System information

This section describes the classes CMachineInfo and CKernelOptions, which provide information about the Raspberry Pi model, on which the application is running, and the runtime options, which can be defined in the file cmdline.txt on the SD card.

CMachineInfo

Normally there is exactly one instance of the class CMachineInfo in the system, which is created by the Circle system initialization code. If another instance is created, it acts as an alias for the first instance.

#include <circle/machineinfo.h>
class CMachineInfo
static CMachineInfo *CMachineInfo::Get(void)

Returns a pointer to the first instance of CMachineInfo.

Model information

TMachineModel CMachineInfo::GetMachineModel(void) const

Returns the Raspberry Pi model, the application is running on. Possible values are:

  • MachineModelA

  • MachineModelBRelease1MB256

  • MachineModelBRelease2MB256

  • MachineModelBRelease2MB512

  • MachineModelAPlus

  • MachineModelBPlus

  • MachineModelZero

  • MachineModelZeroW

  • MachineModelZero2W

  • MachineModel2B

  • MachineModel3B

  • MachineModel3APlus

  • MachineModel3BPlus

  • MachineModelCM

  • MachineModelCM3

  • MachineModelCM3Plus

  • MachineModel4B

  • MachineModel400

  • MachineModelCM4

  • MachineModelCM4S

  • MachineModel5

  • MachineModel500

  • MachineModelCM5

  • MachineModelCM5Lite

  • MachineModelCM0

  • MachineModelUnknown

const char *CMachineInfo::GetMachineName(void) const

Returns the name of the Raspberry Pi model, the application is running on.

unsigned CMachineInfo::GetModelMajor(void) const

Returns the major version (1-4) of the Raspberry Pi model, the application is running on, or zero if it is unknown.

unsigned CMachineInfo::GetModelRevision(void) const

Returns the revision number (1-) of the Raspberry Pi model, the application is running on, or zero if it is unknown.

TSoCType CMachineInfo::GetSoCType(void) const

Returns the type of the SoC (System on a Chip), the application is running on. Possible values are:

  • SoCTypeBCM2835

  • SoCTypeBCM2836

  • SoCTypeBCM2837

  • SoCTypeBCM2711

  • SoCTypeBCM2712

  • SoCTypeUnknown

TSoCStepping CMachineInfo::GetSoCStepping(void) const

Returns the stepping of the SoC (System on a Chip), the application is running on. Possible values are:

  • SoCSteppingC1

  • SoCSteppingD0

  • SoCSteppingUnknown

unsigned CMachineInfo::GetRAMSize(void) const

Returns the size of the SDRAM in MBytes of the Raspberry Pi model, the application is running on, or zero if it is unknown.

const char *CMachineInfo::GetSoCName(void) const

Returns the name of the SoC (System on a Chip), the application is running on.

u32 CMachineInfo::GetRevisionRaw(void) const

Returns the raw revision code of the Raspberry Pi model, the application is running on.

Clocks and peripherals

unsigned CMachineInfo::GetActLEDInfo(void) const

Returns the information, about how the green Activity LED is connected to the system. The result has to be masked with ACTLED_PIN_MASK to extract the GPIO pin number. If the result masked with ACTLED_ACTIVE_LOW is not zero, the LED is on, when the value 0 is written to the GPIO pin. If the result masked with ACTLED_VIRTUAL_PIN is not zero, the LED is connected to a GPIO expander, which is controlled by the firmware.

unsigned CMachineInfo::GetClockRate(u32 nClockId) const

Returns the current frequency in Hz of the system clock, selected by nClockId, which can have the following values:

  • CLOCK_ID_CORE

  • CLOCK_ID_ARM

  • CLOCK_ID_UART

  • CLOCK_ID_EMMC

  • CLOCK_ID_EMMC2

unsigned CMachineInfo::GetGPIOPin(TGPIOVirtualPin Pin) const

Returns the physical GPIO pin number of the PWM audio pins. Pin can have the values GPIOPinAudioLeft or GPIOPinAudioRight.

unsigned CMachineInfo::GetGPIOClockSourceRate(unsigned nSourceId)

This method allows to enumerate the different clock sources for GPIO clocks. It returns the frequency in Hz of the GPIO clock source with the ID nSourceId, which can be zero to GPIO_CLOCK_SOURCE_ID_MAX. The returned value is GPIO_CLOCK_SOURCE_UNUSED, if the clock source is unused.

unsigned CMachineInfo::GetDevice(TDeviceId DeviceId) const

Returns the device number of the default I2C master in the system. DeviceId has to be set to DeviceI2CMaster.

boolean CMachineInfo::ArePWMChannelsSwapped(void) const

Returns TRUE, if the left PWM audio channel is PWM1 (not PWM0).

