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 /* Adapter interrupt definitions */
43 static void tiqdio_thinint_handler(struct airq_struct *airq);
45 static struct airq_struct tiqdio_airq = {
46 .handler = tiqdio_thinint_handler,
50 static struct indicator_t *q_indicators;
54 /* returns addr for the device state change indicator */
55 static u32 *get_indicator(void)
59 for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
60 if (!atomic_read(&q_indicators[i].count)) {
61 atomic_set(&q_indicators[i].count, 1);
62 return &q_indicators[i].ind;
65 /* use the shared indicator */
66 atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
67 return &q_indicators[TIQDIO_SHARED_IND].ind;
70 static void put_indicator(u32 *addr)
76 i = ((unsigned long)addr - (unsigned long)q_indicators) /
77 sizeof(struct indicator_t);
78 atomic_dec(&q_indicators[i].count);
81 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
83 mutex_lock(&tiq_list_lock);
84 list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
85 mutex_unlock(&tiq_list_lock);
88 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
92 q = irq_ptr->input_qs[0];
96 mutex_lock(&tiq_list_lock);
97 list_del_rcu(&q->entry);
98 mutex_unlock(&tiq_list_lock);
100 INIT_LIST_HEAD(&q->entry);
103 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
105 return irq_ptr->nr_input_qs > 1;
108 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
110 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
113 static inline int shared_ind(struct qdio_irq *irq_ptr)
115 return references_shared_dsci(irq_ptr) ||
116 has_multiple_inq_on_dsci(irq_ptr);
119 void clear_nonshared_ind(struct qdio_irq *irq_ptr)
121 if (!is_thinint_irq(irq_ptr))
123 if (shared_ind(irq_ptr))
125 xchg(irq_ptr->dsci, 0);
128 int test_nonshared_ind(struct qdio_irq *irq_ptr)
130 if (!is_thinint_irq(irq_ptr))
132 if (shared_ind(irq_ptr))
140 static inline u32 clear_shared_ind(void)
142 if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
144 return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
147 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
152 if (!references_shared_dsci(irq) &&
153 has_multiple_inq_on_dsci(irq))
156 for_each_input_queue(irq, q, i) {
157 if (q->u.in.queue_start_poll) {
158 /* skip if polling is enabled or already in work */
159 if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
160 &q->u.in.queue_irq_state)) {
161 qperf_inc(q, int_discarded);
165 /* avoid dsci clear here, done after processing */
166 q->u.in.queue_start_poll(irq->cdev, q->nr,
169 if (!shared_ind(irq))
173 * Call inbound processing but not directly
174 * since that could starve other thinint queues.
176 tasklet_schedule(&q->tasklet);
182 * tiqdio_thinint_handler - thin interrupt handler for qdio
183 * @airq: pointer to adapter interrupt descriptor
185 static void tiqdio_thinint_handler(struct airq_struct *airq)
187 u32 si_used = clear_shared_ind();
190 last_ai_time = S390_lowcore.int_clock;
191 inc_irq_stat(IRQIO_QAI);
193 /* protect tiq_list entries, only changed in activate or shutdown */
196 /* check for work on all inbound thinint queues */
197 list_for_each_entry_rcu(q, &tiq_list, entry) {
198 struct qdio_irq *irq;
200 /* only process queues from changed sets */
202 if (unlikely(references_shared_dsci(irq))) {
205 } else if (!*irq->dsci)
208 tiqdio_call_inq_handlers(irq);
210 qperf_inc(q, adapter_int);
215 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
217 struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page;
218 u64 summary_indicator_addr, subchannel_indicator_addr;
222 summary_indicator_addr = 0;
223 subchannel_indicator_addr = 0;
225 summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr);
226 subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci);
229 rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr,
230 subchannel_indicator_addr);
232 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
233 scssc->response.code);
237 DBF_EVENT("setscind");
238 DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr));
239 DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr));
244 /* allocate non-shared indicators and shared indicator */
245 int __init tiqdio_allocate_memory(void)
247 q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
254 void tiqdio_free_memory(void)
259 int __init tiqdio_register_thinints(void)
263 rc = register_adapter_interrupt(&tiqdio_airq);
265 DBF_EVENT("RTI:%x", rc);
271 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
275 if (!is_thinint_irq(irq_ptr))
278 irq_ptr->dsci = get_indicator();
279 DBF_HEX(&irq_ptr->dsci, sizeof(void *));
281 rc = set_subchannel_ind(irq_ptr, 0);
283 put_indicator(irq_ptr->dsci);
288 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
290 if (!is_thinint_irq(irq_ptr))
293 /* reset adapter interrupt indicators */
294 set_subchannel_ind(irq_ptr, 1);
295 put_indicator(irq_ptr->dsci);
298 void __exit tiqdio_unregister_thinints(void)
300 WARN_ON(!list_empty(&tiq_list));
301 unregister_adapter_interrupt(&tiqdio_airq);