linux/drivers/s390/cio/qdio_thinint.c
Jan Glauber cf9a031c2c [S390] qdio: merge AI tasklet into interrupt handler
Since the adapter interrupt tasklet only schedules the queue tasklets
and contains no code that requires serialization in can be merged
with the adapter interrupt handler. That possibly safes some CPU
cycles.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-22 12:08:20 +02:00

300 lines
7.1 KiB
C

/*
* linux/drivers/s390/cio/thinint_qdio.c
*
* thin interrupt support for qdio
*
* Copyright 2000-2008 IBM Corp.
* 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 <asm/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"
#include "qdio_perf.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
/* list of thin interrupt input queues */
static LIST_HEAD(tiq_list);
DEFINE_MUTEX(tiq_list_lock);
/* adapter local summary indicator */
static unsigned char *tiqdio_alsi;
/* 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 */
};
static struct indicator_t *q_indicators;
static int css_qdio_omit_svs;
static inline unsigned long do_clear_global_summary(void)
{
register unsigned long __fn asm("1") = 3;
register unsigned long __tmp asm("2");
register unsigned long __time asm("3");
asm volatile(
" .insn rre,0xb2650000,2,0"
: "+d" (__fn), "=d" (__tmp), "=d" (__time));
return __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)
{
struct qdio_q *q;
int i;
/* No TDD facility? If we must use SIGA-s we can also omit SVS. */
if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
css_qdio_omit_svs = 1;
mutex_lock(&tiq_list_lock);
for_each_input_queue(irq_ptr, q, i)
list_add_rcu(&q->entry, &tiq_list);
mutex_unlock(&tiq_list_lock);
xchg(irq_ptr->dsci, 1);
}
void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
{
struct qdio_q *q;
int i;
for (i = 0; i < irq_ptr->nr_input_qs; i++) {
q = irq_ptr->input_qs[i];
/* if establish triggered an error */
if (!q || !q->entry.prev || !q->entry.next)
continue;
mutex_lock(&tiq_list_lock);
list_del_rcu(&q->entry);
mutex_unlock(&tiq_list_lock);
synchronize_rcu();
}
}
static inline int shared_ind(struct qdio_irq *irq_ptr)
{
return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
}
/**
* tiqdio_thinint_handler - thin interrupt handler for qdio
* @ind: pointer to adapter local summary indicator
* @drv_data: NULL
*/
static void tiqdio_thinint_handler(void *ind, void *drv_data)
{
struct qdio_q *q;
qdio_perf_stat_inc(&perf_stats.thin_int);
/*
* SVS only when needed: issue SVS to benefit from iqdio interrupt
* avoidance (SVS clears adapter interrupt suppression overwrite)
*/
if (!css_qdio_omit_svs)
do_clear_global_summary();
/*
* reset local summary indicator (tiqdio_alsi) to stop adapter
* interrupts for now
*/
xchg((u8 *)ind, 0);
/* 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)
/* only process queues from changed sets */
if (*q->irq_ptr->dsci) {
/* only clear it if the indicator is non-shared */
if (!shared_ind(q->irq_ptr))
xchg(q->irq_ptr->dsci, 0);
/*
* don't call inbound processing directly since
* that could starve other thinint queues
*/
tasklet_schedule(&q->tasklet);
}
rcu_read_unlock();
/*
* if we used the shared indicator clear it now after all queues
* were processed
*/
if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
/* prevent racing */
if (*tiqdio_alsi)
xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
}
}
static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
{
struct scssc_area *scssc_area;
int rc;
scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
memset(scssc_area, 0, PAGE_SIZE);
if (reset) {
scssc_area->summary_indicator_addr = 0;
scssc_area->subchannel_indicator_addr = 0;
} else {
scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
scssc_area->subchannel_indicator_addr =
virt_to_phys(irq_ptr->dsci);
}
scssc_area->request = (struct chsc_header) {
.length = 0x0fe0,
.code = 0x0021,
};
scssc_area->operation_code = 0;
scssc_area->ks = PAGE_DEFAULT_KEY;
scssc_area->kc = PAGE_DEFAULT_KEY;
scssc_area->isc = QDIO_AIRQ_ISC;
scssc_area->schid = irq_ptr->schid;
/* enable the time delay disablement facility */
if (css_general_characteristics.aif_tdd)
scssc_area->word_with_d_bit = 0x10000000;
rc = chsc(scssc_area);
if (rc)
return -EIO;
rc = chsc_error_from_response(scssc_area->response.code);
if (rc) {
DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
scssc_area->response.code);
DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
return rc;
}
DBF_EVENT("setscind");
DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
return 0;
}
/* 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)
{
isc_register(QDIO_AIRQ_ISC);
tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
NULL, QDIO_AIRQ_ISC);
if (IS_ERR(tiqdio_alsi)) {
DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
tiqdio_alsi = NULL;
isc_unregister(QDIO_AIRQ_ISC);
return -ENOMEM;
}
return 0;
}
int qdio_establish_thinint(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return 0;
/* Check for aif time delay disablement. If installed,
* omit SVS even under LPAR
*/
if (css_general_characteristics.aif_tdd)
css_qdio_omit_svs = 1;
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 */
put_indicator(irq_ptr->dsci);
set_subchannel_ind(irq_ptr, 1);
}
void __exit tiqdio_unregister_thinints(void)
{
WARN_ON(!list_empty(&tiq_list));
if (tiqdio_alsi) {
s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
isc_unregister(QDIO_AIRQ_ISC);
}
}