CDI Device Driver

Detailed Description

Usage considerations

• Allowed context for the API call
  • Interrupt handler: No
  • Signal handler: No
  • Thread-safe: No
  • Re-entrant: Yes
  • Async/Sync: Sync
• Required privileges: Yes, with the following conditions:
  • Grants: nonroot, allow
  • Abilities: public_channel
  • Application needs to have access to the SGIDs that SIPL depends on as mentioned in the NVIDIA DRIVE OS Safety Developer Guide
• API group
  • Init: Yes
  • Runtime: Yes
  • De-Init: Yes

Program elements related to DevBlkCDIDeviceDriver, which defines a device driver. The core DevBlkCDI calls the driver when the client calls the related public DevBlkCDI function.

Before the client can create an DevBlkCDIDevice object (a device), it must provide a device driver. The DevBlkCDIDeviceDriver object contains the following data fields and function pointers.

Data Fields

• deviceName The name of the device. This is a null-terminated string.
• regLength Target device offset length in bytes. Valid Range: [1, 2].
• dataLength Target device data length in bytes. Valid Range: [1, 2].

Function Pointers

• DriverCreate (mandatory). Invoked when the client calls DevBlkCDIDeviceCreate().
• DriverDestroy (mandatory). Invoked when the client calls DevBlkCDIDeviceDestroy().
• GetModuleConfig (optional). Invoked when the client calls DevBlkCDIGetModuleConfig(). Not supported for safety use cases.
• ParseTopEmbDataInfo (optional). Invoked when the client calls DevBlkCDIParseTopEmbDataInfo().
• ParseTopEmbDataInfo (optional). Invoked when the client calls DevBlkCDIParseTopEmbDataInfo().
• SetSensorControls (optional). Invoked when the client calls DevBlkCDISetSensorControls().
• GetSensorAttributes (optional). Invoked when the client calls DevBlkCDIGetSensorAttributes().
• SetSensorCharMode (optional). Invoked when the client calls DevBlkCDISetSensorCharMode(). Not supported for safety use cases.
• ReadRegister (optional). Not supported for safety use cases.
• WriteRegister (optional). Not supported for safety use cases.

Here is a sample device driver implementation. The source file defines the driver by creating an DevBlkCDIDeviceDriver struct and setting its function pointers. The header file provides a function that retrieves a pointer to the driver struct.

Header File

#include <devblk_cdi.h>
 
DevBlkCDIDeviceDriver *GetSAMPLEDEVICEDriver(void);

Source File

#include "cdi_sample_device.h"
 
static NvMediaStatus
DriverCreate(
    DevBlkCDIDevice *handle,
    void *clientContext)
{
    if(!handle)
        return NVMEDIA_STATUS_BAD_PARAMETER;
 
    Can be used to maintain local device context
    or can be set to NULL.
    handle->deviceDriverHandle = NULL;
 
    return NVMEDIA_STATUS_OK;
}
 
static DevBlkCDIDeviceDriver deviceDriver = {
    .deviceName = "Sample Sensor Device",
    .DriverCreate = DriverCreate
};
 
DevBlkCDIDeviceDriver *
GetSAMPLEDEVICEDriver(void)
{
    Return device driver descriptor structure
    return &deviceDriver;
}

Data Structures
struct	DevBlkCDIDeviceDriver
	Holds device driver data. More...