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authorHeinrich Schuchardt <xypron.glpk@gmx.de>2019-01-18 19:52:05 +0100
committerAlexander Graf <agraf@suse.de>2019-02-13 09:40:06 +0100
commit77d4d396563c47a0cd74ea31fc8f906157c94b39 (patch)
treed10bcd7f0db5eb670dda9333699e5cbcf2e9385b /lib/efi_loader/efi_variable.c
parent8377ee36d6a6cfdad56649e2cec64cfb97e3ae68 (diff)
efi_loader: comments for variable services
Comment the functions implementing the runtime variable services. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'lib/efi_loader/efi_variable.c')
-rw-r--r--lib/efi_loader/efi_variable.c86
1 files changed, 81 insertions, 5 deletions
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 2ac27731fe..cfb3168e77 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -47,6 +47,19 @@
#define PREFIX_LEN (strlen("efi_xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx_"))
+/**
+ * efi_to_native() - convert the UEFI variable name and vendor GUID to U-Boot
+ * variable name
+ *
+ * The U-Boot variable name is a concatenation of prefix 'efi', the hexstring
+ * encoded vendor GUID, and the UTF-8 encoded UEFI variable name separated by
+ * underscores, e.g. 'efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder'.
+ *
+ * @native: pointer to pointer to U-Boot variable name
+ * @variable_name: UEFI variable name
+ * @vendor: vendor GUID
+ * Return: status code
+ */
static efi_status_t efi_to_native(char **native, const u16 *variable_name,
const efi_guid_t *vendor)
{
@@ -65,6 +78,15 @@ static efi_status_t efi_to_native(char **native, const u16 *variable_name,
return EFI_SUCCESS;
}
+/**
+ * prefix() - skip over prefix
+ *
+ * Skip over a prefix string.
+ *
+ * @str: string with prefix
+ * @prefix: prefix string
+ * Return: string without prefix, or NULL if prefix not found
+ */
static const char *prefix(const char *str, const char *prefix)
{
size_t n = strlen(prefix);
@@ -73,7 +95,16 @@ static const char *prefix(const char *str, const char *prefix)
return NULL;
}
-/* parse attributes part of variable value, if present: */
+/**
+ * parse_attr() - decode attributes part of variable value
+ *
+ * Convert the string encoded attributes of a UEFI variable to a bit mask.
+ * TODO: Several attributes are not supported.
+ *
+ * @str: value of U-Boot variable
+ * @attrp: pointer to UEFI attributes
+ * Return: pointer to remainder of U-Boot variable value
+ */
static const char *parse_attr(const char *str, u32 *attrp)
{
u32 attr = 0;
@@ -111,7 +142,21 @@ static const char *parse_attr(const char *str, u32 *attrp)
return str;
}
-/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetVariable.28.29 */
+/**
+ * efi_efi_get_variable() - retrieve value of a UEFI variable
+ *
+ * This function implements the GetVariable runtime service.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification for
+ * details.
+ *
+ * @variable_name: name of the variable
+ * @vendor: vendor GUID
+ * @attributes: attributes of the variable
+ * @data_size: size of the buffer to which the variable value is copied
+ * @data: buffer to which the variable value is copied
+ * Return: status code
+ */
efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
const efi_guid_t *vendor, u32 *attributes,
efi_uintn_t *data_size, void *data)
@@ -190,7 +235,21 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
return EFI_EXIT(EFI_SUCCESS);
}
-/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetNextVariableName.28.29 */
+/**
+ * efi_efi_get_next_variable() - get next UEFI variable
+ *
+ * This function implements the GetNextVariable runtime service.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification for
+ * details.
+ *
+ * @variable_name_size: on entry size of the buffer for the variable name, on
+ * exit the length of the name of the next variable
+ * @variable_name: on entry name of the current variable, on exit the name
+ * of the next variable
+ * @vendor: vendor GUID
+ * Return: status code
+ */
efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
u16 *variable_name,
const efi_guid_t *vendor)
@@ -200,7 +259,21 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
return EFI_EXIT(EFI_DEVICE_ERROR);
}
-/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#SetVariable.28.29 */
+/**
+ * efi_efi_set_variable() - set value of a UEFI variable
+ *
+ * This function implements the SetVariable runtime service.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification for
+ * details.
+ *
+ * @variable_name: name of the variable
+ * @vendor: vendor GUID
+ * @attributes: attributes of the variable
+ * @data_size: size of the buffer with the variable value
+ * @data: buffer with the variable value
+ * Return: status code
+ */
efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
const efi_guid_t *vendor, u32 attributes,
efi_uintn_t data_size, const void *data)
@@ -250,7 +323,10 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
s = val;
- /* store attributes: */
+ /*
+ * store attributes
+ * TODO: several attributes are not supported
+ */
attributes &= (EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS);
s += sprintf(s, "{");
while (attributes) {