dma_map_single
In some simple systems, the device can do DMA directly to physical address Y. But in many others, there is IOMMU hardware that translates DMA addresses to physical addresses, e.g., it translates Z to Y. This is part of the reason for the DMA API: the driv, dma_map_single and dma_map_page will eventually call dam_ops->map_page - the eventual function is decided by the arch and kernel config. usualy it will be intel_map_page on x86 machines with IOMMU. First of all Jumbo frames from the kernels standpoint
| 相關軟體 Oracle Database Express 資訊 | |
|---|---|
 dma_map_single 相關參考資料
dma_map_single(): 对结构设备的最低要求_linux-kernel_帮酷编程问答
int rc; struct device dev; dev_set_name(&dev,"mydev"); if ((rc = device_register(&dev))!= 0) goto fail; char *kbuf = kmalloc(size, GFP_KERNEL); dma_addr_t handle = dma_map_single(&a... http://hant.ask.helplib.com Dynamic DMA mapping Guide - Kernel.org
In some simple systems, the device can do DMA directly to physical address Y. But in many others, there is IOMMU hardware that translates DMA addresses to physical addresses, e.g., it translates Z to ... https://www.kernel.org intel - dma_map_single and dma_map_page - Stack Overflow
dma_map_single and dma_map_page will eventually call dam_ops->map_page - the eventual function is decided by the arch and kernel config. usualy it will be intel_map_page on x86 machines with IOMMU... https://stackoverflow.com linux kernel - dma_map_single(): minimum requirements to struct ...
I apologize if I wasn't clear enough about the purpose of this code. I just wanted to try the Streaming DMA API, so I needed to be able to simply map/unmap a kernel memory buffer (and try to acce... https://stackoverflow.com Linux source code: dma_map_single identifier (v3.4) - Bootlin
Defined in 26 files: arch/arm/include/asm/dma-mapping.h, line 314 (as a function) · arch/avr32/include/asm/dma-mapping.h, line 117 (as a function) · arch/blackfin/include/asm/dma-mapping... https://elixir.bootlin.com linux中关于dma_alloc_coherent的用法- CSDN博客
DMA_TO_DEVICE 数据发送到设备(如write系统调用) DMA_FROM_DEVICE 数据被发送到CPU DMA_BIDIRECTIONAL 数据可双向移动. DMA_NONE 出于调试目的。 当只有一个缓冲区要被传输的时候，使用dma_map_single函数映射它: dma_addr_t dma_map_single(struct device *dev,void *buffe... https://blog.csdn.net memory management - dma_map_single internals on arm archtecture ...
Not quite. For the streaming DMA API (i.e. dma_map_*() / dma_unmap_*() ), nothing is actually remapped. Only addresses from the kernel linear mapping (i.e. normal kmalloc() memory) are valid for stre... https://stackoverflow.com s3c2440的dma操作的一般步驟@ 程式專欄:: 隨意窩Xuite日誌
這個單元或者是內存中，或者是某個卡上的存儲單元，甚至可能這個地址上沒有對應的存儲器。而在另外一個平台上，或許在PCI總線上產生的訪問是針對地址為0x1fa000的單元。 上述函數是建立一致性映射。使用dma_map_single函數可以建立一致性映射: 2.當只有一個緩沖區要被傳輸的時候，使用dma_map_single函數來映射它 http://blog.xuite.net [問題] linux DMA問題- 看板LinuxDev - 批踢踢實業坊
我想在linux下用DMA和我的硬體溝通網路上很多教學文都是kmalloc一塊記憶體大小用dma_map_single 映射出一個DMA可使用的地址這種方法我也試成功了現在的問題是我有一筆資料要用我的硬體做運算. https://www.ptt.cc 驅動程式中的DMA問題@ Welkin小窩:: 痞客邦:: - 痞客邦PIXNET
另外有一個簡單的作法，就是在準備這些記憶體時，就取得讓記憶體是不會做cache的動作，如此一來就不需要做資料同步動作。 Kernel API 我們從以上知道問題，也知道該如何解決，現在的問題是有多少的kernel API可供使用，以下我們就來看： dma_addr_t dma_map_single(struct device *, void *, size_t, enum dma_data_dir... http://welkinchen.pixnet.net |