FeliCa Emulation: Handle certain Polling commands in firmware #4204
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NFC TagInfo and possibly other readers rely on Polling commands with Request Code of 1 (default System Code request) or non-FFFF System Code to detect card type. Since the NFC controller doesn't seem to handle them in hardware and simply bubbles them up, and then the Flipper firmware will just ignore them and refuse to respond afterwards, this causes the reading operation to fail. This commit adds a simple handler for such Polling commands so that readers behaving like NFC TagInfo could read the emulated card without failing.
The NFC controller should handle Polling commands with the System Code set to FFFF, so it's not necessary for the firmware to handle it.
We already have enough information to determine whether or not the card supports NDEF since SYS_OP register value is included in all current Lite-S card dumps.
This allows the reader to specifically select the service by naming the Service Code.
dogtopus
requested review from
DrZlo13,
hedger,
gsurkov and
gornekich
as code owners
Introduce nfc_felica_listener_timer_anticol_start() and nfc_felica_listener_timer_anticol_stop(). These are for now just wrappers around the block_tx timer that can be used to delay the response until the desired Time Slot. Thanks to the loose timing constraints of FeliCa collision resolution protocol, no compensation seems to be necessary. Also enabled the block_tx timer for FeliCa listener, but with both compensation and fdt set to 0 to keep the original behavior of not using the timer during normal data exchange. This API is now being used for handling Polling commands that are not handled by the NFC controller on the hardware side.
dogtopus
changed the title
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I fixed the |
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Thanks for your work on this PR, NDEF and system codes for Felica are great! But there are some parts of code which would be better to adjust a little bit. I described my idea in review comments. And also here is a complete patch felica_polling.patch, which implements it.
Would you please apply it, validate that it works and update your PR?
Thanks in advance! 🐱
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Any progress on the review? @RebornedBrain |
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It's been 3 months and this PR still isn't merged. Is there a problem with the code? |
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@dogtopus sorry for the delay |
hedger
approved these changes
Sep 24, 2025
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What's new
This is a continuation of #4202.
NFC TagInfo, probably all NDEF Type 3 readers, and possibly other readers rely on Polling commands with Request Code of 1 (default System Code request) and non-FFFF System Code to detect card type. The NFC controller doesn't seem to handle the latter case in hardware and simply bubbles those commands up to the firmware layer. The firmware in its current form then gets confused and interrupts the transaction, resulting in failed reading attempts.
This PR adds a handler for when a Polling command with non-FFFF System Code is seen on the firmware side, so that readers behaving like NFC TagInfo could read the emulated card without failing.
Verification
Checklist (For Reviewer)