From 77d4d396563c47a0cd74ea31fc8f906157c94b39 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Fri, 18 Jan 2019 19:52:05 +0100 Subject: [PATCH] efi_loader: comments for variable services Comment the functions implementing the runtime variable services. Signed-off-by: Heinrich Schuchardt Signed-off-by: Alexander Graf --- lib/efi_loader/efi_variable.c | 86 +++++++++++++++++++++++++++++++++-- 1 file 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) { -- 2.39.5