The directory goal_media contains:

• media adapters: generic driver interfaces

• media interfaces: generic interfaces between media adapters and higher layers

One source and one header files exist for each GOAL media module. Only the sources for the necessary GOAL media modules shall be integrated in the compiler-project of the GOAL system. The registration is described in Chapter: Platform API. The functions are described in detail in the GOAL Reference Manual.
Figure 21 demonstrates the easy exchange of drivers.

Nonvolatile storage

GOAL provides a media adapter and media interface for the nonvolatile storage usable for program downloads and uploads by a bootloader or for the nonvolatile storage of configuration data. The nonvolatile storage media allows:

• to write data to the nonvolatile memory,

• to read data from the nonvolatile memory and

• to erase the nonvolatile memory.

NVS media interface

The media adapter is registered to the media interface by function goal_miNvsReg(). The resource "NVS media interface" must be allocated by function goal_miNvsAlloc(). The media interface is freed by function goal_miNvsFree().
The media interface allows to manage single memory ranges, called regions. Therewith it is possible to assign different memory ranges to various processes and to control the access to the nonvolatile memory process-specific. Each region is identified by an ID, called MI-NVS-REGION-ID, unique. This ID can be specified application-specific. But each ID must only exist once. During registration a unique handle is created for each MI-NVS-REGION-ID. Each region has to be registered to the media interface for nonvolatile storage by higher layers in the state GOAL_FSA_INIT. A region has the following properties:

Table: properties of NVS regions

Implementation guidelines

Registration of a memory region

1. Specify a region and define a MI-NVS-REGION-ID:
   
   

   #define GOAL_ID_MI_NVS_REGION_CONFIG_DATA 2

    

2. Create a MA-handle:
   
   

   GOAL_MA_NVS_T *pMaNvs;

    

3. Select the suitable NVS driver and initialize the driver. The driver registers to the media adapter by itself.

4. Create a MI-handle:
   
   

   GOAL_MI_NVS_T *pMiNvsHdl;

    

5. Register the media interface:
   
   

    

6. Allocate the NVS service:
   
   

    

7. Create a MI-NVS-REGION-handle:
   
   

    

8. Register and configure the memory region: The memory range starts at address 0x0001FFF and has a length of 0x100 byte. The region shall complete. Configurtion data shall be read and written.
   
   

Write data to nonvolatile memory

1. Load MI-NVS-REGION-handle of the memory region with the ID GOAL_ID_MI_NVS_REGION_CONFIG_DATA:
   
   

    

2. Erase the nonvolatile memory region:
   
   

    

3. Write data of size bytes to nonvolatile memory region:
   
   

Read data from nonvolatile memory

1. Load MI-NVS-REGION-handle of the memory region with the ID GOAL_ID_MI_NVS_REGION_CONFIG_DATA:
   
   

    

2. Read data from nonvolatile memory:
   
   

NVS media adapter

The selected NVS driver registers itself to the NVS media adapter.

Implementation guidelines

These implementation guidelines refer to the case, that no NVS media interface is used.

Write data to nonvolatile memory

1. Create a MA-handle:
   
   

    

2. Select the suitable NVS driver and initialize the driver. The driver registers to the media adapter by itself.

3. Create a NVS description:
   
   

    

4. Erase 0x100 bytes in the nonvolatile memory from start address 0x0001FFF:
   
   

    

5. Write 0x100 bytes from the buffer pData to the nonvolatile memory on start address 0x0001FFF:
   
   

Read data from nonvolatile memory

1. Create a MA-handle:
   
   

    

2. Select the suitable NVS driver and initialize the driver. The driver registers to the media adapter by itself.

3. Create a NVS description:
   
   

    

4. Read 0x100 bytes from the start address 0x0001FFFF in the nonvolatile memory and store the data in pData:
   
   

LED

GOAL provides a media adapter for the controlling of LEDs. Standardized communication protocols often need status LEDs. The application can also use the LED media adapter to control LEDs application-specific. The media adapter for LEDs allows to handle

• single LEDS and

• groups of LEDs

The used hardware resources for the controlling of LEDs are encapsulated in the LED driver and depends on the platform. Details are described in the suitable GOAL Platform Manual. It is possible to control the LEDs via GPIOs or about a serial bus as IIC.
The media adapter provides the following functionality:

• open/close a media adapter for a single LED or a group of LEDs,

• get/set the state of a single LED,

• get/set the state of a group of LEDs.

