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Commit eb9fa77a authored by Peter Fink's avatar Peter Fink Committed by Marc Kleine-Budde
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can: gs_usb: add usb quirk for NXP LPC546xx controllers



Introduce 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.

Link: https://lore.kernel.org/all/20220309124132.291861-17-mkl@pengutronix.de
Signed-off-by: default avatarPeter Fink <pfink@christ-es.de>
Signed-off-by: default avatarChristoph Möhring <cmoehring@christ-es.de>
Signed-off-by: default avatarAlexander Schartner <aschartner@christ-es.de>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 26949ac9
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