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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | |
3 | /* | |
4 | * IBM ASM Service Processor Device Driver | |
5 | * | |
1da177e4 LT |
6 | * Copyright (C) IBM Corporation, 2004 |
7 | * | |
d36b6910 | 8 | * Author: Max Asböck <amax@us.ibm.com> |
1da177e4 LT |
9 | */ |
10 | ||
d43c36dc | 11 | #include <linux/sched.h> |
5a0e3ad6 | 12 | #include <linux/slab.h> |
1da177e4 | 13 | #include "ibmasm.h" |
b8acb808 | 14 | #include "lowlevel.h" |
1da177e4 LT |
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 | ||
1da177e4 LT |
26 | static 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 | ||
63969cf2 | 34 | /* |
1da177e4 LT |
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 | |
3a4e3678 | 41 | * responsible for keeping up with the writer, or they will lose events. |
3110dc7a | 42 | */ |
1da177e4 LT |
43 | void 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]; | |
b8acb808 | 54 | memcpy_fromio(event->data, data, data_size); |
1da177e4 LT |
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 | ||
66 | static inline int event_available(struct event_buffer *b, struct event_reader *r) | |
67 | { | |
3110dc7a | 68 | return (r->next_serial_number < b->next_serial_number); |
1da177e4 LT |
69 | } |
70 | ||
63969cf2 | 71 | /* |
1da177e4 LT |
72 | * get_next_event |
73 | * Called by event readers (initiated from user space through the file | |
3110dc7a | 74 | * system). |
1da177e4 LT |
75 | * Sleeps until a new event is available. |
76 | */ | |
77 | int 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 | ||
b8acb808 MA |
84 | reader->cancelled = 0; |
85 | ||
86 | if (wait_event_interruptible(reader->wait, | |
87 | event_available(buffer, reader) || reader->cancelled)) | |
1da177e4 LT |
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 | ||
b8acb808 MA |
110 | void ibmasm_cancel_next_event(struct event_reader *reader) |
111 | { | |
112 | reader->cancelled = 1; | |
113 | wake_up_interruptible(&reader->wait); | |
114 | } | |
115 | ||
1da177e4 LT |
116 | void 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 | ||
127 | void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader) | |
128 | { | |
129 | unsigned long flags; | |
130 | ||
1da177e4 LT |
131 | spin_lock_irqsave(&sp->lock, flags); |
132 | list_del(&reader->node); | |
133 | spin_unlock_irqrestore(&sp->lock, flags); | |
134 | } | |
135 | ||
136 | int 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) | |
f403f85f | 144 | return -ENOMEM; |
1da177e4 LT |
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 | ||
160 | void ibmasm_event_buffer_exit(struct service_processor *sp) | |
161 | { | |
1da177e4 LT |
162 | kfree(sp->event_buffer); |
163 | } |