[V9,0/2] AMD QDMA driver

Message

Lizhi Hou Feb. 27, 2024, 5:08 p.m. UTC

Hello,

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|
            |       |       |       |       |           |
            +-------+       +-------+       +-----------+

Comparing to AMD/Xilinx XDMA subsystem,
    https://lore.kernel.org/lkml/Y+XeKt5yPr1nGGaq@matsya/
the QDMA subsystem is a queue based, configurable scatter-gather DMA
implementation which provides thousands of queues, support for multiple
physical/virtual functions with single-root I/O virtualization (SR-IOV),
and advanced interrupt support. In this mode the IP provides AXI4-MM and
AXI4-Stream user interfaces which may be configured on a per-queue basis.

The QDMA has been used for Xilinx Alveo PCIe devices.
    https://www.xilinx.com/applications/data-center/v70.html

This patch series is to provide the platform driver for AMD QDMA subsystem
to support AXI4-MM DMA transfers. More functions, such as AXI4-Stream
and SR-IOV, will be supported by future patches.

The device driver for any FPGA based PCIe device which leverages QDMA can
call the standard dmaengine APIs to discover and use the QDMA subsystem
without duplicating the QDMA driver code in its own driver.

Changes since v8:
- Replaced dma_alloc_coherent() with dmam_alloc_coherent()

Changes since v7:
- Fixed smatch warnings

Changes since v6:
- Added a patch to create amd/ and empty Kconfig/Makefile for AMD drivers
- Moved source code under amd/qdma/
- Minor changes for code review comments

Changes since v5:
- Add more in patch description.

Changes since v4:
- Convert to use platform driver callback .remove_new()

Changes since v3:
- Minor changes in Kconfig description.

Changes since v2:
- A minor change from code review comments.

Changes since v1:
- Minor changes from code review comments.
- Fixed kernel robot warning.

Lizhi Hou (1):
  dmaengine: amd: Add empty Kconfig and Makefile for AMD drivers

Nishad Saraf (1):
  dmaengine: amd: qdma: Add AMD QDMA driver

 MAINTAINERS                            |    8 +
 drivers/dma/Kconfig                    |    2 +
 drivers/dma/Makefile                   |    1 +
 drivers/dma/amd/Kconfig                |   14 +
 drivers/dma/amd/Makefile               |    6 +
 drivers/dma/amd/qdma/Makefile          |    8 +
 drivers/dma/amd/qdma/qdma-comm-regs.c  |   64 ++
 drivers/dma/amd/qdma/qdma.c            | 1162 ++++++++++++++++++++++++
 drivers/dma/amd/qdma/qdma.h            |  265 ++++++
 include/linux/platform_data/amd_qdma.h |   36 +
 10 files changed, 1566 insertions(+)
 create mode 100644 drivers/dma/amd/Kconfig
 create mode 100644 drivers/dma/amd/Makefile
 create mode 100644 drivers/dma/amd/qdma/Makefile
 create mode 100644 drivers/dma/amd/qdma/qdma-comm-regs.c
 create mode 100644 drivers/dma/amd/qdma/qdma.c
 create mode 100644 drivers/dma/amd/qdma/qdma.h
 create mode 100644 include/linux/platform_data/amd_qdma.h