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-rw-r--r--drivers/s390/cio/crw.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/drivers/s390/cio/crw.c b/drivers/s390/cio/crw.c
new file mode 100644
index 000000000..7b02a6349
--- /dev/null
+++ b/drivers/s390/cio/crw.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Channel report handling code
+ *
+ * Copyright IBM Corp. 2000, 2009
+ * Author(s): Ingo Adlung <adlung@de.ibm.com>,
+ * Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ * Cornelia Huck <cornelia.huck@de.ibm.com>,
+ */
+
+#include <linux/mutex.h>
+#include <linux/kthread.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <asm/crw.h>
+#include <asm/ctl_reg.h>
+#include "ioasm.h"
+
+static DEFINE_MUTEX(crw_handler_mutex);
+static crw_handler_t crw_handlers[NR_RSCS];
+static atomic_t crw_nr_req = ATOMIC_INIT(0);
+static DECLARE_WAIT_QUEUE_HEAD(crw_handler_wait_q);
+
+/**
+ * crw_register_handler() - register a channel report word handler
+ * @rsc: reporting source code to handle
+ * @handler: handler to be registered
+ *
+ * Returns %0 on success and a negative error value otherwise.
+ */
+int crw_register_handler(int rsc, crw_handler_t handler)
+{
+ int rc = 0;
+
+ if ((rsc < 0) || (rsc >= NR_RSCS))
+ return -EINVAL;
+ mutex_lock(&crw_handler_mutex);
+ if (crw_handlers[rsc])
+ rc = -EBUSY;
+ else
+ crw_handlers[rsc] = handler;
+ mutex_unlock(&crw_handler_mutex);
+ return rc;
+}
+
+/**
+ * crw_unregister_handler() - unregister a channel report word handler
+ * @rsc: reporting source code to handle
+ */
+void crw_unregister_handler(int rsc)
+{
+ if ((rsc < 0) || (rsc >= NR_RSCS))
+ return;
+ mutex_lock(&crw_handler_mutex);
+ crw_handlers[rsc] = NULL;
+ mutex_unlock(&crw_handler_mutex);
+}
+
+/*
+ * Retrieve CRWs and call function to handle event.
+ */
+static int crw_collect_info(void *unused)
+{
+ struct crw crw[2];
+ int ccode, signal;
+ unsigned int chain;
+
+repeat:
+ signal = wait_event_interruptible(crw_handler_wait_q,
+ atomic_read(&crw_nr_req) > 0);
+ if (unlikely(signal))
+ atomic_inc(&crw_nr_req);
+ chain = 0;
+ while (1) {
+ crw_handler_t handler;
+
+ if (unlikely(chain > 1)) {
+ struct crw tmp_crw;
+
+ printk(KERN_WARNING"%s: Code does not support more "
+ "than two chained crws; please report to "
+ "linux390@de.ibm.com!\n", __func__);
+ ccode = stcrw(&tmp_crw);
+ printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
+ "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
+ __func__, tmp_crw.slct, tmp_crw.oflw,
+ tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
+ tmp_crw.erc, tmp_crw.rsid);
+ printk(KERN_WARNING"%s: This was crw number %x in the "
+ "chain\n", __func__, chain);
+ if (ccode != 0)
+ break;
+ chain = tmp_crw.chn ? chain + 1 : 0;
+ continue;
+ }
+ ccode = stcrw(&crw[chain]);
+ if (ccode != 0)
+ break;
+ printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
+ "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
+ crw[chain].slct, crw[chain].oflw, crw[chain].chn,
+ crw[chain].rsc, crw[chain].anc, crw[chain].erc,
+ crw[chain].rsid);
+ /* Check for overflows. */
+ if (crw[chain].oflw) {
+ int i;
+
+ pr_debug("%s: crw overflow detected!\n", __func__);
+ mutex_lock(&crw_handler_mutex);
+ for (i = 0; i < NR_RSCS; i++) {
+ if (crw_handlers[i])
+ crw_handlers[i](NULL, NULL, 1);
+ }
+ mutex_unlock(&crw_handler_mutex);
+ chain = 0;
+ continue;
+ }
+ if (crw[0].chn && !chain) {
+ chain++;
+ continue;
+ }
+ mutex_lock(&crw_handler_mutex);
+ handler = crw_handlers[crw[chain].rsc];
+ if (handler)
+ handler(&crw[0], chain ? &crw[1] : NULL, 0);
+ mutex_unlock(&crw_handler_mutex);
+ /* chain is always 0 or 1 here. */
+ chain = crw[chain].chn ? chain + 1 : 0;
+ }
+ if (atomic_dec_and_test(&crw_nr_req))
+ wake_up(&crw_handler_wait_q);
+ goto repeat;
+ return 0;
+}
+
+void crw_handle_channel_report(void)
+{
+ atomic_inc(&crw_nr_req);
+ wake_up(&crw_handler_wait_q);
+}
+
+void crw_wait_for_channel_report(void)
+{
+ crw_handle_channel_report();
+ wait_event(crw_handler_wait_q, atomic_read(&crw_nr_req) == 0);
+}
+
+/*
+ * Machine checks for the channel subsystem must be enabled
+ * after the channel subsystem is initialized
+ */
+static int __init crw_machine_check_init(void)
+{
+ struct task_struct *task;
+
+ task = kthread_run(crw_collect_info, NULL, "kmcheck");
+ if (IS_ERR(task))
+ return PTR_ERR(task);
+ ctl_set_bit(14, 28); /* enable channel report MCH */
+ return 0;
+}
+device_initcall(crw_machine_check_init);