linux device drivers third edition pdf download

... 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 ... <linux/vmalloc.h> didn’t exist in 2.0; the functions were declar ed by <linux/mm.h>instead As usual, sysdep.h makes 2.4 code work with earlier ker-nels; it also includes <linux/vmalloc.h> ... and used by device drivers The allocator module, part of the sample code released on the O’Reilly FTP site, of fers an allocation interface to manage any high memory not used by the Linuxker nel

Ngày tải lên: 13/08/2014, 21:21

... 85-91 drivers/ block directory, 518 drivers/ cdrom directory, 520 drivers/ char directory, 518 drivers/ i2c directory, 524 drivers/ ide directory, 519 drivers/ input directory, 523 drivers/ ... hardware-dependent device drivers you would expect to find in drivers/block, the directory also includes software device drivers that are inher ently cr oss-platform, just like the sbull and spull drivers ... 329, 367 device memory (see I/O memory) DEVICE_ NAME symbol, 329, 367 DEVICE_ NO_RANDOM symbol, 329 DEVICE_ NR symbol, 329, 367 minor_shift value and, 356 DEVICE_ OFF macro, 329 DEVICE_

Ngày tải lên: 13/08/2014, 21:21

... independent of the devices attached tothe SCSI cable imple-Other classes of device drivers have been added to the kernel in recent times,including USB drivers, FireWir e drivers, and I2O drivers In the ... 11a driver to make it work with the system Without device drivers, there is no tioning system.func-Device drivers take on a special role in the Linux kernel They are distinct “blackboxes” that ... commercial devices As Linus Torvalds noted, “We’r e back tothe times when men were men and wrote their own device drivers.” cus-Back in 1996, I was hacking with my own toy device drivers that

Ngày tải lên: 13/08/2014, 21:21

... {device} [0-3] major=‘awk "\\ $2= =\"$module\" {print \\$1}" /proc/devices‘ mknod mknod mknod mknod /dev/$ {device} 0 /dev/$ {device} 1 /dev/$ {device} 2 /dev/$ {device} 3 c c c c... the device ... in the device file entries before the date of last modification, where the file length nor mally appears. These numbers are the major device number and minor device number for the particular device. ... 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 Major

Ngày tải lên: 13/08/2014, 21:21

... most applications ofkiobufs seen in device drivers Mapping User-Space Buffers and Raw I/O Unix systems have long provided a ‘‘raw’’ interface to some devices—blockdevices in particular—which perfor ... two devices The block sbull device was examined in detail in Chapter 12 What we didn’t see in that chapter was a second, char device (called sbullr), which provides raw access to the RAM-disk device ... thekiobuf mechanism It is worth noting that in Linux systems, there is no need for block drivers to pro-vide this sort of interface The raw device, in drivers/char/raw.c, propro-vides this capability

Ngày tải lên: 13/08/2014, 21:21

... might have expected. Differences in Linux 2.2 First of all, Linux 2.3.14 renamed the network device structure, which had always been struct device,tostruct net_device. The new name is certainly ... unregister_netdev(struct net _device *dev); Register and unregister a network device SET_MODULE_OWNER(struct... up to 32 devices, and each device can be a multifunction board (such as an audio device with ... registers of each device, one file per device * You’ll find the ID of any device in its own hardware manual A list... on a bus /device pair The devfn argument represents both the device and function

Ngày tải lên: 13/08/2014, 21:21

... O'Reilly FTP site, as explained in Chapter 1, "An Introduction to Device Drivers". #define MODULE #include <linux/module.h> int init_module(void) { printk("<1>Hello, ... include/linux and include/asm inside the kernel sources (usually found in /usr/src/linux). Older distributions (based on libc version 5 or earlier) used to carry symbolic links from /usr/include/linuxand ... expect. The hard part is understanding your device and how to maximize performance. We'll go deeper into modularization throughout this chapter and leave device-specific issues to later chapters.

Ngày tải lên: 24/12/2013, 01:17

... -f /dev/${device}[0-3] Trang 12major=`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 ... length normally appears These numbers are the major device number and minor device number for the particular device The following listing shows a few devices as they appear on a typical system Their ... 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

... /proc is heavily used in the Linux system Many utilities on a modern Linux distribution, such as ps, top, and uptime, get their information from /proc Some device drivers also export information ... char **argv) Trang 6setconsole uses the special ioctl command TIOCLINUX, which implements Linux-specific functions To use TIOCLINUX, you pass it an argument that is a pointer to a byte array The ... are eight possible loglevel strings, defined in the header Used to report error conditions; device drivers will often use KERN_ERR to report hardware difficulties Trang 3KERN_WARNING Warnings

