axis_driver.c File Reference

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Detailed Description

Top level driver initalisation and removal code + inital open.

Author:

Andrew Roca

This contains the axis driver inital entry code plus the top level initalisation code detailed initalistion occur after a call back from the PCI subsystem. Also contains the first open call (C++ types might think of it as a device instance factory) Modifing a open kernel file structure to dynamically subclass the driver based on the device minor number

#include "axis_driver.h"
#include "axis.h"
#include "axis_pci.h"
#include "axis_sram.h"
#include "des_io.h"
#include "parallel_io.h"
#include "serial_io.h"
#include "spi_io.h"
#include "axis_smart_card.h"

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Defines
#define	TITLE   "Axis2 PCI Bridge"
#define	ISSUE   "0.0"
#define	DRIVER_DESC   "Axis PCI Kernel Driver"
#define	DRIVER_AUTHOR   "Heber Limited <http://www.heber.co.uk>"
#define	DRIVER_SUPPORTED_DEVICES   "Axis"
#define	AXIS_PCI_VENDOR_ID   0x10b5
#define	AXIS_PCI_DEVICE_ID   0x3001
#define	STATIC_RAM_REGION   2
#define	CONTROL_REGION   4
#define	CONTROL_OFFSET   0x800
#define	MAX_REGION   6
#define	MAX_AXIS_ROUTED_SERIAL_PORTS   4
#define	AXIS_MAX_UARTS   8
#define	DIPSWITCH_OFFSET   0x64
#define	IO_REGION   3
Functions
	MODULE_LICENSE ("GPL")
	MODULE_DESCRIPTION ("Axis PCI Kernel Driver")
	MODULE_AUTHOR ("Heber Limited< http://www.heber.co.uk >")
	MODULE_SUPPORTED_DEVICE ("Axis")
int	axis_general_open (struct inode *inode_ptr,struct file *file_ptr)
	The main entry point for open operations against the major character device associated with this driver.
proc_dir_entry *	create_axis_root (struct proc_dir_entry *parent, struct axis_pci_device_entry *device)
	Create axis /proc root directory.
void	delete_axis_root (struct axis_pci_device_entry *device)
	Deletes an axis entry in the /proc file system.
int	add_proc_exports (struct axis_pci_device_entry *device)
	Function to create a set of axis specific entries in the /proc file system.
void	remove_proc_exports (struct axis_pci_device_entry *device)
	Function to delete Axis entries from /proc.
int	axis_activity_thread (void *data)
	Function for a thread scans for missing interrupts and time out the driver.
void	pci_remove (struct pci_dev *dev)
	Callback passed to PCI subsystem so it can signal either a removal or an unload.
int	init_module (void)
	This value is currently unassigned according to Documentation/devices/txt Called by the kernel when the module is first loaded allows module it initialise.
void	cleanup_module (void)
	Called by the kernel when module is about to be unloaded.
Variables
file_operations	driver_file_operations
pci_device_id	pci_id_table []
pci_driver	axis_pci_driver
	Defines a pci driver struct that can be passed to the kernel PCI subsystem.
char *	driver_name = "Axis_2_PCI_Bridge"
	Defines a name for this driver.
int	driver_major_number = 231
	Allocate a major number.

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Define Documentation

#define AXIS_MAX_UARTS   8

#define AXIS_PCI_DEVICE_ID   0x3001

#define AXIS_PCI_VENDOR_ID   0x10b5

#define CONTROL_OFFSET   0x800

#define CONTROL_REGION   4

#define DIPSWITCH_OFFSET   0x64

#define DRIVER_AUTHOR   "Heber Limited <http://www.heber.co.uk>"

#define DRIVER_DESC   "Axis PCI Kernel Driver"

#define DRIVER_SUPPORTED_DEVICES   "Axis"

#define IO_REGION   3

#define ISSUE   "0.0"

#define MAX_AXIS_ROUTED_SERIAL_PORTS   4

#define MAX_REGION   6

#define STATIC_RAM_REGION   2

#define TITLE   "Axis2 PCI Bridge"

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Function Documentation

int add_proc_exports (  struct axis_pci_device_entry *  device  )

Function to create a set of axis specific entries in the /proc file system. Parameters: device  - the master configuration/control structure for each Axis PCI device Returns: always 0 Adds a set of entries to the /proc file system these allow easy configuration and control to be implemented from the command line or via shell scripts as well as from conventional programming

