Re: [PATCH 5/5] arm64: dts: freescale: add DT overlay for MX95-15x15-FRDM RPMSG usage

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `dma-channel-mask` property is incorrectly defined as a mask of unavailable (reserved) channels rather than available channels, violating standard DT binding semantics by relying on a buggy driver implementation.
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commit cbf89994f08b1b68af6ef4fcaffd7d5ceac2c8f0
Author: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>

arm64: dts: freescale: add DT overlay for MX95-15x15-FRDM RPMSG usage

This commit adds an RPMSG device tree overlay for the MX95-15x15-FRDM board.
It configures reserved memory regions for vdev vrings and buffers, and
updates the cm7, edma, and micfil nodes to support remoteproc and audio
use cases.

> diff --git a/arch/arm64/boot/dts/freescale/imx95-15x15-frdm-rpmsg.dtso b/arch/arm64/boot/dts/freescale/imx95-15x15-frdm-rpmsg.dtso
> new file mode 100644
> index 0000000000000..b39444dde66e0
> --- /dev/null
> +++ b/arch/arm64/boot/dts/freescale/imx95-15x15-frdm-rpmsg.dtso

[ ... ]

> +&edma1 {
> +	/* reserved for M7 */
> +	dma-channel-mask = <0x40>;
> +};
> +
> +&edma2 {
> +	/* reserved for M7 and V2X */
> +	dma-channel-mask = <0xf>;
> +};

[Severity: Medium]
Is this property defining available or reserved channels?

The standard device tree binding in dma-common.yaml explicitly defines
dma-channel-mask as a bitmask of available DMA channels that are not reserved
by firmware. However, the comments here indicate the mask is being used to
define reserved channels.

While there appears to be an existing bug in the fsl-edma driver where it
interprets this property as unavailable channels, encoding a driver bug into
the hardware description breaks the device tree ABI and will cause issues
if the driver is ever corrected.

Could this be updated to correctly reflect available channels according to the
standard binding?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260522111849.783-1-laurentiumihalcea111@gmail.com?part=5