qdio: extend API to allow polling
Extend the qdio API to allow polling in the upper-layer driver. This
is needed by qeth to use NAPI.
To use the new interface the upper-layer driver must specify the
queue_start_poll(). This callback is used to signal the upper-layer
driver that is has initiative and must process the inbound queue by
calling qdio_get_next_buffers(). If the upper-layer driver wants to
stop polling it calls qdio_start_irq().
Since adapter interrupts are not completely stoppable qdio implements
a software bit QDIO_QUEUE_IRQS_DISABLED to safely disable interrupts for an
input queue.
The old interface is preserved and will be used as is by zfcp.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 00520f9..5fcfa7f 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -884,8 +884,19 @@
if (unlikely(irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
return;
- for_each_input_queue(irq_ptr, q, i)
- tasklet_schedule(&q->tasklet);
+ for_each_input_queue(irq_ptr, q, i) {
+ if (q->u.in.queue_start_poll) {
+ /* skip if polling is enabled or already in work */
+ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state)) {
+ qperf_inc(q, int_discarded);
+ continue;
+ }
+ q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
+ q->irq_ptr->int_parm);
+ } else
+ tasklet_schedule(&q->tasklet);
+ }
if (!(irq_ptr->qib.ac & QIB_AC_OUTBOUND_PCI_SUPPORTED))
return;
@@ -1519,6 +1530,129 @@
}
EXPORT_SYMBOL_GPL(do_QDIO);
+/**
+ * qdio_start_irq - process input buffers
+ * @cdev: associated ccw_device for the qdio subchannel
+ * @nr: input queue number
+ *
+ * Return codes
+ * 0 - success
+ * 1 - irqs not started since new data is available
+ */
+int qdio_start_irq(struct ccw_device *cdev, int nr)
+{
+ struct qdio_q *q;
+ struct qdio_irq *irq_ptr = cdev->private->qdio_data;
+
+ if (!irq_ptr)
+ return -ENODEV;
+ q = irq_ptr->input_qs[nr];
+
+ WARN_ON(queue_irqs_enabled(q));
+
+ if (!shared_ind(q->irq_ptr))
+ xchg(q->irq_ptr->dsci, 0);
+
+ qdio_stop_polling(q);
+ clear_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state);
+
+ /*
+ * We need to check again to not lose initiative after
+ * resetting the ACK state.
+ */
+ if (!shared_ind(q->irq_ptr) && *q->irq_ptr->dsci)
+ goto rescan;
+ if (!qdio_inbound_q_done(q))
+ goto rescan;
+ return 0;
+
+rescan:
+ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state))
+ return 0;
+ else
+ return 1;
+
+}
+EXPORT_SYMBOL(qdio_start_irq);
+
+/**
+ * qdio_get_next_buffers - process input buffers
+ * @cdev: associated ccw_device for the qdio subchannel
+ * @nr: input queue number
+ * @bufnr: first filled buffer number
+ * @error: buffers are in error state
+ *
+ * Return codes
+ * < 0 - error
+ * = 0 - no new buffers found
+ * > 0 - number of processed buffers
+ */
+int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr,
+ int *error)
+{
+ struct qdio_q *q;
+ int start, end;
+ struct qdio_irq *irq_ptr = cdev->private->qdio_data;
+
+ if (!irq_ptr)
+ return -ENODEV;
+ q = irq_ptr->input_qs[nr];
+ WARN_ON(queue_irqs_enabled(q));
+
+ qdio_sync_after_thinint(q);
+
+ /*
+ * The interrupt could be caused by a PCI request. Check the
+ * PCI capable outbound queues.
+ */
+ qdio_check_outbound_after_thinint(q);
+
+ if (!qdio_inbound_q_moved(q))
+ return 0;
+
+ /* Note: upper-layer MUST stop processing immediately here ... */
+ if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
+ return -EIO;
+
+ start = q->first_to_kick;
+ end = q->first_to_check;
+ *bufnr = start;
+ *error = q->qdio_error;
+
+ /* for the next time */
+ q->first_to_kick = end;
+ q->qdio_error = 0;
+ return sub_buf(end, start);
+}
+EXPORT_SYMBOL(qdio_get_next_buffers);
+
+/**
+ * qdio_stop_irq - disable interrupt processing for the device
+ * @cdev: associated ccw_device for the qdio subchannel
+ * @nr: input queue number
+ *
+ * Return codes
+ * 0 - interrupts were already disabled
+ * 1 - interrupts successfully disabled
+ */
+int qdio_stop_irq(struct ccw_device *cdev, int nr)
+{
+ struct qdio_q *q;
+ struct qdio_irq *irq_ptr = cdev->private->qdio_data;
+
+ if (!irq_ptr)
+ return -ENODEV;
+ q = irq_ptr->input_qs[nr];
+
+ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state))
+ return 0;
+ else
+ return 1;
+}
+EXPORT_SYMBOL(qdio_stop_irq);
+
static int __init init_QDIO(void)
{
int rc;