can: rx-offload: can_rx_offload_add_manual(): add new initialization function

This patch adds a new initialization function:
can_rx_offload_add_manual()

It should be used to add support rx-offload to a driver, if the callback
mechanism should not be used. Use e.g. can_rx_offload_queue_sorted() to queue
skbs into rx-offload.

Link: https://lore.kernel.org/r/20200915223527.1417033-33-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/rx-offload.c

@@ -351,6 +351,17 @@ int can_rx_offload_add_fifo(struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo);
 
+int can_rx_offload_add_manual(struct net_device *dev,
+			      struct can_rx_offload *offload,
+			      unsigned int weight)
+{
+	if (offload->mailbox_read)
+		return -EINVAL;
+
+	return can_rx_offload_init_queue(dev, offload, weight);
+}
+EXPORT_SYMBOL_GPL(can_rx_offload_add_manual);
+
 void can_rx_offload_enable(struct can_rx_offload *offload)
 {
 	napi_enable(&offload->napi);

include/linux/can/rx-offload.h

@@ -35,6 +35,9 @@ int can_rx_offload_add_timestamp(struct net_device *dev,
 int can_rx_offload_add_fifo(struct net_device *dev,
 			    struct can_rx_offload *offload,
 			    unsigned int weight);
+int can_rx_offload_add_manual(struct net_device *dev,
+			      struct can_rx_offload *offload,
+			      unsigned int weight);
 int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload,
 					 u64 reg);
 int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload);