Orange Pi5 kernel

// 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);
}
 
void tiqdio_add_device(struct qdio_irq *irq_ptr)
{
<------>mutex_lock(&tiq_list_lock);
<------>list_add_rcu(&irq_ptr->entry, &tiq_list);
<------>mutex_unlock(&tiq_list_lock);
}
 
void tiqdio_remove_device(struct qdio_irq *irq_ptr)
{
<------>mutex_lock(&tiq_list_lock);
<------>list_del_rcu(&irq_ptr->entry);
<------>mutex_unlock(&tiq_list_lock);
<------>synchronize_rcu();
<------>INIT_LIST_HEAD(&irq_ptr->entry);
}
 
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);
}
 
static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
{
<------>struct qdio_q *q;
<------>int i;
 
<------>if (!references_shared_dsci(irq))
<------><------>xchg(irq->dsci, 0);
 
<------>if (irq->irq_poll) {
<------><------>if (!test_and_set_bit(QDIO_IRQ_DISABLED, &irq->poll_state))
<------><------><------>irq->irq_poll(irq->cdev, irq->int_parm);
<------><------>else
<------><------><------>QDIO_PERF_STAT_INC(irq, int_discarded);
 
<------><------>return;
<------>}
 
<------>for_each_input_queue(irq, q, i) {
<------><------>/*
<------><------> * 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
 * @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)
{
<------>u32 si_used = clear_shared_ind();
<------>struct qdio_irq *irq;
 
<------>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();
 
<------>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;
 
<------><------>tiqdio_call_inq_handlers(irq);
 
<------><------>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;
}
 
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);
}
 
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);
}