scsi: ibmvfc: Map/request irq and register Sub-CRQ interrupt handler

Create an irq mapping for the hw_irq number provided from phyp firmware.
Request an irq assigned our Sub-CRQ interrupt handler. Unmap these irqs at
Sub-CRQ teardown.

Link: https://lore.kernel.org/r/20210114203148.246656-12-tyreld@linux.ibm.com
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ibmvscsi/ibmvfc.c

@@ -5292,12 +5292,34 @@ static int ibmvfc_register_scsi_channel(struct ibmvfc_host *vhost,
 		goto reg_failed;
 	}
 
+	scrq->irq = irq_create_mapping(NULL, scrq->hw_irq);
+
+	if (!scrq->irq) {
+		rc = -EINVAL;
+		dev_err(dev, "Error mapping sub-crq[%d] irq\n", index);
+		goto irq_failed;
+	}
+
+	snprintf(scrq->name, sizeof(scrq->name), "ibmvfc-%x-scsi%d",
+		 vdev->unit_address, index);
+	rc = request_irq(scrq->irq, ibmvfc_interrupt_scsi, 0, scrq->name, scrq);
+
+	if (rc) {
+		dev_err(dev, "Couldn't register sub-crq[%d] irq\n", index);
+		irq_dispose_mapping(scrq->irq);
+		goto irq_failed;
+	}
+
 	scrq->hwq_id = index;
 	scrq->vhost = vhost;
 
 	LEAVE;
 	return 0;
 
+irq_failed:
+	do {
+		plpar_hcall_norets(H_FREE_SUB_CRQ, vdev->unit_address, scrq->cookie);
+	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));
 reg_failed:
 	ibmvfc_free_queue(vhost, scrq);
 	LEAVE;
@@ -5313,6 +5335,9 @@ static void ibmvfc_deregister_scsi_channel(struct ibmvfc_host *vhost, int index)
 
 	ENTER;
 
+	free_irq(scrq->irq, scrq);
+	irq_dispose_mapping(scrq->irq);
+
 	do {
 		rc = plpar_hcall_norets(H_FREE_SUB_CRQ, vdev->unit_address,
 					scrq->cookie);