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1da177e4 LT |
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 | * | |
d36b6910 | 21 | * Author: Max Asböck <amax@us.ibm.com> |
1da177e4 LT |
22 | * |
23 | */ | |
24 | ||
d43c36dc | 25 | #include <linux/sched.h> |
5a0e3ad6 | 26 | #include <linux/slab.h> |
1da177e4 | 27 | #include "ibmasm.h" |
b8acb808 | 28 | #include "lowlevel.h" |
1da177e4 LT |
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 | ||
1da177e4 LT |
40 | static 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 | |
3a4e3678 | 55 | * responsible for keeping up with the writer, or they will lose events. |
3110dc7a | 56 | */ |
1da177e4 LT |
57 | void 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]; | |
b8acb808 | 68 | memcpy_fromio(event->data, data, data_size); |
1da177e4 LT |
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 | ||
80 | static inline int event_available(struct event_buffer *b, struct event_reader *r) | |
81 | { | |
3110dc7a | 82 | return (r->next_serial_number < b->next_serial_number); |
1da177e4 LT |
83 | } |
84 | ||
85 | /** | |
86 | * get_next_event | |
87 | * Called by event readers (initiated from user space through the file | |
3110dc7a | 88 | * system). |
1da177e4 LT |
89 | * Sleeps until a new event is available. |
90 | */ | |
91 | int 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 | ||
b8acb808 MA |
98 | reader->cancelled = 0; |
99 | ||
100 | if (wait_event_interruptible(reader->wait, | |
101 | event_available(buffer, reader) || reader->cancelled)) | |
1da177e4 LT |
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 | ||
b8acb808 MA |
124 | void ibmasm_cancel_next_event(struct event_reader *reader) |
125 | { | |
126 | reader->cancelled = 1; | |
127 | wake_up_interruptible(&reader->wait); | |
128 | } | |
129 | ||
1da177e4 LT |
130 | void 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 | ||
141 | void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader) | |
142 | { | |
143 | unsigned long flags; | |
144 | ||
1da177e4 LT |
145 | spin_lock_irqsave(&sp->lock, flags); |
146 | list_del(&reader->node); | |
147 | spin_unlock_irqrestore(&sp->lock, flags); | |
148 | } | |
149 | ||
150 | int 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) | |
f403f85f | 158 | return -ENOMEM; |
1da177e4 LT |
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 | ||
174 | void ibmasm_event_buffer_exit(struct service_processor *sp) | |
175 | { | |
1da177e4 LT |
176 | kfree(sp->event_buffer); |
177 | } |