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77eafe10 THFL |
1 | /* |
2 | * Copyright 2010 2011 Mark Nelson and Tseng-Hui (Frank) Lin, IBM Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | */ | |
9 | ||
10 | #include <linux/errno.h> | |
11 | #include <linux/slab.h> | |
4b16f8e2 | 12 | #include <linux/export.h> |
77eafe10 THFL |
13 | #include <linux/irq.h> |
14 | #include <linux/interrupt.h> | |
15 | #include <linux/of.h> | |
16 | #include <linux/list.h> | |
17 | #include <linux/notifier.h> | |
18 | ||
19 | #include <asm/machdep.h> | |
20 | #include <asm/rtas.h> | |
21 | #include <asm/irq.h> | |
22 | #include <asm/io_event_irq.h> | |
23 | ||
24 | #include "pseries.h" | |
25 | ||
26 | /* | |
27 | * IO event interrupt is a mechanism provided by RTAS to return | |
28 | * information about hardware error and non-error events. Device | |
29 | * drivers can register their event handlers to receive events. | |
30 | * Device drivers are expected to use atomic_notifier_chain_register() | |
31 | * and atomic_notifier_chain_unregister() to register and unregister | |
32 | * their event handlers. Since multiple IO event types and scopes | |
33 | * share an IO event interrupt, the event handlers are called one | |
34 | * by one until the IO event is claimed by one of the handlers. | |
35 | * The event handlers are expected to return NOTIFY_OK if the | |
36 | * event is handled by the event handler or NOTIFY_DONE if the | |
37 | * event does not belong to the handler. | |
38 | * | |
39 | * Usage: | |
40 | * | |
41 | * Notifier function: | |
42 | * #include <asm/io_event_irq.h> | |
43 | * int event_handler(struct notifier_block *nb, unsigned long val, void *data) { | |
44 | * p = (struct pseries_io_event_sect_data *) data; | |
45 | * if (! is_my_event(p->scope, p->event_type)) return NOTIFY_DONE; | |
46 | * : | |
47 | * : | |
48 | * return NOTIFY_OK; | |
49 | * } | |
50 | * struct notifier_block event_nb = { | |
51 | * .notifier_call = event_handler, | |
52 | * } | |
53 | * | |
54 | * Registration: | |
55 | * atomic_notifier_chain_register(&pseries_ioei_notifier_list, &event_nb); | |
56 | * | |
57 | * Unregistration: | |
58 | * atomic_notifier_chain_unregister(&pseries_ioei_notifier_list, &event_nb); | |
59 | */ | |
60 | ||
61 | ATOMIC_NOTIFIER_HEAD(pseries_ioei_notifier_list); | |
62 | EXPORT_SYMBOL_GPL(pseries_ioei_notifier_list); | |
63 | ||
64 | static int ioei_check_exception_token; | |
65 | ||
77eafe10 THFL |
66 | static char ioei_rtas_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned; |
67 | ||
77eafe10 THFL |
68 | /** |
69 | * Find the data portion of an IO Event section from event log. | |
70 | * @elog: RTAS error/event log. | |
71 | * | |
72 | * Return: | |
73 | * pointer to a valid IO event section data. NULL if not found. | |
74 | */ | |
75 | static struct pseries_io_event * ioei_find_event(struct rtas_error_log *elog) | |
76 | { | |
6431f208 | 77 | struct pseries_errorlog *sect; |
77eafe10 THFL |
78 | |
79 | /* We should only ever get called for io-event interrupts, but if | |
80 | * we do get called for another type then something went wrong so | |
81 | * make some noise about it. | |
82 | * RTAS_TYPE_IO only exists in extended event log version 6 or later. | |
83 | * No need to check event log version. | |
84 | */ | |
85 | if (unlikely(elog->type != RTAS_TYPE_IO)) { | |
86 | printk_once(KERN_WARNING "io_event_irq: Unexpected event type %d", | |
87 | elog->type); | |
88 | return NULL; | |
89 | } | |
90 | ||
6431f208 | 91 | sect = get_pseries_errorlog(elog, PSERIES_ELOG_SECT_ID_IO_EVENT); |
77eafe10 THFL |
92 | if (unlikely(!sect)) { |
93 | printk_once(KERN_WARNING "io_event_irq: RTAS extended event " | |
94 | "log does not contain an IO Event section. " | |
95 | "Could be a bug in system firmware!\n"); | |
96 | return NULL; | |
97 | } | |
98 | return (struct pseries_io_event *) §->data; | |
99 | } | |
100 | ||
101 | /* | |
102 | * PAPR: | |
103 | * - check-exception returns the first found error or event and clear that | |
104 | * error or event so it is reported once. | |
105 | * - Each interrupt returns one event. If a plateform chooses to report | |
106 | * multiple events through a single interrupt, it must ensure that the | |
107 | * interrupt remains asserted until check-exception has been used to | |
108 | * process all out-standing events for that interrupt. | |
109 | * | |
110 | * Implementation notes: | |
111 | * - Events must be processed in the order they are returned. Hence, | |
112 | * sequential in nature. | |
113 | * - The owner of an event is determined by combinations of scope, | |
114 | * event type, and sub-type. There is no easy way to pre-sort clients | |
115 | * by scope or event type alone. For example, Torrent ISR route change | |
116 | * event is reported with scope 0x00 (Not Applicatable) rather than | |
117 | * 0x3B (Torrent-hub). It is better to let the clients to identify | |
118 | * who owns the the event. | |
119 | */ | |
120 | ||
121 | static irqreturn_t ioei_interrupt(int irq, void *dev_id) | |
122 | { | |
123 | struct pseries_io_event *event; | |
124 | int rtas_rc; | |
125 | ||
126 | for (;;) { | |
127 | rtas_rc = rtas_call(ioei_check_exception_token, 6, 1, NULL, | |
128 | RTAS_VECTOR_EXTERNAL_INTERRUPT, | |
129 | virq_to_hw(irq), | |
130 | RTAS_IO_EVENTS, 1 /* Time Critical */, | |
131 | __pa(ioei_rtas_buf), | |
132 | RTAS_DATA_BUF_SIZE); | |
133 | if (rtas_rc != 0) | |
134 | break; | |
135 | ||
136 | event = ioei_find_event((struct rtas_error_log *)ioei_rtas_buf); | |
137 | if (!event) | |
138 | continue; | |
139 | ||
140 | atomic_notifier_call_chain(&pseries_ioei_notifier_list, | |
141 | 0, event); | |
142 | } | |
143 | return IRQ_HANDLED; | |
144 | } | |
145 | ||
146 | static int __init ioei_init(void) | |
147 | { | |
148 | struct device_node *np; | |
149 | ||
150 | ioei_check_exception_token = rtas_token("check-exception"); | |
53876e38 | 151 | if (ioei_check_exception_token == RTAS_UNKNOWN_SERVICE) |
77eafe10 | 152 | return -ENODEV; |
53876e38 | 153 | |
77eafe10 THFL |
154 | np = of_find_node_by_path("/event-sources/ibm,io-events"); |
155 | if (np) { | |
156 | request_event_sources_irqs(np, ioei_interrupt, "IO_EVENT"); | |
53876e38 | 157 | pr_info("IBM I/O event interrupts enabled\n"); |
77eafe10 THFL |
158 | of_node_put(np); |
159 | } else { | |
77eafe10 THFL |
160 | return -ENODEV; |
161 | } | |
162 | return 0; | |
163 | } | |
164 | machine_subsys_initcall(pseries, ioei_init); | |
165 |