[U-Boot] [PATCH v2 05/11] env: save UEFI non-volatile variables in dedicated storage

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

We need a variant of env_save()/env_load() to handle dedicated storage
for UEFI variables.
It is assumed that env_efi_load() will be called only ince at init
and that env_efi_save() will be called at every SetVariable.

In this patch, new parameters will be expected to be configured:
  CONFIG_ENV_EFI_FAT_DEVICE_AND_PART
  CONFIG_ENV_EFI_FAT_FILE
in case of CONFIG_ENV_IS_IN_FAT.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 env/Kconfig                       |  34 ++++++++++
 env/env.c                         |  98 ++++++++++++++++++++++++++-
 env/fat.c                         | 109 ++++++++++++++++++++++++++++++
 include/asm-generic/global_data.h |   1 +
 include/environment.h             |  24 +++++++
 5 files changed, 265 insertions(+), 1 deletion(-)

diff --git a/env/Kconfig b/env/Kconfig
index 78300660c720..8f59e9347d4b 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -438,6 +438,34 @@ config ENV_FAT_FILE
 	  It's a string of the FAT file name. This file use to store the
 	  environment.
 
+config ENV_EFI_FAT_DEVICE_AND_PART
+	string "Device and partition for where to store the UEFI non-volatile variables in FAT"
+	depends on ENV_IS_IN_FAT
+	depends on EFI_LOADER
+	help
+	  Define this to a string to specify the partition of the device. It can
+	  be as following:
+
+	    "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
+	       - "D:P": device D partition P. Error occurs if device D has no
+	                partition table.
+	       - "D:0": device D.
+	       - "D" or "D:": device D partition 1 if device D has partition
+	                      table, or the whole device D if has no partition
+	                      table.
+	       - "D:auto": first partition in device D with bootable flag set.
+	                   If none, first valid partition in device D. If no
+	                   partition table then means device D.
+
+config ENV_EFI_FAT_FILE
+	string "Name of the FAT file to use for the UEFI non-volatile variables"
+	depends on ENV_IS_IN_FAT
+	depends on EFI_LOADER
+	default "uboot_efi.env"
+	help
+	  It's a string of the FAT file name. This file use to store the
+	  UEFI non-volatile variables.
+
 config ENV_EXT4_INTERFACE
 	string "Name of the block device for the environment"
 	depends on ENV_IS_IN_EXT4
@@ -470,6 +498,12 @@ config ENV_EXT4_FILE
 	  It's a string of the EXT4 file name. This file use to store the
 	  environment (explicit path to the file)
 
+config ENV_EFI_SIZE
+	hex "UEFI Variables Environment Size"
+	default 0x20000
+	help
+	  Size of the UEFI variables storage area
+
 if ARCH_ROCKCHIP || ARCH_SUNXI || ARCH_ZYNQ || ARCH_ZYNQMP || ARCH_VERSAL || ARC
 
 config ENV_OFFSET
diff --git a/env/env.c b/env/env.c
index 4b417b90a291..d5af761ba57e 100644
--- a/env/env.c
+++ b/env/env.c
@@ -24,6 +24,10 @@ void env_fix_drivers(void)
 			entry->load += gd->reloc_off;
 		if (entry->save)
 			entry->save += gd->reloc_off;
+		if (entry->efi_load)
+			entry->efi_load += gd->reloc_off;
+		if (entry->efi_save)
+			entry->efi_save += gd->reloc_off;
 		if (entry->init)
 			entry->init += gd->reloc_off;
 	}
@@ -125,7 +129,8 @@ __weak enum env_location env_get_location(enum env_operation op, int prio)
 	if (prio >= ARRAY_SIZE(env_locations))
 		return ENVL_UNKNOWN;
 
