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dm: core: Add an option to support SPL in read-only memory

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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 <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2021-03-15 17:25:35 +13:00
parent 6c914e4232
commit 95a5825f31
2 changed files with 46 additions and 0 deletions
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24
common/spl/Kconfig
View File

@ -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

22
dts/Kconfig
View File

@ -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