> 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. Okay. I was not aware of it. I will test it. Thank you for your feedback. -- Sanket
