diff options
Diffstat (limited to 'doc/bsp_howto/init.t')
| -rw-r--r-- | doc/bsp_howto/init.t | 58 |
1 files changed, 18 insertions, 40 deletions
diff --git a/doc/bsp_howto/init.t b/doc/bsp_howto/init.t index f0dde45cb3..f91d15f934 100644 --- a/doc/bsp_howto/init.t +++ b/doc/bsp_howto/init.t @@ -147,34 +147,29 @@ The @code{boot_card()} routine performs the following functions: @item It disables processor interrupts. -@item It sets the global program name and command line argument variables +@item It sets the command line argument variables for later use by the application. -@item If the macro is BSP_BOOTCARD_HANDLES_RAM_ALLOCATION is defined, it -will invoke the BSP specific @code{bsp_get_work_area} function to obtain -information on the amount and location of BSP RAM that is available to -be allocated to the C Program Heap and RTEMS Workspace. If the amount -of memory available for the RTEMS Workspace is less than that required -by the application (e.g. @code{rtems_configuration_get_work_space_size()}, -then a message is printed using @code{printk}, @code{bsp_cleanup} is -invoked, and -1 is return to the assembly language start code. BSPs which -use this memory allocation functionality in @code{bootcard.c} -must invoke the RTEMS specific autoconf macro -@code{RTEMS_BSP_BOOTCARD_HANDLES_RAM_ALLOCATION} in the BSP's -@code{configure.ac} file. - @item It invokes the BSP specific routine @code{bsp_start()} which is written in C and thus able to perform more advanced initialization. Often MMU and bus initialization occurs here. +@item It invokes the BSP specific routine @code{bsp_work_area_initialize()} +which is supposed to initialize the RTEMS Workspace and the C Program Heap. +Usually the default implementation in +@code{c/src/lib/libbsp/shared/bspgetworkarea.c} should be sufficient. Custom +implementations can use @code{bsp_work_area_initialize_default()} or +@code{bsp_work_area_initialize_with_table()} available as inline functions from +@code{#include <bsp/bootcard.h>}. + @item It invokes the RTEMS directive @code{rtems_initialize_data_structures()} to initialize the RTEMS executive to a state where objects can be created but tasking is not enabled. -@item If the macro is BSP_BOOTCARD_HANDLES_RAM_ALLOCATION is defined, -it will calculate the memory available for the C Program Heap and invoke -the initialization routine for the C Library with this information. +@item It invokes the BSP specific routine @code{bsp_libc_init()} to initialize +the C Library. Usually the default implementation in +@code{c/src/lib/libbsp/shared/bsplibc.c} should be sufficient. @item It invokes the BSP specific routine @code{bsp_pretasking_hook}. On most BSPs which utilize the framework, this routine does nothing. @@ -188,9 +183,7 @@ thread in a multiprocessor configuration and execute API specific extensions. @item It invokes the BSP specific routine @code{bsp_predriver_hook}. For -most BSPs, the implementation of this routine does nothing. However, -on some BSPs, required subsystems which utilize the C Library -(e.g. @code{malloc} in particular) may be initialized at this point. +most BSPs, the implementation of this routine does nothing. @item It invokes the RTEMS directive @code{rtems_initialize_device_drivers()} to initialize the statically @@ -255,28 +248,13 @@ routine. @subsection RTEMS Pretasking Callback -The method @code{bsp_pretasking_hook()} is the BSP specific routine -invoked once RTEMS API initialization is complete but before interrupts -and tasking are enabled. No tasks -- not even the IDLE task -- have -been created when this hook is invoked. The pretasking hook is optional +The method @code{bsp_pretasking_hook()} is the BSP specific routine invoked +once RTEMS API initialization is complete but before interrupts and tasking are +enabled. The idle thread exists at this time. The pretasking hook is optional and the user may use the shared version. -The @code{bsp_pretasking_hook()} routine is the appropriate place to -initialize any support components which depend on the RTEMS APIs. -Older BSPs that do not take full advantage of @code{boot_card()} -may initialize the RTEMS C Library in their implementation of -@code{bsp_pretasking_hook()}. This initialization includes the -application heap used by the @code{malloc} family of routines as well -as the reentrancy support for the C Library. - -The routine @code{bsp_libc_init} routine invoked from the -either @code{boot_card()} or (less preferable) the BSP specific -@code{bsp_pretasking_hook()} routine is passed the starting address, -length, and growth amount passed to @code{sbrk}. This "sbrk amount" -is only used if the heap runs out of memory. In this case, the RTEMS -malloc implementation will invoked @code{sbrk} to obtain more memory. -See @ref{Miscellaneous Support Files sbrk() Implementation} for more -details. +The @code{bsp_pretasking_hook()} routine is the appropriate place to initialize +any BSP specific support components which depend on the RTEMS APIs. @subsection RTEMS Predriver Callback |