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qdio: extend API to allow polling

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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>
This commit is contained in:
Jan Glauber
2010-09-07 21:14:39 +00:00
committed by David S. Miller
parent e508be174a
commit d36deae750
7 changed files with 226 additions and 62 deletions
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29
drivers/s390/cio/qdio.h
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@@ -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);