1 files changed, 49 insertions, 0 deletions
diff --git a/gcip-kernel-driver/include/gcip/gcip-domain-pool.h b/gcip-kernel-driver/include/gcip/gcip-domain-pool.h
new file mode 100644
index 0000000..b740bf9
--- /dev/null
+++ b/gcip-kernel-driver/include/gcip/gcip-domain-pool.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * GCIP IOMMU domain allocator.
+ *
+ * Copyright (C) 2022 Google LLC
+ */
+
+#ifndef __GCIP_DOMAIN_POOL_H__
+#define __GCIP_DOMAIN_POOL_H__
+
+#include <linux/idr.h>
+#include <linux/iommu.h>
+
+struct gcip_domain_pool {
+	struct ida idp; /* ID allocator to keep track of used domains. */
+	/*
+	 * Size of the pool. Can be set to 0, in which case the implementation will fall back to
+	 * dynamic domain allocation using the IOMMU API directly.
+	 */
+	unsigned int size;
+	struct iommu_domain **array; /* Array holding the pointers to pre-allocated domains. */
+	struct device *dev; /* The device used for logging warnings/errors. */
+};
+
+/*
+ * Initializes a domain pool.
+ *
+ * @dev: pointer to device structure.
+ * @pool: caller-allocated pool structure.
+ * @size: size of the pre-allocated domains pool.
+ * Set to zero to fall back to dynamically allocated domains.
+ *
+ * returns 0 on success or negative error value.
+ */
+int gcip_domain_pool_init(struct device *dev, struct gcip_domain_pool *pool, unsigned int size);
+
+/*
+ * Allocates a domain from the pool
+ * returns NULL on error.
+ */
+struct iommu_domain *gcip_domain_pool_alloc(struct gcip_domain_pool *pool);
+
+/* Releases a domain from the pool. */
+void gcip_domain_pool_free(struct gcip_domain_pool *pool, struct iommu_domain *domain);
+
+/* Cleans up all resources used by the domain pool. */
+void gcip_domain_pool_destroy(struct gcip_domain_pool *pool);
+
+#endif /* __GCIP_DOMAIN_POOL_H__ */