motorola device drivers

Memdev.h#ifndef _memdev_h#define _memdev_h#define mem_magic ' m ' #define Mem_restart _io (mem_magic, 0)//Use the kernel-provided macros to generate commands #define MEM _set _iow (mem_magic, 1, int)//change command to pass a shaping parameter to the kernel #endifDriver MEMDEV.C#include Application MEM_READ.C#include The device number is dynamically assigned in the driver and the device number assigned

, scheduling modes, and how to map them to the corresponding user space. It is equally important to port the RTOS hardware interface code to a more standardized Linux Device Driver in an I/O-intensive embedded program. This article will outline several common memory ing I/O methods that often appear in existing embedded applications. They cover a range from special use of interrupt service routines and access to hardware by user threads to a semi-sta

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

Linux driver module parameters-Linux Device DriversModule Parameters In many cases, we expect to control our drive behavior through parameters. For example, because of different systems, to ensure good portability of our drivers, sometimes we want to control our driven behavior by passing parameters. In this way, drivers may have different behavior controls in d

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_operations member is not an operation at all; It is

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 interrupt context.----A simple way to use:----if (Dow

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 commercial value, what kind of stuff can be use

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

The development environment of LDD3 recommended is 2.6.10, installed RHEL4-UPDATE4, its kernel version is 2.6.9.42, compiling the mmap program times wrong: Unknown symbol Remap_pfn_rangeOn the Internet, the above error should be changed to Remap_page_range, and Remap_page_range is no longer recommended, two kernel functions The second parameter definition is not the same: int Remap_page_range (struct vm_area_struct *vma, unsigned long from, unsigned long phys_addr,//

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

> 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