[PATCH 3/7] efi: payload: initrd: implement efi initrd media protocol.

[chalianis1@gmail.com]

From: Chali Anis <chalianis1@gmail.com>

Add the ability to install an initrd media protocol from an initrd file
or a fitImage, support both the initrd media protocol or installing the
initramfs directly to efi like what linux do.

Signed-off-by: Chali Anis <chalianis1@gmail.com>
---
 efi/guid.c                |   7 +++
 efi/payload/Makefile      |   1 +
 efi/payload/efi-initrd.c  | 123 ++++++++++++++++++++++++++++++++++++++
 include/efi.h             |   4 ++
 include/efi/efi-payload.h |   3 +
 5 files changed, 138 insertions(+)
 create mode 100644 efi/payload/efi-initrd.c

diff --git a/efi/guid.c b/efi/guid.c
index ef230a2b2403..7b572acb768b 100644
--- a/efi/guid.c
+++ b/efi/guid.c
@@ -44,6 +44,7 @@ const efi_guid_t efi_load_file_protocol_guid = EFI_LOAD_FILE_PROTOCOL_GUID;
 const efi_guid_t efi_load_file2_protocol_guid = EFI_LOAD_FILE2_PROTOCOL_GUID;
 const efi_guid_t efi_device_path_utilities_protocol_guid =
 	EFI_DEVICE_PATH_UTILITIES_PROTOCOL_GUID;
+const efi_guid_t efi_linux_initrd_media_guid = EFI_LINUX_INITRD_MEDIA_GUID;
 
 #define EFI_GUID_STRING(guid, short, long) do {	\
 	if (!efi_guidcmp(guid, *g))		\
@@ -128,5 +129,11 @@ const char *efi_guid_string(efi_guid_t *g)
 	EFI_GUID_STRING(EFI_ISCSIDXE_INF_GUID, "IScsiDxe.inf", "EFI IScsiDxe.inf File GUID");
 	EFI_GUID_STRING(EFI_VLANCONFIGDXE_INF_GUID, "VlanConfigDxe.inf", "EFI VlanConfigDxe.inf File GUID");
 
+	/* FDT */
+	EFI_GUID_STRING(EFI_DEVICE_TREE_GUID, "DeviceTree", "EFI Device Tree GUID");
+
+	/* Ramdisk */
+	EFI_GUID_STRING(EFI_LINUX_INITRD_MEDIA_GUID, "Initrd Media", "EFI Linux Initrd Media GUID");
+
 	return "unknown";
 }
diff --git a/efi/payload/Makefile b/efi/payload/Makefile
index a4a0332a8288..1250535302d3 100644
--- a/efi/payload/Makefile
+++ b/efi/payload/Makefile
@@ -2,6 +2,7 @@
 
