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1// SPDX-License-Identifier: GPL-2.0-or-later
2
3/*
4 * IBM ASM Service Processor Device Driver
5 *
6 * Copyright (C) IBM Corporation, 2004
7 *
8 * Author: Max Asböck <amax@us.ibm.com>
9 */
10
11#include <linux/sched.h>
12#include <linux/slab.h>
13#include "ibmasm.h"
14#include "lowlevel.h"
15
16/*
17 * ASM service processor event handling routines.
18 *
19 * Events are signalled to the device drivers through interrupts.
20 * They have the format of dot commands, with the type field set to
21 * sp_event.
22 * The driver does not interpret the events, it simply stores them in a
23 * circular buffer.
24 */
25
26static void wake_up_event_readers(struct service_processor *sp)
27{
28 struct event_reader *reader;
29
30 list_for_each_entry(reader, &sp->event_buffer->readers, node)
31 wake_up_interruptible(&reader->wait);
32}
33
34/*
35 * receive_event
36 * Called by the interrupt handler when a dot command of type sp_event is
37 * received.
38 * Store the event in the circular event buffer, wake up any sleeping
39 * event readers.
40 * There is no reader marker in the buffer, therefore readers are
41 * responsible for keeping up with the writer, or they will lose events.
42 */
43void ibmasm_receive_event(struct service_processor *sp, void *data, unsigned int data_size)
44{
45 struct event_buffer *buffer = sp->event_buffer;
46 struct ibmasm_event *event;
47 unsigned long flags;
48
49 data_size = min(data_size, IBMASM_EVENT_MAX_SIZE);
50
51 spin_lock_irqsave(&sp->lock, flags);
52 /* copy the event into the next slot in the circular buffer */
53 event = &buffer->events[buffer->next_index];
54 memcpy_fromio(event->data, data, data_size);
55 event->data_size = data_size;
56 event->serial_number = buffer->next_serial_number;
57
58 /* advance indices in the buffer */
59 buffer->next_index = (buffer->next_index + 1) % IBMASM_NUM_EVENTS;
60 buffer->next_serial_number++;
61 spin_unlock_irqrestore(&sp->lock, flags);
62
63 wake_up_event_readers(sp);
64}
65
66static inline int event_available(struct event_buffer *b, struct event_reader *r)
67{
68 return (r->next_serial_number < b->next_serial_number);
69}
70
71/*
72 * get_next_event
73 * Called by event readers (initiated from user space through the file
74 * system).
75 * Sleeps until a new event is available.
76 */
77int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *reader)
78{
79 struct event_buffer *buffer = sp->event_buffer;
80 struct ibmasm_event *event;
81 unsigned int index;
82 unsigned long flags;
83
84 reader->cancelled = 0;
85
86 if (wait_event_interruptible(reader->wait,
87 event_available(buffer, reader) || reader->cancelled))
88 return -ERESTARTSYS;
89
90 if (!event_available(buffer, reader))
91 return 0;
92
93 spin_lock_irqsave(&sp->lock, flags);
94
95 index = buffer->next_index;
96 event = &buffer->events[index];
97 while (event->serial_number < reader->next_serial_number) {
98 index = (index + 1) % IBMASM_NUM_EVENTS;
99 event = &buffer->events[index];
100 }
101 memcpy(reader->data, event->data, event->data_size);
102 reader->data_size = event->data_size;
103 reader->next_serial_number = event->serial_number + 1;
104
105 spin_unlock_irqrestore(&sp->lock, flags);
106
107 return event->data_size;
108}
109
110void ibmasm_cancel_next_event(struct event_reader *reader)
111{
112 reader->cancelled = 1;
113 wake_up_interruptible(&reader->wait);
114}
115
116void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader)
117{
118 unsigned long flags;
119
120 reader->next_serial_number = sp->event_buffer->next_serial_number;
121 init_waitqueue_head(&reader->wait);
122 spin_lock_irqsave(&sp->lock, flags);
123 list_add(&reader->node, &sp->event_buffer->readers);
124 spin_unlock_irqrestore(&sp->lock, flags);
125}
126
127void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader)
128{
129 unsigned long flags;
130
131 spin_lock_irqsave(&sp->lock, flags);
132 list_del(&reader->node);
133 spin_unlock_irqrestore(&sp->lock, flags);
134}
135
136int ibmasm_event_buffer_init(struct service_processor *sp)
137{
138 struct event_buffer *buffer;
139 struct ibmasm_event *event;
140 int i;
141
142 buffer = kmalloc(sizeof(struct event_buffer), GFP_KERNEL);
143 if (!buffer)
144 return -ENOMEM;
145
146 buffer->next_index = 0;
147 buffer->next_serial_number = 1;
148
149 event = buffer->events;
150 for (i=0; i<IBMASM_NUM_EVENTS; i++, event++)
151 event->serial_number = 0;
152
153 INIT_LIST_HEAD(&buffer->readers);
154
155 sp->event_buffer = buffer;
156
157 return 0;
158}
159
160void ibmasm_event_buffer_exit(struct service_processor *sp)
161{
162 kfree(sp->event_buffer);
163}
1
2/*
3 * IBM ASM Service Processor Device Driver
4 *
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.
