arch/powerpc/platforms/pseries/io_event_irq.c

   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