1 // SPDX-License-Identifier: GPL-2.0
2 /*
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>
7 */
8 #include <linux/io.h>
9 #include <linux/slab.h>
10 #include <linux/kernel_stat.h>
11 #include <linux/atomic.h>
12 #include <linux/rculist.h>
13
14 #include <asm/debug.h>
15 #include <asm/qdio.h>
16 #include <asm/airq.h>
17 #include <asm/isc.h>
18
19 #include "cio.h"
20 #include "ioasm.h"
21 #include "qdio.h"
22 #include "qdio_debug.h"
23
24 /*
25 * Restriction: only 63 iqdio subchannels would have its own indicator,
26 * after that, subsequent subchannels share one indicator
27 */
28 #define TIQDIO_NR_NONSHARED_IND 63
29 #define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)
30 #define TIQDIO_SHARED_IND 63
31
32 /* device state change indicators */
33 struct indicator_t {
34 u32 ind; /* u32 because of compare-and-swap performance */
35 atomic_t count; /* use count, 0 or 1 for non-shared indicators */
36 };
37
38 /* list of thin interrupt input queues */
39 static LIST_HEAD(tiq_list);
40 static DEFINE_MUTEX(tiq_list_lock);
41
42 static struct indicator_t *q_indicators;
43
44 u64 last_ai_time;
45
46 /* returns addr for the device state change indicator */
get_indicator(void)47 static u32 *get_indicator(void)
48 {
49 int i;
50
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;
54
55 /* use the shared indicator */
56 atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
57 return &q_indicators[TIQDIO_SHARED_IND].ind;
58 }
59
put_indicator(u32 * addr)60 static void put_indicator(u32 *addr)
61 {
62 struct indicator_t *ind = container_of(addr, struct indicator_t, ind);
63
64 if (!addr)
65 return;
66 atomic_dec(&ind->count);
67 }
68
references_shared_dsci(struct qdio_irq * irq_ptr)69 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
70 {
71 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
72 }
73
test_nonshared_ind(struct qdio_irq * irq_ptr)74 int test_nonshared_ind(struct qdio_irq *irq_ptr)
75 {
76 if (!is_thinint_irq(irq_ptr))
77 return 0;
78 if (references_shared_dsci(irq_ptr))
79 return 0;
80 if (*irq_ptr->dsci)
81 return 1;
82 else
83 return 0;
84 }
85
clear_shared_ind(void)86 static inline u32 clear_shared_ind(void)
87 {
88 if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
89 return 0;
90 return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
91 }
92
93 /**
94 * tiqdio_thinint_handler - thin interrupt handler for qdio
95 * @airq: pointer to adapter interrupt descriptor
96 * @floating: flag to recognize floating vs. directed interrupts (unused)
97 */
tiqdio_thinint_handler(struct airq_struct * airq,bool floating)98 static void tiqdio_thinint_handler(struct airq_struct *airq, bool floating)
99 {
100 u64 irq_time = S390_lowcore.int_clock;
101 u32 si_used = clear_shared_ind();
102 struct qdio_irq *irq;
103
104 last_ai_time = irq_time;
105 inc_irq_stat(IRQIO_QAI);
106
107 /* protect tiq_list entries, only changed in activate or shutdown */
108 rcu_read_lock();
109
110 list_for_each_entry_rcu(irq, &tiq_list, entry) {
111 /* only process queues from changed sets */
112 if (unlikely(references_shared_dsci(irq))) {
113 if (!si_used)
114 continue;
115 } else {
116 if (!*irq->dsci)
117 continue;
118
119 xchg(irq->dsci, 0);
120 }
121
122 qdio_deliver_irq(irq);
123 irq->last_data_irq_time = irq_time;
124
125 QDIO_PERF_STAT_INC(irq, adapter_int);
126 }
127 rcu_read_unlock();
128 }
129
130 static struct airq_struct tiqdio_airq = {
131 .handler = tiqdio_thinint_handler,
132 .isc = QDIO_AIRQ_ISC,
133 };
134
set_subchannel_ind(struct qdio_irq * irq_ptr,int reset)135 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
136 {
137 struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page;
138 u64 summary_indicator_addr, subchannel_indicator_addr;
139 int rc;
140
141 if (reset) {
142 summary_indicator_addr = 0;
143 subchannel_indicator_addr = 0;
144 } else {
145 summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr);
146 subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci);
147 }
148
149 rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr,
150 subchannel_indicator_addr, tiqdio_airq.isc);
151 if (rc) {
152 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
153 scssc->response.code);
154 goto out;
155 }
156
157 DBF_EVENT("setscind");
158 DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr));
159 DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr));
160 out:
161 return rc;
162 }
163
qdio_establish_thinint(struct qdio_irq * irq_ptr)164 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
165 {
166 int rc;
167
168 if (!is_thinint_irq(irq_ptr))
169 return 0;
170
171 irq_ptr->dsci = get_indicator();
172 DBF_HEX(&irq_ptr->dsci, sizeof(void *));
173
174 rc = set_subchannel_ind(irq_ptr, 0);
175 if (rc) {
176 put_indicator(irq_ptr->dsci);
177 return rc;
178 }
179
180 mutex_lock(&tiq_list_lock);
181 list_add_rcu(&irq_ptr->entry, &tiq_list);
182 mutex_unlock(&tiq_list_lock);
183 return 0;
184 }
185
qdio_shutdown_thinint(struct qdio_irq * irq_ptr)186 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
187 {
188 if (!is_thinint_irq(irq_ptr))
189 return;
190
191 mutex_lock(&tiq_list_lock);
192 list_del_rcu(&irq_ptr->entry);
193 mutex_unlock(&tiq_list_lock);
194 synchronize_rcu();
195
196 /* reset adapter interrupt indicators */
197 set_subchannel_ind(irq_ptr, 1);
198 put_indicator(irq_ptr->dsci);
199 }
200
qdio_thinint_init(void)201 int __init qdio_thinint_init(void)
202 {
203 int rc;
204
205 q_indicators = kcalloc(TIQDIO_NR_INDICATORS, sizeof(struct indicator_t),
206 GFP_KERNEL);
207 if (!q_indicators)
208 return -ENOMEM;
209
210 rc = register_adapter_interrupt(&tiqdio_airq);
211 if (rc) {
212 DBF_EVENT("RTI:%x", rc);
213 kfree(q_indicators);
214 return rc;
215 }
216 return 0;
217 }
218
qdio_thinint_exit(void)219 void __exit qdio_thinint_exit(void)
220 {
221 WARN_ON(!list_empty(&tiq_list));
222 unregister_adapter_interrupt(&tiqdio_airq);
223 kfree(q_indicators);
224 }
225