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Linux/arch/powerpc/platforms/pseries/io_event_irq.c

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  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>
 12 #include <linux/export.h>
 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 
 66 /* pSeries event log format */
 67 
 68 /* Two bytes ASCII section IDs */
 69 #define PSERIES_ELOG_SECT_ID_PRIV_HDR           (('P' << 8) | 'H')
 70 #define PSERIES_ELOG_SECT_ID_USER_HDR           (('U' << 8) | 'H')
 71 #define PSERIES_ELOG_SECT_ID_PRIMARY_SRC        (('P' << 8) | 'S')
 72 #define PSERIES_ELOG_SECT_ID_EXTENDED_UH        (('E' << 8) | 'H')
 73 #define PSERIES_ELOG_SECT_ID_FAILING_MTMS       (('M' << 8) | 'T')
 74 #define PSERIES_ELOG_SECT_ID_SECONDARY_SRC      (('S' << 8) | 'S')
 75 #define PSERIES_ELOG_SECT_ID_DUMP_LOCATOR       (('D' << 8) | 'H')
 76 #define PSERIES_ELOG_SECT_ID_FW_ERROR           (('S' << 8) | 'W')
 77 #define PSERIES_ELOG_SECT_ID_IMPACT_PART_ID     (('L' << 8) | 'P')
 78 #define PSERIES_ELOG_SECT_ID_LOGIC_RESOURCE_ID  (('L' << 8) | 'R')
 79 #define PSERIES_ELOG_SECT_ID_HMC_ID             (('H' << 8) | 'M')
 80 #define PSERIES_ELOG_SECT_ID_EPOW               (('E' << 8) | 'P')
 81 #define PSERIES_ELOG_SECT_ID_IO_EVENT           (('I' << 8) | 'E')
 82 #define PSERIES_ELOG_SECT_ID_MANUFACT_INFO      (('M' << 8) | 'I')
 83 #define PSERIES_ELOG_SECT_ID_CALL_HOME          (('C' << 8) | 'H')
 84 #define PSERIES_ELOG_SECT_ID_USER_DEF           (('U' << 8) | 'D')
 85 
 86 /* Vendor specific Platform Event Log Format, Version 6, section header */
 87 struct pseries_elog_section {
 88         uint16_t id;                    /* 0x00 2-byte ASCII section ID */
 89         uint16_t length;                /* 0x02 Section length in bytes */
 90         uint8_t version;                /* 0x04 Section version         */
 91         uint8_t subtype;                /* 0x05 Section subtype         */
 92         uint16_t creator_component;     /* 0x06 Creator component ID    */
 93         uint8_t data[];                 /* 0x08 Start of section data   */
 94 };
 95 
 96 static char ioei_rtas_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned;
 97 
 98 /**
 99  * Find data portion of a specific section in RTAS extended event log.
100  * @elog: RTAS error/event log.
101  * @sect_id: secsion ID.
102  *
103  * Return:
104  *      pointer to the section data of the specified section
105  *      NULL if not found
106  */
107 static struct pseries_elog_section *find_xelog_section(struct rtas_error_log *elog,
108                                                        uint16_t sect_id)
109 {
110         struct rtas_ext_event_log_v6 *xelog =
111                 (struct rtas_ext_event_log_v6 *) elog->buffer;
112         struct pseries_elog_section *sect;
113         unsigned char *p, *log_end;
114 
115         /* Check that we understand the format */
116         if (elog->extended_log_length < sizeof(struct rtas_ext_event_log_v6) ||
117             xelog->log_format != RTAS_V6EXT_LOG_FORMAT_EVENT_LOG ||
118             xelog->company_id != RTAS_V6EXT_COMPANY_ID_IBM)
119                 return NULL;
120 
121         log_end = elog->buffer + elog->extended_log_length;
122         p = xelog->vendor_log;
123         while (p < log_end) {
124                 sect = (struct pseries_elog_section *)p;
125                 if (sect->id == sect_id)
126                         return sect;
127                 p += sect->length;
128         }
129         return NULL;
130 }
131 
132 /**
133  * Find the data portion of an IO Event section from event log.
