+ /*
+ * Seeing the PAST_END, RX_BAD_DATA, or NOT_READY
+ * markers are all signs that the EC didn't fully
+ * receive our command. e.g., if the EC is flashing
+ * itself, it can't respond to any commands and instead
+ * clocks out EC_SPI_PAST_END from its SPI hardware
+ * buffer. Similar occurrences can happen if the AP is
+ * too slow to clock out data after asserting CS -- the
+ * EC will abort and fill its buffer with
+ * EC_SPI_RX_BAD_DATA.
+ *
+ * In all cases, these errors should be safe to retry.
+ * Report -EAGAIN and let the caller decide what to do
+ * about that.
+ */