A simple device driver that reads/write data from a block of memory in RAM. More...

#include <RamDisk.hxx>

Inheritance diagram for RamDiskBase:

Public Member Functions
	RamDiskBase (const char path, void data, unsigned size, bool read_only)
	Constructor.

Public Member Functions inherited from Device
	Device (const char *name)
	Constructor.

virtual	~Device ()
	Destructor.

Protected Member Functions
off_t	file_size ()

Protected Member Functions inherited from Node
	Node (const char *name)
	Constructor.

virtual	~Node ()
	Destructor.

int	close (File *) OVERRIDE
	Close method.

virtual int	fstat (File file, struct stat stat) override
	Get the status information of a file or device.

Protected Member Functions inherited from FileIO
	FileIO (const char *name)
	Constructor.

virtual	~FileIO ()
	Destructor.

virtual off_t	lseek (File *f, off_t offset, int whence)
	Seek method.

virtual int	ioctl (File *file, unsigned long int key, unsigned long data)
	Request an ioctl transaction.

virtual int	fcntl (File *file, int cmd, unsigned long data)
	Manipulate a file descriptor.

virtual bool	select (File *file, int mode)
	Device select method.

Protected Attributes
uint8_t *	data_
	Pointer to data content.

unsigned	actualSize_ = 0
	What's the larget file offset that we received an actual write for.

unsigned	size_: 30
	How many bytes we are exporting.

unsigned	readOnly_: 1
	1 ifreadonly file.

unsigned	owned_: 1
	1 if we own the data bytes and need to free()them upon exit.

Protected Attributes inherited from Node
OSMutex	lock_
	protects internal structures.

mode_t	mode_
	File open mode, such as O_NONBLOCK.

unsigned int	references_
	number of open references

Protected Attributes inherited from FileIO
const char *	name
	device name

Private Member Functions
void	enable () OVERRIDE
	This will be called once when reference-count goes from 0 to positive.

void	disable () OVERRIDE
	This will be called when reference count goes from non-zero to 0.

void	flush_buffers () OVERRIDE
	Instructs the device driver to drop all TX and RX queues.

int	open (File file, const char name, int flags, int mode) OVERRIDE
	Open method.

ssize_t	read (File file, void buf, size_t count) OVERRIDE
	Read from a file or device.

ssize_t	write (File file, const void buf, size_t count) OVERRIDE
	Write to a file or device.

Additional Inherited Members
Static Public Member Functions inherited from Device
static int	open (struct _reent reent, const char path, int flags, int mode)
	Open a file or device.

static int	close (struct _reent *reent, int fd)
	Close a file or device.

static int	stat (struct _reent reent, const char path, struct stat *stat)
	Get the status information of a file or device.

static int	select (int nfds, fd_set readfds, fd_set writefds, fd_set *exceptfds, long long timeout)
	POSIX select().

static void	select_clear ()
	Clears the current thread's select bits.

Static Public Member Functions inherited from FileIO
static ssize_t	read (struct _reent reent, int fd, void buf, size_t count)
	Read from a file or device.

static ssize_t	write (struct _reent reent, int fd, const void buf, size_t count)
	Write to a file or device.

static _off_t	lseek (struct _reent *reent, int fd, _off_t offset, int whence)
	Change the offset index of a file or device.

static int	fstat (struct _reent reent, int fd, struct stat stat)
	Get the status information of a file or device.

static int	ioctl (int fd, unsigned long int key, unsigned long data)
	Request and ioctl transaction.

static int	fcntl (int fd, int cmd, unsigned long data)
	Manipulate a file descriptor.

static bool	is_device (int fd)
	Test if the file descriptor belongs to a device.

Static Protected Member Functions inherited from Device
static void	select_insert (SelectInfo *info)
	Add client to list of clients needing woken.

static void	select_wakeup (SelectInfo *info)
	Wakeup the list of clients needing woken.

static void	select_wakeup_from_isr (SelectInfo info, int woken)
	Wakeup the list of clients needing woken.

Static Protected Member Functions inherited from FileIO
static int	fd_alloc (void)
	Allocate a free file descriptor.

static void	fd_free (int fd)
	Free up a file descriptor.

static File *	file_lookup (int fd)
	Looks up a reference to a File corresponding to a given file descriptor.

static int	fd_lookup (File *file)
	Looks up a file descriptor corresponding to a given File reference.

