linux device drivers 4th edition

> define_per_cpu (type, name); get_cpu_var (variable); put_cpu_var (variable); per_cpu (variable, int cpu_id); void *alloc_percpu (type); void *__alloc_percpu (size_t size, size_t align); per_cpu_ptr (void *per_cpu_var, int cpu_id); Export_per_cpu_symbol (Per_cpu_var); EXPORT_PER_CPU_SYMBOL_GPL (Per_cpu_var); declare_per_cpu (type, name); Get a large buffer Obtai

http://blog.csdn.net/yuesichiu/article/details/8286469The interruption of the device interrupts the normal scheduling and operation of processes in the kernel, and the system's quest for higher throughput is bound to require that the interrupt service program be as concise as possible. However, this good desire often does not coincide with reality.in most real systems, when interrupts arrive, the work to be done is often not short, and it may take a l

When you start learning to drive, you compile the driver into a module and then manually set up the device node with the Mknod command to make it available to the application call. This is a common way to start debugging a driver. However, when there is a need to have the driver ready when the system starts, supply the layer program call. At this point, you can no longer manually set up the device node, but

when a per-cpu variable is created. Each processor in the system will have a unique copy of the variable does not need to be locked can be saved in a fast cache of the appropriate processor DEFI NE_PER_CPU (type, name); get_cpu_var (variable); put_cpu_var (variable); per_cpu (variable, int cpu_id); void *alloc_percpu (type); void *__alloc_percpu (size_t size, size_t align); per_cpu_ptr (vo

The method structure of the device file registration in the Linxu driver is also the body that provides the operation interface to the user layer, my version is 3.1.10Writing is not easy, reprint need to indicate the source: http://blog.csdn.net/jscese/article/details/43408625The prototype is defined in the kernel source/include/linux/fs.h:struct File_operations {struct module *owner; The first file_operati

critical section cannot be too long; spin----lock can be used in an interrupt contextSignal Volume----need a header file linux/semaphore.h----struct semaphore sem; Define the semaphore----Sema_init (sem,1); Initialize the semaphore----Down_interruptible (SEM); Get the semaphore----......//Critical area code----Up (SEM); Release semaphore----Description: The semaphore differs from the spin lock, which is a sleep lock that cannot be used in an interrup

function returns, any work function that was committed before the call does not run anywhere on the system.After you have finished using the work queue, you can call the following function to release the related resources:void Destroy_workqueue (struct work_queue_struct *queue);Shared queuesThe device driver can use the shared default work queue provided by the kernel.Initializing the WORK_STRUCT structurestatic struct work_struct jiq_work;Init_work

Today the Linux device Driver (third edition) of the first module Hello module compiled passed, this thing card for me for a long time, during which I spent a lot of time to see the Linux Program Design (second edition), finally today the mechanical completion of this experi

The Linux application layer wants to manipulate the API of the kernel layer, for example, to manipulate the relevant Gpio or register, which can be achieved by writing a character device driver.1, first in the Rootfs in the/dev/under the generation of a character device. Note The main device number and the from

Clock management for linux Device Drivers (4) ---- it turns out to be a child When I was a child, I saw a TV series called "Little Dragon man". You don't have to mention it. It's actually very inspirational. To find my mother, it's a great TV series, what are the children watching? Xuanyuan sword, god of every day, magic, illusion, and flashy stuff. Apart from co

moduleType is the kind of parameterPerm is a parameter's permissionFor example, to add in a moduleint disk_size = 1024;module_param_named (size, disk_size, int, s_irugo);You can add a parameter named "Size" to the module, and if the module is loaded using Insmod thismodule size=1, thenThe value of Disk_size in the module code is 1.Conversely, if you do not specify a parameter when loading the module, the value of Disk_size in the module code is still the default of 1024S_IRUGO specifies that th

Foreword IfYou're holding this book, you may be asking yourself: Why "yet another"Linux Device Driver book? Aren't there already a bunch of them?The answer is: This book is a quantum leap ahead of the others.First,It is up-to-date, covering recent 2.6 kernels. Second, and moreImportant, this book is thorough. Most Device Driver books just coverThe topics descri

, released in 1969, is the most widely used serial interface for embedded systems and is designed to connect DTE (data Terminal equipment) with DCE (data communication devices). The RS-232 standard interface has 25 interfaces (4 data lines, 11 control lines, 3 timing lines, 7 spare and undefined lines), only 9 are commonly used, they are rts/cts (request send/clear Send flow control), RXD/TXD (data transmit/receive), DSR/DTR (Data Terminal ready/ Data set Ready flow control), DCD (Data carrier d

The kernel is driven by a device.ProgramInteraction with I/O devices. The device driver is included in the kernel and consists of data structures and functions that control one or more devices, these devices include hard disk, keyboard, mouse, monitor, network interface, and devices connected to the SCSI bus. Through a specific interface, each driver interacts with the rest of the kernel (including other drivers