-	gd->env_load_prio = prio;
+	if (op != ENVOP_EFI)
+		gd->env_load_prio = prio;
 
 	return env_locations[prio];
 }
@@ -280,3 +285,94 @@ int env_init(void)
 
 	return ret;
 }
+
+#ifdef CONFIG_EFI_LOADER
+extern struct hsearch_data efi_var_htab;
+extern struct hsearch_data efi_nv_var_htab;
+
+/* TODO: experimental */
+int env_efi_save(void)
+{
+	struct env_driver *drv = NULL;
+	int ret;
+
+	if (!efi_nv_var_htab.table)
+		return 0;
+
+	if (gd->env_efi_prio == -1) {
+		printf("Cannot save UEFI non-volatile variable\n");
+		return -1;
+	}
+
+	drv = _env_driver_lookup(env_get_location(ENVOP_EFI, gd->env_efi_prio));
+	if (!drv) {
+		printf("Cannot save UEFI non-volatile variable\n");
+		return -1;
+	}
+
+	ret = drv->efi_save();
+	if (ret)
+		printf("Saving UEFI non-volatile variable failed\n");
+
+	return ret;
+}
+
+/* TODO: experimental */
+/* This function should be called only once at init */
+int env_efi_load(void)
+{
+	struct env_driver *drv = NULL;
+	int prio, ret;
+	enum env_location loc;
+
+	gd->env_efi_prio = -1;
+
+	/* volatile variables */
+	if (!efi_var_htab.table) {
+		ret = himport_r(&efi_var_htab, NULL, 0, '\0', 0, 0, 0, NULL);
+		if (!ret) {
+			printf("Creating default UEFI variables failed\n");
+			return -1;
+		}
+	}
+
+	/* non-loratile variables */
+	if (efi_nv_var_htab.table)
+		return 0;
+
+	for (prio = 0; prio < ARRAY_SIZE(env_locations); prio++) {
+		loc = env_get_location(ENVOP_EFI, prio);
+		drv = _env_driver_lookup(loc);
+		if (!drv)
+			continue;
+
+		if (drv->efi_load && drv->efi_save)
+			break;
+	}
+	if (!drv || prio == ARRAY_SIZE(env_locations)) {
+		printf("No driver for UEFI storage is available\n");
+		return -1;
+	}
+
+	gd->env_efi_prio = prio;
+
+	ret = drv->efi_load();
+	if (ret) {
+		printf("Loading UEFI non-volatile variables failed\n");
+		return -1;
+	}
+
+	/* FIXME: init needed here? */
+	if (!efi_nv_var_htab.table) {
+		ret = himport_r(&efi_nv_var_htab, NULL, 0, '\0', 0, 0, 0, NULL);
+		if (!ret) {
+			printf("Creating default UEFI non-volatile variables failed\n");
+			return -1;
+		}
+
+		return 0;
+	}
+
+	return 0;
+}
+#endif /* CONFIG_EFI_LOADER */
diff --git a/env/fat.c b/env/fat.c
index 7f74c64dfe7e..e2b050d4553d 100644
--- a/env/fat.c
+++ b/env/fat.c
@@ -14,6 +14,7 @@
 #include <malloc.h>
 #include <memalign.h>
 #include <search.h>
+#include <efi_loader.h>
 #include <errno.h>
 #include <fat.h>
 #include <mmc.h>
@@ -128,6 +129,110 @@ err_env_relocate:
 }
 #endif /* LOADENV */
 
