Tài liệu Linux Device Drivers-Chapter 13 :mmap and DMA pptx

... mappings, for a buffer that will last the lifetime of the driver. PCI _DMA_ TODEVICE PCI _DMA_ FROMDEVICE PCI _DMA_ BIDIRECTIONAL PCI _DMA_ NONE These symbols are used to tell the streaming mapping functions ... struct file *vm_file; Chapter 13 :mmap and DMA This chapter delves into the area of Linux memory management, with an emphasis on techniques that are useful to t...

Ngày tải lên : 21/01/2014, 07:20

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

... is a virtual address and is mapped to physical addresses through a complex structure of so-called page tables (see "Page Tables" in Chapter 13, "mmap and DMA& quot;). When an invalid ... identifies a command to be performed and (optionally) another argument, usually a pointer. As an alternative to using the /proc filesystem, you can implement a few ioctl commands t...

Ngày tải lên : 24/12/2013, 01:17

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

... /etc/modules.conf). The commands accept the specification of integer and string values on the command line. Thus, if your module were to provide an integer parameter called skull_ival and a string parameter ... imposes a performance penalty. [13] to use your driver at the same time. Most devices are capable of interrupting the processor; interrupt handlers run asynchronously and c...

Ngày tải lên : 24/12/2013, 01:17

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Tài liệu Linux Device Drivers-Chapter 11 : kmod and Advanced docx

... (unused) es1370 34832 1 Both the return value from request_module and the /proc/modules file (described in "Initialization and Shutdown" in Chapter 2, "Building and Running ... used primarily by the hot-plug subsystem (i.e., for USB devices and such) to perform module loading and configuration tasks when a new device is attached to the system. Its prototype i...

Ngày tải lên : 21/01/2014, 07:20

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

... Chapter 13, "mmap and DMA& quot; explains what we left out from the previous treatment of memory management: mmap and direct memory access (DMA) . At this point, everything about char and block ... vendors, by making a Linux driver available for their products, can add the large and growing Linux user base to their potential markets. And the open source nature of the C...

Ngày tải lên : 24/12/2013, 01:17

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

... sequential or 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 ... /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 m...

Ngày tải lên : 24/12/2013, 01:17

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

... handle than ioctl. 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 ... the ioctl system call offers a device specific entry point for the driver to handle "commands.'' ioctl is device specific in that, unlike read and other methods, it...

Ngày tải lên : 24/12/2013, 01:17

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

... kernel functions udelay and mdelay serve this purpose.[27] Their prototypes are [27] The u in udelay represents the Greek letter mu and stands for micro. #include < ;linux/ delay.h> void ... most useful when writing interrupt handlers, and we'll see them again in "Tasklets and Bottom-Half Processing", in Chapter 9, "Interrupt Handling". Kernel timer...

Ngày tải lên : 24/12/2013, 01:17

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

... to "Memory Management in Linux& quot; in Chapter 13, "mmap and DMA& quot;. The Real Story of kmalloc The kmalloc allocation engine is a powerful tool, and easily learned because of ... "The mmap Device Operation" in Chapter 13, "mmap and DMA& quot;. To allocate pages, the following functions are available: get_zeroed_page Returns a pointer to a ne...

Ngày tải lên : 24/12/2013, 01:17

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

... easy to use. I/O Ports and I/O Memory Every peripheral device is controlled by writing and reading its registers. Most of the time a device has several registers, and they are accessed at ... misc-progs/inp.c and misc-progs/outp.c are a minimal tool for reading and writing ports from the command line, in user space. They expect to be installed under multiple names (i.e., i...

Ngày tải lên : 24/12/2013, 01:17

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