Introduce volume_index for compatability with tf-a
To allow for reuse of tf-a io_dev volume access components, the
tf-a interface function plat_get_image_source() needs to be
realized. The volume_index provides a realization where the
it acts as a singleton for holding per deployment volume ID
io_dev mappings. Deployment configuration code may add
mappings to suite the needs of the deployment. This helps to
isolate the tf-a io subsystem from tf-a specific configuration
conventions.
Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I913b6229d78be0c803ebe6a2f6cf06f8d1160c96
diff --git a/components/media/volume/index/volume_index.c b/components/media/volume/index/volume_index.c
new file mode 100644
index 0000000..fe8b209
--- /dev/null
+++ b/components/media/volume/index/volume_index.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <plat/common/platform.h>
+#include "volume_index.h"
+
+#ifndef VOLUME_INDEX_MAX_ENTRIES
+#define VOLUME_INDEX_MAX_ENTRIES (4)
+#endif
+
+/**
+ * Singleton index of volume IDs to IO devices.
+ */
+static struct
+{
+ size_t size;
+ struct
+ {
+ unsigned int volume_id;
+ uintptr_t dev_handle;
+ uintptr_t volume_spec;
+ } entries[VOLUME_INDEX_MAX_ENTRIES];
+
+} volume_index;
+
+/**
+ * @brief Gets a device for volume IO operations
+ *
+ * @param[in] volume_id Identifies the image
+ * @param[out] dev_handle Handle for IO operations
+ * @param[out] volume_spec Opaque configuration data
+ *
+ * This function realizes the interface expected by tf-a components to
+ * provide a concrete IO device for the specified volume ID. When used in
+ * TS deployments, the set of IO devices required for a deployment
+ * are registered during service configuration.
+ */
+int plat_get_image_source(
+ unsigned int volume_id,
+ uintptr_t *dev_handle,
+ uintptr_t *volume_spec)
+{
+ int result = -1;
+
+ for (size_t i = 0; i < volume_index.size; i++) {
+
+ if (volume_index.entries[i].volume_id == volume_id) {
+
+ *dev_handle = volume_index.entries[i].dev_handle;
+ *volume_spec = volume_index.entries[i].volume_spec;
+
+ result = 0;
+ break;
+ }
+ }
+
+ return result;
+}
+
+void volume_index_init(void)
+{
+ volume_index_clear();
+}
+
+void volume_index_clear(void)
+{
+ memset(&volume_index, 0, sizeof(volume_index));
+}
+
+int volume_index_add(
+ unsigned int volume_id,
+ uintptr_t dev_handle,
+ uintptr_t volume_spec)
+{
+ int result = -1;
+
+ if (volume_index.size < VOLUME_INDEX_MAX_ENTRIES)
+ {
+ size_t i = volume_index.size;
+
+ ++volume_index.size;
+ volume_index.entries[i].volume_id = volume_id;
+ volume_index.entries[i].dev_handle = dev_handle;
+ volume_index.entries[i].volume_spec = volume_spec;
+
+ result = 0;
+ }
+
+ return result;
+}