[intel] Report any unexpected interrupt causes

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/intel.c

 	if ( icr & INTEL_IRQ_LSC )
 		intel_check_link ( netdev );
 
+	/* Check for unexpected interrupts */
+	if ( icr & ~( INTEL_IRQ_TXDW | INTEL_IRQ_TXQE | INTEL_IRQ_LSC |
+		      INTEL_IRQ_RXDMT0 | INTEL_IRQ_RXT0 | INTEL_IRQ_RXO ) ) {
+		DBGC ( intel, "INTEL %p unexpected ICR %08x\n", intel, icr );
+		/* Report as a TX error */
+		netdev_tx_err ( netdev, NULL, -ENOTSUP );
+	}
+
 	/* Refill RX ring */
 	intel_refill_rx ( intel );
 }

src/drivers/net/intel.h

 /** Interrupt Cause Read Register */
 #define INTEL_ICR 0x000c0UL
 #define INTEL_IRQ_TXDW		0x00000001UL	/**< Transmit descriptor done */
+#define INTEL_IRQ_TXQE		0x00000002UL	/**< Transmit queue empty */
 #define INTEL_IRQ_LSC		0x00000004UL	/**< Link status change */
+#define INTEL_IRQ_RXDMT0	0x00000010UL	/**< Receive queue low */
 #define INTEL_IRQ_RXT0		0x00000080UL	/**< Receive timer */
 #define INTEL_IRQ_RXO		0x00000400UL	/**< Receive overrun */