Static Protected Attributes inherited from FileIO
static const unsigned int	numOpenFiles = 20

static File	files []
	File descriptor pool.

static OSMutex	mutex
	mutual exclusion for fileio

Detailed Description

A simple device driver that reads/write data from a block of memory in RAM.

Example: extern uint8_t __flash_config_block_start[]; extern uint8_t __flash_config_block_end[]; static const size_t flash_config_block_length = __flash_config_block_end

__flash_config_block_start; RamDiskBase flashdisk("/dev/rdonly_config, __flash_config_block_start, flash_config_block_length, true);

then add appropriate linker symbols in the memory_map.ld for the project.

Definition at line 51 of file RamDisk.hxx.

Constructor & Destructor Documentation

◆ RamDiskBase()

RamDiskBase::RamDiskBase	(	const char *	path,
		void *	data,
		unsigned	size,
		bool	read_only
	)

inline

Constructor.

Parameters

path	device node name (e.g. "/etc/ramdisk_nodeid");
data	Blcok of RAM assigned to the file.
size	How many bytes should be exported.
read_only	if true, writes will be ignored.

Definition at line 60 of file RamDisk.hxx.

Member Function Documentation

◆ disable()

void RamDiskBase::disable ( )

inlineprivatevirtual

This will be called when reference count goes from non-zero to 0.

Called with lock_ held.

Implements Node.

Definition at line 71 of file RamDisk.hxx.

◆ enable()

void RamDiskBase::enable ( )

inlineprivatevirtual

This will be called once when reference-count goes from 0 to positive.

Called with lock_ held.

Implements Node.

Definition at line 70 of file RamDisk.hxx.

◆ file_size()

off_t RamDiskBase::file_size ( )

inlineprotected

Returns: the file end offset. This is either the size presented at the constructor for read-only files (that are filled with data when this device gets instantiated), or the actual bytes written.

Definition at line 123 of file RamDisk.hxx.

◆ flush_buffers()

void RamDiskBase::flush_buffers ( )

inlineprivatevirtual

Instructs the device driver to drop all TX and RX queues.

This is called after disable() still under the device lock.

Implements Node.

Definition at line 72 of file RamDisk.hxx.

◆ open()

int RamDiskBase::open	(	File *	file,
		const char *	name,
		int	flags,
		int	mode
	)

inlineprivatevirtual

Open method.

Reimplemented from Node.

Definition at line 75 of file RamDisk.hxx.

◆ read()

ssize_t RamDiskBase::read	(	File *	file,
		void *	buf,
		size_t	count
	)

inlineprivatevirtual

Read from a file or device.

Parameters

file	file reference for this device
buf	location to place read data
count	number of bytes to read

Returns: number of bytes read upon success, -1 upon failure with errno containing the cause

Implements FileIO.

Definition at line 85 of file RamDisk.hxx.

◆ write()

ssize_t RamDiskBase::write	(	File *	file,
		const void *	buf,
		size_t	count
	)

inlineprivatevirtual

Write to a file or device.

Parameters

file	file reference for this device
buf	location to find write data
count	number of bytes to write

Returns: number of bytes written upon success, -1 upon failure with errno containing the cause

Implements FileIO.

Definition at line 98 of file RamDisk.hxx.

Member Data Documentation

◆ actualSize_

unsigned RamDiskBase::actualSize_ = 0

protected

What's the larget file offset that we received an actual write for.

Definition at line 138 of file RamDisk.hxx.

◆ data_

uint8_t* RamDiskBase::data_

protected

Pointer to data content.

Definition at line 136 of file RamDisk.hxx.

◆ owned_

unsigned RamDiskBase::owned_

protected

1 if we own the data bytes and need to free()them upon exit.

Definition at line 144 of file RamDisk.hxx.

◆ readOnly_

unsigned RamDiskBase::readOnly_

protected

1 ifreadonly file.

Definition at line 142 of file RamDisk.hxx.

◆ size_

unsigned RamDiskBase::size_

protected

How many bytes we are exporting.

Definition at line 140 of file RamDisk.hxx.

The documentation for this class was generated from the following file:

RamDisk.hxx

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ RamDiskBase()

Member Function Documentation

◆ disable()

◆ enable()

◆ file_size()

◆ flush_buffers()

◆ open()

◆ read()

◆ write()

Member Data Documentation

◆ actualSize_

◆ data_

◆ owned_

◆ readOnly_

◆ size_