdlpp from iverilog barfs on them.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
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 d21ef5836d Pass wishbone record to bram memory module
(And rename it to mw_soc_memory).

This makes soc.vhdl simpler and provides the same interface as
the simulated memory, which will help when sharing soc.vhdl
with sim later

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
5 years ago