The get-functions require, that the current LED state is readable from the platform.
The connection between the LED driver and the LED media adapter is identified by a MA-ID unique. The determination of the MA-ID is described in the suitable GOAL Platform Manual. The most LED drivers uses a MA-ID created by the application. The application has to assign single LEDs and/or groups of LEDs to MA-IDs during the platform initialization in the state GOAL_FSA_INIT.
A group of LEDs can consist of maximal 32 LEDs. The mask and state value have data type uint32_t and are bit-coded. Each LED in the LED group shall use the same bit position in the mask and state value. The interpretation of the bit values of the LED states is platform-specific. Maybe the application has to consider the polarity of the LEDs. The bit values for the mask are defined as follow:

Table: mask bit coding for groups of LEDs

Implementation guidelines

Switch on/off and get the state of a single LED

1. Define a MA-ID for a single LED:
   
   

    

2. Call the LED driver function to initialize the LED hardware resource and to register the LED driver for a single LED to the LED media adapter in state GOAL_FSA_INIT.

3. Open a media adapter instance and get the MA-SPI handle:
   
   

    

4. Switch on the LED:
   
   

    

5. Get the current state of the LED:
   
   

    

6. Close the media adapter instance:
   
   

Switch on/off and get the state of a LED group

A group of 32 LEDs shall be controlled.

1. Define a MA-ID for a group of LEDs:
   
   

    

2. Call the LED driver function to initialize the hardware resource for all LEDs and to register the LED driver for a group of LEDs to the LED media adapter in state GOAL_FSA_INIT.

3. Open a media adapter instance and get the MA-SPI handle:
   
   

    

4. Switch on the LEDs assigned to bit 31-24, do not change the LEDs assigned to bit 23-16, switch off LEDs assigned to bit 15-0:
   
   

    

5. Get the current state of all LEDs in the LED group:
   
   

    

6. Close the media adapter instance:
   
   

SPI

GOAL provides a media adapter for the SPI communication. The media adapter provides the following functionality:

• open/close a media adapter for a SPI-channel

• get/set a general SPI-configuration

• read data from the SPI-bus

• write data to the SPI-bus

• write and read data to/from the SPI-bus

• report events to higher layers

GOAL defines the following general SPI configuration settings:

Table: general SPI configuration settings

The SPI-configuration can be set by function goal_maSpiConfigSet(). The current SPI-configuration can be read by function goal_maSpiConfigGet(). The support of the SPI configuration settings depends on the SPI driver and the SPI controller. Details are described in the suitable GOAL Platform Manual.
SPI events are handled event-driven about an application-specific callback function. The supported events depend on the SPI driver and the availability on the SPI controller. GOAL provides the following events:

Table: general SPI events

The connection between the SPI driver and the SPI media adapter is identified by a MA-ID unique. The determination of the MA-ID is described in the suitable GOAL Platform Manual. The most SPI drivers determine the MA-ID by itself.

Callback functions

Table: Callback functions

Implementation guidelines

Read and write data via the SPI-bus

1. Call the SPI driver function to initialize the SI controller and to register the SPI driver to the SPI media adapter in state GOAL_FSA_INIT. During this guideline GOAL_MA_ID_SPI is used to mark the MA-ID. During the registration a unique MA-SPI handle is created.

2. Implement a callback function to handle SPI events:
   
   

    

3. Open the media adapter, specify the callback function to handle SPI events and get the MA-SPI handle:
   
   

    

4. Write 4 byte stored in pData to the SPI-bus:
   
   

    

5. Read data from the SPI-bus and store the data to pData:
   
   

    

6. Write 4 byte stored in pWriteData to the SPI-bus and read data from SPI-bus and store the read data to pReadData at the same time:
   
   

Configure the SPI interface

1. Get the current general SPI configuration of an opened MA:
   
   

    

2. Specify SPI mode 0:
   
   

    

3. Set SPI configuration:
   
   

Handle SPI events

1. Call the SPI driver function to initialize the SI controller and to register the SPI driver to the SPI media adapter in state GOAL_FSA_INIT. During this guideline GOAL_MA_ID_SPI is used to mark the MA-ID. During the registration a unique MA-SPI handle is created.

2. Implement a callback function to handle SPI events:
   
   

    

3. Open the media adapter, specify the callback function to handle SPI events and get the MA-SPI handle:
   
   

    

4. If a SPI event occurs, the callback function cbApplMaSpiEvent is called.

TLS

GOAL provides a functionality for encryption and authentication of TCP packets on the base of the Transport Layer Security (TLS) protocol /TLS_RFC_5246/. The functionality of TLS requires:

• a TLS library,

• a GOAL driver for the integration of the TLS library into the GOAL system,

• a GOAL media adapter for TLS in order to use a generic interface for TLS in GOAL and.

