ethtool: Add reset operation

After updating firmware stored in flash, users may wish to reset the
relevant hardware and start the new firmware immediately. This should
not be completely automatic as it may be disruptive.

A selective reset may also be useful for debugging or diagnostics.

This adds a separate reset operation which takes flags indicating the
components to be reset. Drivers are allowed to reset only a subset of
those requested, and must indicate the actual subset. This allows the
use of generic component masks and some future expansion.

Signed-off-by: Ben Hutchings <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/ethtool.h

···
 	int	(*get_rxnfc)(struct net_device *, struct ethtool_rxnfc *, void *);
 	int	(*set_rxnfc)(struct net_device *, struct ethtool_rxnfc *);
 	int     (*flash_device)(struct net_device *, struct ethtool_flash *);
+	int	(*reset)(struct net_device *, u32 *);
 };
 #endif /* __KERNEL__ */
 
···
 #define	ETHTOOL_SRXCLSRLDEL	0x00000031 /* Delete RX classification rule */
 #define	ETHTOOL_SRXCLSRLINS	0x00000032 /* Insert RX classification rule */
 #define	ETHTOOL_FLASHDEV	0x00000033 /* Flash firmware to device */
+#define	ETHTOOL_RESET		0x00000034 /* Reset hardware */
 
 /* compatibility with older code */
 #define SPARC_ETH_GSET		ETHTOOL_GSET
···
 #define	RXH_DISCARD	(1 << 31)
 
 #define	RX_CLS_FLOW_DISC	0xffffffffffffffffULL
+
+/* Reset flags */
+/* The reset() operation must clear the flags for the components which
+ * were actually reset.  On successful return, the flags indicate the
+ * components which were not reset, either because they do not exist
+ * in the hardware or because they cannot be reset independently.  The
+ * driver must never reset any components that were not requested.
+ */
+enum ethtool_reset_flags {
+	/* These flags represent components dedicated to the interface
+	 * the command is addressed to.  Shift any flag left by
+	 * ETH_RESET_SHARED_SHIFT to reset a shared component of the
+	 * same type.
+	 */
+	ETH_RESET_MGMT		= 1 << 0,	/* Management processor */
+	ETH_RESET_IRQ		= 1 << 1,	/* Interrupt requester */
+	ETH_RESET_DMA		= 1 << 2,	/* DMA engine */
+	ETH_RESET_FILTER	= 1 << 3,	/* Filtering/flow direction */
+	ETH_RESET_OFFLOAD	= 1 << 4,	/* Protocol offload */
+	ETH_RESET_MAC		= 1 << 5,	/* Media access controller */
+	ETH_RESET_PHY		= 1 << 6,	/* Transceiver/PHY */
+	ETH_RESET_RAM		= 1 << 7,	/* RAM shared between
+						 * multiple components */
+
+	ETH_RESET_DEDICATED	= 0x0000ffff,	/* All components dedicated to
+						 * this interface */
+	ETH_RESET_ALL		= 0xffffffff,	/* All components used by this
+						 * interface, even if shared */
+};
+#define ETH_RESET_SHARED_SHIFT	16
 
 #endif /* _LINUX_ETHTOOL_H */

net/core/ethtool.c

···
 	return ret;
 }
 
+static int ethtool_reset(struct net_device *dev, char __user *useraddr)
+{
+	struct ethtool_value reset;
+	int ret;
+
+	if (!dev->ethtool_ops->reset)
+		return -EOPNOTSUPP;
+
+	if (copy_from_user(&reset, useraddr, sizeof(reset)))
+		return -EFAULT;
+
+	ret = dev->ethtool_ops->reset(dev, &reset.data);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(useraddr, &reset, sizeof(reset)))
+		return -EFAULT;
+	return 0;
+}
+
 static int ethtool_get_wol(struct net_device *dev, char __user *useraddr)
 {
 	struct ethtool_wolinfo wol = { ETHTOOL_GWOL };
···
 		break;
 	case ETHTOOL_FLASHDEV:
 		rc = ethtool_flash_device(dev, useraddr);
+		break;
+	case ETHTOOL_RESET:
+		rc = ethtool_reset(dev, useraddr);
 		break;
 	default:
 		rc = -EOPNOTSUPP;