9 *
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.
14 *
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.
18 *
19 * Copyright (C) IBM Corporation, 2004
20 *
21 * Author: Max Asböck <amax@us.ibm.com>
22 *
23 */
24
25#include <linux/sched.h>
26#include <linux/slab.h>
27#include "ibmasm.h"
28#include "lowlevel.h"
29
30/*
31 * ASM service processor event handling routines.
32 *
33 * Events are signalled to the device drivers through interrupts.
34 * They have the format of dot commands, with the type field set to
35 * sp_event.
36 * The driver does not interpret the events, it simply stores them in a
37 * circular buffer.
38 */
39
40static void wake_up_event_readers(struct service_processor *sp)
41{
42 struct event_reader *reader;
43
44 list_for_each_entry(reader, &sp->event_buffer->readers, node)
45 wake_up_interruptible(&reader->wait);
46}
47
48/**
49 * receive_event
50 * Called by the interrupt handler when a dot command of type sp_event is
51 * received.
52 * Store the event in the circular event buffer, wake up any sleeping
53 * event readers.
54 * There is no reader marker in the buffer, therefore readers are
55 * responsible for keeping up with the writer, or they will lose events.
56 */
57void ibmasm_receive_event(struct service_processor *sp, void *data, unsigned int data_size)
58{
59 struct event_buffer *buffer = sp->event_buffer;
60 struct ibmasm_event *event;
61 unsigned long flags;
62
63 data_size = min(data_size, IBMASM_EVENT_MAX_SIZE);
64
65 spin_lock_irqsave(&sp->lock, flags);
66 /* copy the event into the next slot in the circular buffer */
67 event = &buffer->events[buffer->next_index];
68 memcpy_fromio(event->data, data, data_size);
69 event->data_size = data_size;
70 event->serial_number = buffer->next_serial_number;
71
72 /* advance indices in the buffer */
73 buffer->next_index = (buffer->next_index + 1) % IBMASM_NUM_EVENTS;
74 buffer->next_serial_number++;
75 spin_unlock_irqrestore(&sp->lock, flags);
76
77 wake_up_event_readers(sp);
78}
79
80static inline int event_available(struct event_buffer *b, struct event_reader *r)
81{
82 return (r->next_serial_number < b->next_serial_number);
83}
84
85/**
86 * get_next_event
87 * Called by event readers (initiated from user space through the file
88 * system).
89 * Sleeps until a new event is available.
90 */
91int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *reader)
92{
93 struct event_buffer *buffer = sp->event_buffer;
94 struct ibmasm_event *event;
95 unsigned int index;
96 unsigned long flags;
97
98 reader->cancelled = 0;
99
100 if (wait_event_interruptible(reader->wait,
101 event_available(buffer, reader) || reader->cancelled))
102 return -ERESTARTSYS;
103
104 if (!event_available(buffer, reader))
105 return 0;
106
107 spin_lock_irqsave(&sp->lock, flags);
108
109 index = buffer->next_index;
110 event = &buffer->events[index];
111 while (event->serial_number < reader->next_serial_number) {
112 index = (index + 1) % IBMASM_NUM_EVENTS;
113 event = &buffer->events[index];
114 }
115 memcpy(reader->data, event->data, event->data_size);
116 reader->data_size = event->data_size;
117 reader->next_serial_number = event->serial_number + 1;
118
119 spin_unlock_irqrestore(&sp->lock, flags);
120
121 return event->data_size;
122}
123
124void ibmasm_cancel_next_event(struct event_reader *reader)
125{
126 reader->cancelled = 1;
127 wake_up_interruptible(&reader->wait);
128}
129
130void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader)
131{
132 unsigned long flags;
133
134 reader->next_serial_number = sp->event_buffer->next_serial_number;
135 init_waitqueue_head(&reader->wait);
136 spin_lock_irqsave(&sp->lock, flags);
137 list_add(&reader->node, &sp->event_buffer->readers);
138 spin_unlock_irqrestore(&sp->lock, flags);
139}
140
141void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader)
142{
143 unsigned long flags;
144
145 spin_lock_irqsave(&sp->lock, flags);
146 list_del(&reader->node);
147 spin_unlock_irqrestore(&sp->lock, flags);
148}
149
150int ibmasm_event_buffer_init(struct service_processor *sp)
151{
152 struct event_buffer *buffer;
153 struct ibmasm_event *event;
154 int i;
155
156 buffer = kmalloc(sizeof(struct event_buffer), GFP_KERNEL);
157 if (!buffer)
158 return -ENOMEM;
159
160 buffer->next_index = 0;
161 buffer->next_serial_number = 1;
162
163 event = buffer->events;
164 for (i=0; i<IBMASM_NUM_EVENTS; i++, event++)
165 event->serial_number = 0;
166
167 INIT_LIST_HEAD(&buffer->readers);
168
169 sp->event_buffer = buffer;
170
171 return 0;
172}
173
174void ibmasm_event_buffer_exit(struct service_processor *sp)
175{
176 kfree(sp->event_buffer);
177}