Ngày tải lên: 24/12/2013, 01:17

... Char Driver Operations In Chapter 3, "Char Drivers", we built a complete device driver that the user can write to and read from But a real device usually offers more functionality than ... Nonetheless, sometimes it's a useful approach to device control and is used by tty's and other devices We'll describe it later in this chapter in "Device Control Without ioctl" As we suggested ... first versions of Linux used 16-bit numbers: the top eight were the "magic'' number associated with the device, and the bottom eight were a sequential number, unique within the device This happened

Ngày tải lên: 24/12/2013, 01:17

... cache Device drivers normally do not exhibit the sort of memory behavior that justifies using a lookaside cache, but there can be exceptions; the USB and ISDN drivers in Linux 2.4 use caches Linux ... GFP_KERNEL and GFP_ATOMIC, although those two cover most of the needs of device drivers All the flags are defined in <linux/mm.h>: individual flags are prefixed with a double underscore, ... freeing of memory The Linux kernel offers a richer set of memory allocation primitives, however In this chapter we look at other ways of making use of memory in device drivers and at how to make

Ngày tải lên: 24/12/2013, 01:17

... scull and similar toys is a good introduction to the software interface of a Linux device driver, implementing a real device requires hardware The driver is the abstraction layer between software ... those manuals are usually available for download as PDF files on the Web Using Digital I/O Ports The sample code we use to show port I/O from within a device driver acts on general-purpose digital ... peripheral devices, usually by means of external chipsets or extra circuitry in the CPU core The latter solution is only common within tiny processors meant for embedded use For the same reason, Linux

Ngày tải lên: 24/12/2013, 01:17

... :Interrupt Handling Although some devices can be controlled using nothing but their I/O regions, most real-world devices are a bit more complicated than that. Devices have to deal with the external ... IRQ number just means probing the device, ... modern devices supply their interrupt configuration The PCI standard solves the problem by requiring peripheral devices to declare what interrupt ... every device is programmer friendly, and autodetection might require some probing The technique is quite simple: the driver tells the device. .. however, exploit our knowledge of the device

Ngày tải lên: 24/12/2013, 01:17

... developers. This is the third edition of Linux Device Drivers. The kernel has changed greatly since this book was first published, and we have tried to evolve the text to match. This edition covers the ... reader), or a network device (a USB Ethernet interface). Other classes of device drivers have been added to the kernel in recent times, includ- ing FireWire drivers and I2O drivers. In the same ... code without being overwhelmed by com- plexity. Often, device drivers provide that gateway. Device drivers take on a special role in the Linux kernel. They are distinct “black boxes” that make...

Ngày tải lên: 21/02/2014, 19:20

... there. The devices are released when scull_cleanup is called. This code uses the generic Linux linked list mechanism in preference to reimple- menting the same capability from scratch. Linux lists ... discussion of device methods. static int scull_c_release(struct inode *inode, struct file *filp) { /* * Nothing to do, because the device is persistent. * A `real' cloned device should ... release the device */ return 0; } Normally, we recommend that you put the open flag scull_s_available within the device structure ( Scull_Dev here) because, conceptually, it belongs to the device. ...

Ngày tải lên: 09/08/2014, 04:21

... device_ close instead of device_ release. Either way, the device method should perfor m the following tasks: ã Deallocate anything that open allocated in filp->private_data ã Shut down the device ... THREE CHAR DRIVERS The goal of this chapter is to write a complete char device driver. We’ll develop a character driver because this class is suitable for most simple hardware devices. Char drivers ... imple- mentations. 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 hard- war e. According to...

Ngày tải lên: 25/03/2014, 10:48

... developers. This is the third edition of Linux Device Drivers. The kernel has changed greatly since this book was first published, and we have tried to evolve the text to match. This edition covers the ... writing drivers for PCI devices, and Chapter 13 examines the API for working with USB devices. With an understanding of peripheral buses in place, we can take a detailed look at the Linux device ... plan for the fourth edition, and look for a fourth author to help. Greg’s Introduction It seems like a long time ago that I picked up the first edition of this Linux Device Drivers book in order...

Ngày tải lên: 09/08/2014, 04:21

... -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 ... the cdev structure, num is the first device number to which this device responds, and count is the number of device numbers that should be associated with the device. Often count is one, but there ... option. CONFIG_INPUT_EVBUG This option (under Device drivers/ Input device support”) turns on verbose log- ging of input events. If you are working on a driver for an input device, this option may be helpful....

Ngày tải lên: 09/08/2014, 04:21

... scull_nr_devs; i++) { scull_devices[i].quantum = scull_quantum; scull_devices[i].qset = scull_qset; init_MUTEX(&scull_devices[i].sem); scull_setup_cdev(&scull_devices[i], i); } Note that ... implementing device control this way is that the user can control the device just by writing data, without needing to use (or sometimes write) programs built just for configuring the device. When devices ... the two techniques would be avoided. Device Control Without ioctl Sometimes controlling the device is better accomplished by writing control sequences to the device itself. For example, this technique...

Ngày tải lên: 09/08/2014, 04:21