aboutsummaryrefslogtreecommitdiff
path: root/drivers/misc/ibmasm/event.c
blob: fe1e819235a49c18938a775d4f9d2fb75176abfc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
/*
 * 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 Asb�ck <amax@us.ibm.com> 
 *
 */

#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 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_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 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)
{
	kfree(sp->event_buffer);
}