pcmcia: CompactFlash driver for PA Semi Electra boards
[pv_ops_mirror.git] / drivers / misc / ibmasm / event.c
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2 /*
3 * IBM ASM Service Processor Device Driver
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * Copyright (C) IBM Corporation, 2004
21 * Author: Max Asböck <amax@us.ibm.com>
25 #include "ibmasm.h"
26 #include "lowlevel.h"
29 * ASM service processor event handling routines.
31 * Events are signalled to the device drivers through interrupts.
32 * They have the format of dot commands, with the type field set to
33 * sp_event.
34 * The driver does not interpret the events, it simply stores them in a
35 * circular buffer.
38 static void wake_up_event_readers(struct service_processor *sp)
40 struct event_reader *reader;
42 list_for_each_entry(reader, &sp->event_buffer->readers, node)
43 wake_up_interruptible(&reader->wait);
46 /**
47 * receive_event
48 * Called by the interrupt handler when a dot command of type sp_event is
49 * received.
50 * Store the event in the circular event buffer, wake up any sleeping
51 * event readers.
52 * There is no reader marker in the buffer, therefore readers are
53 * responsible for keeping up with the writer, or they will loose events.
55 void ibmasm_receive_event(struct service_processor *sp, void *data, unsigned int data_size)
57 struct event_buffer *buffer = sp->event_buffer;
58 struct ibmasm_event *event;
59 unsigned long flags;
61 data_size = min(data_size, IBMASM_EVENT_MAX_SIZE);
63 spin_lock_irqsave(&sp->lock, flags);
64 /* copy the event into the next slot in the circular buffer */
65 event = &buffer->events[buffer->next_index];
66 memcpy_fromio(event->data, data, data_size);
67 event->data_size = data_size;
68 event->serial_number = buffer->next_serial_number;
70 /* advance indices in the buffer */
71 buffer->next_index = (buffer->next_index + 1) % IBMASM_NUM_EVENTS;
72 buffer->next_serial_number++;
73 spin_unlock_irqrestore(&sp->lock, flags);
75 wake_up_event_readers(sp);
78 static inline int event_available(struct event_buffer *b, struct event_reader *r)
80 return (r->next_serial_number < b->next_serial_number);
83 /**
84 * get_next_event
85 * Called by event readers (initiated from user space through the file
86 * system).
87 * Sleeps until a new event is available.
89 int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *reader)
91 struct event_buffer *buffer = sp->event_buffer;
92 struct ibmasm_event *event;
93 unsigned int index;
94 unsigned long flags;
96 reader->cancelled = 0;
98 if (wait_event_interruptible(reader->wait,
99 event_available(buffer, reader) || reader->cancelled))
100 return -ERESTARTSYS;
102 if (!event_available(buffer, reader))
103 return 0;
105 spin_lock_irqsave(&sp->lock, flags);
107 index = buffer->next_index;
108 event = &buffer->events[index];
109 while (event->serial_number < reader->next_serial_number) {
110 index = (index + 1) % IBMASM_NUM_EVENTS;
111 event = &buffer->events[index];
113 memcpy(reader->data, event->data, event->data_size);
114 reader->data_size = event->data_size;
115 reader->next_serial_number = event->serial_number + 1;
117 spin_unlock_irqrestore(&sp->lock, flags);
119 return event->data_size;
122 void ibmasm_cancel_next_event(struct event_reader *reader)
124 reader->cancelled = 1;
125 wake_up_interruptible(&reader->wait);
128 void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader)
130 unsigned long flags;
132 reader->next_serial_number = sp->event_buffer->next_serial_number;
133 init_waitqueue_head(&reader->wait);
134 spin_lock_irqsave(&sp->lock, flags);
135 list_add(&reader->node, &sp->event_buffer->readers);
136 spin_unlock_irqrestore(&sp->lock, flags);
139 void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader)
141 unsigned long flags;
143 spin_lock_irqsave(&sp->lock, flags);
144 list_del(&reader->node);
145 spin_unlock_irqrestore(&sp->lock, flags);
148 int ibmasm_event_buffer_init(struct service_processor *sp)
150 struct event_buffer *buffer;
151 struct ibmasm_event *event;
152 int i;
154 buffer = kmalloc(sizeof(struct event_buffer), GFP_KERNEL);
155 if (!buffer)
156 return 1;
158 buffer->next_index = 0;
159 buffer->next_serial_number = 1;
161 event = buffer->events;
162 for (i=0; i<IBMASM_NUM_EVENTS; i++, event++)
163 event->serial_number = 0;
165 INIT_LIST_HEAD(&buffer->readers);
167 sp->event_buffer = buffer;
169 return 0;
172 void ibmasm_event_buffer_exit(struct service_processor *sp)
174 kfree(sp->event_buffer);