1 files changed, 169 insertions, 0 deletions

diff --git a/drivers/misc/ibmasm/event.c b/drivers/misc/ibmasm/event.c
new file mode 100644
index 000000000000..e100f34f1587
--- /dev/null
+++ b/drivers/misc/ibmasm/event.c
@@ -0,0 +1,169 @@
+
+/*
+ * IBM ASM Service Processor Device Driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2004
+ *
+ * Author: Max Asböck <amax@us.ibm.com> 
+ *
+ */
+
+#include "ibmasm.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 loose 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(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;
+
+        if (wait_event_interruptible(reader->wait, event_available(buffer, reader)))
+                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_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;
+
+        wake_up_interruptible(&reader->wait);
+
+        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 1;
+
+        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)
+{
+        wake_up_event_readers(sp);
+        kfree(sp->event_buffer);
+}