Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 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> |
Paul Gortmaker | 4b16f8e | 2011-07-22 18:24:23 -0400 | [diff] [blame] | 12 | #include <linux/export.h> |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 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 | |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 66 | static char ioei_rtas_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned; |
| 67 | |
| 68 | /** |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 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 | { |
Anton Blanchard | 6431f20 | 2012-03-21 15:47:07 +0000 | [diff] [blame] | 77 | struct pseries_errorlog *sect; |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 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 | */ |
Greg Kurz | a08a53ea | 2014-04-04 09:35:13 +0200 | [diff] [blame] | 85 | if (unlikely(rtas_error_type(elog) != RTAS_TYPE_IO)) { |
| 86 | printk_once(KERN_WARNING"io_event_irq: Unexpected event type %d", |
| 87 | rtas_error_type(elog)); |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 88 | return NULL; |
| 89 | } |
| 90 | |
Anton Blanchard | 6431f20 | 2012-03-21 15:47:07 +0000 | [diff] [blame] | 91 | sect = get_pseries_errorlog(elog, PSERIES_ELOG_SECT_ID_IO_EVENT); |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 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 |
Michael Ellerman | 027dfac | 2016-06-01 16:34:37 +1000 | [diff] [blame] | 116 | * event is reported with scope 0x00 (Not Applicable) rather than |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 117 | * 0x3B (Torrent-hub). It is better to let the clients to identify |
Sebastien Bessiere | e1b85c1 | 2013-06-14 17:57:03 +0200 | [diff] [blame] | 118 | * who owns the event. |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 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"); |
Anton Blanchard | 53876e3 | 2011-07-31 19:30:04 +0000 | [diff] [blame] | 151 | if (ioei_check_exception_token == RTAS_UNKNOWN_SERVICE) |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 152 | return -ENODEV; |
Anton Blanchard | 53876e3 | 2011-07-31 19:30:04 +0000 | [diff] [blame] | 153 | |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 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"); |
Anton Blanchard | 53876e3 | 2011-07-31 19:30:04 +0000 | [diff] [blame] | 157 | pr_info("IBM I/O event interrupts enabled\n"); |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 158 | of_node_put(np); |
| 159 | } else { |
Tseng-Hui (Frank) Lin | 77eafe1 | 2011-05-05 12:32:48 +0000 | [diff] [blame] | 160 | return -ENODEV; |
| 161 | } |
| 162 | return 0; |
| 163 | } |
| 164 | machine_subsys_initcall(pseries, ioei_init); |
| 165 | |