diff options
Diffstat (limited to 'doc/develop')
-rw-r--r-- | doc/develop/bloblist.rst | 16 | ||||
-rw-r--r-- | doc/develop/driver-model/migration.rst | 8 | ||||
-rw-r--r-- | doc/develop/environment.rst | 51 | ||||
-rw-r--r-- | doc/develop/index.rst | 1 | ||||
-rw-r--r-- | doc/develop/trace.rst | 9 |
5 files changed, 78 insertions, 7 deletions
diff --git a/doc/develop/bloblist.rst b/doc/develop/bloblist.rst index 317ebc4919..47274cf8e2 100644 --- a/doc/develop/bloblist.rst +++ b/doc/develop/bloblist.rst @@ -59,6 +59,22 @@ Bloblist provides a fairly simple API which allows blobs to be created and found. All access is via the blob's tag. Blob records are zeroed when added. +Placing the bloblist +-------------------- + +The bloblist is typically positioned at a fixed address by TPL, or SPL. This +is controlled by `CONFIG_BLOBLIST_ADDR`. But in some cases it is preferable to +allocate the bloblist in the malloc() space. Use the `CONFIG_BLOBLIST_ALLOC` +option to enable this. + +The bloblist is automatically relocated as part of U-Boot relocation. Sometimes +it is useful to expand the bloblist in U-Boot proper, since it may want to add +information for use by Linux. Note that this does not mean that Linux needs to +know anything about the bloblist format, just that it is convenient to use +bloblist to place things contiguously in memory. Set +`CONFIG_BLOBLIST_SIZE_RELOC` to define the expanded size, if needed. + + Finishing the bloblist ---------------------- diff --git a/doc/develop/driver-model/migration.rst b/doc/develop/driver-model/migration.rst index 8bb8601c58..3dbeea6537 100644 --- a/doc/develop/driver-model/migration.rst +++ b/doc/develop/driver-model/migration.rst @@ -98,3 +98,11 @@ Deadline: 2021.10 The I2C subsystem has supported the driver model since early 2015. Maintainers should submit patches switching over to using CONFIG_DM_I2C and other base driver model options in time for inclusion in the 2021.10 release. + +CONFIG_KEYBOARD +--------------- +Deadline: 2022.10 + +This is a legacy option which has been replaced by driver model. +Maintainers should submit patches switching over to using CONFIG_DM_KEYBOARD and +other base driver model options in time for inclusion in the 2022.10 release. diff --git a/doc/develop/environment.rst b/doc/develop/environment.rst new file mode 100644 index 0000000000..0b86fafbff --- /dev/null +++ b/doc/develop/environment.rst @@ -0,0 +1,51 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +Environment implementation +========================== + +See :doc:`../usage/environment` for usage information. + +Callback functions for environment variables +-------------------------------------------- + +For some environment variables, the behavior of u-boot needs to change +when their values are changed. This functionality allows functions to +be associated with arbitrary variables. On creation, overwrite, or +deletion, the callback will provide the opportunity for some side +effect to happen or for the change to be rejected. + +The callbacks are named and associated with a function using the +U_BOOT_ENV_CALLBACK macro in your board or driver code. + +These callbacks are associated with variables in one of two ways. The +static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC +in the board configuration to a string that defines a list of +associations. The list must be in the following format:: + + entry = variable_name[:callback_name] + list = entry[,list] + +If the callback name is not specified, then the callback is deleted. +Spaces are also allowed anywhere in the list. + +Callbacks can also be associated by defining the ".callbacks" variable +with the same list format above. Any association in ".callbacks" will +override any association in the static list. You can define +CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the +".callbacks" environment variable in the default or embedded environment. + +If CONFIG_REGEX is defined, the variable_name above is evaluated as a +regular expression. This allows multiple variables to be connected to +the same callback without explicitly listing them all out. + +The signature of the callback functions is:: + + int callback(const char *name, const char *value, enum env_op op, int flags) + +* name - changed environment variable +* value - new value of the environment variable +* op - operation (create, overwrite, or delete) +* flags - attributes of the environment variable change, see flags H_* in + include/search.h + +The return value is 0 if the variable change is accepted and 1 otherwise. diff --git a/doc/develop/index.rst b/doc/develop/index.rst index b3871b16f3..9592d193fc 100644 --- a/doc/develop/index.rst +++ b/doc/develop/index.rst @@ -16,6 +16,7 @@ Implementation devicetree/index distro driver-model/index + environment global_data logging makefiles diff --git a/doc/develop/trace.rst b/doc/develop/trace.rst index 09f5745a90..b22e068ef9 100644 --- a/doc/develop/trace.rst +++ b/doc/develop/trace.rst @@ -30,16 +30,11 @@ Sandbox is a build of U-Boot that can run under Linux so it is a convenient way of trying out tracing before you use it on your actual board. To do this, follow these steps: -Add the following to include/configs/sandbox.h (if not already there) +Add the following to config/sandbox_defconfig .. code-block:: c - #define CONFIG_TRACE - #define CONFIG_CMD_TRACE - #define CONFIG_TRACE_BUFFER_SIZE (16 << 20) - #define CONFIG_TRACE_EARLY_SIZE (8 << 20) - #define CONFIG_TRACE_EARLY - #define CONFIG_TRACE_EARLY_ADDR 0x00100000 + CONFIG_TRACE=y Build sandbox U-Boot with tracing enabled: |