Hi Lizhi, On Tue, Sep 3, 2024 at 6:50 PM Lizhi Hou <lizhi.hou@xxxxxxx> wrote: > On 9/3/24 02:20, Geert Uytterhoeven wrote: > > On Thu, Apr 18, 2024 at 7:51 PM Lizhi Hou <lizhi.hou@xxxxxxx> wrote: > >> From: Nishad Saraf <nishads@xxxxxxx> > >> > >> Adds driver to enable PCIe board which uses AMD QDMA (the Queue-based > >> Direct Memory Access) subsystem. For example, Xilinx Alveo V70 AI > >> Accelerator devices. > >> https://www.xilinx.com/applications/data-center/v70.html > >> > >> The QDMA subsystem is used in conjunction with the PCI Express IP block > >> to provide high performance data transfer between host memory and the > >> card's DMA subsystem. > >> > >> +-------+ +-------+ +-----------+ > >> PCIe | | | | | | > >> Tx/Rx | | | | AXI | | > >> <=======> | PCIE | <===> | QDMA | <====>| User Logic| > >> | | | | | | > >> +-------+ +-------+ +-----------+ > >> > >> The primary mechanism to transfer data using the QDMA is for the QDMA > >> engine to operate on instructions (descriptors) provided by the host > >> operating system. Using the descriptors, the QDMA can move data in both > >> the Host to Card (H2C) direction, or the Card to Host (C2H) direction. > >> The QDMA provides a per-queue basis option whether DMA traffic goes > >> to an AXI4 memory map (MM) interface or to an AXI4-Stream interface. > >> > >> The hardware detail is provided by > >> https://docs.xilinx.com/r/en-US/pg302-qdma > >> > >> Implements dmaengine APIs to support MM DMA transfers. > >> - probe the available DMA channels > >> - use dma_slave_map for channel lookup > >> - use virtual channel to manage dmaengine tx descriptors > >> - implement device_prep_slave_sg callback to handle host scatter gather > >> list > >> > >> Signed-off-by: Nishad Saraf <nishads@xxxxxxx> > >> Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxx> > > Thanks for your patch, which is now commit 73d5fc92a11cacb7 > > ("dmaengine: amd: qdma: Add AMD QDMA driver") in dmaengine/next. > > > >> --- /dev/null > >> +++ b/drivers/dma/amd/Kconfig > >> @@ -0,0 +1,14 @@ > >> +# SPDX-License-Identifier: GPL-2.0-only > >> + > >> +config AMD_QDMA > >> + tristate "AMD Queue-based DMA" > >> + depends on HAS_IOMEM > > Any other subsystem or platform dependencies, to prevent asking the > > user about this driver when configuring a kernel for a system which > > cannot possibly have this hardware? > > E.g. depends on PCI, or can this be used with other transports than PCIe? > > No, this driver does not have other dependencies. It can be used with > other transports. > > It is similar with dmaengine/xilinx/xdma OK. > >> --- /dev/null > >> +++ b/drivers/dma/amd/qdma/qdma-comm-regs.c > >> +static struct platform_driver amd_qdma_driver = { > >> + .driver = { > >> + .name = "amd-qdma", > > Which code is responsible for creating "amd-qdma" platform devices? I still would like to receive an answer to this question? Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
