linux/drivers/s390/cio/qdio_thinint.c
Martin Schwidefsky f4eae94f71 s390/airq: simplify adapter interrupt code
There are three users of adapter interrupts: AP, QDIO and PCI. Each
registers a single adapter interrupt with independent ISCs. Define
a "struct airq" with the interrupt handler, a pointer and a mask for
the local summary indicator and the ISC for the adapter interrupt
source. Convert the indicator array with its fixed number of adapter
interrupt sources per ISE to an array of hlists. This removes the
limitation to 32 adapter interrupts per ISC and allows for arbitrary
memory locations for the local summary indicator.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-06-26 21:10:28 +02:00

300 lines
6.7 KiB
C

/*
* Copyright IBM Corp. 2000, 2009
* Author(s): Utz Bacher <utz.bacher@de.ibm.com>
* Cornelia Huck <cornelia.huck@de.ibm.com>
* Jan Glauber <jang@linux.vnet.ibm.com>
*/
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/kernel_stat.h>
#include <linux/atomic.h>
#include <asm/debug.h>
#include <asm/qdio.h>
#include <asm/airq.h>
#include <asm/isc.h>
#include "cio.h"
#include "ioasm.h"
#include "qdio.h"
#include "qdio_debug.h"
/*
* Restriction: only 63 iqdio subchannels would have its own indicator,
* after that, subsequent subchannels share one indicator
*/
#define TIQDIO_NR_NONSHARED_IND 63
#define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)
#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 */
};
/* list of thin interrupt input queues */
static LIST_HEAD(tiq_list);
static DEFINE_MUTEX(tiq_list_lock);
/* Adapter interrupt definitions */
static void tiqdio_thinint_handler(struct airq_struct *airq);
static struct airq_struct tiqdio_airq = {
.handler = tiqdio_thinint_handler,
.isc = QDIO_AIRQ_ISC,
};
static struct indicator_t *q_indicators;
u64 last_ai_time;
/* returns addr for the device state change indicator */
static u32 *get_indicator(void)
{
int i;
for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
if (!atomic_read(&q_indicators[i].count)) {
atomic_set(&q_indicators[i].count, 1);
return &q_indicators[i].ind;
}
/* use the shared indicator */
atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
return &q_indicators[TIQDIO_SHARED_IND].ind;
}
static void put_indicator(u32 *addr)
{
int i;
if (!addr)
return;
i = ((unsigned long)addr - (unsigned long)q_indicators) /
sizeof(struct indicator_t);
atomic_dec(&q_indicators[i].count);
}
void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
{
mutex_lock(&tiq_list_lock);
list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
mutex_unlock(&tiq_list_lock);
xchg(irq_ptr->dsci, 1 << 7);
}
void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
{
struct qdio_q *q;
q = irq_ptr->input_qs[0];
/* if establish triggered an error */
if (!q || !q->entry.prev || !q->entry.next)
return;
mutex_lock(&tiq_list_lock);
list_del_rcu(&q->entry);
mutex_unlock(&tiq_list_lock);
synchronize_rcu();
}
static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
{
return irq_ptr->nr_input_qs > 1;
}
static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
{
return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
}
static inline int shared_ind(struct qdio_irq *irq_ptr)
{
return references_shared_dsci(irq_ptr) ||
has_multiple_inq_on_dsci(irq_ptr);
}
void clear_nonshared_ind(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return;
if (shared_ind(irq_ptr))
return;
xchg(irq_ptr->dsci, 0);
}
int test_nonshared_ind(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return 0;
if (shared_ind(irq_ptr))
return 0;
if (*irq_ptr->dsci)
return 1;
else
return 0;
}
static inline u32 clear_shared_ind(void)
{
if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
return 0;
return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
}
static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
{
struct qdio_q *q;
int i;
for_each_input_queue(irq, q, i) {
if (!references_shared_dsci(irq) &&
has_multiple_inq_on_dsci(irq))
xchg(q->irq_ptr->dsci, 0);
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;
}
/* avoid dsci clear here, done after processing */
q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
q->irq_ptr->int_parm);
} else {
if (!shared_ind(q->irq_ptr))
xchg(q->irq_ptr->dsci, 0);
/*
* Call inbound processing but not directly
* since that could starve other thinint queues.
*/
tasklet_schedule(&q->tasklet);
}
}
}
/**
* tiqdio_thinint_handler - thin interrupt handler for qdio
* @alsi: pointer to adapter local summary indicator
* @data: NULL
*/
static void tiqdio_thinint_handler(struct airq_struct *airq)
{
u32 si_used = clear_shared_ind();
struct qdio_q *q;
last_ai_time = S390_lowcore.int_clock;
inc_irq_stat(IRQIO_QAI);
/* protect tiq_list entries, only changed in activate or shutdown */
rcu_read_lock();
/* check for work on all inbound thinint queues */
list_for_each_entry_rcu(q, &tiq_list, entry) {
struct qdio_irq *irq;
/* only process queues from changed sets */
irq = q->irq_ptr;
if (unlikely(references_shared_dsci(irq))) {
if (!si_used)
continue;
} else if (!*irq->dsci)
continue;
tiqdio_call_inq_handlers(irq);
qperf_inc(q, adapter_int);
}
rcu_read_unlock();
}
static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
{
struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page;
u64 summary_indicator_addr, subchannel_indicator_addr;
int rc;
if (reset) {
summary_indicator_addr = 0;
subchannel_indicator_addr = 0;
} else {
summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr);
subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci);
}
rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr,
subchannel_indicator_addr);
if (rc) {
DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
scssc->response.code);
goto out;
}
DBF_EVENT("setscind");
DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr));
DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr));
out:
return rc;
}
/* allocate non-shared indicators and shared indicator */
int __init tiqdio_allocate_memory(void)
{
q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
GFP_KERNEL);
if (!q_indicators)
return -ENOMEM;
return 0;
}
void tiqdio_free_memory(void)
{
kfree(q_indicators);
}
int __init tiqdio_register_thinints(void)
{
int rc;
rc = register_adapter_interrupt(&tiqdio_airq);
if (rc) {
DBF_EVENT("RTI:%x", rc);
return rc;
}
return 0;
}
int qdio_establish_thinint(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return 0;
return set_subchannel_ind(irq_ptr, 0);
}
void qdio_setup_thinint(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return;
irq_ptr->dsci = get_indicator();
DBF_HEX(&irq_ptr->dsci, sizeof(void *));
}
void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return;
/* reset adapter interrupt indicators */
set_subchannel_ind(irq_ptr, 1);
put_indicator(irq_ptr->dsci);
}
void __exit tiqdio_unregister_thinints(void)
{
WARN_ON(!list_empty(&tiq_list));
unregister_adapter_interrupt(&tiqdio_airq);
}