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Merge pull request #46 from wom-bat/master

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Explain seed argument to foboot-bitstream.py
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Sean Cross 2020-01-25 18:13:46 +08:00 committed by GitHub
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@ -23,14 +23,39 @@ To build the software, you need:
The hardware half will take care of building the software half, if it is run with `--boot-source bios` (which is the default). Therefore, to build Foboot, enter the `hw/` directory and run:
```
$ python3 foboot-bitstream.py --revision hacker
$ python3 foboot-bitstream.py --revision hacker --seed 19
```
This will verify you have the correct dependencies installed, compile the Foboot software, then synthesize the Foboot bitstream. The resulting output will be in `build/gateware/`. You should write `build/gateware/top-multiboot.bin` to your Fomu device in order to get basic bootloader support.
The `seed` argument is to set initial conditions for the
place-and-route phase. `nextpnr-ice40` uses a simulated annealing
algorithm that can result in one of several locally optimal layouts.
Only some of these will meet the timing requirements for Fomu.
If you see something like
```
ERROR: Max frequency for clock 'clk48_$glb_clk': 45.41 MHz (FAIL at 48.00 MHz)
```
try a different seed. You can search for an appropriate seed with:
```
for seed in $(seq 0 100)
do
python3 ./foboot-bitstream.py --revision pvt --seed $seed 2>&1 |
grep 'FAIL at 48.00 MHz' && continue
echo "Working Seed is $seed"
break
done
```
This can take a considerable time.
### Usage
You can write the bitstream to your SPI flash. If you're using `fomu-flash`, you would run the following:
You can write the bitstream to your SPI flash.
#### Loading using `fomu-flash`
If you're using `fomu-flash`, you would run the following:
```sh
$ fomu-flash -w build/gateware/top-multiboot.bin
@ -51,6 +76,63 @@ Fomu should now show up when you connect it to your machine:
[172294.445692] usb 1-1.3: Manufacturer: Kosagi
```
#### Using `dfu-util` to flash the bootloader
##### Safe way to test
Just do
```sh
dfu-util -D build/gateware/top.bin
```
to copy into the SPI flash, then
```sh
dfu-util -e
```
each time you want to run the generated bitstream after a reboot.
A multiboot enabled bootloader is also generated; you can try that out
with
```sh
dfu-util -D build/gateware/top-multiboot.bin
```
`dfu-util` loads the bootloader into flash at 0x40000; it'll be overridden
by any other code you attempt to flash using `dfu-util`
##### Loading the bootloader as first bootloader
**WARNING: Flashing a new bootloader could _brick your device_**
**It's best to wait for an official release**
First build the flasher program, that will run on the Fomu (you only
need to do this once):
```sh
cd booster
cc -O2 -o make-booster -I ./include make-booster.c
```
Then package everything up ready for loading:
```sh
cd releases
bash ./release.sh pvt
```
This will create a new directory in `releases` named by the head of
your git tree and the last official release. So you'll see something
like `v2.0.3-8-g485d232`
In that directory will be a file named `pvt-updater-`_version_`.dfu`
Load it onto the Fomu using `dfu-util`:
```sh
dfu-util -D pvt-updater-v2.0.3-8-g485d232.dfu
```
Your Fomu will flash rainbow for about five seconds, then reboot and
go back to blinking steadily. To verify that your code has loaded, use
```sh
dfu-util -l
```
and look at the version output.
#### Loading and running other bitstreams
To load a new bitstream, use the `dfu-util -D` command. For example:
```sh
@ -69,4 +151,4 @@ $ dfu-util -e
## Building the Software
Software is contained in the `sw/` directory.
Software is contained in the `sw/` directory.