dma_addr_t dma_map_single(struct device *dev,void *buffer,size_t size, enum dma_data_direction direction); 返回值是总线地址,可以把它传递给设备。 当传输完毕后,使用dma_unmap_single函数删除映射: void dma_unmap_single(struct device *dev,dma_addr_t dma_addr,size_t size, enum dma_data_dire...
⼀个DMA映射是要分配的DMA缓冲区与为该缓冲区⽣成的、设备可访问地址的组合。DMA映射建⽴了⼀个新的结构类型——dma_addr_t来表⽰总线地址。dma_addr_t类型的变量对驱动程序是不透明的，唯⼀允许的操作是将它们传递给DMA⽀持例程以及设备本⾝。根据DMA缓冲区期望保留的时间长短，PCI代码有两种DMA...
目前，Marek Szyprowski和Michal Nazarewicz实现了一套全新的Contiguous Memory Allocator。通过这套机制，...
#if defined(CONFIG_X86_64) || defined(CONFIG_HIGHMEM64G) /* DMA addresses come in 32-bit and 64-bit flavours. */ typedef u64 dma_addr_t; #else typedef u32 dma_addr_t; #endif #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* _ASM_X86_TYPES_H * === Enviro...
as the phybase paramter only used for DMA operation, change it's type from resource_size_t to dma_addr_t Signed-off-by: Bo Shen <voice.shen@atmel.com> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@linaro.org>Loading...
_dma_buffer *dmab, size_t offset) { struct snd_sg_buf *sgbuf = dmab->private_data; dma_addr_t addr = sgbuf->table[offset >> PAGE_SHIFT].addr; addr &= PAGE_MASK; return addr + offset % PAGE_SIZE; } where PAGE_MASK in a 32bit kernel is zeroing the upper 32bit af addr. ...
楼主 我感觉 第一个 USARTx->DR = (Data & (uint16_t)0x01FF);和 return (uint16_t)(USARTx->DR & (uint16_t)0x01FF) 你上面 说了 是 给数据 给 寄存器 下面 的 DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART1->DR; 是取寄存器的地址 我就说个 ...