When using an FPGA which routes the SPI clock via STARTUPE2 as is
done on the Nexys Video (or optionally on Arty), the HW needs at
least 3 beats of that clock to complete the switch from the internal
config clock to the one we provide.
This works around it by having the SPI controller send 8 dummy
clocks at boot time with CS held high.
Without this, flash identification will fail those boards
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Means we can synthesize at 40Mhz (where we currently make timing) and
our UART still works at 115200 baud.
Tested working hello world unmodified with ECP5 eval board. Orange
Crab is updated but is untested.
Signed-off-by: Michael Neuling <mikey@neuling.org>
This allows these targets
FPGA_TARGET=ORANGE-CRAB make microwatt.bit
FPGA_TARGET=ECP5-EVN make microwatt.bit
Default is ORANGE-CRAB as before
ECP5-EVN is tested on real hardware. The console only works at 38400 so
needs this in console.c and a recompile of hello_world to work:
-#define UART_FREQ 115200
+#define UART_FREQ 38400
With this 'FPGA_TARGET=ECP5-EVN make prog' works on the ECP5 dev board.
Signed-off-by: Michael Neuling <mikey@neuling.org>
This is useful to specify "-noflatten" which helps CI stay under 8GB
limit.
Normally the AUTONAME stage of yosys will take around 10GB if
operating on the whole design. With -noflatten, AUTONAME occurs only
per VHDL entity, so only consumes around 3GB of memory. This gets us
under the limitations on github actions.
More discussion here:
https://github.com/antonblanchard/microwatt/pull/209#issuecomment-652186078
Signed-off-by: Michael Neuling <mikey@neuling.org>
These are needed for synthesis that doesn't use fusesoc natively.
These were pulled in via 'fusesoc fetch ::uart16550:1.5.5-r1'
Signed-off-by: Michael Neuling <mikey@neuling.org>
nextpnr will leave an output file around even when it errors out, so
build to a tmp file and move it when we succeed so we don't confuse
make.
Signed-off-by: Michael Neuling <mikey@neuling.org>
This adds a path to allow the CR result of one instruction to be
forwarded to the next instruction, so that sequences such as
cmp; bc can avoid having a 1-cycle bubble.
Forwarding is not available for dot-form (Rc=1) instructions,
since the CR result for them is calculated in writeback. The
decode.output_cr field is used to identify those instructions
that compute the CR result in execute1.
For some reason, the multiply instructions incorrectly had
output_cr = 1 in the decode tables. This fixes that.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This latches the redirect signal inside execute1, so that it is sent
a cycle later to fetch1 (and to decode/icache as flush). This breaks
a long combinatorial chain from the branch and interrupt detection
in execute1 through the redirect/flush signals all the way back to
fetch1, icache and decode.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
It's not needed for the other ops (popcnt, parity, etc.) and the
logical unit shows up as a critical path from time to time.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This implements the CFAR SPR as a slow SPR stored in 'ctrl'. Taken
branches and rfid update it to the address of the branch or rfid
instruction.
To simplify the logic, this makes rfid use the branch logic to
generate its redirect (requiring SRR0 to come in to execute1 on
the B input and SRR1 on the A input), and the masking of the bottom
2 bits of NIA is moved to fetch1.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The sdram_init ELF fails to link:
powerpc64le-linux-gnu-ld -static -nostdlib -T sdram_init.lds \
--gc-sections -o sdram_init.elf head.o main.o sdram.o console.o \
libc.o sdram_init.lds
powerpc64le-linux-gnu-ld: error: linker script file 'sdram_init.lds'
appears multiple times
make: *** [Makefile:70: sdram_init.elf] Error 1
This is because sdram_init.lds is one of the prerequisites, and thus is
contained in $^. However, it is also explicitly specified as part of
LDFLAGS, as the argument to -T.
Signed-off-by: Boris Shingarov <shingarov@labware.com>
Under some circumstances we get POLLHUP which we incorrectly
treat as having a character in the buffer.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This adds a flag (currently not set) to indicate that the core is using
the architected timebase frequency of 512Mhz. When not set, the core is
using the proc frequency for the timebase.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Use a more generic console_init() instead of potato_uart_init(),
and do the same for interrupt control. There should be no
change in behaviour.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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>
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>
This makes the ICS support less than the 8 architected bits
and sets the soc to use 3 bits by default.
All the supported bits set translates to "masked" (and will read
back at 0xff), any small value is used as-is.
Linux doesn't use priorities above 5, so this is a way to save
silicon. The number of supported priority bits is exposed to the
OS via the config register.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Move the external interrupt generation to a separate module
"ICS" (source controller) which a register per source containing
currently only the priority control.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
That's how Linux expects it. This also simplifies the
register access implementation since the bit fields now
align properly regardless of the access size.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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%.
Benjamin Herrenschmidt
Paul Mackerras
Michael Neuling