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 ---
(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 645a2d2b84d..a6bfa706637 100644 --- a/dts/Kconfig +++ b/dts/Kconfig @@ -379,6 +379,17 @@ config SPL_OF_PLATDATA_NO_BIND This removes the ability to bind devices at run time, thus saving some code space in U-Boot.
+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 @@ -427,6 +438,17 @@ config TPL_OF_PLATDATA_NO_BIND This removes the ability to bind devices at run time, thus saving some code space in U-Boot.
+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