[PATCH 1/3] lib: sbi: domain: add domain registration notifier infrastructure

[Pawandeep Oza]

From: Oza Pawandeep <pawandeep.oza at oss.qualcomm.com>

Introduce a notifier callback mechanism that allows subsystems to
register interest in domain registration events. When a new domain
is registered via sbi_domain_register(), all registered notifiers
are invoked before domain sanitization.

The following public interfaces are added to sbi_domain.h:

  - sbi_domain_register_notifier(): registers a notifier callback.
    Duplicate (fn, priv) pairs are silently ignored.

  - sbi_domain_unregister_notifier(): removes a previously registered
    notifier callback.

Signed-off-by: Oza Pawandeep <pawandeep.oza at oss.qualcomm.com>
---
 include/sbi/sbi_domain.h | 10 +++++++
 lib/sbi/sbi_domain.c     | 59 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/include/sbi/sbi_domain.h b/include/sbi/sbi_domain.h
index b35ea99f..2471df48 100644
--- a/include/sbi/sbi_domain.h
+++ b/include/sbi/sbi_domain.h
@@ -358,4 +358,14 @@ int sbi_domain_finalize(struct sbi_scratch *scratch);
 /** Initialize domains */
 int sbi_domain_init(struct sbi_scratch *scratch, u32 cold_hartid);
 
+/** Notifier callback */
+typedef void (*sbi_domain_notifier_fn)(const struct sbi_domain *dom,
+                                      void *priv);
+
+/** Regitser domain notifier */
+int sbi_domain_register_notifier(sbi_domain_notifier_fn notifier, void *priv);
+
+/** Unregitser domain notifier */
+int sbi_domain_unregister_notifier(sbi_domain_notifier_fn notifier, void *priv);
+
 #endif
diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
index 747c346c..99f201cf 100644
--- a/lib/sbi/sbi_domain.c
+++ b/lib/sbi/sbi_domain.c
@@ -36,7 +36,65 @@ struct sbi_domain root = {
 	.fw_region_inited = false,
 };
 
+struct sbi_domain_notifier_entry {
+       struct sbi_dlist        node;
+       sbi_domain_notifier_fn  fn;
+       void                   *priv;
+};
+
+
 static unsigned long domain_hart_ptr_offset;
+static SBI_LIST_HEAD(domain_notifier_list);
+
+int sbi_domain_register_notifier(sbi_domain_notifier_fn notifier, void *priv)
+{
+	struct sbi_domain_notifier_entry *entry;
+
+	if (!notifier)
+		return SBI_EINVAL;
+
+	sbi_list_for_each_entry(entry, &domain_notifier_list, node) {
+		if (entry->fn == notifier && entry->priv == priv)
+			return SBI_OK;
+	}
+
+	entry = sbi_zalloc(sizeof(*entry));
+	if (!entry)
+		return SBI_ENOMEM;
+
+	entry->fn   = notifier;
+	entry->priv = priv;
+	sbi_list_add_tail(&entry->node, &domain_notifier_list);
+	return SBI_OK;
+}
+
+int sbi_domain_unregister_notifier(sbi_domain_notifier_fn notifier, void *priv)
+{
+	struct sbi_domain_notifier_entry *entry, *tmp;
+
+	if (!notifier)
+		return SBI_EINVAL;
+
+	sbi_list_for_each_entry_safe(entry, tmp, &domain_notifier_list, node) {
+		if (entry->fn == notifier && entry->priv == priv) {
+			sbi_list_del(&entry->node);
+			sbi_free(entry);
+			return SBI_OK;
+		}
+	}
+
+	return SBI_ENODEV;
+}
+
+void sbi_domain_notify_all(const struct sbi_domain *dom)
+{
+	struct sbi_domain_notifier_entry *entry;
+
+	sbi_list_for_each_entry(entry, &domain_notifier_list, node) {
+		if (entry->fn)
+			entry->fn(dom, entry->priv);
+	}
+}
 
 struct sbi_domain *sbi_hartindex_to_domain(u32 hartindex)
 {
@@ -650,6 +708,7 @@ int sbi_domain_register(struct sbi_domain *dom)
 			return SBI_EALREADY;
 	}
 
+	sbi_domain_notify_all(dom);
 	/* Sanitize discovered domain */
 	rc = sanitize_domain(dom);
 	if (rc) {
-- 
2.43.0