• a GOAL media interface for TLS to handle TLS connections in a driver independent abstract layer.

GOAL allows to implement various libraries for cryptographic and transport layer security capabilities. The GOAL TLS media adapter makes it possible to exchange the TLS library with less effort. The TLS functionality is embedded into the GOAL core module for the network handling.
The TLS functionality comprises:

• encryption/decryption of TCP packets and

• the authentication by a X509-certificate.

The authentication is realized by a X509-certificate. The application can specify an own private key and an own X509-certificate by function goal_miTlsOpen(). The private key must have a length between 1024 bit and 2048 bit. If no X509-certificate is specified a default certificate is taken. The default certificate is port-specific.
The GOAL TLS media adapter allows:

• to open/close a GOAL TLS channel and

• to get information from the X509-certificate about the certification authority, the organization providing the web-server and the validity period

The encryption and decryption are made by the TLS library internally.

• example:

  • …\goal\appl\00410_goal\tls*

Configuration

The following compiler-defines are available to configure TLS:

• GOAL_CONFIG_TLS:

  • 0: TLS is disabled (default)

  • 1: TLS is enabled

mbed TLS library

GOAL supports the open source library mbed TLS. The following sources must be added to the compiler-project:

Table: mbed TLS libary

The GOAL driver for the mbed TLS library provides the following function for the registration to the GOAL TLS media adapter:

Table: goal_tlsMbedtlsInit

The application has to specify a MA-ID. There is no driver-specific rule for the construction of the MA-ID.
The execution of the algorithm for encryption/decryption needs some time and is processed in an own task to allow, that the algorithm can be interrupted by functions with higher priority. This method requires an operating system.
Further the application has to specify a MI-ID. This can be the same as the MA-ID This allows to switch between differnt TLS drivers more easily. The opening function of the GOAL TLS media is executed by function goal_miTlsOpen(). The application has to call the function goal_miTlsOpen() in the state GOAL_FSA_INIT_SETUP to initialize and to open the channels.
The function for getting information from the X509-certificate the GOAL TLS driver function is mapped to the function goal_miTlsReadInfo(). The function goal_miTlsReadInfo() is called by the application in the state GOAL_FSA_OPERATION.

Implementation guidelines

Initialize TLS

This example uses the mbed TLS library.

1. Define both a MA-ID and a MI_ID.

    

2. Integrate the initialization of the GOAL TLS media adapter in the stage GOAL_STAGE_MODULES in application-specific function appl_setup(). Here a certificate structure may be given to the media adapter. If no is given, the media adapter uses a default certificate.

    

3. Create a GOAL net channel for the output of the GOAL TLS media adapter.

    

4. Configure the GOAL net channel as non-blocking.

    

5. Get the handle for the TLS session determined by the MI-ID and open the TLS channel.

    

6. Connect the GOAL net channel (TLS) to the GOAL net channel and specify a callback function to handle packets from the TCP client.

    

7. Create a callback function to handle packets from the TCP client, see Chapter: Callback functions: cbNetFunc().

Use a TLS channel

1. TCP/IP packets are transmitted and received encrypted. Only valid TCP/IP packages pass the TLS module.

2. Information from the certificate can be required.

CMFS

CMFS is a media interface working on top of the NVS media interface. It requires 2 serparate NVS regions for storing CM variables. Despite the plain CM implementation, which stores the whole CM variable store as a binary blob in flash, CMFS only writes modifications to the NVS region. Thereby the NVS region is sequientially written, thus a time consuming erase of the NVS region is not required. However if the NVS region is nearly fully written, the current state of variables is transferred to the secondary NVS region, where all continuing write operations take place.
This CMFS has some advantages over the plan CM implementation:

• NVS write operations can be performed much faster

• Data loss during reset while NVS is written can be omitted

To achive this, more NVS storage space needs to be reserved.

Integration of CMFS

Following except from goal_target_board.c shows integration of CMFS.

In order to utilize CMFS, the following configuration option must be enabled.

