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-rw-r--r--drivers/misc/ibmasm/event.c163
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/misc/ibmasm/event.c b/drivers/misc/ibmasm/event.c
new file mode 100644
index 0000000000..40ce75f897
--- /dev/null
+++ b/drivers/misc/ibmasm/event.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/*
+ * IBM ASM Service Processor Device Driver
+ *
+ * Copyright (C) IBM Corporation, 2004
+ *
+ * Author: Max Asböck <amax@us.ibm.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include "ibmasm.h"
+#include "lowlevel.h"
+
+/*
+ * ASM service processor event handling routines.
+ *
+ * Events are signalled to the device drivers through interrupts.
+ * They have the format of dot commands, with the type field set to
+ * sp_event.
+ * The driver does not interpret the events, it simply stores them in a
+ * circular buffer.
+ */
+
+static void wake_up_event_readers(struct service_processor *sp)
+{
+ struct event_reader *reader;
+
+ list_for_each_entry(reader, &sp->event_buffer->readers, node)
+ wake_up_interruptible(&reader->wait);
+}
+
+/*
+ * receive_event
+ * Called by the interrupt handler when a dot command of type sp_event is
+ * received.
+ * Store the event in the circular event buffer, wake up any sleeping
+ * event readers.
+ * There is no reader marker in the buffer, therefore readers are
+ * responsible for keeping up with the writer, or they will lose events.
+ */
+void ibmasm_receive_event(struct service_processor *sp, void *data, unsigned int data_size)
+{
+ struct event_buffer *buffer = sp->event_buffer;
+ struct ibmasm_event *event;
+ unsigned long flags;
+
+ data_size = min(data_size, IBMASM_EVENT_MAX_SIZE);
+
+ spin_lock_irqsave(&sp->lock, flags);
+ /* copy the event into the next slot in the circular buffer */
+ event = &buffer->events[buffer->next_index];
+ memcpy_fromio(event->data, data, data_size);
+ event->data_size = data_size;
+ event->serial_number = buffer->next_serial_number;
+
+ /* advance indices in the buffer */
+ buffer->next_index = (buffer->next_index + 1) % IBMASM_NUM_EVENTS;
+ buffer->next_serial_number++;
+ spin_unlock_irqrestore(&sp->lock, flags);
+
+ wake_up_event_readers(sp);
+}
+
+static inline int event_available(struct event_buffer *b, struct event_reader *r)
+{
+ return (r->next_serial_number < b->next_serial_number);
+}
+
+/*
+ * get_next_event
+ * Called by event readers (initiated from user space through the file
+ * system).
+ * Sleeps until a new event is available.
+ */
+int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *reader)
+{
+ struct event_buffer *buffer = sp->event_buffer;
+ struct ibmasm_event *event;
+ unsigned int index;
+ unsigned long flags;
+
+ reader->cancelled = 0;
+
+ if (wait_event_interruptible(reader->wait,
+ event_available(buffer, reader) || reader->cancelled))
+ return -ERESTARTSYS;
+
+ if (!event_available(buffer, reader))
+ return 0;
+
+ spin_lock_irqsave(&sp->lock, flags);
+
+ index = buffer->next_index;
+ event = &buffer->events[index];
+ while (event->serial_number < reader->next_serial_number) {
+ index = (index + 1) % IBMASM_NUM_EVENTS;
+ event = &buffer->events[index];
+ }
+ memcpy(reader->data, event->data, event->data_size);
+ reader->data_size = event->data_size;
+ reader->next_serial_number = event->serial_number + 1;
+
+ spin_unlock_irqrestore(&sp->lock, flags);
+
+ return event->data_size;
+}
+
+void ibmasm_cancel_next_event(struct event_reader *reader)
+{
+ reader->cancelled = 1;
+ wake_up_interruptible(&reader->wait);
+}
+
+void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader)
+{
+ unsigned long flags;
+
+ reader->next_serial_number = sp->event_buffer->next_serial_number;
+ init_waitqueue_head(&reader->wait);
+ spin_lock_irqsave(&sp->lock, flags);
+ list_add(&reader->node, &sp->event_buffer->readers);
+ spin_unlock_irqrestore(&sp->lock, flags);
+}
+
+void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&sp->lock, flags);
+ list_del(&reader->node);
+ spin_unlock_irqrestore(&sp->lock, flags);
+}
+
+int ibmasm_event_buffer_init(struct service_processor *sp)
+{
+ struct event_buffer *buffer;
+ struct ibmasm_event *event;
+ int i;
+
+ buffer = kmalloc(sizeof(struct event_buffer), GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+
+ buffer->next_index = 0;
+ buffer->next_serial_number = 1;
+
+ event = buffer->events;
+ for (i=0; i<IBMASM_NUM_EVENTS; i++, event++)
+ event->serial_number = 0;
+
+ INIT_LIST_HEAD(&buffer->readers);
+
+ sp->event_buffer = buffer;
+
+ return 0;
+}
+
+void ibmasm_event_buffer_exit(struct service_processor *sp)
+{
+ kfree(sp->event_buffer);
+}