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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright IBM Corp. 2000, 20094 * 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 indicator28 */29#define TIQDIO_NR_NONSHARED_IND 6330#define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)31#define TIQDIO_SHARED_IND 6332 33/* device state change indicators */34struct 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 */40static LIST_HEAD(tiq_list);41static DEFINE_MUTEX(tiq_list_lock);42 43static struct indicator_t *q_indicators;44 45u64 last_ai_time;46 47/* returns addr for the device state change indicator */48static 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 61static 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 70static inline int references_shared_dsci(struct qdio_irq *irq_ptr)71{72 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;73}74 75int 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 else84 return 0;85}86 87static 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 qdio96 * @airq: pointer to adapter interrupt descriptor97 * @tpi_info: interrupt information (e.g. floating vs directed -- unused)98 */99static 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 132static struct airq_struct tiqdio_airq = {133 .handler = tiqdio_thinint_handler,134 .isc = QDIO_AIRQ_ISC,135};136 137static 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));162out:163 return rc;164}165 166int 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 188void 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 203int __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 221void __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