MityDSP::tcDspMmc Class Reference

Instances of this class handle access to a MultiMedia Card via the MityDSP SPI interface. More...

#include <core/DspMmc.h>

Inheritance diagram for MityDSP::tcDspMmc:

Classes
union	tuMmcStatus
	status information returned by MMC card More...
Public Member Functions
	tcDspMmc (tcDspSpi apSpi, tcDspOutputLatch apLatch, unsigned int anLatchID, LCK_Handle ahLock=NULL)
	This constructor is used to open an interface to a MMC device via the provided SPI interface.
	~tcDspMmc ()
	Default destructor.
virtual bool	reinit (void)
	This method reinitializes the MMC device, places it in on-line mode, and queries the device for its Chip-Specific Data.
virtual int	write (void apAddr, void apData, int anBytes)
	This routine writes an arbitrary amount of data to an MMC device at a specified offset from the start of the device.
virtual int	write (unsigned int anSector, unsigned int anOffset, void *apData, int anBytes)
	Sector-based version of the write method.
virtual int	read (void apStartAddr, void apBuffer, int anBytes)
	This routine reads an arbitrary amount of data from an MMC device from the specified offset position.
virtual int	read (unsigned int anSector, unsigned int anOffset, void *apBuffer, int anBytes)
	Sector-based version of the read method.
virtual void	setCardDetectGPIO (tcDspGpio *aGpio, int anThreadPri)
	Sets the GPIO used for card detect.
virtual void	cardDetectInterrupt (void)
	Interrupt service routine for the MMC class.
virtual tuMmcStatus	get_status (void)
	This method reads the MMC card Status register and returns its contents.
virtual const char *	get_info (void)
	This method reads the MMC card CID register, decodes the information, and returns a summary information string.
Static Public Member Functions
static void	interrupt_dispatch (tcDspGpio aGpio, unsigned int mask, void aMmc)
	Static interrupt dispatch routine.
static void	cardDetectDispatch (Arg mmcCard)
	Static thread dispatch routine.
Static Public Attributes
static const int	gnSTAT_LENGTH = 2
	length (in bytes) of status info
static const int	gnBLOCK_SIZE = 512
	fixed block size for high capacity SD cards;
Protected Member Functions
virtual void	cardDetectThread ()
	Thread to pend on the card detect semaphore.
bool	initialize (void)
	This method resets the MMC device, places it in on-line mode, and queries the device for its Chip-Specific Data.
bool	read_sector (unsigned int anSector)
	This method reads the specified sector of the MMC device into the page buffer.
bool	write_sector (unsigned int anSector)
	This method writes the page buffer out to the specified sector of the MMC device.
bool	check_write (void)
	This method checks to see if a previous write operation was successful.
void	setup_spi (void)
	This method is used to set the SPI in the required mode for the MMC interface.
bool	wait_for_response (unsigned char anExpected, int anAttempts=256, int *apRequired=NULL)
	This method reads the SPI interface repeatedly, waiting for a specified response.
Protected Attributes
LCK_Handle	mhMutex
	Lock to serialize access.
tcDspSpi *	mpSpi
	Access to the SPI bus.
tcDspOutputLatch *	mpLatch
	Access to latch selector.
unsigned int	mnLatchID
	ID of latch to use (if any).
unsigned int	mnSectorSize
	Sector size (bytes).
bool	mbIsHighCapacity
	if true, a high capacity SD card
bool	mbMutexCreated
	True if mutex created locally.
unsigned char *	mpPageBuffer
	Buffer for a sector of data.
tcDspGpio *	mpGpio
	GPIO for card detect interrupt.
unsigned short	mnMyIntMask
	core interrupt mask.
int	mnMyIntLevel
	core interrupt level.
int	mnMyIntVector
	core interrupt vector.
SEM_Handle	mhCardDetectSem
	Semaphore for card detect.
TSK_Handle	mhCardDetectThrd
	Thread used for card detect "debounce".

Detailed Description

Instances of this class handle access to a MultiMedia Card via the MityDSP SPI interface.