DMA channels

unsigned CMachineInfo::AllocateDMAChannel(unsigned nChannel)

Allocates an available DMA channel from the platform DMA controller. nChannel can be DMA_CHANNEL_NORMAL (normal DMA engine requested), DMA_CHANNEL_LITE (lite (or normal) DMA engine requested), DMA_CHANNEL_EXTENDED (“large address” DMA4 engine requested, on Raspberry Pi 4 and 5 only) or an explicit channel number (0-15). Returns the allocated channel number or DMA_CHANNEL_NONE on failure.

void CMachineInfo::FreeDMAChannel(unsigned nChannel)

Release an allocated DMA channel. nChannel is the channel number (0-15).

unsigned CMachineInfo::AllocateDMAChannelRP1(unsigned nChannel)

Allocates an available DMA channel from the RP1 southbridge of the Raspberry Pi 5. nChannel can be DMA_CHANNEL_RP1_NORMAL (normal (or fast) DMA channel requested) or DMA_CHANNEL_RP1_FAST (fast DMA channel requested) or an explicit channel number (0-7). Returns the allocated channel number or DMA_CHANNEL_NONE on failure.

Note

RP1 DMA channels 0 and 1 have the highest priority and a larger temporary storage and are therefore treated as “fast” channels.

void CMachineInfo::FreeDMAChannelRP1(unsigned nChannel)

Release an allocated DMA channel from the RP1 southbridge. nChannel is the channel number (0-7).

CKernelOptions

The class CKernelOptions provides the values of runtime options, which can be defined in the file cmdline.txt on the SD card. The supported options are listed in doc/cmdline.txt. There is exactly one or no instance of this class in the system. Only relatively simple programs can work without an instance of CKernelOptions.

#include <circle/koptions.h>
class CKernelOptions
static CKernelOptions *CKernelOptions::Get(void)

Returns a pointer to the only instance of CKernelOptions.

unsigned CKernelOptions::GetWidth(void) const
unsigned CKernelOptions::GetHeight(void) const

Return the requested width and height of the screen, or zero if not specified. These values will normally handed over to the constructor for the class CScreenDevice.

const char *CKernelOptions::GetLogDevice(void) const
unsigned CKernelOptions::GetLogLevel(void) const

Return the name of the target device for the system log (default tty1) and the log level (default LogDebug), to be handed over to the constructor of the class CLogger.

const char *CKernelOptions::GetKeyMap(void) const

Returns the country code of the requested keyboard map (option keymap=). The default can be set with the system option DEFAULT_KEYMAP.

unsigned CKernelOptions::GetUSBPowerDelay(void) const

Returns the requested USB power-on delay in milliseconds, or zero to use the default value.

boolean CKernelOptions::GetUSBFullSpeed(void) const

Returns TRUE, if the option usbspeed=full is given in cmdline.txt.

const char *CKernelOptions::GetSoundDevice(void) const

Returns the configured sound device (option sounddev=). Defaults to an empty string.

unsigned CKernelOptions::GetSoundOption(void) const

Returns the value configured with the option soundopt= in cmdline.txt (0-2, default 0).

TCPUSpeed CKernelOptions::GetCPUSpeed(void) const

Returns CPUSpeedMaximum, if the option fast=true is given in cmdline.txt, or CPUSpeedLow otherwise.

unsigned CKernelOptions::GetSoCMaxTemp(void) const

Returns the enforced maximal temperature of the SoC (option socmaxtemp=) in degrees Celsius (default 60).

const unsigned *CKernelOptions::GetTouchScreen(void) const

Returns the calibration parameters for the touchscreen. The returned pointer refers to an array with four elements (min-x, max-x, min-y, max-y). It is nullptr, if the option touchscreen= is not set.

unsigned CKernelOptions::GetBacklight(void) const

Returns the backlight level to be set on the Raspberry Pi Official 7” Touchscreen, or 0, if the option is not defined.

const char *CKernelOptions::GetAppOptionString(const char *pOption, const char *pDefault = nullptr) const

Returns the value of the application-defined option pOption as a pointer to a C-string, or pDefault if the option is not found in the command line.

unsigned CKernelOptions::GetAppOptionDecimal(const char *pOption, unsigned nDefault = -1) const

Returns the value of the application-defined option pOption as a number, or nDefault if the option is not found in the command line.

int CKernelOptions::GetAppOptionSignedDecimal(const char *pOption, int nDefault = -1) const

Returns the value of the application-defined option pOption as a number, or nDefault if the option is not found in the command line.