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/module.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 *) §->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 pr_warning("IO Event IRQ not supported on this system !\n"); 217 return -ENODEV; 218 } 219 np = of_find_node_by_path("/event-sources/ibm,io-events"); 220 if (np) { 221 request_event_sources_irqs(np, ioei_interrupt, "IO_EVENT"); 222 of_node_put(np); 223 } else { 224 pr_err("io_event_irq: No ibm,io-events on system! " 225 "IO Event interrupt disabled.\n"); 226 return -ENODEV; 227 } 228 return 0; 229 } 230 machine_subsys_initcall(pseries, ioei_init); 231 232