essential linux device drivers pdf free download

... the same device) is often best solved by implementing one device node for each access policy Anexample of this practice can be found in the Linux tape driver, which provides multi-ple device files ... the same device Different device files will, for example, cause thedrive to record with or without compression, or to automatically rewind the tapewhen the device is closed Cloning the Device on ... /dev/scullpriv device node implements virtual devices within the scull package The scullpriv implementation uses the device number of the process’s controlling tty as a key to access the virtual device

Ngày tải lên: 09/08/2014, 04:21

... for the same device) is bestsolved by implementing one device node for each access policy An example ofthis practice can be found in the Linux tape driver, which provides multiple devicefiles ... the same device Differ ent device files will, for example, cause the drive torecord with or without compression, or to automatically rewind the tape when thedevice is closed Cloning the Device ... there The devices are released when * Nothing to do, because the device is persistent. Access Control on a Device File Trang 8Chapter 5: Enhanced Char Driver OperationsWait Queues in Linux 2.2

Ngày tải lên: 13/08/2014, 21:21

... the device or assigned by system firmwar e at boot time The former istrue, for example, of ISA devices, whose addresses are either burned in devicelogic circuits, statically assigned in local device ... mapping obtained with vr emap would be freed with vfr ee Also, the header <linux/vmalloc.h> didn’t exist in 2.0; the functions were declar ed by <linux/mm.h>instead As usual, sysdep.h ... <linux/vmalloc.h> if <linux/mm.h> is included, thushiding this differ ence as well Quick Reference The functions and symbols related to memory allocation follow #include <linux/malloc.h>

Ngày tải lên: 13/08/2014, 21:21

... Use of Standard C Types Although most programmers are accustomed to freely using standard types likeintand long, writing device drivers requir es some care to avoid typing conflictsand obscure bugs ... wait_event_interruptible macr os did not exist in Linux 2.0. Quick Reference These symbols related to interrupt management were intr oduced in this chapter #include <linux/sched.h> int request_irq(unsigned ... running the program on differ entLinux computers: fer-arch Size: char shor int long ptr long-long u8 u16 u32 u64 It’s interesting to note that the user space of Linux-spar c64 runs 32-bit code,

Ngày tải lên: 13/08/2014, 21:21

... 85-91drivers/block directory, 518drivers/cdr om dir ectory, 520drivers/char directory, 518drivers/i2c directory, 524drivers/ide directory, 519drivers/input directory, 523drivers/md directory, 519drivers/media ... I/O memory)DEVICE_NAME symbol, 329, 367DEVICE_NO_RANDOM symbol, 329DEVICE_NR symbol, 329, 367minor_shift value and, 356DEVICE_OFF macro, 329DEVICE_ON macro, 329DEVICE_REQUEST symbol, 329device-dependent ... new class of device drivers), drivers/isdn (all ISDN controllers supported by Linux and their common support functions), drivers/atm (the same, for ATM net- work connections), and drivers/ieee1394

Ngày tải lên: 13/08/2014, 21:21

... wasting kernel memory by keeping drivers in core when they are not in use, and to allow the creation of "generic'' kernels that can support a wide variety of hardware, Linux offers support for automatic ... this way: char and block drivers, filesystems, line disciplines, network protocols, and so on One example of a driver that benefits from demand loading is the Advanced Linux Sound Architecture ... sound es1370 This file tells modprobe which drivers to load to make the SCSI system, Ethernet, and sound cards work It also ensures that if the PCMCIA drivers are loaded, a startup script is invoked

Ngày tải lên: 21/01/2014, 07:20

... and minor numbers of the device holding the file that has been mapped Confusingly, for device mappings, the major and minor numbers refer to the disk partition holding the device special file that ... at the most important fields in struct vm_area_struct (defined in <linux/mm.h>) These fields may be used by device drivers in their mmap implementation Note that the kernel maintains lists ... 25Mapping a device means associating a range of user-space addresses to device memory Whenever the program reads or writes in the assigned address range, it is actually accessing the device In

Ngày tải lên: 21/01/2014, 07:20

... conditional compilation in the code: morgana% grep -c ifdef linux-2.[024]/init/main.c Trang 6linux-2.0/init/main.c:120 linux-2.2/init/main.c:246 linux-2.4/init/main.c:35 Despite the huge addition of ... :Physical Layout of the Kernel Source So far, we've talked about the Linux kernel from the perspective of writing device drivers Once you begin playing with the kernel, however, you may find ... flexible than ELF For this reason, uClinux[64] developers switched from COFF to ELF while porting their system from 2.0 to 2.4 [64]uClinuxis a version of the Linux kernel that can run on processors

Ngày tải lên: 21/01/2014, 07:20

... Trang 2DEVICE DRIVERS Trang 3Other Linux resources from O’ReillyRelated titles Understanding the Linux KernelLinux in a NutshellRunning LinuxLinux NetworkAdministrator’s Guide Linux Pocket ... cover to cover or sim-ply flip to the page you need Try it today with a free trial Trang 4DEVICE DRIVERS Trang 5Linux Device Drivers, Third Editionby Jonathan Corbet, Alessandro Rubini, and Greg ... Interface Trang 26Classes of Devices and Modules | 7Block devices Like char devices, block devices are accessed by filesystem nodes in the /dev directory A block device is a device (e.g., a disk) that

Ngày tải lên: 09/08/2014, 04:21

... rm -f /dev/${device}[0-3] major=$(awk "\\$2= =\"$module\" {print \\$1}" /proc/devices) mknod /dev/${device}0 c $major 0 mknod /dev/${device}1 c $major 1 mknod /dev/${device}2 c ... Allocation of Major Numbers Some major device numbers are statically assigned to the most common devices A list of those devices can be found in Documentation/devices.txt within the kernel source ... devis the cdevstructure, numis the first device number to which this deviceresponds, andcountis the number of device numbers that should be associated withthe device Oftencountis one, but there are

