Needed for hcan->TxState to reset. In some cases when the host reboots, the TxState get locked forever and there's no way to recover other than resetting the controller.
The documents a workaround for a NXP chip errata on LPC546xx
controllers (Errata sheet LPC546xx / USB.15).
According to the document corruption can occur when the following
conditions are met:
* A TX (IN) transfer happens after a RX (OUT) transfer.
* The RX (OUT) transfer length is 4 + N * 16 (N >= 0) bytes.
Even though the struct gs_host_frame has a size of 76 bytes for a FD
frame, which does not apply to the above rule, corruption could be
seen.
Adding a dummy byte to break the second condition also on transfer
lengths with 4 + N * 8 bytes reliably circumvents USB transfer data
corruption.
The firmware can now request this quirk by setting
GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX.
The CANtact FD and other devices implement a gs-usb compatible USB
protocol. The protocol has been extended to support CAN-FD and the
changes on the Linux gs_usb driver will be mainlined soon.
This patch adds the new GS_CAN_MODE_*, GS_CAN_FEATURE_*,
GS_USB_BREQ_DATA_BITTIMING, and GS_CAN_FLAG_* bits as well as struct
gs_host_frame_canfd to the candlelight driver.
This is mainly for documentation purpose, as the STM32F042 and
STM32F072 don't support CAN-FD. But there are some ports to CAN-FD
capable STM32 µC that can make use of these definitions.
[1] https://github.com/linklayer/gs_usb_fd/issues/2
The bits in GS_CAN_MODE_ correspond to the bits in GS_CAN_FEATURE_*.
This means the bits 5 and 6 of GS_CAN_MODE_ are not "free", document
this by adding a comment to the corresponding GS_CAN_FEATURE_*.
Avoid using <assert.h> because the standard assert() pulls in
fprintf and its of dependencies, as well as including __FILE__:__LINE__
strings for each assert() call. All this has an unacceptable memory
cost, as well as being useless since there is nothing to printf *to*.
Currently assert_basic() was added to check calloc() return values;
in case of failure we simply halt the core with BKPT(0). This could be
improved and refined.
The project uses tabs with a length of 4 spaces, and spaces for
continuation, so lets use that for the whole project. There are
many trailing whitespaces and empty lines here and there; get
rid of them as well.
Some files have Windows line endings which is annoying, since pathes
won't apply, diffs looks ugly etc. So do convert the few files which
have Windows line endings to use Unix line endings as well.
Instead of hardcoding the serial number in the firmware, use the
device's manufacturer-provided UID as the serial number.
This makes it easier to distinguish between multiple adaptors plugged
into the same host without having to build a separate firmware for each
one.
