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1// SPDX-License-Identifier: GPL-2.02/*3 * Channel report handling code4 *5 * Copyright IBM Corp. 2000, 20096 * Author(s): Ingo Adlung <adlung@de.ibm.com>,7 * Martin Schwidefsky <schwidefsky@de.ibm.com>,8 * Cornelia Huck <cornelia.huck@de.ibm.com>,9 */10 11#include <linux/mutex.h>12#include <linux/kthread.h>13#include <linux/init.h>14#include <linux/wait.h>15#include <asm/ctlreg.h>16#include <asm/crw.h>17#include "ioasm.h"18 19static DEFINE_MUTEX(crw_handler_mutex);20static crw_handler_t crw_handlers[NR_RSCS];21static atomic_t crw_nr_req = ATOMIC_INIT(0);22static DECLARE_WAIT_QUEUE_HEAD(crw_handler_wait_q);23 24/**25 * crw_register_handler() - register a channel report word handler26 * @rsc: reporting source code to handle27 * @handler: handler to be registered28 *29 * Returns %0 on success and a negative error value otherwise.30 */31int crw_register_handler(int rsc, crw_handler_t handler)32{33 int rc = 0;34 35 if ((rsc < 0) || (rsc >= NR_RSCS))36 return -EINVAL;37 mutex_lock(&crw_handler_mutex);38 if (crw_handlers[rsc])39 rc = -EBUSY;40 else41 crw_handlers[rsc] = handler;42 mutex_unlock(&crw_handler_mutex);43 return rc;44}45 46/**47 * crw_unregister_handler() - unregister a channel report word handler48 * @rsc: reporting source code to handle49 */50void crw_unregister_handler(int rsc)51{52 if ((rsc < 0) || (rsc >= NR_RSCS))53 return;54 mutex_lock(&crw_handler_mutex);55 crw_handlers[rsc] = NULL;56 mutex_unlock(&crw_handler_mutex);57}58 59/*60 * Retrieve CRWs and call function to handle event.61 */62static int crw_collect_info(void *unused)63{64 struct crw crw[2];65 int ccode, signal;66 unsigned int chain;67 68repeat:69 signal = wait_event_interruptible(crw_handler_wait_q,70 atomic_read(&crw_nr_req) > 0);71 if (unlikely(signal))72 atomic_inc(&crw_nr_req);73 chain = 0;74 while (1) {75 crw_handler_t handler;76 77 if (unlikely(chain > 1)) {78 struct crw tmp_crw;79 80 printk(KERN_WARNING"%s: Code does not support more "81 "than two chained crws; please report to "82 "linux390@de.ibm.com!\n", __func__);83 ccode = stcrw(&tmp_crw);84 printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "85 "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",86 __func__, tmp_crw.slct, tmp_crw.oflw,87 tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,88 tmp_crw.erc, tmp_crw.rsid);89 printk(KERN_WARNING"%s: This was crw number %x in the "90 "chain\n", __func__, chain);91 if (ccode != 0)92 break;93 chain = tmp_crw.chn ? chain + 1 : 0;94 continue;95 }96 ccode = stcrw(&crw[chain]);97 if (ccode != 0)98 break;99 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "100 "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",101 crw[chain].slct, crw[chain].oflw, crw[chain].chn,102 crw[chain].rsc, crw[chain].anc, crw[chain].erc,103 crw[chain].rsid);104 /* Check for overflows. */105 if (crw[chain].oflw) {106 int i;107 108 pr_debug("%s: crw overflow detected!\n", __func__);109 mutex_lock(&crw_handler_mutex);110 for (i = 0; i < NR_RSCS; i++) {111 if (crw_handlers[i])112 crw_handlers[i](NULL, NULL, 1);113 }114 mutex_unlock(&crw_handler_mutex);115 chain = 0;116 continue;117 }118 if (crw[0].chn && !chain) {119 chain++;120 continue;121 }122 mutex_lock(&crw_handler_mutex);123 handler = crw_handlers[crw[chain].rsc];124 if (handler)125 handler(&crw[0], chain ? &crw[1] : NULL, 0);126 mutex_unlock(&crw_handler_mutex);127 /* chain is always 0 or 1 here. */128 chain = crw[chain].chn ? chain + 1 : 0;129 }130 if (atomic_dec_and_test(&crw_nr_req))131 wake_up(&crw_handler_wait_q);132 goto repeat;133 return 0;134}135 136void crw_handle_channel_report(void)137{138 atomic_inc(&crw_nr_req);139 wake_up(&crw_handler_wait_q);140}141 142void crw_wait_for_channel_report(void)143{144 crw_handle_channel_report();145 wait_event(crw_handler_wait_q, atomic_read(&crw_nr_req) == 0);146}147 148/*149 * Machine checks for the channel subsystem must be enabled150 * after the channel subsystem is initialized151 */152static int __init crw_machine_check_init(void)153{154 struct task_struct *task;155 156 task = kthread_run(crw_collect_info, NULL, "kmcheck");157 if (IS_ERR(task))158 return PTR_ERR(task);159 system_ctl_set_bit(14, CR14_CHANNEL_REPORT_SUBMASK_BIT);160 return 0;161}162device_initcall(crw_machine_check_init);163