FreeRTOS portage to PIP kernel.

• Demo/Common/: FreeRTOS original extension (version 9.0)
• Demo/pip-kernel/: FreeRTOS entry point
• libfreertos/: user-space FreeRTOS library
• Source/: FreeRTOS core and portage sources

Required changes :

• In Source/include/FreeRTOSConfig.h change the macro MAX_PAGE size of default allocated memory size for each child
• In main.c, you have to initialize the available memory for FreeRTOS with Libpip function initPaging. In the case of using FreeRTOS as the root partition, you can do it like this :

initPaging((void*)bootinfo->membegin,(void*)bootinfo->memend);

or in FreeRTOS as support for subpartition :

  initPaging((void*)0x1C00000,(void*)(0x1C00000+(MAX_PAGE*0x1000)));

bootinfo is a C struct available for each root partition, given by Pip through the entrypoint first parameter.

To add new task-partitions :

• To add task-partitions for FreeRTOS, you have to put them into Demo/pip-kernel/Support_Files/aes.hpartitions_images/

• Include the binary corresponding to the task into Demo/pip-kernel/Support_Files/partition.S

• Create a new protected task into your source code, example for two binary file per task-partition :

  In partitions.S

  .section .partition1
  .incbin "Support_Files/partitions_images/part1.bin"
  
  .section .partition2
  .incbin "Support_Files/partitions_images/part2.bin"

  In main.c :

  extern void* _partition1, *_epartition1;
  extern void* _partition2, *_epartition2;
  static const struct {
      uint32_t start, end;
  } partitions[] = { { (uint32_t) &_partition1, (uint32_t) &_epartition1 },
      (uint32_t) &_partition2, (uint32_t) &_epartition2 };

  You have to create the task-partition with the function xTaskCreateProtected :

  uint32_t size = partitions[0].end - partitions[0].start;
  xTaskCreateProtected(partitions[0].start, "partition name", size, NULL, configMAX_PRIORITIES - 1, NULL);

To use FreeRTOS task-partition services

FreeRTOS for Pip implment a set of services. Theses services are :

• QUEUE message service
• SBRK-like service
• to be continue...

Theses services are implemented through Pip software interrupt mechanism.

Queue message service

The queue message service is accessible via notifying FreeRTOS for Pip with this interrupt numbers :

#define queueCreate     0x15
#define queueSend       0x16
#define queueReceive    0x17
#define channelCom      0x19

Each service is associated to a data structure containing all required information by FreeRTOS for Pip. Otherwise, in the child partition, for creating a queue, the structure is :

struct xQueueCreateParameters_s {
  uint32_t lenght;
  uint32_t size_type;
  uint32_t returnCall;
};
typedef struct xQueueCreateParameters_s xQueueCreateParameters;

All other associated structure are available in Source/portable/GCC/pip-kernel/partitionServices.h

And the procedure is :

xQueueCreateParameters * createArgs = (xQueueCreateParameters*) allocPage();
createArgs->lenght = SIZE_OF_THE_QUEUE;
createArgs->size_type = SIZE_OF_EACH_MESSAGE;
createArgs->returnCall = (uint32_t)0xDEADBEEF;

Pip_Notify(0,0x80,0x15,createArgs);
/* */

List of parameters :

• 0 for the parent (FreeRTOS),
• 0x80 is the service interrupt number in FreeRTOS
• 0x15 is the service code for createQueue,
• createArgs is the pointer to the structure needed for Queue creating

An example of typical child partition using theses services is available in Service_example.md