1 files changed, 112 insertions, 0 deletions
diff --git a/lib/efi_loader/efi_rng.c b/lib/efi_loader/efi_rng.c
new file mode 100644
index 00000000000..47aaa6adca8
--- /dev/null
+++ b/lib/efi_loader/efi_rng.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <efi_loader.h>
+#include <efi_rng.h>
+#include <rng.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+__weak efi_status_t platform_get_rng_device(struct udevice **dev)
+{
+	int ret;
+	struct udevice *devp;
+
+	ret = uclass_get_device(UCLASS_RNG, 0, &devp);
+	if (ret) {
+		debug("Unable to get rng device\n");
+		return EFI_DEVICE_ERROR;
+	}
+
+	*dev = devp;
+
+	return EFI_SUCCESS;
+}
+
+static efi_status_t EFIAPI rng_getinfo(struct efi_rng_protocol *this,
+				       efi_uintn_t *rng_algorithm_list_size,
+				       efi_guid_t *rng_algorithm_list)
+{
+	efi_status_t ret = EFI_SUCCESS;
+	efi_guid_t rng_algo_guid = EFI_RNG_ALGORITHM_RAW;
+
+	EFI_ENTRY("%p, %p, %p", this, rng_algorithm_list_size,
+		  rng_algorithm_list);
+
+	if (!this || !rng_algorithm_list_size) {
+		ret = EFI_INVALID_PARAMETER;
+		goto back;
+	}
+
+	if (!rng_algorithm_list ||
+	    *rng_algorithm_list_size < sizeof(*rng_algorithm_list)) {
+		*rng_algorithm_list_size = sizeof(*rng_algorithm_list);
+		ret = EFI_BUFFER_TOO_SMALL;
+		goto back;
+	}
+
+	/*
+	 * For now, use EFI_RNG_ALGORITHM_RAW as the default
+	 * algorithm. If a new algorithm gets added in the
+	 * future through a Kconfig, rng_algo_guid will be set
+	 * based on that Kconfig option
+	 */
+	*rng_algorithm_list_size = sizeof(*rng_algorithm_list);
+	guidcpy(rng_algorithm_list, &rng_algo_guid);
+
+back:
+	return EFI_EXIT(ret);
+}
+
+static efi_status_t EFIAPI getrng(struct efi_rng_protocol *this,
+				  efi_guid_t *rng_algorithm,
+				  efi_uintn_t rng_value_length,
+				  uint8_t *rng_value)
+{
+	int ret;
+	efi_status_t status = EFI_SUCCESS;
+	struct udevice *dev;
+	const efi_guid_t rng_raw_guid = EFI_RNG_ALGORITHM_RAW;
+
+	EFI_ENTRY("%p, %p, %zu, %p", this, rng_algorithm, rng_value_length,
+		  rng_value);
+
+	if (!this || !rng_value || !rng_value_length) {
+		status = EFI_INVALID_PARAMETER;
+		goto back;
+	}
+
+	if (rng_algorithm) {
+		EFI_PRINT("RNG algorithm %pUl\n", rng_algorithm);
+		if (guidcmp(rng_algorithm, &rng_raw_guid)) {
+			status = EFI_UNSUPPORTED;
+			goto back;
+		}
+	}
+
+	ret = platform_get_rng_device(&dev);
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("Rng device not found\n");
+		status = EFI_UNSUPPORTED;
+		goto back;
+	}
+
+	ret = dm_rng_read(dev, rng_value, rng_value_length);
+	if (ret < 0) {
+		EFI_PRINT("Rng device read failed\n");
+		status = EFI_DEVICE_ERROR;
+		goto back;
+	}
+
+back:
+	return EFI_EXIT(status);
+}
+
+const struct efi_rng_protocol efi_rng_protocol = {
+	.get_info = rng_getinfo,
+	.get_rng = getrng,
+};