It is derived from tcDspStorageBase to provide a consistent interface for higher-level drivers (such as filesystems).

See also:: tcDspMmc Page

Constructor & Destructor Documentation

tcDspMmc::tcDspMmc	(	tcDspSpi *	apSpi,
		tcDspOutputLatch *	apLatch,
		unsigned int	anLatchID,
		LCK_Handle	ahLock = `NULL`
	)

This constructor is used to open an interface to a MMC device via the provided SPI interface.

Parameters:

`[in]`	apSpi	Pointer to the SPI interface for the MMC.
`[in]`	apLatch	Pointer to an output latch controlling Chip Select.
`[in]`	anLatchID	ID of the latch to use for this device.
`[in]`	ahLock	Optional parameter specifying a lock to use to protect MMC (and SPI) writes.

Note:: Specifying a shared lock to all devices sharing a SPI bus allows them to operate simultaneously. Not necessary if the SPI is used exclusively for the MMC device.

Returns:: None.

See also:: DspMmc.h

tcDspMmc::~tcDspMmc ( )

Default destructor.

Returns:: None.

See also:: DspMmc.h

Member Function Documentation

void tcDspMmc::interrupt_dispatch	(	tcDspGpio *	aGpio,
		unsigned int	aMask,
		void *	aMmc
	)			`[static]`

Static interrupt dispatch routine.

Required because of the hidden this pointer associated with a member function, which cannot be passed directly to the interrupt dispatcher.

Parameters:

`[in]`	aGpio	The GPIO pointer
`[in]`	aMask	The GPIO bit that triggered the interrupt
`[in]`	aMmc	The tcDspMmc pointer

Returns:: 0

void tcDspMmc::cardDetectDispatch ( Arg mmcCard ) [static]

Static thread dispatch routine.

Required because of the hidden this pointer associated with a member function, which cannot be passed directly to the thread.

Parameters:

[in] mmcCard The "this->" pointer for the instance of tcDspMmc associated with this thread.

Returns:: 0

bool tcDspMmc::reinit ( void ) [virtual]

This method reinitializes the MMC device, places it in on-line mode, and queries the device for its Chip-Specific Data.

If the sector size, the number of sectors available, or the overall device size changes, the sector map and page buffer are recreated.

Returns:: True if reinitialization was successful.

See also:: DspMmc.h

int tcDspMmc::write	(	void *	apAddr,
		void *	apData,
		int	anBytes
	)			`[virtual]`

This routine writes an arbitrary amount of data to an MMC device at a specified offset from the start of the device.

The routine handles preservation of data when only a partial sector is written. The data does not have to be sector aligned, although writing aligned, full sectors is most efficient.

Parameters:

`[in]`	apAddr	Pointer to the offset position on the MMC device.
`[in]`	apData	A buffer containing the data to be written.
`[in]`	anBytes	Size of the data to be written in bytes.

Returns:: The number of bytes successfully written.

See also:: DspMmc.h

Implements MityDSP::tcDspStorageBase.

int tcDspMmc::write	(	unsigned int	anSector,
		unsigned int	anOffset,
		void *	apData,
		int	anBytes
	)			`[virtual]`

Sector-based version of the write method.

Parameters:

`[in]`	anSector	The sector to write to.
`[in]`	anOffset	The offset from the start of the sector.
`[in]`	apData	A buffer containing the data to be written.
`[in]`	anBytes	Size of the data to be written in bytes.

Returns:: The number of bytes successfully written.

See also:: DspMmc.h

Implements MityDSP::tcDspStorageBase.

int tcDspMmc::read	(	void *	apStartAddr,
		void *	apBuffer,
		int	anBytes
	)			`[virtual]`

This routine reads an arbitrary amount of data from an MMC device from the specified offset position.

Results of the read are stored in apBuffer.

Parameters:

`[in]`	apStartAddr	Pointer to the data offset on the MMC device.
`[out]`	apBuffer	A buffer to hold the data that is read.
`[in]`	anBytes	Size of the data to be read in bytes.

Returns:: The number of bytes successfully read.

