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 */ 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 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 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 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 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 */ 99 static void tiqdio_thinint_handler(struct airq_struct *airq, 100 struct tpi_info *tpi_info) 101 { 102 u64 irq_time = S390_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 }; 136 137 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 } 165 166 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 } 187 188 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 } 202 203 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 } 220 221 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