mrf24j40: fix security-enabled processing on inbound frames

When receiving a security-enabled IEEE 802.15.4 frame, the MRF24J40
triggers a SECIF interrupt that needs to be handled for RX processing
to keep functioning properly.

This patch enables the SECIF interrupt and makes the MRF ignores all
hardware processing of security-enabled frames, that is handled by the
ieee802154 stack instead.

Signed-off-by: Alexander Aring <aar@pengutronix.de>
Signed-off-by: Alexandre Macabies <web+oss@zopieux.com>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Acked-by: Alan Ott <alan@signal11.us>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/mrf24j40.c

@@ -85,10 +85,13 @@
 #define REG_INTSTAT	0x31  /* Interrupt Status */
 #define BIT_TXNIF	BIT(0)
 #define BIT_RXIF	BIT(3)
+#define BIT_SECIF	BIT(4)
+#define BIT_SECIGNORE	BIT(7)
 
 #define REG_INTCON	0x32  /* Interrupt Control */
 #define BIT_TXNIE	BIT(0)
 #define BIT_RXIE	BIT(3)
+#define BIT_SECIE	BIT(4)
 
 #define REG_GPIO	0x33  /* GPIO */
 #define REG_TRISGPIO	0x34  /* GPIO direction */
@@ -616,7 +619,7 @@ static int mrf24j40_start(struct ieee802154_hw *hw)
 
 	/* Clear TXNIE and RXIE. Enable interrupts */
 	return regmap_update_bits(devrec->regmap_short, REG_INTCON,
-				  BIT_TXNIE | BIT_RXIE, 0);
+				  BIT_TXNIE | BIT_RXIE | BIT_SECIE, 0);
 }
 
 static void mrf24j40_stop(struct ieee802154_hw *hw)
@@ -1025,6 +1028,11 @@ static void mrf24j40_intstat_complete(void *context)
 
 	enable_irq(devrec->spi->irq);
 
+	/* Ignore Rx security decryption */
+	if (intstat & BIT_SECIF)
+		regmap_write_async(devrec->regmap_short, REG_SECCON0,
+				   BIT_SECIGNORE);
+
 	/* Check for TX complete */
 	if (intstat & BIT_TXNIF)
 		ieee802154_xmit_complete(devrec->hw, devrec->tx_skb, false);