从哪里开始学习linux DMA /设备驱动程序/内存分配

时间:2010-03-03 07:22:55

标签: linux embedded memory-management dma

我正在移植/调试设备驱动程序(由另一个内核模块使用)并面临死胡同,因为dma_sync_single_for_device()因内核oops而失败。

我不知道该功能应该做什么,谷歌搜索并没有真正帮助,所以我可能需要更多地了解这些东西。

问题是,从哪里开始?

哦,是的,如果它是相关的,代码应该在PowerPC上运行(并且linux是OpenWRT)

编辑: 在线资源是可取的(书籍需要几天才能交付:)

3 个答案:

答案 0 :(得分:9)

在线方式:

Anatomy of the Linux slab allocator

Understanding the Linux Virtual Memory Manager

Linux Device Drivers, Third Edition

The Linux Kernel Module Programming Guide

Writing device drivers in Linux: A brief tutorial

书籍:

Linux Kernel Development (2nd Edition)

Essential Linux Device Drivers(仅限前4至5章)

有用的资源:

the Linux Cross Reference(所有内核的可搜索内核源代码)

API changes in the 2.6 kernel series


dma_sync_single_for_device 在文件中进一步调用dma_sync_single_range_for_cpu这是源文档(我假设即使这是针对arm的接口和行为是同样):

/**
 380 * dma_sync_single_range_for_cpu
 381 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 382 * @handle: DMA address of buffer
 383 * @offset: offset of region to start sync
 384 * @size: size of region to sync
 385 * @dir: DMA transfer direction (same as passed to dma_map_single)
 386 *
 387 * Make physical memory consistent for a single streaming mode DMA
 388 * translation after a transfer.
 389 *
 390 * If you perform a dma_map_single() but wish to interrogate the
 391 * buffer using the cpu, yet do not wish to teardown the PCI dma
 392 * mapping, you must call this function before doing so.  At the
 393 * next point you give the PCI dma address back to the card, you
 394 * must first the perform a dma_sync_for_device, and then the
 395 * device again owns the buffer.
 396 */

答案 1 :(得分:5)

答案 2 :(得分:3)

Linux Device Drivers书的章节(与理解Linux内核相同的系列,由@Matthew Flaschen推荐)可能很有用。

您可以从LWN Website下载indiivudal章节。 Chapter 16处理DMA。