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Commit d36deae7 authored by Jan Glauber's avatar Jan Glauber Committed by David S. Miller
Browse files

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: default avatarJan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarFrank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e508be17

arch/s390/include/asm/qdio.h

+8 −5
Original line number Diff line number Diff line
@@ -360,6 +360,7 @@ struct qdio_initialize { 
	unsigned int no_output_qs;

	qdio_handler_t *input_handler;

	qdio_handler_t *output_handler;

	void (*queue_start_poll) (struct ccw_device *, int, unsigned long);

	unsigned long int_parm;

	void **input_sbal_addr_array;

	void **output_sbal_addr_array;
@@ -377,11 +378,13 @@ struct qdio_initialize { 
extern int qdio_allocate(struct qdio_initialize *);

extern int qdio_establish(struct qdio_initialize *);

extern int qdio_activate(struct ccw_device *);



extern int do_QDIO(struct ccw_device *cdev, unsigned int callflags,

		   int q_nr, unsigned int bufnr, unsigned int count);

extern int do_QDIO(struct ccw_device *, unsigned int, int, unsigned int,

		   unsigned int);

extern int qdio_start_irq(struct ccw_device *, int);

extern int qdio_stop_irq(struct ccw_device *, int);

extern int qdio_get_next_buffers(struct ccw_device *, int, int *, int *);

extern int qdio_shutdown(struct ccw_device *, int);

extern int qdio_free(struct ccw_device *);

extern int qdio_get_ssqd_desc(struct ccw_device *dev, struct qdio_ssqd_desc*);

extern int qdio_get_ssqd_desc(struct ccw_device *, struct qdio_ssqd_desc *);



#endif /* __QDIO_H__ */

drivers/s390/cio/qdio.h

+29 −0
Original line number Diff line number Diff line
@@ -208,6 +208,7 @@ struct qdio_dev_perf_stat { 
	unsigned int eqbs_partial;

	unsigned int sqbs;

	unsigned int sqbs_partial;

	unsigned int int_discarded;

} ____cacheline_aligned;



struct qdio_queue_perf_stat {
@@ -222,6 +223,10 @@ struct qdio_queue_perf_stat { 
	unsigned int nr_sbal_total;

};



enum qdio_queue_irq_states {

	QDIO_QUEUE_IRQS_DISABLED,

};



struct qdio_input_q {

	/* input buffer acknowledgement flag */

	int polling;
@@ -231,6 +236,10 @@ struct qdio_input_q { 
	int ack_count;

	/* last time of noticing incoming data */

	u64 timestamp;

	/* upper-layer polling flag */

	unsigned long queue_irq_state;

	/* callback to start upper-layer polling */

	void (*queue_start_poll) (struct ccw_device *, int, unsigned long);

};



struct qdio_output_q {
@@ -399,6 +408,26 @@ static inline int multicast_outbound(struct qdio_q *q) 
#define sub_buf(bufnr, dec) \

	((bufnr - dec) & QDIO_MAX_BUFFERS_MASK)



#define queue_irqs_enabled(q)			\

	(test_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state) == 0)

#define queue_irqs_disabled(q)			\

	(test_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state) != 0)



#define TIQDIO_SHARED_IND		63



/* device state change indicators */

struct indicator_t {

	u32 ind;	/* u32 because of compare-and-swap performance */

	atomic_t count; /* use count, 0 or 1 for non-shared indicators */

};



extern struct indicator_t *q_indicators;



static inline int shared_ind(struct qdio_irq *irq_ptr)

{

	return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;

}



/* prototypes for thin interrupt */

void qdio_setup_thinint(struct qdio_irq *irq_ptr);

int qdio_establish_thinint(struct qdio_irq *irq_ptr);

drivers/s390/cio/qdio_debug.c

+12 −21
Original line number Diff line number Diff line
@@ -56,9 +56,16 @@ static int qstat_show(struct seq_file *m, void *v) 


	seq_printf(m, "DSCI: %d   nr_used: %d\n",

		   *(u32 *)q->irq_ptr->dsci, atomic_read(&q->nr_buf_used));

	seq_printf(m, "ftc: %d  last_move: %d\n", q->first_to_check, q->last_move);

	seq_printf(m, "ftc: %d  last_move: %d\n",

		   q->first_to_check, q->last_move);

	if (q->is_input_q) {

		seq_printf(m, "polling: %d  ack start: %d  ack count: %d\n",

		   q->u.in.polling, q->u.in.ack_start, q->u.in.ack_count);

			   q->u.in.polling, q->u.in.ack_start,

			   q->u.in.ack_count);

		seq_printf(m, "IRQs disabled: %u\n",

			   test_bit(QDIO_QUEUE_IRQS_DISABLED,

			   &q->u.in.queue_irq_state));

	}

	seq_printf(m, "SBAL states:\n");

	seq_printf(m, "|0      |8      |16     |24     |32     |40     |48     |56  63|\n");
@@ -113,22 +120,6 @@ static int qstat_show(struct seq_file *m, void *v) 
	return 0;

}



static ssize_t qstat_seq_write(struct file *file, const char __user *buf,

			       size_t count, loff_t *off)

{

	struct seq_file *seq = file->private_data;

	struct qdio_q *q = seq->private;



	if (!q)

		return 0;

	if (q->is_input_q)

		xchg(q->irq_ptr->dsci, 1);

	local_bh_disable();

	tasklet_schedule(&q->tasklet);

	local_bh_enable();

	return count;

}



static int qstat_seq_open(struct inode *inode, struct file *filp)

{

	return single_open(filp, qstat_show,
@@ -139,7 +130,6 @@ static const struct file_operations debugfs_fops = { 
	.owner	 = THIS_MODULE,

	.open	 = qstat_seq_open,

	.read	 = seq_read,

	.write	 = qstat_seq_write,

	.llseek  = seq_lseek,

	.release = single_release,

};
@@ -166,7 +156,8 @@ static char *qperf_names[] = { 
	"QEBSM eqbs",

	"QEBSM eqbs partial",

	"QEBSM sqbs",

	"QEBSM sqbs partial"

	"QEBSM sqbs partial",

	"Discarded interrupts"

};



static int qperf_show(struct seq_file *m, void *v)

drivers/s390/cio/qdio_main.c

+136 −2
Original line number Diff line number Diff line
@@ -884,8 +884,19 @@ static void qdio_int_handler_pci(struct qdio_irq *irq_ptr) 
	if (unlikely(irq_ptr->state == QDIO_IRQ_STATE_STOPPED))

		return;



	for_each_input_queue(irq_ptr, q, i)

	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 @@ int do_QDIO(struct ccw_device *cdev, unsigned int callflags, 
}

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;

drivers/s390/cio/qdio_setup.c

+1 −0
Original line number Diff line number Diff line
@@ -161,6 +161,7 @@ static void setup_queues(struct qdio_irq *irq_ptr, 
		setup_queues_misc(q, irq_ptr, qdio_init->input_handler, i);



		q->is_input_q = 1;

		q->u.in.queue_start_poll = qdio_init->queue_start_poll;

		setup_storage_lists(q, irq_ptr, input_sbal_array, i);

		input_sbal_array += QDIO_MAX_BUFFERS_PER_Q;