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// SPDX-License-Identifier: GPL-2.0
/*
* 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 <linux/rculist.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);
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_cmpxchg(&q_indicators[i].count, 0, 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)
{
struct indicator_t *ind = container_of(addr, struct indicator_t, ind);
if (!addr)
return;
atomic_dec(&ind->count);
}
static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
{
return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
}
int test_nonshared_ind(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return 0;
if (references_shared_dsci(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);
}
/**
* tiqdio_thinint_handler - thin interrupt handler for qdio
* @airq: pointer to adapter interrupt descriptor
* @floating: flag to recognize floating vs. directed interrupts (unused)
*/
static void tiqdio_thinint_handler(struct airq_struct *airq, bool floating)
{
u64 irq_time = S390_lowcore.int_clock;
u32 si_used = clear_shared_ind();
struct qdio_irq *irq;
last_ai_time = irq_time;
inc_irq_stat(IRQIO_QAI);
/* protect tiq_list entries, only changed in activate or shutdown */
rcu_read_lock();
list_for_each_entry_rcu(irq, &tiq_list, entry) {
/* only process queues from changed sets */
if (unlikely(references_shared_dsci(irq))) {
if (!si_used)
continue;
} else {
if (!*irq->dsci)
continue;
xchg(irq->dsci, 0);
}
qdio_deliver_irq(irq);
irq->last_data_irq_time = irq_time;
QDIO_PERF_STAT_INC(irq, adapter_int);
}
rcu_read_unlock();
}
static struct airq_struct tiqdio_airq = {
.handler = tiqdio_thinint_handler,
.isc = QDIO_AIRQ_ISC,
};
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, tiqdio_airq.isc);
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;
}
int qdio_establish_thinint(struct qdio_irq *irq_ptr)
{
int rc;
if (!is_thinint_irq(irq_ptr))
return 0;
irq_ptr->dsci = get_indicator();
DBF_HEX(&irq_ptr->dsci, sizeof(void *));
rc = set_subchannel_ind(irq_ptr, 0);
if (rc) {
put_indicator(irq_ptr->dsci);
return rc;
}
mutex_lock(&tiq_list_lock);
list_add_rcu(&irq_ptr->entry, &tiq_list);
mutex_unlock(&tiq_list_lock);
return 0;
}
void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
{
if (!is_thinint_irq(irq_ptr))
return;
mutex_lock(&tiq_list_lock);
list_del_rcu(&irq_ptr->entry);
mutex_unlock(&tiq_list_lock);
synchronize_rcu();
/* reset adapter interrupt indicators */
set_subchannel_ind(irq_ptr, 1);
put_indicator(irq_ptr->dsci);
}
int __init qdio_thinint_init(void)
{
int rc;
q_indicators = kcalloc(TIQDIO_NR_INDICATORS, sizeof(struct indicator_t),
GFP_KERNEL);
if (!q_indicators)
return -ENOMEM;
rc = register_adapter_interrupt(&tiqdio_airq);
if (rc) {
DBF_EVENT("RTI:%x", rc);
kfree(q_indicators);
return rc;
}
return 0;
}
void __exit qdio_thinint_exit(void)
{
WARN_ON(!list_empty(&tiq_list));
unregister_adapter_interrupt(&tiqdio_airq);
kfree(q_indicators);
}
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