Ngày tải lên: 09/08/2014, 04:21

... Chapter 9 ioctl Most drivers need—in addition to the ability to read and write the device—the ity to perform various types of hardware control via the device driver Most devicescan perform operations ... thatcontrols access to its device While the lockis held, the device issues an interrupt,which causes your interrupt handler to run The interrupt handler, before accessingthe device, must also obtain ... can be safely freed Trang 26Chapter 6 CHAPTER 6Advanced Char Driver Operations In Chapter 3, we built a complete device driver that the user can write to and read from But a real device usually

Ngày tải lên: 09/08/2014, 04:21

... must have free access to the underlying hard-ware device (by default, the parallel interface); thus, no other driver may have cated it Most modern distributions set up the parallel port drivers ... modem, as long as you don’t use the two devices at the same time It is quite common forusers to load the module for a special device at system boot, even if the device israrely used A data acquisition ... to call request_irq is when the device is first opened, before the hardware is instructed to generate interrupts The place to call free_irq is the last time the device is closed, after the hardware

Ngày tải lên: 09/08/2014, 04:21

... a device, control how that single device looks tothe host computer as a USB device As the term “USB device drivers” is very confus-ing, the USB developers have created the term “USB gadget drivers” ... remembering that each deviceboard can host up to eight devices; each device uses a single interrupt pin and reports it in its own configuration register Different devices on the same device board canuse ... systemand drivers on a device The USB drivers for a host system control the USB devicesthat are plugged into it, from the host’s point of view (a common USB host is a desk-top computer.) The USB drivers

Ngày tải lên: 09/08/2014, 04:21

... struct device *parent The device’s “parent” device—the device to which it is attached In most cases,aparent device is some sort of bus or host controller IfparentisNULL,the device is a top-level device, ... the usual pair of functions:int device_create_file(struct device *device, struct device_attribute *entry); void device_remove_file(struct device *dev, struct device_attribute *attr); Thedev_attrsfield ... <linux/device.h> This structure looks like: struct bus_type { char *name; struct subsystem subsys; struct kset drivers; struct kset devices; int (*match)(struct device *dev, struct device_driver

Ngày tải lên: 09/08/2014, 04:21

... functions below require a pointer to astruct device This structure isthe low-level representation of a device within the Linux device model It is notsomething that drivers often have to work with directly, ... specific that describes your device For example, it can be found as thedevfield instruct pci_deviceorstruct usb_device Thedevicestructure is covered in detail in Chapter 14 Drivers that use the following ... purpose: DMA_TO_DEVICE DMA_FROM_DEVICE These two symbols should be reasonably self-explanatory If data is being sent to the device (in response, perhaps, to a write system call),DMA_TO_DEVICEshould

Ngày tải lên: 09/08/2014, 04:21

... for fiber-channel devices, alloc_fddidev (<linux/ fddidevice.h>) for FDDI devices, or alloc_trdev (<linux/trdevice.h>) for token ring devices snull could use alloc_etherdev without ... Writers of drivers for other types of devices may want to take advantage of one of the other helper functions, such as alloc_fcdev (defined in <linux/fcdevice.h>) for fiber-channel devices, ... ltalk_setup(struct net_device *dev); Sets up the fields for a LocalTalk device void fc_setup(struct net_device *dev); Initializes fields for fiber-channel devices void fddi_setup(struct net_device *dev);

Ngày tải lên: 09/08/2014, 04:21

... for newer drivers. The basic idea being exploited is that whenever a new device appears during the system's lifetime, all available device drivers must check whether the new device is ... the usual case of a static device list is handled by scanning the device list once for each device at system boot; modularized drivers will just unload as usual if no device is there, and an external ... pair. A device driver usually relies on the signature to identify its device; you can find what value to look for in the hardware manual for the target device. class Every peripheral device...

Ngày tải lên: 21/01/2014, 07:20

... 1 :An Introduction to Device Drivers As the popularity of the Linux system continues to grow, the interest in writing Linux device drivers steadily increases. Most of Linux is independent ... independent of the devices attached to the SCSI cable. Other classes of device drivers have been added to the kernel in recent times, including USB drivers, FireWire drivers, and I2O drivers. In ... by Linux, somebody somewhere has written a driver to make it work with the system. Without device drivers, there is no functioning system. Device drivers take on a special role in the Linux...

Ngày tải lên: 24/12/2013, 01:17

... implementations. For example, the video-for -linux set of drivers is split into a generic module that exports symbols used by lower- level device drivers for specific hardware. According to your ... new device, it will be able to avoid probing those ports that are already in use by other drivers. ISA probing is in fact a risky task, and several drivers distributed with the official Linux ... not belong to any of the classes listed in "Classes of Devices and Modules" in Chapter 1, "An Introduction to Device Drivers& quot;. The sample driver shown in this chapter is called...

Ngày tải lên: 24/12/2013, 01:17

... the minor number of the device, so the driver is free to use it at will. In practice, different minor numbers are used to access different devices or to open the same device in a different way. ... of setting up the devices. for (i=0; i < scull_nr_devs; i++) { scull_devices[i].quantum = scull_quantum; scull_devices[i].qset = scull_qset; sema_init(&scull_devices[i].sem, 1); ... Allocation of Major Numbers Some major device numbers are statically assigned to the most common devices. A list of those devices can be found in Documentation/devices.txt within the kernel source...

Ngày tải lên: 24/12/2013, 01:17