[PATCH v3 25/27] media: rockchip: rga: disable multi-core support

[Nicolas Dufresne]

Le mardi 27 janvier 2026 à 15:39 +0100, Sven Püschel a écrit :
> Disable multi-core support in preparation of the RGA3 addition. The
> RK3588 SoC features two equal RGA3 cores. This allows scheduling of the
> work between both cores, which is not yet implemented. Until it is
> implemented avoid exposing both cores as independent video devices to
> prevent an ABI breakage when multi-core support is added.
> 
> This patch is copied from the Hantro driver patch to disable multi core
> support by Sebastian Reichel. See
> commit ccdeb8d57f7f ("media: hantro: Disable multicore support")
> 
> Link: https://lore.kernel.org/all/20240618183816.77597-4-sebastian.reichel@collabora.com/
> Signed-off-by: Sven Püschel <s.pueschel at pengutronix.de>

Reviewed-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>

> ---
>  drivers/media/platform/rockchip/rga/rga.c | 47 +++++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
> index 43644995c152e..e45b9c853d659 100644
> --- a/drivers/media/platform/rockchip/rga/rga.c
> +++ b/drivers/media/platform/rockchip/rga/rga.c
> @@ -708,6 +708,49 @@ static int rga_parse_dt(struct rockchip_rga *rga)
>  	return 0;
>  }
>  
> +/*
> + * Some SoCs, like RK3588 have multiple identical RGA3 cores, but the
> + * kernel is currently missing support for multi-core handling. Exposing
> + * separate devices for each core to userspace is bad, since that does
> + * not allow scheduling tasks properly (and creates ABI). With this workaround
> + * the driver will only probe for the first core and early exit for the other
> + * cores. Once the driver gains multi-core support, the same technique
> + * for detecting the main core can be used to cluster all cores together.
> + */
> +static int rga_disable_multicore(struct device *dev)
> +{
> +	struct device_node *node = NULL;
> +	const char *compatible;
> +	bool is_main_core;
> +	int ret;
> +
> +	/* Intentionally ignores the fallback strings */
> +	ret = of_property_read_string(dev->of_node, "compatible", &compatible);
> +	if (ret)
> +		return ret;
> +
> +	/* The first compatible and available node found is considered the main core */
> +	do {
> +		node = of_find_compatible_node(node, NULL, compatible);
> +		if (of_device_is_available(node))
> +			break;
> +	} while (node);
> +
> +	if (!node)
> +		return -EINVAL;
> +
> +	is_main_core = (dev->of_node == node);
> +
> +	of_node_put(node);
> +
> +	if (!is_main_core) {
> +		dev_info(dev, "missing multi-core support, ignoring this instance\n");
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
>  static int rga_probe(struct platform_device *pdev)
>  {
>  	struct rockchip_rga *rga;
> @@ -718,6 +761,10 @@ static int rga_probe(struct platform_device *pdev)
>  	if (!pdev->dev.of_node)
>  		return -ENODEV;
>  
> +	ret = rga_disable_multicore(&pdev->dev);
> +	if (ret)
> +		return ret;
> +
>  	rga = devm_kzalloc(&pdev->dev, sizeof(*rga), GFP_KERNEL);
>  	if (!rga)
>  		return -ENOMEM;
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