On 18/05/2018 16:28, Daniel Thompson wrote:
On Fri, May 18, 2018 at 02:06:09PM +0100, Grant Likely wrote:
Be specific that an EBBR platform must provide either ACPI or Devicetree
data in the EFI configuration table, but not both. Platforms are allowed
to support both ACPI & DT booting as a configuration option, but only
one interface can be presented to the OS at a time.
Also add references to the ACPI and Devicetree specifications.
Fixes #5
Signed-off-by: Grant Likely <[email protected]>
---
source/ebbr.rst | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/source/ebbr.rst b/source/ebbr.rst
index 7adcd0a..858bd01 100644
--- a/source/ebbr.rst
+++ b/source/ebbr.rst
@@ -198,9 +198,16 @@ Configuration Tables
--------------------
A UEFI system that complies with this specification may provide the additional
-tables via the EFI Configuration Table.
-For example, ACPI table or Device Tree table may be needed to support
-configuration and power management.
+tables via the EFI Configuration Table. At a minimum, the system must provide
Perhaps remove "At a minium"? It implies both might acceptable but that
is then ruled out in the following paragraph.
I was trying to get across that it isn't acceptable to provide neither,
without ruling out other supplmental tables. ie. SMBIOS.
Would this be better?
A UEFI system that complies with this specification may provide
the additional tables via the EFI Configuration Table.
+
+EBBR systems are required to provide one, but not both, of the
+following supplimental tables.
+
+- An Advanced Configuration and Power Interface[ACPI_] table, or
+- A Devicetree[DTSPEC_] system description.
+
+As stated above, an EBBR system must not provide both ACPI and
+Devicetree tables at the same time. Platforms that want to offer
+both ACPI and Devicetree solutions must implement a boot time
+mechanism to select one or the other, before the OS Loader is
+executed.
+system data that conforms with either:
+
+- the Advanced Configuration and Power Interface specification[ACPI_], or
+- the Devicetree Specification[DTSPEC_].
+
+While a platform may provide either ACPI or Devicetree, it must not
+provide both at the same time. Platforms that want to offer
+both ACPI and Devicetree solutions must implement a boot time mechanism
+to select one or the other before an OS Loader is executed.
UEFI Secure Boot (Optional)
---------------------------
@@ -524,6 +531,9 @@ EFI_ISCSI_INITIATOR_NAME_PROTOCOL 16.2
.. [ACPI] `Advanced Configuration and Power Interface specification v6.2A
<http://www.uefi.org/sites/default/files/resources/ACPI%206_2_A_Sept29.pdf>`_,
September 2017, `UEFI Forum <http://www.uefi.org>`_
+.. [DTSPEC] `Devicetree specification v0.2
+
<https://github.com/devicetree-org/devicetree-specification/releases/tag/v0.2>`_,
+ `Devicetree.org <https://devicetree.org>`_
.. [PSCI] `Power State Coordination Interface Issue D (PSCI v1.1)
<http://infocenter.arm.com/help//topic/com.arm.doc.den0022d/Power_State_Coordination_Interface_PDD_v1_1_DEN0022D.pdf>`_,
21 April 2017, `Arm Limited <http://arm.com>`_
--
2.13.0
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