• GOAL_CONFIG_MEDIA_MI_CMFS:

  • 0: CMFS is not utilized (default)

  • 1: CMFS is utilized
    
    

This configuration option and the required files are added when the following feature is enabled in the Makefile, when using the GOAL build system:

Ethernet Frame Handler

Introduction

GOAL provides a Media Interface and Adapter for Ethernet based data exchange and protocols like HTTP or EtherCAT over Ethernet, see Figure 11.
The Ethernet Frame Handler in the Media Interface receives all Ethernet frames through the generic Ethernet Media Adapter and the Ethernet driver. The frame processing load can be reduced by activating the MAC address filtering by the compiler-define GOAL_CONFIG_MAC_ADDR_FILTER. Then only all broadcast/multicast and the own unicast Ethernet frames pass the MAC filter and are received. This is only a software filter, which drop packets not directed to the device.
The Ethernet Frame Handler identifies received Ethernet frames on base of the

• MAC address

• the Ether Type

The values for the Ether Type are standardized in IEEE 802.3. GOAL supports the following Ether Types:

• 0800h: IP Internet Protocol, version 4 (IPv4)

• 0806h: Address Resolution Protocol (ARP)

• 8100h: VLAN Tag

Other Ether Types are registeres by additional software components, such as the PNIO communication stack,
The Ethernet Frame Handler accepts all Ethernet frames if the Ether Type is set to GOAL_ETH_ETHERTYPE_ANY.
The kind of the identification is configured by function goal_miEthProtoAdd() or goal_miEthProtoAddPos().

The Ethernet frames can be divided in frames with low and high priority. The priority is also specified by function goal_miEthProtoAdd() or goal_miEthProtoAddPos(). The type of identification and the priority determine the handling of received frames, see Figure 12.

During the interrupt-controlled receipt the callback function specified by function goal_miEthProtoAdd() or goal_miEthProtoAddPos() is called immediately. For the loop-controlled handling the received message is stored internal and the callback function is called in the GOAL loop. The Ethernet Frame handler registers the function goal_miEthLoop() for this purpose.
Ethernet Frame HandlerEthernet controllers provide possibilities to analyze the Ethernet communication by counting of events represented as statistics, see Chapter: Statistics.
The generic Ethernet Frame Handler can be controlled via the command line interface, see Chapter Command line interface.

Configuration

Compiler-defines

The following compiler-defines are available to configure the generic Ethernet Frame Handler:

Table: Compiler-defines

CM-variables

The following CM-variables are available to configure the Configuration Manager:

Table: ETH_CM_VAR_MAC

Table: ETH_CM_VAR_LINK

Table: ETH_CM_VAR_SPEED

Table: ETH_CM_VAR_DUPLEX

Table: ETH_CM_VAR_PORTCNT

The generic Ethernet Frame Handler uses GOAL queues internally. The size of these queues can be optimized for the current platform. The configuration is described in Chapter: Internal queue usage.

Callback functions

The Ethernet frame handler supports callback functions

• for the receipt of Ethernet frames and

• to inform the application about the changed state of the Ethernet port.

The names of the callback functions are application-specific.

Table: cbEthFrameReceivedFunc()

Table: cbEthPortChangedFunc()

Ethernet interface

GOAL makes a general interface available to configure the Ethernet interface and to get state information about the Ethernet interface, e.g. the switch or PHY. There are two possibilities to access to the configuration setting or the state information:

• via special functions of the Ethernet Frame Handler or

• via the Ethernet command and the function goal_miEthCmd().

The implementation and the support of the Ethernet commands depend on the platform. The platform-specific details are described in the GOAL Platform Manual.
GOAL provides the following commands for the configuration of the Ethernet interface:

Table: GOAL_ETH_CMD_AUTONEG_PROGRESS

Table: GOAL_ETH_CMD_AUTONEG

Table: GOAL_ETH_CMD_AUTONEG_RESTART

Table: GOAL_ETH_CMD_DUPLEX

Table: GOAL_ETH_CMD_HW_FAULT

Table: GOAL_ETH_CMD_SPEED

Table: GOAL_ETH_CMD_SPEED_MAX

Table: GOAL_ETH_CMD_LINK_STATE

Table: GOAL_ETH_CMD_PORT_STATE

Table: GOAL_ETH_CMD_LINK_CAPABILITIES

Table: GOAL_ETH_CMD_AUTONEG_ADVERTISMENT

Table: GOAL_ETH_CMD_PORT_ADMIN_STATE

Table: GOAL_ETH_CMD_LED_LINK

Table: GOAL_ETH_CMD_PORT_COUNT

VLAN

GOAL makes a general interface available to configure the VLAN capabilities of the underlying switch. The access to the configuration setting or the state information is realized via Ethernet commands and the function goal_miEthCmd(). The implementation and the support of the Ethernet commands depend on the platform.
GOAL provides the following Ethernet commands for the VLAN capabilities:

Table: VLAN capabilities

MAC table

The MAC table subgroup provides an interface to the MAC table settings and allows to access to specific MAC table entries.
GOAL provides the following Ethernet commands for the handling of MAC table settings:

Table: Ethernet commands for the handling of MAC table settings

Port settings

Table: Ethernet commands for the handling of Port settings

QoS settings

Table: Ethernet commands for the handling of QoS settings

Implementation guidelines

Configure MAC address

With the generic Ethernet frame handler you can set an own MAC address in the application.

