1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright IBM Corp. 2000, 2009
4 * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
5 * Cornelia Huck <cornelia.huck@de.ibm.com>
6 * Jan Glauber <jang@linux.vnet.ibm.com>
9 #include <linux/slab.h>
10 #include <linux/kernel_stat.h>
11 #include <linux/atomic.h>
12 #include <linux/rculist.h>
14 #include <asm/debug.h>
22 #include "qdio_debug.h"
25 * Restriction: only 63 iqdio subchannels would have its own indicator,
26 * after that, subsequent subchannels share one indicator
28 #define TIQDIO_NR_NONSHARED_IND 63
29 #define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)
30 #define TIQDIO_SHARED_IND 63
32 /* device state change indicators */
34 u32 ind; /* u32 because of compare-and-swap performance */
35 atomic_t count; /* use count, 0 or 1 for non-shared indicators */
38 /* list of thin interrupt input queues */
39 static LIST_HEAD(tiq_list);
40 static DEFINE_MUTEX(tiq_list_lock);
42 static struct indicator_t *q_indicators;
46 /* returns addr for the device state change indicator */
47 static u32 *get_indicator(void)
51 for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
52 if (!atomic_cmpxchg(&q_indicators[i].count, 0, 1))
53 return &q_indicators[i].ind;
55 /* use the shared indicator */
56 atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
57 return &q_indicators[TIQDIO_SHARED_IND].ind;
60 static void put_indicator(u32 *addr)
62 struct indicator_t *ind = container_of(addr, struct indicator_t, ind);
66 atomic_dec(&ind->count);
69 void tiqdio_add_device(struct qdio_irq *irq_ptr)
71 mutex_lock(&tiq_list_lock);
72 list_add_rcu(&irq_ptr->entry, &tiq_list);
73 mutex_unlock(&tiq_list_lock);
76 void tiqdio_remove_device(struct qdio_irq *irq_ptr)
78 mutex_lock(&tiq_list_lock);
79 list_del_rcu(&irq_ptr->entry);
80 mutex_unlock(&tiq_list_lock);
82 INIT_LIST_HEAD(&irq_ptr->entry);
85 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
87 return irq_ptr->nr_input_qs > 1;
90 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
92 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
95 static inline int shared_ind(struct qdio_irq *irq_ptr)
97 return references_shared_dsci(irq_ptr) ||
98 has_multiple_inq_on_dsci(irq_ptr);
101 void clear_nonshared_ind(struct qdio_irq *irq_ptr)
103 if (!is_thinint_irq(irq_ptr))
105 if (shared_ind(irq_ptr))
107 xchg(irq_ptr->dsci, 0);
110 int test_nonshared_ind(struct qdio_irq *irq_ptr)
112 if (!is_thinint_irq(irq_ptr))
114 if (shared_ind(irq_ptr))
122 static inline u32 clear_shared_ind(void)
124 if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
126 return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
129 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
134 if (!references_shared_dsci(irq) &&
135 has_multiple_inq_on_dsci(irq))
138 for_each_input_queue(irq, q, i) {
139 if (q->u.in.queue_start_poll) {
140 /* skip if polling is enabled or already in work */
141 if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
142 &q->u.in.queue_irq_state)) {
143 QDIO_PERF_STAT_INC(irq, int_discarded);
147 /* avoid dsci clear here, done after processing */
148 q->u.in.queue_start_poll(irq->cdev, q->nr,
151 if (!shared_ind(irq))
155 * Call inbound processing but not directly
156 * since that could starve other thinint queues.
158 tasklet_schedule(&q->tasklet);
164 * tiqdio_thinint_handler - thin interrupt handler for qdio
165 * @airq: pointer to adapter interrupt descriptor
166 * @floating: flag to recognize floating vs. directed interrupts (unused)
168 static void tiqdio_thinint_handler(struct airq_struct *airq, bool floating)
170 u32 si_used = clear_shared_ind();
171 struct qdio_irq *irq;
173 last_ai_time = S390_lowcore.int_clock;
174 inc_irq_stat(IRQIO_QAI);
176 /* protect tiq_list entries, only changed in activate or shutdown */
179 list_for_each_entry_rcu(irq, &tiq_list, entry) {
180 /* only process queues from changed sets */
181 if (unlikely(references_shared_dsci(irq))) {
184 } else if (!*irq->dsci)
187 tiqdio_call_inq_handlers(irq);
189 QDIO_PERF_STAT_INC(irq, adapter_int);
194 static struct airq_struct tiqdio_airq = {
195 .handler = tiqdio_thinint_handler,
196 .isc = QDIO_AIRQ_ISC,
199 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
201 struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page;
202 u64 summary_indicator_addr, subchannel_indicator_addr;
206 summary_indicator_addr = 0;
207 subchannel_indicator_addr = 0;
209 summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr);
210 subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci);
213 rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr,
214 subchannel_indicator_addr);
216 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
217 scssc->response.code);
221 DBF_EVENT("setscind");
222 DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr));
223 DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr));
228 /* allocate non-shared indicators and shared indicator */
229 int __init tiqdio_allocate_memory(void)
231 q_indicators = kcalloc(TIQDIO_NR_INDICATORS,
232 sizeof(struct indicator_t),
239 void tiqdio_free_memory(void)
244 int __init tiqdio_register_thinints(void)
248 rc = register_adapter_interrupt(&tiqdio_airq);
250 DBF_EVENT("RTI:%x", rc);
256 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
258 if (!is_thinint_irq(irq_ptr))
260 return set_subchannel_ind(irq_ptr, 0);
263 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
265 if (!is_thinint_irq(irq_ptr))
267 irq_ptr->dsci = get_indicator();
268 DBF_HEX(&irq_ptr->dsci, sizeof(void *));
271 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
273 if (!is_thinint_irq(irq_ptr))
276 /* reset adapter interrupt indicators */
277 set_subchannel_ind(irq_ptr, 1);
278 put_indicator(irq_ptr->dsci);
281 void __exit tiqdio_unregister_thinints(void)
283 WARN_ON(!list_empty(&tiq_list));
284 unregister_adapter_interrupt(&tiqdio_airq);