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
  35 _Static_assert(ARRAY_SIZE(type_name) == EVT_COUNT, "event type_name size");
  36 #endif
  37
  38 static const char *event_type_name(enum event_t type)
  39 {
  40 #if CONFIG_IS_ENABLED(EVENT_DEBUG)
  41         return type_name[type];
  42 #else
  43         return "(unknown)";
  44 #endif
  45 }
  46
  47 static int notify_static(struct event *ev)
  48 {
  49         struct evspy_info *start =
  50                 ll_entry_start(struct evspy_info, evspy_info);
  51         const int n_ents = ll_entry_count(struct evspy_info, evspy_info);
  52         struct evspy_info *spy;
  53
  54         for (spy = start; spy != start + n_ents; spy++) {
  55                 if (spy->type == ev->type) {
  56                         int ret;
  57
  58                         log_debug("Sending event %x/%s to spy '%s'\n", ev->type,
  59                                   event_type_name(ev->type), event_spy_id(spy));
  60                         ret = spy->func(NULL, ev);
  61
  62                         /*
  63                          * TODO: Handle various return codes to
  64                          *
  65                          * - claim an event (no others will see it)
  66                          * - return an error from the event
  67                          */
  68                         if (ret)
  69                                 return log_msg_ret("spy", ret);
  70                 }
  71         }
  72
  73         return 0;
  74 }
  75
  76 static int notify_dynamic(struct event *ev)
  77 {
  78         struct event_state *state = gd_event_state();
  79         struct event_spy *spy, *next;
  80
  81         list_for_each_entry_safe(spy, next, &state->spy_head, sibling_node) {
  82                 if (spy->type == ev->type) {
  83                         int ret;
  84
  85                         log_debug("Sending event %x/%s to spy '%s'\n", ev->type,
  86                                   event_type_name(ev->type), spy->id);
  87                         ret = spy->func(spy->ctx, ev);
  88
  89                         /*
  90                          * TODO: Handle various return codes to
  91                          *
  92                          * - claim an event (no others will see it)
  93                          * - return an error from the event
  94                          */
  95                         if (ret)
  96                                 return log_msg_ret("spy", ret);
  97                 }
  98         }
  99
 100         return 0;
 101 }
 102
 103 int event_notify(enum event_t type, void *data, int size)
 104 {
 105         struct event event;
 106         int ret;
 107
 108         event.type = type;
 109         if (size > sizeof(event.data))
 110                 return log_msg_ret("size", -E2BIG);
 111         memcpy(&event.data, data, size);
 112
 113         ret = notify_static(&event);
 114         if (ret)
 115                 return log_msg_ret("dyn", ret);
 116
 117         if (CONFIG_IS_ENABLED(EVENT_DYNAMIC)) {
 118                 ret = notify_dynamic(&event);
 119                 if (ret)
 120                         return log_msg_ret("dyn", ret);
 121         }
 122
 123         return 0;
 124 }
 125
 126 int event_notify_null(enum event_t type)
 127 {
 128         return event_notify(type, NULL, 0);
 129 }
 130
 131 void event_show_spy_list(void)
 132 {
 133         struct evspy_info *start =
 134                 ll_entry_start(struct evspy_info, evspy_info);
 135         const int n_ents = ll_entry_count(struct evspy_info, evspy_info);
 136         struct evspy_info *spy;
 137         const int size = sizeof(ulong) * 2;
 138
 139         printf("Seq  %-24s  %*s  %s\n", "Type", size, "Function", "ID");
 140         for (spy = start; spy != start + n_ents; spy++) {
 141                 printf("%3x  %-3x %-20s  %*p  %s\n", (uint)(spy - start),
 142                        spy->type, event_type_name(spy->type), size, spy->func,
 143                        event_spy_id(spy));
 144         }
 145 }
 146
 147 #if CONFIG_IS_ENABLED(EVENT_DYNAMIC)
 148 static void spy_free(struct event_spy *spy)
 149 {
 150         list_del(&spy->sibling_node);
 151 }
 152
 153 int event_register(const char *id, enum event_t type, event_handler_t func, void *ctx)
 154 {
 155         struct event_state *state = gd_event_state();
 156         struct event_spy *spy;
 157
 158         if (!CONFIG_IS_ENABLED(EVENT_DYNAMIC))
 159                 return -ENOSYS;
 160         spy = malloc(sizeof(*spy));
 161         if (!spy)
 162                 return log_msg_ret("alloc", -ENOMEM);
 163
 164         spy->id = id;
 165         spy->type = type;
 166         spy->func = func;
 167         spy->ctx = ctx;
 168         list_add_tail(&spy->sibling_node, &state->spy_head);
 169
 170         return 0;
 171 }
 172
 173 int event_uninit(void)
 174 {
 175         struct event_state *state = gd_event_state();
 176         struct event_spy *spy, *next;
 177
 178         list_for_each_entry_safe(spy, next, &state->spy_head, sibling_node)
 179                 spy_free(spy);
 180
 181         return 0;
 182 }
 183
 184 int event_init(void)
 185 {
 186         struct event_state *state = gd_event_state();
 187
 188         INIT_LIST_HEAD(&state->spy_head);
 189
 190         return 0;
 191 }
 192 #endif /* EVENT_DYNAMIC */