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int axis_activity_thread (  void *  data  )

Function for a thread scans for missing interrupts and time out the driver. Parameters: data  - typed as void as this function is a callback but casted back to pointer to Master control structure Returns: 0 but not relevent This function becomes the main loop in a kernel thread tracking the Axis hardware in the background. Main use is to timeout IO which stall pending a non occuring interrupt

int axis_general_open (  struct inode *  inode_ptr, struct file *  file_ptr )  [static]

The main entry point for open operations against the major character device associated with this driver. Parameters: inode_ptr  - pointer to inode structure the kernel will associate with this instance file_ptr  - pointer to the file structure the kernel uses to track this open instance Returns: 0 on sucess error code otherwise This open splits the minor number and chooses the correct physical device it then uses the type field to replace the file operations pointer in the file * with one corresponding to the selected hardware element requested. It then calls the hardware specific open

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void cleanup_module (  void   )

Called by the kernel when module is about to be unloaded. Returns: none Called by the kernel prior to the axis module being unloaded (rmmod axis). Unregisters the Axis hardware from PCI system this calls the callback pci_remove. This then cleans up the axis data structures. The cleanup then removes the character driver

struct proc_dir_entry * create_axis_root (  struct proc_dir_entry *  parent, struct axis_pci_device_entry *  device )  [static]

Create axis /proc root directory. Parameters: parent  - were in the existing /proc tree to attach axis root device  - pointer to master control structure for each PCI instance Returns: pointer to root of axis /proc tree Creates a root directory within the /proc directory entry for each axis device

void delete_axis_root (  struct axis_pci_device_entry *  device  )  [static]

Deletes an axis entry in the /proc file system. Parameters: device  - pointer to master structure for each set of axis hardware Returns: none Code is built in theory to support multiple devices so multiple entries might exit one for each device. So code checks in the PCI structure to work out which one to clobber

int init_module (  void   )

This value is currently unassigned according to Documentation/devices/txt Called by the kernel when the module is first loaded allows module it initialise. Returns: 0 on success error no otherwise All modules have at least two entry points the first init_module is called by the kernel and the driver must initalise itself starting from this entry point. Function is quite simple first it creates a character device so it can be accessed through /dev type special files created with mknod. Then it registers a structure with the PCI subsystem. The structure identifies the Axis hardware and includes call backs that the PCI system calls if it recognises Axis hardware, the callbacks then build the structures needed.

MODULE_AUTHOR (  "Heber Limited< http://www.heber.co.uk >"   )

MODULE_DESCRIPTION (  "Axis PCI Kernel Driver"   )

MODULE_LICENSE (  "GPL"   )

MODULE_SUPPORTED_DEVICE (  "Axis"   )

void pci_remove (  struct pci_dev *  dev  )  [static]

Callback passed to PCI subsystem so it can signal either a removal or an unload. Parameters: dev  - pointer to pci_dev structure Returns: none This function is a callback its included in a stucture passed to the PCI subsystem when the Axis driver signals interest in PCI devices with the Axis idenity. If the Axis device is unplugged or rather more likely the driver calls pci_unregister as part of its unload procedure the PCI system calls this call back. In practice the tear down of Axis resources is started from this callback.

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void remove_proc_exports (  struct axis_pci_device_entry *  device  )

Function to delete Axis entries from /proc. Parameters: device  - master structure pointer for each Axis Returns: none

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Variable Documentation

struct pci_driver axis_pci_driver [static]

Initial value: { name: "Axis2_PCI_Bridge", id_table: pci_id_table, probe: pci_probe, remove: pci_remove } Defines a pci driver struct that can be passed to the kernel PCI subsystem.

struct file_operations driver_file_operations [static]

Initial value: { open: axis_general_open, } Defines a table of file operations callbacks for an Axis device (mostly NULL) All opens to the axis major number go through this table. The open function then replaces the file op table in the open file * structure with a new one based upon the minor number

int driver_major_number = 231 [static]

Allocate a major number.

char* driver_name = "Axis_2_PCI_Bridge" [static]

Defines a name for this driver.

struct pci_device_id pci_id_table[] [static]

Initial value: { { 0x10b5 , 0x3001 , PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 }, {0,} } Table of PCI Identifiers the driver should respond to This is passed to the kernel PCI subsystem so it knows Which devices the Axis driver is interested in

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