134  * @elog: RTAS error/event log.
135  *
136  * Return:
137  *      pointer to a valid IO event section data. NULL if not found.
138  */
139 static struct pseries_io_event * ioei_find_event(struct rtas_error_log *elog)
140 {
141         struct pseries_elog_section *sect;
142 
143         /* We should only ever get called for io-event interrupts, but if
144          * we do get called for another type then something went wrong so
145          * make some noise about it.
146          * RTAS_TYPE_IO only exists in extended event log version 6 or later.
147          * No need to check event log version.
148          */
149         if (unlikely(elog->type != RTAS_TYPE_IO)) {
150                 printk_once(KERN_WARNING "io_event_irq: Unexpected event type %d",
151                             elog->type);
152                 return NULL;
153         }
154 
155         sect = find_xelog_section(elog, PSERIES_ELOG_SECT_ID_IO_EVENT);
156         if (unlikely(!sect)) {
157                 printk_once(KERN_WARNING "io_event_irq: RTAS extended event "
158                             "log does not contain an IO Event section. "
159                             "Could be a bug in system firmware!\n");
160                 return NULL;
161         }
162         return (struct pseries_io_event *) &sect->data;
163 }
164 
165 /*
166  * PAPR:
167  * - check-exception returns the first found error or event and clear that
168  *   error or event so it is reported once.
169  * - Each interrupt returns one event. If a plateform chooses to report
170  *   multiple events through a single interrupt, it must ensure that the
171  *   interrupt remains asserted until check-exception has been used to
172  *   process all out-standing events for that interrupt.
173  *
174  * Implementation notes:
175  * - Events must be processed in the order they are returned. Hence,
176  *   sequential in nature.
177  * - The owner of an event is determined by combinations of scope,
178  *   event type, and sub-type. There is no easy way to pre-sort clients
179  *   by scope or event type alone. For example, Torrent ISR route change
180  *   event is reported with scope 0x00 (Not Applicatable) rather than
181  *   0x3B (Torrent-hub). It is better to let the clients to identify
182  *   who owns the the event.
183  */
184 
185 static irqreturn_t ioei_interrupt(int irq, void *dev_id)
186 {
187         struct pseries_io_event *event;
188         int rtas_rc;
189 
190         for (;;) {
191                 rtas_rc = rtas_call(ioei_check_exception_token, 6, 1, NULL,
192                                     RTAS_VECTOR_EXTERNAL_INTERRUPT,
193                                     virq_to_hw(irq),
194                                     RTAS_IO_EVENTS, 1 /* Time Critical */,
195                                     __pa(ioei_rtas_buf),
196                                     RTAS_DATA_BUF_SIZE);
197                 if (rtas_rc != 0)
198                         break;
199 
200                 event = ioei_find_event((struct rtas_error_log *)ioei_rtas_buf);
201                 if (!event)
202                         continue;
203 
204                 atomic_notifier_call_chain(&pseries_ioei_notifier_list,
205                                            0, event);
206         }
207         return IRQ_HANDLED;
208 }
209 
210 static int __init ioei_init(void)
211 {
212         struct device_node *np;
213 
214         ioei_check_exception_token = rtas_token("check-exception");
215         if (ioei_check_exception_token == RTAS_UNKNOWN_SERVICE)
216                 return -ENODEV;
217 
218         np = of_find_node_by_path("/event-sources/ibm,io-events");
219         if (np) {
220                 request_event_sources_irqs(np, ioei_interrupt, "IO_EVENT");
221                 pr_info("IBM I/O event interrupts enabled\n");
222                 of_node_put(np);
223         } else {
224                 return -ENODEV;
225         }
226         return 0;
227 }
228 machine_subsys_initcall(pseries, ioei_init);
229 
230 

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