Change in coreboot[master]: option: Allow to use the EFI variable driver as option backend

[Patrick Rudolph (Code Review)]

Patrick Rudolph has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/62562 )

Change subject: option: Allow to use the EFI variable driver as option backend
......................................................................

option: Allow to use the EFI variable driver as option backend

Use the introduced EFI variable store driver on top of the SMMSTORE region
in SPI flash to read/write options.

Change-Id: I520eca96bcd573f825ed35a29bf8f750e313a02d
Signed-off-by: Patrick Rudolph 
---
M src/Kconfig
M src/drivers/efi/Makefile.inc
A src/drivers/efi/option.c
3 files changed, 58 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/62/62562/1

diff --git a/src/Kconfig b/src/Kconfig
index 44e84bf..e19345a 100644
--- a/src/Kconfig
+++ b/src/Kconfig
@@ -124,6 +124,8 @@
    prompt "Option backend to use"
    default USE_MAINBOARD_SPECIFIC_OPTION_BACKEND if HAVE_MAINBOARD_SPECIFIC_OPTION_BACKEND
    default USE_OPTION_TABLE if NVRAMCUI_SECONDARY_PAYLOAD
+	default USE_UEFI_VARIABLE_STORE if DRIVERS_EFI_VARIABLE_STORE && \
+		PAYLOAD_TIANOCORE && SMMSTORE_V2

config OPTION_BACKEND_NONE
    bool "None"
@@ -135,6 +137,15 @@
      Enable this option if coreboot shall read options from the "CMOS"
      NVRAM instead of using hard-coded values.

+config USE_UEFI_VARIABLE_STORE
+	bool "Use UEFI variable-store in SPI flash as option backend"
+	depends on DRIVERS_EFI_VARIABLE_STORE
+	depends on SMMSTORE_V2
+	help
+	  Enable this option if coreboot shall read/write options from the
+	  SMMSTORE region within the SPI flash. The region must be formatted
+	  by the payload first before it can be used.
+
 config USE_MAINBOARD_SPECIFIC_OPTION_BACKEND
    bool "Use mainboard-specific option backend"
    depends on HAVE_MAINBOARD_SPECIFIC_OPTION_BACKEND
diff --git a/src/drivers/efi/Makefile.inc b/src/drivers/efi/Makefile.inc
index e059c48..bc332df 100644
--- a/src/drivers/efi/Makefile.inc
+++ b/src/drivers/efi/Makefile.inc
@@ -1,3 +1,7 @@

all-$(CONFIG_DRIVERS_EFI_VARIABLE_STORE)	+= efivars.c
 smm-$(CONFIG_DRIVERS_EFI_VARIABLE_STORE)	+= efivars.c
+
+all-$(CONFIG_USE_UEFI_VARIABLE_STORE)           += option.c
+smm-$(CONFIG_USE_UEFI_VARIABLE_STORE)           += option.c
+
diff --git a/src/drivers/efi/option.c b/src/drivers/efi/option.c
new file mode 100644
index 0000000..3960cfc
--- /dev/null
+++ b/src/drivers/efi/option.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <stdlib.h>
+#include <string.h>
+#include <option.h>
+#include <smmstore.h>
+
+#include <Uefi/UefiBaseType.h>
+
+#include "efivars.h"
+
+static const EFI_GUID EficorebootNvDataGuid = {
+	0xceae4c1d, 0x335b, 0x4685, { 0xa4, 0xa0, 0xfc, 0x4a, 0x94, 0xee, 0xa0, 0x85 } };
+
+unsigned int get_uint_option(const char *name, const unsigned int fallback)
+{
+	struct region_device rdev;
+	enum cb_err ret;
+	uint32_t var;
+	uint32_t size;
+
+	if (smmstore_lookup_region(&rdev))
+		return fallback;
+
+	var = 0;
+	size = sizeof(var);
+	ret = efi_fv_get_option(&rdev, &EficorebootNvDataGuid, name, &var, &size);
+	if (ret != CB_SUCCESS)
+		return fallback;
+
+	return var;
+}
+
+enum cb_err set_uint_option(const char *name, unsigned int value)
+{
+	struct region_device rdev;
+	uint32_t var = value;
+
+	if (smmstore_lookup_region(&rdev))
+		return CB_CMOS_OTABLE_DISABLED;
+
+	return efi_fv_set_option(&rdev, &EficorebootNvDataGuid, name, &var, sizeof(var));
+}