Re: [PATCH v2 03/23] dmaengine: sdxi: Add PCI initialization

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] The Kconfig symbol `CONFIG_SDXI` lacks a dependency on `PCI` or `PCI_MSI`, and the Makefile conditionally links `pci.o` using `sdxi-$(CONFIG_PCI_MSI) += pci.o`.
- [Low] The return value of `dma_set_mask_and_coherent()` is ignored in `sdxi_pci_init()`.
--

commit bdb690a4c497e7a353f0143e03e32ba75daa6013
Author: Nathan Lynch <nathan.lynch@amd.com>

dmaengine: sdxi: Add PCI initialization

This commit adds PCI initialization to bind an SDXI device via the class
code. It maps the control registers and doorbell region, managing resources
with devres and registering the device with the generic SDXI core.

> diff --git a/drivers/dma/sdxi/Makefile b/drivers/dma/sdxi/Makefile
> new file mode 100644
> --- /dev/null
> +++ b/drivers/dma/sdxi/Makefile
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_SDXI) += sdxi.o
> +
> +sdxi-objs += device.o
> +
> +sdxi-$(CONFIG_PCI_MSI) += pci.o

If CONFIG_SDXI is enabled but CONFIG_PCI_MSI is disabled, pci.o is omitted
from the build. Because pci.c is the only file containing the driver
registration macro (module_pci_driver) and the module license declaration,
would this result in a module that lacks an initialization entry point and
fails to load properly while also tainting the kernel?

[ ... ]

> diff --git a/drivers/dma/sdxi/pci.c b/drivers/dma/sdxi/pci.c
> new file mode 100644
> --- /dev/null
> +++ b/drivers/dma/sdxi/pci.c
[ ... ]
> +static int sdxi_pci_init(struct sdxi_dev *sdxi)
> +{
> +	struct pci_dev *pdev = sdxi_to_pci_dev(sdxi);
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	ret = pcim_enable_device(pdev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to enable device\n");
> +
> +	dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));

The return value of dma_set_mask_and_coherent() is ignored here. If the
platform or IOMMU does not support 64-bit DMA, this function returns an error
code and leaves the device's DMA mask at its default 32-bit value.

Is it expected to proceed without handling the fallback or logging a warning?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260511-sdxi-base-v2-0-889cfed17e3f@amd.com?part=3