 obj-y += init.o
 obj-y += image.o
+obj-y += efi-initrd.o
 obj-$(CONFIG_OFTREE) += fdt.o
 bbenv-y += env-efi
 obj-$(CONFIG_CMD_IOMEM) += iomem.o
diff --git a/efi/payload/efi-initrd.c b/efi/payload/efi-initrd.c
new file mode 100644
index 000000000000..633fbc29c137
--- /dev/null
+++ b/efi/payload/efi-initrd.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * efi-initrd.c - barebox EFI payload support
+ *
+ * Copyright (c) 2025 Anis Chali <chalianis1@gmail.com>
+ */
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+#include <linux/hw_random.h>
+#include <efi.h>
+#include <efi/efi-device.h>
+#include <efi/device-path.h>
+#include <efi/efi-payload.h>
+
+static efi_status_t EFIAPI efi_initrd_load_file2(
+	struct efi_load_file_protocol *this, struct efi_device_path *file_path,
+	bool boot_policy, unsigned long *buffer_size, void *buffer);
+
+static const struct {
+	struct efi_device_path_vendor vendor;
+	struct efi_device_path end;
+} __packed initrd_dev_path = { { {
+					 DEVICE_PATH_TYPE_MEDIA_DEVICE,
+					 DEVICE_PATH_SUB_TYPE_VENDOR_PATH,
+					 sizeof(initrd_dev_path.vendor),
+				 },
+				 EFI_LINUX_INITRD_MEDIA_GUID },
+			       { DEVICE_PATH_TYPE_END, DEVICE_PATH_SUB_TYPE_END,
+				 DEVICE_PATH_END_LENGTH } };
+
+static struct efi_device_path_memory *initrd_dev;
+static efi_handle_t lf2_handle;
+static struct efi_load_file_protocol efi_lf2_p = {
+	.load_file = efi_initrd_load_file2
+};
+
+static efi_status_t EFIAPI efi_initrd_load_file2(
+	struct efi_load_file_protocol *this, struct efi_device_path *file_path,
+	bool boot_policy, unsigned long *buffer_size, void *buffer)
+{
+	size_t initrd_size;
+
+	if (!this || this != &efi_lf2_p || !buffer_size)
+		return EFI_INVALID_PARAMETER;
+
+	if (file_path->type != initrd_dev_path.end.type ||
+	    file_path->sub_type != initrd_dev_path.end.sub_type)
+		return EFI_INVALID_PARAMETER;
+
+	if (boot_policy)
+		return EFI_UNSUPPORTED;
+
+	initrd_size = initrd_dev->ending_address - initrd_dev->starting_address;
+	if (!buffer || *buffer_size < initrd_size) {
+		*buffer_size = initrd_size;
+		return EFI_BUFFER_TOO_SMALL;
+	}
+
+	else {
+		memcpy(buffer, (void *)(uintptr_t)initrd_dev->starting_address,
+		       initrd_size);
+		*buffer_size = initrd_size;
+	}
+
+	return EFI_SUCCESS;
+}
+
+int efi_initrd_register(void *initrd, size_t initrd_sz)
+{
+	efi_physical_addr_t mem;
+	efi_status_t efiret;
+	size_t sz;
+	int ret;
+
+	sz = sizeof(struct efi_device_path_memory) +
+	     sizeof(struct efi_device_path);
+	efiret = BS->allocate_pool(EFI_BOOT_SERVICES_DATA, sz, (void **)&mem);
+	if (EFI_ERROR(efiret)) {
+		pr_err("Failed to allocate memory for INITRD %s\n",
+		       efi_strerror(efiret));
+		ret = -efi_errno(efiret);
+		return ret;
+	}
+
+	initrd_dev = efi_phys_to_virt(mem);
+	initrd_dev->header.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
+	initrd_dev->header.sub_type = DEVICE_PATH_SUB_TYPE_MEMORY;
+	initrd_dev->header.length = sizeof(struct efi_device_path_memory);
+	initrd_dev->memory_type = EFI_LOADER_DATA;
+	initrd_dev->starting_address = efi_virt_to_phys(initrd);
+	initrd_dev->ending_address = efi_virt_to_phys(initrd) + initrd_sz;
+
+	memcpy(&initrd_dev[1], &initrd_dev_path.end, DEVICE_PATH_END_LENGTH);
+
+	efiret = BS->install_multiple_protocol_interfaces(
+		&lf2_handle, &efi_load_file2_protocol_guid, &efi_lf2_p,
+		&efi_device_path_protocol_guid, &initrd_dev_path, NULL);
+	if (EFI_ERROR(efiret)) {
+		pr_err("Failed to install protocols for INITRD %s\n",
+		       efi_strerror(efiret));
+		ret = -efi_errno(efiret);
+		goto out;
+	}
+
+	return 0;
+out:
+	BS->free_pool(efi_phys_to_virt(mem));
+	return ret;
+}
+
+void efi_initrd_unregister(void)
+{
+	if (!initrd_dev)
+		return;
+
+	BS->uninstall_multiple_protocol_interfaces(
+		lf2_handle, &efi_device_path_protocol_guid, &initrd_dev_path,
+		&efi_load_file2_protocol_guid, &efi_lf2_p, NULL);
+
+	BS->free_pool(initrd_dev);
+	initrd_dev = NULL;
+}
diff --git a/include/efi.h b/include/efi.h
index 40b69fdb0188..bd339ea097c3 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -558,6 +558,9 @@ extern struct efi_runtime_services *RT;
 #define EFI_DRIVER_BINDING_PROTOCOL_GUID \
     EFI_GUID(0x18a031ab, 0xb443, 0x4d1a, 0xa5, 0xc0, 0x0c, 0x09, 0x26, 0x1e, 0x9f, 0x71)
 
+#define EFI_LINUX_INITRD_MEDIA_GUID \
+	EFI_GUID(0x5568e427, 0x68fc, 0x4f3d,  0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68)
+
 struct efi_driver_binding_protocol {
 	efi_status_t (EFIAPI * supported)(
 			struct efi_driver_binding_protocol *this,
@@ -603,6 +606,7 @@ extern const efi_guid_t efi_guid_event_group_reset_system;
 extern const efi_guid_t efi_load_file_protocol_guid;
 extern const efi_guid_t efi_load_file2_protocol_guid;
 extern const efi_guid_t efi_device_path_utilities_protocol_guid;
+extern const efi_guid_t efi_linux_initrd_media_guid;
 
 struct efi_config_table {
 	efi_guid_t guid;
diff --git a/include/efi/efi-payload.h b/include/efi/efi-payload.h
index fe45864dd8a7..d8e66a187a87 100644
--- a/include/efi/efi-payload.h
+++ b/include/efi/efi-payload.h
@@ -34,4 +34,7 @@ int efi_set_variable_usec(char *name, efi_guid_t *vendor, uint64_t usec);
 void *efi_earlymem_alloc(const struct efi_system_table *sys_table,
 			 size_t *memsize, enum efi_memory_type mem_type);
 
+int efi_initrd_register(void *initrd, size_t initrd_size);
+void efi_initrd_unregister(void);
+
 #endif
-- 
2.34.1