On Tue, Mar 09, 2021 at 10:18:43AM +0000, Sanket Parmar wrote: > > On Tue, Mar 09, 2021 at 06:19:40AM +0100, Sanket Parmar wrote: > > > dma_alloc_coherent() might fail on the platform with a small DMA region. > > > > > > To avoid such failure in cdns3_prepare_aligned_request_buf(), > > > dma_alloc_coherent() is replaced with kmalloc and dma_map API to > > > allocate aligned request buffer of dynamic length. > > > > dma_alloc_noncoherent is the proper API instead of using kmalloc, which > > can lead to unaddressable memory that might require bounce buffering. > > cdns3 device required DMA coherent buffer to perform operations. So > dma_alloc_noncoherent will not help here. > > Also all gadget classes(except g_ether) use kmalloc to allocated request buffer, > and device driver uses usb_gadget_map_request_by_dev to map the request > buffer. Similar approach is used to allocate aligned buffer. If you can use kmalloc and dma_map_single you can use dma_alloc_noncoherent per definition.