See also:: DspMmc.h

Implements MityDSP::tcDspStorageBase.

int tcDspMmc::read	(	unsigned int	anSector,
		unsigned int	anOffset,
		void *	apBuffer,
		int	anBytes
	)			`[virtual]`

Sector-based version of the read method.

Parameters:

`[in]`	anSector	The sector to copy from.
`[in]`	anOffset	The offset from the start of the sector.
`[out]`	apBuffer	A buffer to hold the data that is read.
`[in]`	anBytes	Size of the data to be read in bytes.

Returns:: The number of bytes successfully read.

See also:: DspMmc.h

Implements MityDSP::tcDspStorageBase.

void tcDspMmc::setCardDetectGPIO	(	tcDspGpio *	aGpio,
		int	anThreadPri
	)			`[virtual]`

Sets the GPIO used for card detect.

This function enablesd interrupts on GPIO_2 for use as a card detect.

Parameters:

`[in]`	aGpio	The GPIO with GPIO_2 as card detect line(NULL for none).
`[in]`	anThreadPri	Thread priority of the debouncer

Returns:: None.

void tcDspMmc::cardDetectInterrupt ( void ) [virtual]

Interrupt service routine for the MMC class.

The ISR reads and clears the pending interrupt. If the pending interrupt has a callback registered for it, the routine is called.

"Interrupt-ness" is taken care of by the 'dispatcher' in DSP/BIOS. Installed by the constructor.

tcDspMmc::tuMmcStatus tcDspMmc::get_status ( void ) [virtual]

This method reads the MMC card Status register and returns its contents.

Note:: The returned structure contains an mbZERO field. This field is non-zero if the status request fails.

Returns:: MMC status register contents.

See also:: DspMmc.h

const char * tcDspMmc::get_info ( void ) [virtual]

This method reads the MMC card CID register, decodes the information, and returns a summary information string.

Note:: The returned string is valid until the next time the info() method is called.

Returns:: Pointer to the information string (which contains "No Response" if there was a failure).

See also:: DspMmc.h

void tcDspMmc::cardDetectThread ( ) [protected, virtual]

Thread to pend on the card detect semaphore.

When the semaphore is posted the thread will sleep for a tenth of a second then wake and re-enable interrupts, then call the callback if it's set.

Returns:: 0

bool tcDspMmc::initialize ( void ) [protected]

This method resets the MMC device, places it in on-line mode, and queries the device for its Chip-Specific Data.

This data is used to determine the sector size, the number of sectors available, and the overall device size.

Returns:: True if initialization was successful.

See also:: DspMmc.h

bool tcDspMmc::read_sector ( unsigned int anSector ) [protected]

This method reads the specified sector of the MMC device into the page buffer.

Parameters:

[in] anSector The sector to read into the page buffer.

Returns:: True if the sector was successfully read.

See also:: DspMmc.h

bool tcDspMmc::write_sector ( unsigned int anSector ) [protected]

This method writes the page buffer out to the specified sector of the MMC device.

Parameters:

[in] anSector The sector to write the page buffer to.

Returns:: True if the page buffer was successfully written.

See also:: DspMmc.h

bool tcDspMmc::check_write ( void ) [protected]

This method checks to see if a previous write operation was successful.

Returns:: True if successful.

See also:: DspMmc.h

void tcDspMmc::setup_spi ( void ) [protected]

This method is used to set the SPI in the required mode for the MMC interface.

It is called before every read and write, so that the SPI may be used with multiple devices simultaneously (in conjunction with a shared lock).

Returns:: None.

See also:: DspMmc.h

bool tcDspMmc::wait_for_response	(	unsigned char	anExpected,
		int	anAttempts = `256`,
		int *	apRequired = `NULL`
	)			`[protected]`

This method reads the SPI interface repeatedly, waiting for a specified response.

The routine returns "true" if the response is received within the specified number of attempts.

Parameters:

`[in]`	anExpected	The 8-bit response to wait for.
`[in]`	anAttempts	Number of attempts to read the expected response (default: 256).
`[out]`	apRequired	if passed in (default is NULL), will be set to the number of cycles required to complete the response.