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Diffstat (limited to '')
| -rw-r--r-- | drivers/s390/cio/qdio_thinint.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/s390/cio/qdio_thinint.c b/drivers/s390/cio/qdio_thinint.c new file mode 100644 index 000000000..7a440e432 --- /dev/null +++ b/drivers/s390/cio/qdio_thinint.c @@ -0,0 +1,250 @@ +// 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); +} |