Tài liệu Linux Device Drivers-Chapter 9 :Interrupt Handling Although doc

... IO-APIC-level aic7xxx 12: 8 890 91 884276 IO-APIC-edge PS/2 Mouse 13: 1 0 XT-PIC fpu 15: 17 596 69 1734520 IO-APIC-edge ide1 NMI: 695 20 392 695 20 392 LOC: 695 13717 695 13716 ERR: 0 The first ... */ } Chapter 9 :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 ... intr 884865 695 557 4527 0 31 09 490 7 1127 59 3 0 0 0 11314 0 17747 1 0 3 494 1 0 0 0 0 0 0 0 When using edge-triggered interrupts, on the other hand, interrupts may be lost: if one device pulls...

Tài liệu Linux Device Drivers-Chapter 3: Char Drivers docx

... /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 ... random-access device, one device or many, and so on. To make scull be useful as a template for writing real drivers for real devices, we'll show you how to implement several device abstractions ... number and how the driver uses it to differentiate among devices. Every time the kernel calls a device driver, it tells the driver which device is being acted upon. The major and minor numbers...

Tài liệu Linux Device Drivers-Chapter 8 :Hardware Management docx

... 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 ... we suggest that you not use pins 9 and 10, because we'll be connecting them together later to run the sample code shown in Chapter 9, "Interrupt Handling& quot;. As far as short is ... instructions. There are eight such devices, from short0 to short7. Although the PC parallel interface has only three ports, you may need more of them if using a different I/O device to run your tests....

Tài liệu Linux Device Drivers-Chapter 1 :An Introduction to Device Drivers ppt

... 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 ... 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 ... acquired image using mmap or lseek. Block devices Like char devices, block devices are accessed by filesystem nodes in the /dev directory. A block device is something that can host a filesystem,...

Tài liệu Linux Device Drivers-Chapter 2 : Building and Running Modules pptx

... to Device Drivers". #define MODULE #include < ;linux/ module.h> buffer-based graphics environments, where the X server acts only as a server based on a real kernel-space device ... multiple processors. Exporting Symbols in Linux 2.0 The Linux 2.0 symbol export mechanism was built around a function called register_symtab. A Linux 2.0 module would build a table describing ... the headers of Linux 2.0: static struct symbol_table skull_syms = { #include < ;linux/ symtab_begin.h> X(skull_fn1), X(skull_fn2), X(skull_variable), #include < ;linux/ symtab_end.h>...

Tài liệu Linux Device Drivers-Chapter 4 : Debugging Techniques pptx

... (Inappropriate ioctl for device) write(1, "MAKEDEV\natibm\naudio\naudio1\na" , 4 096 ) = 4000 write(1, "d2\nsdd3\nsdd4\nsdd5\nsdd6\nsdd7" , 96 ) = 96 write(1, "4\nsde5\nsde6\nsde7\nsde8\nsde9\n" ... = 0x8055000 lseek(4, 0, SEEK_CUR) = 0 getdents(4, /* 70 entries */, 393 3) = 1260 [ ] getdents(4, /* 0 entries */, 393 3) = 0 close(4) = 0 fstat(1, {st_mode=S_IFCHR|0664, st_rdev=makedev(253, ... limit; i++) { Scull_Dev *d = &scull_devices[i]; if (down_interruptible(&d->sem)) return -ERESTARTSYS; len += sprintf(buf+len,"\nDevice %i: qset %i, q %i, sz %li\n",...

Tài liệu Linux Device Drivers-Chapter 5 : Enhanced Char Driver Operations pptx

... the same device) is best solved by implementing one device node for each access policy. An example of this practice can be found in the Linux tape driver, which provides multiple device files ... same device. Different device files will, for example, cause the drive to record with or without compression, or to automatically rewind the tape when the device is closed. Cloning the Device ... represents. When copies of the device are created by the software driver, we call them virtual devices just as virtual consoles use a single physical tty device. Although this kind of access...

Tài liệu Linux Device Drivers-Chapter 6 : Flow of Time pptx

... Bottom-Half Processing", in Chapter 9, "Interrupt Handling& quot;. For now, suffice it to say that a bottom half is a mechanism provided by a device driver to handle asynchronous tasks ... serve the interrupt. Interrupts and ISR implementation issues are covered in Chapter 9, "Interrupt Handling& quot;. cycles_t get_cycles(void); The function is defined for every platform, ... intervals, while one millisecond is a long enough delay for hardware activities. Although mdelay is not available in Linux 2.0, sysdep.h fills the gap. Task Queues One feature many drivers need...

Tài liệu Linux Device Drivers-Chapter 7 : Getting Hold of Memory doc

... of or in addition to 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 ... cat /tmp/bigfile > /dev/scullv0; head -5 /proc/scullvmem Device 0: qset 500, order 4, sz 1048576 item at e0000000303 699 c0, qset at e000000025c87000 0:a000000000034000 1:a000000000078000 ... /proc/scullpmem Device 0: qset 500, order 0, sz 1048576 item at c4184780, qset at c71c4800 0:c262b000 1:c2 193 000 rudo% cat /tmp/bigfile > /dev/scullv0; head -5 /proc/scullvmem Device 0:...

Tài liệu Linux Device Drivers-Chapter 10 :Judicious Use of Data Types doc

... integers are always the same size, at least on all the platforms currently supported by Linux. The C 99 standard defines the intptr_t and uintptr_t types for an integer variable which can hold ... remember that these types are Linux specific, and using them hinders porting software to other Unix flavors. Systems with recent compilers will support the C 99- standard types, such as uint8_t ... itself. See the include file for the rest. Not all Linux versions defined all the macros that deal with byte ordering. In particular, the linux/ byteorderdirectory appeared in version 2.1.72...

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