| aba554cc | 23-Nov-2016 |
Jocelyn Bohr <bohr@google.com> |
Handle slow MMC writes
Flashing a 400Mb sparse system image takes ~10 minutes. The fastboot UDP
protocol expects a response within 1 minute, so during long flash
operations, the device must send fas
Handle slow MMC writes
Flashing a 400Mb sparse system image takes ~10 minutes. The fastboot UDP
protocol expects a response within 1 minute, so during long flash
operations, the device must send fastboot "INFO" packets.
This patch does the following:
- Separate large writes into writes of size FASTBOOT_MAX_BLK_WRITE.
This parameter was tuned by hand to result in a ~10 second write.
- Keep a timer and send an INFO packet every 30 seconds.
- Adjust the sequence number in the header of the fastboot OKAY packet
to account for any INFO packets sent during flashing.
- Reduce busywaiting in the bcm2835 MMC driver. This change is based on
what the kernel does, and doesn't seem to corrupt the MMC. Without
this change, "flashall" takes 25 minutes.
Bug: 31887729
Test: "fastboot -s udp:$RPI_IP flashall" works, rpi3 boots
- Compute CRC checksum over every write to verify written data
was not corrupted.
Change-Id: Ib17ef6a85715705a8b5f722a8b7d3e5fd1a6625d
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