EBBR only requires a subset of UEFI. Provide a replacement for the UEFI
section that lists base requirements.
Fixes: #60
Fixes: #61
Fixes: #64
---
This is my first complete draft itemizing the specific UEFI requirements
for EBBR. Please review and comment.
Cheers,
g.
source/chapter2-uefi.rst | 155 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 152 insertions(+), 3 deletions(-)
diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst
index aab1c2c..5864a17 100644
--- a/source/chapter2-uefi.rst
+++ b/source/chapter2-uefi.rst
@@ -14,8 +14,157 @@ This document uses version 2.8 Errata A of the UEFI
specification [UEFI]_.
UEFI Compliance
===============
-EBBR compliant platforms shall conform to the requirements in [UEFI]_ § 2.6,
-except where explicit exemptions are provided by this document.
+EBBR compliant platform shall conform to a subset of the [UEFI]_ spec as listed
+in this section.
+Normally, UEFI compliance would require full compliance with all items listed
+in section 2.6 of the UEFI spec.
+However, the EBBR target market has a reduced set of requirements,
+and so some UEFI features are omitted as unnecessary.
+
+Required Elements
+-----------------
+
+This section replaces the list of required elements in [UEFI]_ § 2.6.1.
+All of the following UEFI elements are required for EBBR compliance.
+
+.. list-table:: UEFI Required Elements
+ :widths: 50 50
+ :header-rows: 1
+
+ * - Element
+ - Requirement
+ * - `EFI_SYSTEM_TABLE`
+ - The system table is required to provide required to access UEFI Boot
Services,
+ UEFI Runtime Services, consoles, and other firmware, vendor and platform
+ information.
+ * - `EFI_BOOT_SERVICES`
+ - All functions defined as boot services must exist.
+ Methods for unsupported or unimplemented behavour must return an
appropriate error code.
+ * - `EFI_RUNTIME_SERVICES`
+ - All functions defined as runtime services must exist.
+ Methods for unsupported or unimplemented behavour must return an
appropriate error code.
+ * - `EFI_LOADED_IMAGE_PROTOCOL`
+ - Must be installed for each loaded image
+ * - `EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL`
+ - Must be installed for each loaded image
+ * - `EFI_DEVICE_PATH_PROTOCOL`
+ - Interface to provide location of a device
+ * - `EFI_DEVICE_PATH_UTILITIES_PROTOCOL`
+ - Interface for creating and manipulating UEFI device paths
+
+.. list-table:: Notible Omissions from UEFI section 2.6.1
+ :header-rows: 1
+
+ * - Element
+ - Note
+ * - EFI_DECOMPRESS_PROTOCOL
+ - Native EFI Decompression is rarely used and therefore not required.
+
+Required Platform Specific Elements
+-----------------------------------
+
+This section replaces the list of required elements in [UEFI]_ § 2.6.2.
+All of the following UEFI elements are required for EBBR compliance.
+
+.. list-table:: UEFI Platform-Specific Required Elements
+ :widths: 50 50
+ :header-rows: 1
+
+ * - Element
+ - Description
+ * - Console devices
+ - The platform must have at least one console device
+ * - `EFI_SIMPLE_TEXT_INPUT_PROTOCOL`
+ - Needed for console input
+ * - `EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL`
+ - Needed for console input
+ * - `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL`
+ - Needed for console output
+ * - `EFI_DEVICE_PATH_TO_TEXT_PROTOCOL`
+ - Needed for console output
+ * - `EFI_HII_STRING_PROTOCOL`
+ - Required by EFI shell and for compliance testing
+ * - `EFI_HII_DATABASE_PROTOCOL`
+ - Required by EFI shell and for compliance testing
+ * - `EFI_UNICODE_COLLATION2_PROTOCOL`
+ - Required by EFI shell and for compliance testing
+ * - `EFI_BLOCK_IO_PROTOCOL`
+ - Required for block device access
+ * - `EFI_SIMPLE_FILE_SYSTEM_PROTOCOL`
+ - Required if booting from block device is supported
+ * - `EFI_RNG_PROTOCOL`
+ - Required if platform has a hardware entropy source
+ * - Network booting
+ - If the platform supports network booting via TFTP,
+ then `EFI_SIMPLE_NETWORK_PROTOCOL` and
+ `EFI_PXE_BASE_CODE_PROTOCOL` must be implemented.
+
+The following table is a list of notable deviations from UEFI section 2.6.2.
+Many of these deviations are because the EBBR use cases do not require
+interface specific UEFI protocols, and so they have been made optional.
+
+.. list-table:: Notible Deviations from UEFI section 2.6.2
+ :widths: 50 50
+ :header-rows: 1
+
+ * - Element
+ - Description of deviation
+ * - `EFI_HII_CONFIG_ACCESS_PROTOCOL`
+ - UEFI requires this for console devices, but it is rarely necessary in
practice.
+ Therefore this protocol is not requried.
+ * - `EFI_HII_CONFIG_ROUTING_PROTOCOL`
+ - UEFI requires this for console devices, but it is rarely necessary in
practice.
+ Therefore this protocol is not requried.
+ * - Graphical console
+ - Platforms with a graphical device are not required to expose it as a
graphical console.
+ * - EFI_DISK_IO_PROTOCOL
+ - Rarely used interface that isn't requried for EBBR use cases
+ * - Network protocols
+ - A full implementation of the UEFI general purpose networking ABIs is
not required,
+ including `EFI_NETWORK_INTERFACE_IDENTIFIER_PROTOCOL`,
`EFI_MANAGED_NETWORK_PROTOCOL`,
+ `EFI_*_SERVICE_BINDING_PROTOCOL`, or any of the IPv4 or IPv6 protocols.
+ * - Byte stream device support (UART)
+ - UEFI protocols not required
+ * - PCI bus support
+ - UEFI protocols not required
+ * - USB bus support
+ - UEFI protocols not required
+ * - NVMe pass through support
+ - UEFI protocols not required
+ * - SCSI pass through support
+ - UEFI protocols not required
+ * - SCSI pass through support
+ - UEFI protocols not required
+ * - `EFI_DRIVER_FAMILY_OVERRIDE_PROTOCOL`
+ - Not required
+ * - Option ROM support
+ - EBBR implementations are not required to support option ROM loading
+
+Required Global Variables
+-------------------------
+
+EBBR compliant platforms are required to implement the following Global
+Variables as found in [UEFI]_ § 3.3.
+
+.. list-table:: Required UEFI Variables
+ :widths: 25 75
+ :header-rows: 1
+
+ * - Variable Name
+ - Description
+ * - `Boot####`
+ - A boot load option. #### is a numerical hex value
+ * - `BootCurrent`
+ - The boot option that was selected for the current boot
+ * - `BootNext`
+ - The boot option that will be used for the next boot only
+ * - `BootOrder`
+ - An ordered list of boot options.
+ Firmware will attempt each Boot#### entry in this order
+ * - `OsIndications`
+ - Method for OS to request features from firmware
+ * - `OsIndicationsSupported`
+ - Variable for firmware to indicate which features can be enabled
Block device partitioning
-------------------------
@@ -148,7 +297,7 @@ are required to be implemented during boot services and
runtime services.
.. table:: EFI_RUNTIME_SERVICES Implementation Requirements
============================== ============= ================
- EFI_RUNTIME_SERVICES function Boot Services Runtime Services
+ EFI_RUNTIME_SERVICES function Before EBS() After EBS()
============================== ============= ================
EFI_GET_TIME Optional Optional
EFI_SET_TIME Optional Optional
--
2.20.1
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