+#ifdef CONFIG_EFI_LOADER
+#if 1
+extern int efi_variable_import(const char *buf, int check);
+extern int efi_variable_export(env_t *env_out);
+#endif
+static int env_fat_efi_save(void)
+{
+	env_t __aligned(ARCH_DMA_MINALIGN) env_new;
+	struct blk_desc *dev_desc = NULL;
+	disk_partition_t info;
+	int dev, part;
+	int err;
+	loff_t size;
+
+	err = efi_variable_export(&env_new);
+	if (err)
+		return err;
+
+	part = blk_get_device_part_str(CONFIG_ENV_FAT_INTERFACE,
+				       CONFIG_ENV_EFI_FAT_DEVICE_AND_PART,
+				       &dev_desc, &info, 1);
+	if (part < 0)
+		return 1;
+
+	dev = dev_desc->devnum;
+	if (fat_set_blk_dev(dev_desc, &info) != 0) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to use %s %d:%d... ",
+		       CONFIG_ENV_FAT_INTERFACE, dev, part);
+		return 1;
+	}
+
+	err = file_fat_write(CONFIG_ENV_EFI_FAT_FILE,
+			     (void *)&env_new, 0, sizeof(env_t), &size);
+	if (err < 0) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to write \"%s\" from %s%d:%d... ",
+		       CONFIG_ENV_EFI_FAT_FILE, CONFIG_ENV_FAT_INTERFACE,
+		       dev, part);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int env_fat_efi_load(void)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(char, buf, CONFIG_ENV_EFI_SIZE);
+	struct blk_desc *dev_desc = NULL;
+	disk_partition_t info;
+	int dev, part;
+	int err;
+
+#ifdef CONFIG_MMC
+	if (!strcmp(CONFIG_ENV_FAT_INTERFACE, "mmc"))
+		mmc_initialize(NULL);
+#endif
+
+	part = blk_get_device_part_str(CONFIG_ENV_FAT_INTERFACE,
+				       CONFIG_ENV_EFI_FAT_DEVICE_AND_PART,
+				       &dev_desc, &info, 1);
+	if (part < 0)
+		goto err_env_relocate;
+
+	dev = dev_desc->devnum;
+	if (fat_set_blk_dev(dev_desc, &info) != 0) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to use %s %d:%d...\n",
+		       CONFIG_ENV_FAT_INTERFACE, dev, part);
+		goto err_env_relocate;
+	}
+
+	err = file_fat_read(CONFIG_ENV_EFI_FAT_FILE, buf, CONFIG_ENV_EFI_SIZE);
+	if (err <= 0 && (err != -ENOENT)) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to read \"%s\" from %s %d:%d...\n",
+		       CONFIG_ENV_EFI_FAT_FILE, CONFIG_ENV_FAT_INTERFACE,
+		       dev, part);
+		goto err_env_relocate;
+	}
+
+	if (err > 0)
+		return efi_variable_import(buf, 1);
+	else
+		return 0;
+
+err_env_relocate:
+
+	return -EIO;
+}
+#endif /* CONFIG_EFI_LOADER */
+
 U_BOOT_ENV_LOCATION(fat) = {
 	.location	= ENVL_FAT,
 	ENV_NAME("FAT")
@@ -137,4 +242,8 @@ U_BOOT_ENV_LOCATION(fat) = {
 #ifdef CMD_SAVEENV
 	.save		= env_save_ptr(env_fat_save),
 #endif
+#ifdef CONFIG_EFI_LOADER
+	.efi_load	= env_fat_efi_load,
+	.efi_save	= env_fat_efi_save,
+#endif
 };
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 78dcf40bff48..8c4d56c346f3 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -51,6 +51,7 @@ typedef struct global_data {
 	unsigned long env_valid;	/* Environment valid? enum env_valid */
 	unsigned long env_has_init;	/* Bitmask of boolean of struct env_location offsets */
 	int env_load_prio;		/* Priority of the loaded environment */
+	int env_efi_prio;		/* Priority of the UEFI variables */
 
 	unsigned long ram_base;		/* Base address of RAM used by U-Boot */
 	unsigned long ram_top;		/* Top address of RAM used by U-Boot */
diff --git a/include/environment.h b/include/environment.h
index cd966761416e..f62399863ef9 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -200,6 +200,7 @@ enum env_operation {
 	ENVOP_INIT,	/* we want to call the init function */
 	ENVOP_LOAD,	/* we want to call the load function */
 	ENVOP_SAVE,	/* we want to call the save function */
+	ENVOP_EFI,	/* we want to call the efi_load/save function */
 };
 
 struct env_driver {
@@ -225,6 +226,24 @@ struct env_driver {
 	 */
 	int (*save)(void);
 
+	/**
+	 * efi_load() - Load UEFI non-volatile variables from storage
+	 *
+	 * This method is required for UEFI non-volatile variables
+	 *
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*efi_load)(void);
+
+	/**
+	 * efi_save() - Save UEFI non-volatile variables to storage
+	 *
+	 * This method is required for UEFI non-volatile variables
+	 *
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*efi_save)(void);
+
 	/**
 	 * init() - Set up the initial pre-relocation environment
 	 *
@@ -312,6 +331,11 @@ void eth_parse_enetaddr(const char *addr, uint8_t *enetaddr);
 int eth_env_get_enetaddr(const char *name, uint8_t *enetaddr);
 int eth_env_set_enetaddr(const char *name, const uint8_t *enetaddr);
 
+#ifdef CONFIG_EFI_LOADER
+int env_efi_load(void);
+int env_efi_save(void);
+#endif
+
 #endif /* DO_DEPS_ONLY */
 
 #endif /* _ENVIRONMENT_H_ */
-- 
2.20.1