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, bool floating);
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_cmpxchg(&q_indicators[i].count, 0, 1))
61 return &q_indicators[i].ind;
63 /* use the shared indicator */
64 atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
65 return &q_indicators[TIQDIO_SHARED_IND].ind;
68 static void put_indicator(u32 *addr)
70 struct indicator_t *ind = container_of(addr, struct indicator_t, ind);
74 atomic_dec(&ind->count);
77 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
79 mutex_lock(&tiq_list_lock);
80 list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
81 mutex_unlock(&tiq_list_lock);
84 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
88 q = irq_ptr->input_qs[0];
92 mutex_lock(&tiq_list_lock);
93 list_del_rcu(&q->entry);
94 mutex_unlock(&tiq_list_lock);
96 INIT_LIST_HEAD(&q->entry);
99 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
101 return irq_ptr->nr_input_qs > 1;
104 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
106 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
109 static inline int shared_ind(struct qdio_irq *irq_ptr)
111 return references_shared_dsci(irq_ptr) ||
112 has_multiple_inq_on_dsci(irq_ptr);
115 void clear_nonshared_ind(struct qdio_irq *irq_ptr)
117 if (!is_thinint_irq(irq_ptr))
119 if (shared_ind(irq_ptr))
121 xchg(irq_ptr->dsci, 0);
124 int test_nonshared_ind(struct qdio_irq *irq_ptr)
126 if (!is_thinint_irq(irq_ptr))
128 if (shared_ind(irq_ptr))
136 static inline u32 clear_shared_ind(void)
138 if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
140 return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
143 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
148 if (!references_shared_dsci(irq) &&
149 has_multiple_inq_on_dsci(irq))
152 for_each_input_queue(irq, q, i) {
153 if (q->u.in.queue_start_poll) {
154 /* skip if polling is enabled or already in work */
155 if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
156 &q->u.in.queue_irq_state)) {
157 qperf_inc(q, int_discarded);
161 /* avoid dsci clear here, done after processing */
162 q->u.in.queue_start_poll(irq->cdev, q->nr,
165 if (!shared_ind(irq))
169 * Call inbound processing but not directly
170 * since that could starve other thinint queues.
172 tasklet_schedule(&q->tasklet);
178 * tiqdio_thinint_handler - thin interrupt handler for qdio
179 * @airq: pointer to adapter interrupt descriptor
180 * @floating: flag to recognize floating vs. directed interrupts (unused)
182 static void tiqdio_thinint_handler(struct airq_struct *airq, bool floating)
184 u32 si_used = clear_shared_ind();
187 last_ai_time = S390_lowcore.int_clock;
188 inc_irq_stat(IRQIO_QAI);
190 /* protect tiq_list entries, only changed in activate or shutdown */
193 /* check for work on all inbound thinint queues */
194 list_for_each_entry_rcu(q, &tiq_list, entry) {
195 struct qdio_irq *irq;
197 /* only process queues from changed sets */
199 if (unlikely(references_shared_dsci(irq))) {
202 } else if (!*irq->dsci)
205 tiqdio_call_inq_handlers(irq);
207 qperf_inc(q, adapter_int);
212 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
214 struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page;
215 u64 summary_indicator_addr, subchannel_indicator_addr;
219 summary_indicator_addr = 0;
220 subchannel_indicator_addr = 0;
222 summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr);
223 subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci);
226 rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr,
227 subchannel_indicator_addr);
229 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
230 scssc->response.code);
234 DBF_EVENT("setscind");
235 DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr));
236 DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr));
241 /* allocate non-shared indicators and shared indicator */
242 int __init tiqdio_allocate_memory(void)
244 q_indicators = kcalloc(TIQDIO_NR_INDICATORS,
245 sizeof(struct indicator_t),
252 void tiqdio_free_memory(void)
257 int __init tiqdio_register_thinints(void)
261 rc = register_adapter_interrupt(&tiqdio_airq);
263 DBF_EVENT("RTI:%x", rc);
269 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
271 if (!is_thinint_irq(irq_ptr))
273 return set_subchannel_ind(irq_ptr, 0);
276 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
278 if (!is_thinint_irq(irq_ptr))
280 irq_ptr->dsci = get_indicator();
281 DBF_HEX(&irq_ptr->dsci, sizeof(void *));
284 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
286 if (!is_thinint_irq(irq_ptr))
289 /* reset adapter interrupt indicators */
290 set_subchannel_ind(irq_ptr, 1);
291 put_indicator(irq_ptr->dsci);
294 void __exit tiqdio_unregister_thinints(void)
296 WARN_ON(!list_empty(&tiq_list));
297 unregister_adapter_interrupt(&tiqdio_airq);