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hw: document warmboot some more 

Realized that there are 5 images and not 4.  With this, everything
works as it should.

Signed-off-by: Sean Cross <sean@xobs.io>
This commit is contained in:
Sean Cross 2019-04-05 17:34:10 +08:00
parent fd76536351
commit db65ccc199
1 changed files with 16 additions and 3 deletions
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19
hw/foboot-bitstream.py
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@ -351,7 +351,7 @@ class SBWarmBoot(Module, AutoCSR):
self.ctrl = CSRStorage(size=8)
do_reset = Signal()
self.comb += [
# "Reset Key" is 0xac
# "Reset Key" is 0xac (0b101011xx)
do_reset.eq(self.ctrl.storage[2] & self.ctrl.storage[3] & ~self.ctrl.storage[4]
& self.ctrl.storage[5] & ~self.ctrl.storage[6] & self.ctrl.storage[7])
]
@ -564,7 +564,7 @@ class BaseSoC(SoCCore):
# # Add a "Multiboot" variant
# platform.toolchain.nextpnr_build_template[3] = "icepack -s {build_name}.txt {build_name}-multi.bin"
def make_multiboot_header(filename, boot_offsets=[128]):
def make_multiboot_header(filename, boot_offsets=[160]):
"""
ICE40 allows you to program the SB_WARMBOOT state machine by adding the following
values to the bitstream, before any given image:
@ -574,10 +574,22 @@ def make_multiboot_header(filename, boot_offsets=[128]):
[44 03 o1 o2 o3] Boot address
[82 00 00] Bank offset
[01 08] Reboot
[...] Padding (up to 32 bytes)
Note that in ICE40, the second nybble indicates the number of remaining bytes
(with the exception of the sync header)
(with the exception of the sync header).
The above construct is repeated five times:
INITIAL_BOOT The image loaded at first boot
BOOT_S00 The first image for SB_WARMBOOT
BOOT_S01 The second image for SB_WARMBOOT
BOOT_S10 The third image for SB_WARMBOOT
BOOT_S11 The fourth image for SB_WARMBOOT
"""
while len(boot_offsets) < 5:
boot_offsets.append(boot_offsets[0])
with open(filename, 'wb') as output:
for offset in boot_offsets:
# Sync Header
@ -602,6 +614,7 @@ def make_multiboot_header(filename, boot_offsets=[128]):
output.write(bytes([0]))
def main():
make_multiboot_header("build/gateware/multiboot.bin", [160, 262144])
parser = argparse.ArgumentParser(
description="Build Fomu Main Gateware")
parser.add_argument(