Hi Geert,
On 9/27/24 02:01, Geert Uytterhoeven wrote:
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!
Sorry, I missed this question.
The driver of device which uses qdma IP will create amd-qdma platform
device. E.g. for our FPGA device:
https://github.com/houlz0507/XRT-1/blob/qdma_v2_usage/src/runtime_src/core/pcie/driver/linux/xocl/subdev/qdma.c#L614
Thanks,
Lizhi
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
