common/event.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Events provide a general-purpose way to react to / subscribe to changes
   4  * within U-Boot
   5  *
   6  * Copyright 2021 Google LLC
   7  * Written by Simon Glass <sjg@chromium.org>
   8  */
   9
  10 #define LOG_CATEGORY    LOGC_EVENT
  11
  12 #include <common.h>
  13 #include <event.h>
  14 #include <event_internal.h>
  15 #include <log.h>
  16 #include <linker_lists.h>
  17 #include <malloc.h>
  18 #include <asm/global_data.h>
  19 #include <linux/list.h>
  20
  21 DECLARE_GLOBAL_DATA_PTR;
  22
  23 #if CONFIG_IS_ENABLED(EVENT_DEBUG)
  24 const char *const type_name[] = {
  25         "none",
  26         "test",
  27
  28         /* Events related to driver model */
  29         "dm_pre_probe",
  30         "dm_post_probe",
  31         "dm_pre_remove",
  32         "dm_post_remove",
  33
  34         /* init hooks */
  35         "misc_init_f",
  36 };
  37
  38 _Static_assert(ARRAY_SIZE(type_name) == EVT_COUNT, "event type_name size");
  39 #endif
  40
  41 static const char *event_type_name(enum event_t type)
  42 {
  43 #if CONFIG_IS_ENABLED(EVENT_DEBUG)
  44         return type_name[type];
  45 #else
  46         return "(unknown)";
  47 #endif
  48 }
  49
  50 static int notify_static(struct event *ev)
  51 {
  52         struct evspy_info *start =
  53                 ll_entry_start(struct evspy_info, evspy_info);
  54         const int n_ents = ll_entry_count(struct evspy_info, evspy_info);
  55         struct evspy_info *spy;
  56
  57         for (spy = start; spy != start + n_ents; spy++) {
  58                 if (spy->type == ev->type) {
  59                         int ret;
  60
  61                         log_debug("Sending event %x/%s to spy '%s'\n", ev->type,
  62                                   event_type_name(ev->type), event_spy_id(spy));
  63                         ret = spy->func(NULL, ev);
  64
  65                         /*
  66                          * TODO: Handle various return codes to
  67                          *
  68                          * - claim an event (no others will see it)
  69                          * - return an error from the event
  70                          */
  71                         if (ret)
  72                                 return log_msg_ret("spy", ret);
  73                 }
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int notify_dynamic(struct event *ev)
  80 {
  81         struct event_state *state = gd_event_state();
  82         struct event_spy *spy, *next;
  83
  84         list_for_each_entry_safe(spy, next, &state->spy_head, sibling_node) {
  85                 if (spy->type == ev->type) {
  86                         int ret;
  87
  88                         log_debug("Sending event %x/%s to spy '%s'\n", ev->type,
  89                                   event_type_name(ev->type), spy->id);
  90                         ret = spy->func(spy->ctx, ev);
  91
  92                         /*
  93                          * TODO: Handle various return codes to
  94                          *
  95                          * - claim an event (no others will see it)
  96                          * - return an error from the event
  97                          */
  98                         if (ret)
  99                                 return log_msg_ret("spy", ret);
 100                 }
 101         }
 102
 103         return 0;
 104 }
 105
 106 int event_notify(enum event_t type, void *data, int size)
 107 {
 108         struct event event;
 109         int ret;
 110
 111         event.type = type;
 112         if (size > sizeof(event.data))
 113                 return log_msg_ret("size", -E2BIG);
 114         memcpy(&event.data, data, size);
 115
 116         ret = notify_static(&event);
 117         if (ret)
 118                 return log_msg_ret("dyn", ret);
 119
 120         if (CONFIG_IS_ENABLED(EVENT_DYNAMIC)) {
 121                 ret = notify_dynamic(&event);
 122                 if (ret)
 123                         return log_msg_ret("dyn", ret);
 124         }
 125
 126         return 0;
 127 }
 128
 129 int event_notify_null(enum event_t type)
 130 {
 131         return event_notify(type, NULL, 0);
 132 }
 133
 134 void event_show_spy_list(void)
 135 {
 136         struct evspy_info *start =
 137                 ll_entry_start(struct evspy_info, evspy_info);
 138         const int n_ents = ll_entry_count(struct evspy_info, evspy_info);
 139         struct evspy_info *spy;
 140         const int size = sizeof(ulong) * 2;
 141
 142         printf("Seq  %-24s  %*s  %s\n", "Type", size, "Function", "ID");
 143         for (spy = start; spy != start + n_ents; spy++) {
 144                 printf("%3x  %-3x %-20s  %*p  %s\n", (uint)(spy - start),
 145                        spy->type, event_type_name(spy->type), size, spy->func,
 146                        event_spy_id(spy));
 147         }
 148 }
 149
 150 #if CONFIG_IS_ENABLED(EVENT_DYNAMIC)
 151 static void spy_free(struct event_spy *spy)
 152 {
 153         list_del(&spy->sibling_node);
 154 }
 155
 156 int event_register(const char *id, enum event_t type, event_handler_t func, void *ctx)
 157 {
 158         struct event_state *state = gd_event_state();
 159         struct event_spy *spy;
 160
 161         if (!CONFIG_IS_ENABLED(EVENT_DYNAMIC))
 162                 return -ENOSYS;
 163         spy = malloc(sizeof(*spy));
 164         if (!spy)
 165                 return log_msg_ret("alloc", -ENOMEM);
 166
 167         spy->id = id;
 168         spy->type = type;
 169         spy->func = func;
 170         spy->ctx = ctx;
 171         list_add_tail(&spy->sibling_node, &state->spy_head);
 172
 173         return 0;
 174 }
 175
 176 int event_uninit(void)
 177 {
 178         struct event_state *state = gd_event_state();
 179         struct event_spy *spy, *next;
 180
 181         list_for_each_entry_safe(spy, next, &state->spy_head, sibling_node)
 182                 spy_free(spy);
 183
 184         return 0;
 185 }
 186
 187 int event_init(void)
 188 {
 189         struct event_state *state = gd_event_state();
 190
 191         INIT_LIST_HEAD(&state->spy_head);
 192
 193         return 0;
 194 }
 195 #endif /* EVENT_DYNAMIC */