drivers/efi: add optional ESRT-friently coreboot table tag

New CONFIG_DRIVERS_EFI_FW_INFO is off by default, enabling it adds
DRIVERS_EFI_FW_{GUID,VERSION,LSV} to be used to specify firmware
version/update information.

Existing forms of versions woudn't be sufficient because there is no
universal way of conversion to 32-bit unsigned integers and there are no
GUIDs or lowest supported versions.

Change-Id: Ic1b768d7bed43edf7ca8e41552087734054de033
Signed-off-by: Sergii Dmytruk <[email protected]>

src/commonlib/include/commonlib/coreboot_tables.h

@@ -87,6 +87,7 @@ enum {
 	LB_TAG_TYPE_C_INFO		= 0x0042,
 	LB_TAG_ACPI_RSDP		= 0x0043,
 	LB_TAG_PCIE			= 0x0044,
+	LB_TAG_EFI_FW_INFO		= 0x0046,
 	LB_TAG_LOGO			= 0x00a0,
 	/* The following options are CMOS-related */
 	LB_TAG_CMOS_OPTION_TABLE	= 0x00c8,
@@ -587,4 +588,22 @@ struct bootlogo_header {
 	uint64_t size;
 } __packed;
 
+/*
+ * Machine-friendly version of a system firmware component.  A component is
+ * identified by a GUID.  coreboot is an obvious main component but there could
+ * be others (like EC) which should get their own instances of the tag.
+ *
+ * The main consumer of this information is UEFI firmware but something else
+ * could reuse it too.
+ *
+ * Larger number in version fields correspond to more recent versions.
+ */
+struct lb_efi_fw_info {
+	uint32_t tag;
+	uint32_t size;
+	uint8_t guid[16];			/* Called "firmware class" in UEFI */
+	uint32_t version;			/* Current version */
+	uint32_t lowest_supported_version;	/* Lowest allowed version for downgrades */
+} __packed;
+
 #endif

src/drivers/efi/Kconfig

@@ -6,3 +6,35 @@ config DRIVERS_EFI_VARIABLE_STORE
 	help
 	  Adds a driver that is able to read and write an EFI formatted
 	  VariableStore as used by tianocore.
+
+config DRIVERS_EFI_FW_INFO
+	bool "Expose firmware version in a EFI-friendly form"
+	depends on UDK_BASE
+	help
+	  Adds firmware version information to coreboot table in a form similar to
+	  EFI System Resource Table (ESRT) that can be used for firmware updates.
+
+config DRIVERS_EFI_FW_GUID
+	string "GUID of the firmware"
+	default "00112233-4455-6677-8899-aabbccddeeff"
+	depends on DRIVERS_EFI_FW_INFO
+	help
+	  GUID used to identify firmware kind for the purposes of updates.
+
+config DRIVERS_EFI_FW_VERSION
+	hex "Version of the firmware"
+	range 0x00000000 0xFFFFFFFF
+	default 0x00000000
+	depends on DRIVERS_EFI_FW_INFO
+	help
+	  32-bit unsigned integer representing current firmware's version.
+
+config DRIVERS_EFI_FW_LSV
+	hex "Lowest supported firmware version"
+	range 0x00000000 0xFFFFFFFF
+	default 0x00000000
+	depends on DRIVERS_EFI_FW_INFO
+	help
+	  32-bit unsigned integer representing lowest firmware version number
+	  that is allowed to replace the current one.  Can be used to forbid
+	  bugged versions.

src/drivers/efi/Makefile.mk

@@ -5,3 +5,5 @@ smm-$(CONFIG_DRIVERS_EFI_VARIABLE_STORE)	+= efivars.c
 
 all-$(CONFIG_USE_UEFI_VARIABLE_STORE)	+= option.c
 smm-$(CONFIG_USE_UEFI_VARIABLE_STORE)	+= option.c
+
+ramstage-$(CONFIG_DRIVERS_EFI_FW_INFO)	+= info.c

src/drivers/efi/info.c

@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <boot/coreboot_tables.h>
+#include <console/console.h>
+#include <stdint.h>
+#include <string.h>
+#include <uuid.h>
+
+void lb_efi_fw_info(struct lb_header *header)
+{
+	uint8_t guid[16];
+	struct lb_efi_fw_info *fw_info;
+
+	if (parse_uuid(guid, CONFIG_DRIVERS_EFI_FW_GUID)) {
+		printk(BIOS_ERR, "%s(): failed to parse firmware's GUID: '%s'\n", __func__,
+		       CONFIG_DRIVERS_EFI_FW_GUID);
+		return;
+	}
+
+	fw_info = (struct lb_efi_fw_info *)lb_new_record(header);
+	fw_info->tag = LB_TAG_EFI_FW_INFO;
+	fw_info->size = sizeof(*fw_info);
+
+	memcpy(fw_info->guid, guid, sizeof(guid));
+	fw_info->version = CONFIG_DRIVERS_EFI_FW_VERSION;
+	fw_info->lowest_supported_version = CONFIG_DRIVERS_EFI_FW_LSV;
+}

src/include/boot/coreboot_tables.h

@@ -27,6 +27,9 @@ enum cb_err fill_lb_pcie(struct lb_pcie *pcie);
 /* Define this in mainboard.c to add board-specific table entries. */
 void lb_board(struct lb_header *header);
 
+/* Adds LB_TAG_EFI_FW_INFO table entry (or entries). */
+void lb_efi_fw_info(struct lb_header *header);
+
 /* Define this function to fill in the frame buffer returning 0 on success and
    < 0 on error. */
 int fill_lb_framebuffer(struct lb_framebuffer *framebuffer);

src/lib/coreboot_table.c

@@ -572,6 +572,10 @@ static uintptr_t write_coreboot_table(uintptr_t rom_table_end)
 	/* Add board-specific table entries, if any. */
 	lb_board(head);
 
+	/* Add information about firmware in form suitable for EFI updates. */
+	if (CONFIG(DRIVERS_EFI_FW_INFO))
+		lb_efi_fw_info(head);
+
 	if (CONFIG(CHROMEOS_RAMOOPS))
 		lb_ramoops(head);