Hello Karel,
On 30/11/2021 12:04, Karel Gardas wrote:
just a question. Do you plan to preserve functionality of _Heap_Extend()
in the future?
this feature is still available. However, there was a significant change
in the handling of BSP-provided memory areas between RTEMS 5 and 6.
Asking since I'm using it for amd64/uefi bsp. During the
bsp start I get efi services pointers and use that to traverse memory
map. Based on available free blocks I try to allocate memory using EFI
API and if successful I'm calling _Heap_Extend with it to pass ram to
RTEMS. That's the way I found out by searching in the tree in lpc24xx
and lpc176x bsps. Pity I've not found altera-cyclone-v at that time
since this looks even more similar to what I need to achieve here. Will
need to analyze it better (weekend task).
As I'm still trying to understand better memory allocation in RTEMS, I'm
of course open to any idea how to implement this in the most clean way
acceptable for RTEMS and not using _Heap_Extend() -- if it would not be
allowed or right thing to do or scheduled for future removal.
In RTEMS 6, the BSP has to provide a _Memory_Get() function which
returns the memory areas which may be used by RTEMS at runtime. Most
BSPs just return a single memory area. A BSP can also return multiple
memory areas:
static Memory_Area _Memory_Areas[ 123 ];
static const Memory_Information _Memory_Information =
MEMORY_INFORMATION_INITIALIZER( _Memory_Areas );
static void bsp_memory_initialize( void )
{
size_t i;
for ( i = 0; i < RTEMS_ARRAY_SIZE( _Memory_Areas ); ++i ) {
_Memory_Initialize( &_Memory_Areas[ i ], begin( i ), end( i ) );
}
}
RTEMS_SYSINIT_ITEM(
bsp_memory_initialize,
RTEMS_SYSINIT_MEMORY,
RTEMS_SYSINIT_ORDER_MIDDLE
);
const Memory_Information *_Memory_Get( void )
{
return &_Memory_Information;
}
What the patch set changed is that the BSP provides specialized
implementations to initialize the RTEMS Workspace and the separate C
Program Heap according to the _Memory_Get() implementation.
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