1. Configure the MAC address:
   
   

    

2. Set the MAC address:
   
   

It is highly recommended to set the MAC address before other function calls. The Ethernet frame handler will set the MAC address temporarily in the platform afterwards.

Open Media Interface and Adapter

The generic Ethernet frame handler in GOAL version 2.20.0 uses a new API, which requires an opened Media Interface, Adapter handle and Ethernet driver. In future the new API will make it possible to use more than one virtual Ethernet interface at a time.
To use the new API, you have to define CONFIG_MAKE_FEAT_MEDIA_MI_ETH = 1 in the file goal/projects/…/gcc/Makefile. Thereby you have to open the Media Interface and Adapter manually.
If you don't use this define, the default Ethernet Media Interface and Adapter will be opened and used.

1. Open the Media Interface Ethernet with the desired driver to use the Ethernet interface provided by the target. The specific driver is choosen by the Media Adapter ID. Per default it is GOAL_MA_ID_ETH.
   
   

   At this time there are only two Media Adapter ID's available: GOAL_MA_ID_ETH for Ethernet and GOAL_MA_ID_EOE for EtherCAT over Ethernet.
   
   

2. Open the TCP/IP stack to enable generic Ethernet frame handling.
   
   

   This is necessary to register intern callback functions of the TCP/IP stack, which reacts to received frames like ARP's et cetera.

Send and receive Ethernet frames

Ethernet frames shall be sent from the application directly, see Figure 11 Ethernet channel2:

1. Create a callback function to handle received Ethernet frames application-specific:
   
   

    

2. Register the callback function for the receipt of IPv4 Ethernet frames with a high priority:
   
   

    

3. If an Ethernet frame was received, the callback function cbEthFrameReceivedFunc() is called and the application can handle the Ethernet frame.

4. Send an Ethernet frame:
   
   

    

Dynamic Heap Memory Allocator

Various embedded platforms feature an OS, like Linux or FreeRTOS. These operating systems have their own memory management where allocating and freeing memory during runtime is common.

The Media Adapter for dynamic heap memory offers a generic interface of the OS it’s memory management unit to GOAL. So, memory can be allocate and free from OS heap. Even at runtime. But because the Dynamic Heap Memory Allocator is only as efficient as the OS, freeing may still result into fragmented memory regions. Thus, GOAL is using static heap prior the dynamic heap.

Open

schematic relation of static and dynamic heap on targets with OS

And what’s about bare metal platforms where are no OS available? For these targets, GOAL provides an own module for dynamic memory management.

Open

schematic relation of static and dynamic heap on bare metal targets

Comparison of static and dynamic Heap memory

Implementation guidelines

• GOAL files:

  • goal_media/goal_ma_heap.[h,c] – Header/Source file for dynamic HEAP Memory allocator

  • plat/drv/mem/heap/ - drivers for accessing OS or GOAL heap management unit

• example:

  • appl/00410_goal/heap - This module is an application, showing the dynamic HEAP access by running some tests.

There are two APIs for handling dynamic heap memory. First starts function naming by goal_maHeap and is confirm to the media adapter, requiring a driver ID. Second starts function naming by goal_maHeap and simplified the arguments by using GOAL_ID_DEFAULT as driver ID.

The following header has to be include for using the dynamic heap API.

Configuration

The size of the dynamic heap depends on the platform in use.

Targets with OS pretending the heap size by it’s configuration.
Targets without OS are using the GOAL heap management unit, which offers following compiler-defines.

• GOAL_CONFIG_HEAP_DYNAMIC_SIZE: absolute size of dynamic heap in bytes

• GOAL_CONFIG_HEAP_DYNAMIC_ADD_SIZE: offset size in bytes, increasing the minimum required heap (equals GOAL_CONFIG_HEAP_SIZE)

Allocate memory from dynamic heap

Code: example for allocate dynamic heap

Callocate memory from dynamic heap

Code: example for callocate dynamic heap

Free dynamic heap

Code: example for freeing heap

Reallocate dynamic heap memory

Code: example for reallocate memory

Code: reallocate can also be used allocate or free memory

Get dynamic heap statistics

GOAL offers some statistics about the dynamic heap.

Code: getting heap statistics