Some systems (e.g. x86 APL) run SPL from read-only memory. The device
instances created by dtoc are therefore not writeable. To make things work
we would need to copy the devices to read/write memory.
To avoid this, add an option to use a separate runtime struct for devices,
just as is done for drivers. This can be used to hold information that
changes at runtime, avoiding the need for a copy.
Also add a Kconfig option for read-only SPL, which selects this feature.
Signed-off-by: Simon Glass <s...@chromium.org>
---
(no changes since v1)
common/spl/Kconfig | 24 ++++++++++++++++++++++++
dts/Kconfig | 22 ++++++++++++++++++++++
2 files changed, 46 insertions(+)
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 774541c02bc..584f8483e2e 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -276,6 +276,19 @@ config SPL_SEPARATE_BSS
location is used. Normally we put the device tree at the end of BSS
but with this option enabled, it goes at _image_binary_end.
+config SPL_READ_ONLY
+ bool
+ depends on SPL_OF_PLATDATA
+ # Bind cannot be supported because the udevice structs are in read-only
+ # memory so we cannot update the linked lists.
+ select SPL_OF_PLATDATA_NO_BIND
+ select SPL_OF_PLATDATA_RT
+ help
+ Some platforms (e.g. x86 Apollo Lake) load SPL into a read-only
+ section of memory. This means that of-platdata must make a copy (in
+ writeable memory) of anything it wants to modify, such as
+ device-private data.
+
config SPL_BANNER_PRINT
bool "Enable output of the SPL banner 'U-Boot SPL ...'"
default y
@@ -1440,6 +1453,17 @@ config TPL_STACK
The address of the initial stack-pointer for the TPL stage.
Usually this will be the (aligned) top-of-stack.
+config TPL_READ_ONLY
+ bool
+ depends on TPL_OF_PLATDATA
+ select TPL_OF_PLATDATA_NO_BIND
+ select TPL_OF_PLATDATA_RT
+ help
+ Some platforms (e.g. x86 Apollo Lake) load SPL into a read-only
+ section of memory. This means that of-platdata must make a copy (in
+ writeable memory) of anything it wants to modify, such as
+ device-private data.
+
config TPL_BOOTROM_SUPPORT
bool "Support returning to the BOOTROM (from TPL)"
help
diff --git a/dts/Kconfig b/dts/Kconfig
index d289752a139..e6bbdc596bd 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -380,6 +380,17 @@ config SPL_OF_PLATDATA_NO_BIND
some code space in U-Boot. This can be disabled if binding is needed,
at the code of some code size increase.
+config SPL_OF_PLATDATA_RT
+ bool "Use a separate struct for device runtime data"
+ depends on SPL_OF_PLATDATA_INST
+ default y
+ help
+ For systems running SPL from read-only memory it is convenient to
+ separate out the runtime information, so that the devices don't need
+ to be copied before being used. This moves the read-write parts of
+ struct udevice (at present just the flags) into a separate struct,
+ which is allocated at runtime.
+
endif
config TPL_OF_PLATDATA
@@ -429,6 +440,17 @@ config TPL_OF_PLATDATA_NO_BIND
some code space in U-Boot. This can be disabled if binding is needed,
at the code of some code size increase.
+config TPL_OF_PLATDATA_RT
+ bool "Use a separate struct for device runtime data"
+ depends on TPL_OF_PLATDATA_INST
+ default y
+ help
+ For systems running TPL from read-only memory it is convenient to
+ separate out the runtime information, so that the devices don't need
+ to be copied before being used. This moves the read-write parts of
+ struct udevice (at present just the flags) into a separate struct,
+ which is allocated at runtime.
+
endif
endmenu
--
2.30.0.478.g8a0d178c01-goog
