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 */ 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 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 69 void tiqdio_add_device(struct qdio_irq *irq_ptr) 70 { 71 mutex_lock(&tiq_list_lock); 72 list_add_rcu(&irq_ptr->entry, &tiq_list); 73 mutex_unlock(&tiq_list_lock); 74 } 75 76 void tiqdio_remove_device(struct qdio_irq *irq_ptr) 77 { 78 mutex_lock(&tiq_list_lock); 79 list_del_rcu(&irq_ptr->entry); 80 mutex_unlock(&tiq_list_lock); 81 synchronize_rcu(); 82 INIT_LIST_HEAD(&irq_ptr->entry); 83 } 84 85 static inline int references_shared_dsci(struct qdio_irq *irq_ptr) 86 { 87 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind; 88 } 89 90 int test_nonshared_ind(struct qdio_irq *irq_ptr) 91 { 92 if (!is_thinint_irq(irq_ptr)) 93 return 0; 94 if (references_shared_dsci(irq_ptr)) 95 return 0; 96 if (*irq_ptr->dsci) 97 return 1; 98 else 99 return 0; 100 } 101 102 static inline u32 clear_shared_ind(void) 103 { 104 if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) 105 return 0; 106 return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0); 107 } 108 109 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq) 110 { 111 struct qdio_q *q; 112 int i; 113 114 if (!references_shared_dsci(irq)) 115 xchg(irq->dsci, 0); 116 117 if (irq->irq_poll) { 118 if (!test_and_set_bit(QDIO_IRQ_DISABLED, &irq->poll_state)) 119 irq->irq_poll(irq->cdev, irq->int_parm); 120 else 121 QDIO_PERF_STAT_INC(irq, int_discarded); 122 123 return; 124 } 125 126 for_each_input_queue(irq, q, i) { 127 /* 128 * Call inbound processing but not directly 129 * since that could starve other thinint queues. 130 */ 131 tasklet_schedule(&q->tasklet); 132 } 133 } 134 135 /** 136 * tiqdio_thinint_handler - thin interrupt handler for qdio 137 * @airq: pointer to adapter interrupt descriptor 138 * @floating: flag to recognize floating vs. directed interrupts (unused) 139 */ 140 static void tiqdio_thinint_handler(struct airq_struct *airq, bool floating) 141 { 142 u32 si_used = clear_shared_ind(); 143 struct qdio_irq *irq; 144 145 last_ai_time = S390_lowcore.int_clock; 146 inc_irq_stat(IRQIO_QAI); 147 148 /* protect tiq_list entries, only changed in activate or shutdown */ 149 rcu_read_lock(); 150 151 list_for_each_entry_rcu(irq, &tiq_list, entry) { 152 /* only process queues from changed sets */ 153 if (unlikely(references_shared_dsci(irq))) { 154 if (!si_used) 155 continue; 156 } else if (!*irq->dsci) 157 continue; 158 159 tiqdio_call_inq_handlers(irq); 160 161 QDIO_PERF_STAT_INC(irq, adapter_int); 162 } 163 rcu_read_unlock(); 164 } 165 166 static struct airq_struct tiqdio_airq = { 167 .handler = tiqdio_thinint_handler, 168 .isc = QDIO_AIRQ_ISC, 169 }; 170 171 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset) 172 { 173 struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page; 174 u64 summary_indicator_addr, subchannel_indicator_addr; 175 int rc; 176 177 if (reset) { 178 summary_indicator_addr = 0; 179 subchannel_indicator_addr = 0; 180 } else { 181 summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr); 182 subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci); 183 } 184 185 rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr, 186 subchannel_indicator_addr, tiqdio_airq.isc); 187 if (rc) { 188 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no, 189 scssc->response.code); 190 goto out; 191 } 192 193 DBF_EVENT("setscind"); 194 DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr)); 195 DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr)); 196 out: 197 return rc; 198 } 199 200 /* allocate non-shared indicators and shared indicator */ 201 int __init tiqdio_allocate_memory(void) 202 { 203 q_indicators = kcalloc(TIQDIO_NR_INDICATORS, 204 sizeof(struct indicator_t), 205 GFP_KERNEL); 206 if (!q_indicators) 207 return -ENOMEM; 208 return 0; 209 } 210 211 void tiqdio_free_memory(void) 212 { 213 kfree(q_indicators); 214 } 215 216 int __init tiqdio_register_thinints(void) 217 { 218 int rc; 219 220 rc = register_adapter_interrupt(&tiqdio_airq); 221 if (rc) { 222 DBF_EVENT("RTI:%x", rc); 223 return rc; 224 } 225 return 0; 226 } 227 228 int qdio_establish_thinint(struct qdio_irq *irq_ptr) 229 { 230 if (!is_thinint_irq(irq_ptr)) 231 return 0; 232 return set_subchannel_ind(irq_ptr, 0); 233 } 234 235 void qdio_setup_thinint(struct qdio_irq *irq_ptr) 236 { 237 if (!is_thinint_irq(irq_ptr)) 238 return; 239 irq_ptr->dsci = get_indicator(); 240 DBF_HEX(&irq_ptr->dsci, sizeof(void *)); 241 } 242 243 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr) 244 { 245 if (!is_thinint_irq(irq_ptr)) 246 return; 247 248 /* reset adapter interrupt indicators */ 249 set_subchannel_ind(irq_ptr, 1); 250 put_indicator(irq_ptr->dsci); 251 } 252 253 void __exit tiqdio_unregister_thinints(void) 254 { 255 WARN_ON(!list_empty(&tiq_list)); 256 unregister_adapter_interrupt(&tiqdio_airq); 257 } 258