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 #include <asm/tpi.h>
19
20 #include "cio.h"
21 #include "ioasm.h"
22 #include "qdio.h"
23 #include "qdio_debug.h"
24
25 /*
26 * Restriction: only 63 iqdio subchannels would have its own indicator,
27 * after that, subsequent subchannels share one indicator
28 */
29 #define TIQDIO_NR_NONSHARED_IND 63
30 #define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)
31 #define TIQDIO_SHARED_IND 63
32
33 /* device state change indicators */
34 struct indicator_t {
35 u32 ind; /* u32 because of compare-and-swap performance */
36 atomic_t count; /* use count, 0 or 1 for non-shared indicators */
37 };
38
39 /* list of thin interrupt input queues */
40 static LIST_HEAD(tiq_list);
41 static DEFINE_MUTEX(tiq_list_lock);
42
43 static struct indicator_t *q_indicators;
44
45 u64 last_ai_time;
46
47 /* returns addr for the device state change indicator */
get_indicator(void)48 static u32 *get_indicator(void)
49 {
50 int i;
51
52 for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
53 if (!atomic_cmpxchg(&q_indicators[i].count, 0, 1))
54 return &q_indicators[i].ind;
55
56 /* use the shared indicator */
57 atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
58 return &q_indicators[TIQDIO_SHARED_IND].ind;
59 }
60
put_indicator(u32 * addr)61 static void put_indicator(u32 *addr)
62 {
63 struct indicator_t *ind = container_of(addr, struct indicator_t, ind);
64
65 if (!addr)
66 return;
67 atomic_dec(&ind->count);
68 }
69
references_shared_dsci(struct qdio_irq * irq_ptr)70 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
71 {
72 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
73 }
74
test_nonshared_ind(struct qdio_irq * irq_ptr)75 int test_nonshared_ind(struct qdio_irq *irq_ptr)
76 {
77 if (!is_thinint_irq(irq_ptr))
78 return 0;
79 if (references_shared_dsci(irq_ptr))
80 return 0;
81 if (*irq_ptr->dsci)
82 return 1;
83 else
84 return 0;
85 }
86
clear_shared_ind(void)87 static inline u32 clear_shared_ind(void)
88 {
89 if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
90 return 0;
91 return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
92 }
93
94 /**
95 * tiqdio_thinint_handler - thin interrupt handler for qdio
96 * @airq: pointer to adapter interrupt descriptor
97 * @tpi_info: interrupt information (e.g. floating vs directed -- unused)
98 */
tiqdio_thinint_handler(struct airq_struct * airq,struct tpi_info * tpi_info)99 static void tiqdio_thinint_handler(struct airq_struct *airq,
100 struct tpi_info *tpi_info)
101 {
102 u64 irq_time = get_lowcore()->int_clock;
103 u32 si_used = clear_shared_ind();
104 struct qdio_irq *irq;
105
106 last_ai_time = irq_time;
107 inc_irq_stat(IRQIO_QAI);
108
109 /* protect tiq_list entries, only changed in activate or shutdown */
110 rcu_read_lock();
111
112 list_for_each_entry_rcu(irq, &tiq_list, entry) {
113 /* only process queues from changed sets */
114 if (unlikely(references_shared_dsci(irq))) {
115 if (!si_used)
116 continue;
117 } else {
118 if (!*irq->dsci)
119 continue;
120
121 xchg(irq->dsci, 0);
122 }
123
124 qdio_deliver_irq(irq);
125 irq->last_data_irq_time = irq_time;
126
127 QDIO_PERF_STAT_INC(irq, adapter_int);
128 }
129 rcu_read_unlock();
130 }
131
132 static struct airq_struct tiqdio_airq = {
133 .handler = tiqdio_thinint_handler,
134 .isc = QDIO_AIRQ_ISC,
135 };
136
set_subchannel_ind(struct qdio_irq * irq_ptr,int reset)137 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
138 {
139 struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page;
140 dma64_t summary_indicator_addr, subchannel_indicator_addr;
141 int rc;
142
143 if (reset) {
144 summary_indicator_addr = 0;
145 subchannel_indicator_addr = 0;
146 } else {
147 summary_indicator_addr = virt_to_dma64(tiqdio_airq.lsi_ptr);
148 subchannel_indicator_addr = virt_to_dma64(irq_ptr->dsci);
149 }
150
151 rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr,
152 subchannel_indicator_addr, tiqdio_airq.isc);
153 if (rc) {
154 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
155 scssc->response.code);
156 goto out;
157 }
158
159 DBF_EVENT("setscind");
160 DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr));
161 DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr));
162 out:
163 return rc;
164 }
165
qdio_establish_thinint(struct qdio_irq * irq_ptr)166 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
167 {
168 int rc;
169
170 if (!is_thinint_irq(irq_ptr))
171 return 0;
172
173 irq_ptr->dsci = get_indicator();
174 DBF_HEX(&irq_ptr->dsci, sizeof(void *));
175
176 rc = set_subchannel_ind(irq_ptr, 0);
177 if (rc) {
178 put_indicator(irq_ptr->dsci);
179 return rc;
180 }
181
182 mutex_lock(&tiq_list_lock);
183 list_add_rcu(&irq_ptr->entry, &tiq_list);
184 mutex_unlock(&tiq_list_lock);
185 return 0;
186 }
187
qdio_shutdown_thinint(struct qdio_irq * irq_ptr)188 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
189 {
190 if (!is_thinint_irq(irq_ptr))
191 return;
192
193 mutex_lock(&tiq_list_lock);
194 list_del_rcu(&irq_ptr->entry);
195 mutex_unlock(&tiq_list_lock);
196 synchronize_rcu();
197
198 /* reset adapter interrupt indicators */
199 set_subchannel_ind(irq_ptr, 1);
200 put_indicator(irq_ptr->dsci);
201 }
202
qdio_thinint_init(void)203 int __init qdio_thinint_init(void)
204 {
205 int rc;
206
207 q_indicators = kcalloc(TIQDIO_NR_INDICATORS, sizeof(struct indicator_t),
208 GFP_KERNEL);
209 if (!q_indicators)
210 return -ENOMEM;
211
212 rc = register_adapter_interrupt(&tiqdio_airq);
213 if (rc) {
214 DBF_EVENT("RTI:%x", rc);
215 kfree(q_indicators);
216 return rc;
217 }
218 return 0;
219 }
220
qdio_thinint_exit(void)221 void __exit qdio_thinint_exit(void)
222 {
223 WARN_ON(!list_empty(&tiq_list));
224 unregister_adapter_interrupt(&tiqdio_airq);
225 kfree(q_indicators);
226 }
227