drivers\of\address.c里的of_dma_is_coherent( )读取属性"dma-coherent"。 b}oolof_dma_is_coherent(structdevice_node *np){structdevice_node*node =of_node_get(np);while(node) {if(of_property_read_bool(node,"dma-coherent")) {of_node_put(node);returntrue; } node =of_get_next_parent(no...
DMA的设备树里可以配置属性"dma-coherent"。 drivers\of\address.c里的of_dma_is_coherent( )读取属性"dma-coherent"。 bool of_dma_is_coherent(struct device_node *np) { struct device_node *node = of_node_get(np); while (node) { if (of_property_read_bool(node, "dma-coherent")) { of_...
void*dma_alloc_coherent(structdevice *dev, size_t size, dma_addr_t *handle, gfp_t gfp);voiddma_free_coherent(structdevice *dev, size_t size,void*cpu_addr, dma_addr_t handle); 一般驱动使用多,申请一片uncache mem,这样无需考虑data 一致性。代码流程:对page property,也就是是kernel页管理的...
DMA的设备树里可以配置属性"dma-coherent"。 drivers\of\address.c里的of_dma_is_coherent( )读取属性"dma-coherent"。 bool of_dma_is_coherent(struct device_node *np) { struct device_node *node = of_node_get(np); while (node) { if (of_property_read_bool(node, "dma-coherent")) { of_n...
dma-coherent If thedma-coherentproperty is specified, indicates that coherency between DMA buffer and CPU cache can be guaranteed by hardware. Thedma-coherentproperty is optional. When thedma-coherentproperty is not specified, indicates that coherency between DMA buffer and CPU cache can not be gua...
dma_mask和coherent_dma_mask 的默认值 PCI设备: coherent_dma_mask :用来分配连续一致性dma。 dma_mask:在dma_map_single->dma_map_page,dma_capable用。 先看默认设置。后续可以通过pci_set_dma_mask/pci_set_consistent_dma_mask分别设置 设置:
If the dma-coherent property is specified in the device tree, specify that coherency can be guaranteed with hardware. In this case, the cache control described in "2. Manual cache management with the CPU cache still being enabled" described later is not performed....
The device file/sys/class/udmabuf/<device-name>/dma_coherentcan read whether the coherency of DMA buffer and CPU cache can be guaranteed by hardware. It is able to specify whether or not it is able to guarantee by hardware with thedma-coherentproperty in the device tree, but this device ...
DMA 控制器通常有多个通道,每个通道可以独立工作来处理不同的传输任务。每个设备会分配一个或多个 DMA 通道来进行数据传输。 多通道 DMA:允许多个设备同时使用 DMA,避免了设备间的冲突,提升系统整体的吞吐量。 1.2.2. 源地址 (Source Address) 源地址是 DMA 传输中数据的读取起始地址,通常是外部设备(如硬盘、网...
Highly Scalable Mesh for Intelligent Connected Systems The Arm CoreLink CMN-700 Coherent Mesh Network is designed for intelligent connected systems across a wide range of applications, including ... 29 ULL PCIe DMA Controller Offers new options for your design by supporting multiple configurations in...