Message-ID: <spejairpdsb5sa3jwuogkl3edkglqoxa4eqz6zriq5w53ic4a6@4gyymeidqy5d>
Date: Tue, 3 Feb 2026 13:40:48 +0530
From: Manivannan Sadhasivam <mani@...nel.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
Cc: andersson@...nel.org, konradybcio@...nel.org, 
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, stable@...r.kernel.org, 
	Abel Vesa <abel.vesa@....qualcomm.com>, Sumit Garg <sumit.garg@....qualcomm.com>
Subject: Re: [PATCH] soc: qcom: ice: Remove platform_driver support and
 expose as a pure library

On Tue, Feb 03, 2026 at 01:37:12PM +0530, Manivannan Sadhasivam wrote:
> The current platform driver design causes probe ordering races with clients
> (UFS, eMMC) due to ICE's dependency on SCM firmware calls. If ICE probe
> fails (missing ICE SCM or DT registers), devm_of_qcom_ice_get() loops with
> -EPROBE_DEFER, leaving clients non-functional even when ICE should be
> gracefully disabled. devm_of_qcom_ice_get() cannot know if the ICE driver
> probe has failed due to above reasons or it is waiting for the SCM driver.
> 
> Moreover, there is no devlink dependency between ICE and client drivers
> as 'qcom,ice' is not considered as a DT 'supplier'. So the client drivers
> have no idea of when the ICE driver is going to probe.
> 
> To avoid all this hassle, remove the platform driver support altogether and
> just expose the ICE driver as a pure library to client drivers. With this
> design, when devm_of_qcom_ice_get() is called, it will check if the ICE
> instance is available or not. If not, it will create one based on the ICE
> DT node, increase the refcount and return the handle. When the next client
> calls the API again, the ICE instance would be available. So this function
> will just increment the refcount and return the instance.
> 
> Finally, when the client devices get destroyed, refcount will be
> decremented and finally the cleanup will happen once all clients are
> destroyed.
> 
> For the clients using the old DT binding of providing the separate 'ice'
> register range in their node, this change has no impact.
> 
> Cc: stable@...r.kernel.org
> Cc: Abel Vesa <abel.vesa@....qualcomm.com>
> Reported-by: Sumit Garg <sumit.garg@....qualcomm.com>
> Fixes: 2afbf43a4aec ("soc: qcom: Make the Qualcomm UFS/SDCC ICE a dedicated driver")
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
> ---
>  drivers/soc/qcom/ice.c | 100 ++++++++++++++++-------------------------
>  1 file changed, 39 insertions(+), 61 deletions(-)
> 
> diff --git a/drivers/soc/qcom/ice.c b/drivers/soc/qcom/ice.c
> index b203bc685cad..b5a9cf8de6e4 100644
> --- a/drivers/soc/qcom/ice.c
> +++ b/drivers/soc/qcom/ice.c
> @@ -107,12 +107,16 @@ struct qcom_ice {
>  	struct device *dev;
>  	void __iomem *base;
>  
> +	struct kref refcount;
>  	struct clk *core_clk;
>  	bool use_hwkm;
>  	bool hwkm_init_complete;
>  	u8 hwkm_version;
>  };
>  
> +static DEFINE_MUTEX(ice_mutex);
> +struct qcom_ice *ice_handle;
> +
>  static bool qcom_ice_check_supported(struct qcom_ice *ice)
>  {
>  	u32 regval = qcom_ice_readl(ice, QCOM_ICE_REG_VERSION);
> @@ -599,8 +603,8 @@ static struct qcom_ice *qcom_ice_create(struct device *dev,
>   * This function will provide an ICE instance either by creating one for the
>   * consumer device if its DT node provides the 'ice' reg range and the 'ice'
>   * clock (for legacy DT style). On the other hand, if consumer provides a
> - * phandle via 'qcom,ice' property to an ICE DT, the ICE instance will already
> - * be created and so this function will return that instead.
> + * phandle via 'qcom,ice' property to an ICE DT node, then the ICE instance will
> + * be created if not already done and will be returned.
>   *
>   * Return: ICE pointer on success, NULL if there is no ICE data provided by the
>   * consumer or ERR_PTR() on error.
> @@ -611,11 +615,12 @@ static struct qcom_ice *of_qcom_ice_get(struct device *dev)
>  	struct qcom_ice *ice;
>  	struct resource *res;
>  	void __iomem *base;
> -	struct device_link *link;
>  
>  	if (!dev || !dev->of_node)
>  		return ERR_PTR(-ENODEV);
>  
> +	guard(mutex)(&ice_mutex);
> +
>  	/*
>  	 * In order to support legacy style devicetree bindings, we need
>  	 * to create the ICE instance using the consumer device and the reg
> @@ -631,6 +636,16 @@ static struct qcom_ice *of_qcom_ice_get(struct device *dev)
>  		return qcom_ice_create(&pdev->dev, base);
>  	}
>  
> +	/*
> +	 * If the ICE node has been initialized already, just increase the
> +	 * refcount and return the handle.
> +	 */
> +	if (ice_handle) {
> +		kref_get(&ice_handle->refcount);
> +
> +		return ice_handle;
> +	}
> +
>  	/*
>  	 * If the consumer node does not provider an 'ice' reg range
>  	 * (legacy DT binding), then it must at least provide a phandle
> @@ -643,41 +658,43 @@ static struct qcom_ice *of_qcom_ice_get(struct device *dev)
>  
>  	pdev = of_find_device_by_node(node);
>  	if (!pdev) {
> -		dev_err(dev, "Cannot find device node %s\n", node->name);
> +		dev_err(dev, "Cannot find ICE platform device\n");
> +		platform_device_put(pdev);

This somehow slipped in...

- Mani

>  		return ERR_PTR(-EPROBE_DEFER);
>  	}
>  
> -	ice = platform_get_drvdata(pdev);
> -	if (!ice) {
> -		dev_err(dev, "Cannot get ice instance from %s\n",
> -			dev_name(&pdev->dev));
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base)) {
> +		dev_warn(&pdev->dev, "ICE registers not found\n");
>  		platform_device_put(pdev);
> -		return ERR_PTR(-EPROBE_DEFER);
> +		return base;
>  	}
>  
> -	link = device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
> -	if (!link) {
> -		dev_err(&pdev->dev,
> -			"Failed to create device link to consumer %s\n",
> -			dev_name(dev));
> +	ice = qcom_ice_create(&pdev->dev, base);
> +	if (IS_ERR(ice)) {
>  		platform_device_put(pdev);
> -		ice = ERR_PTR(-EINVAL);
> +		return ice_handle;
>  	}
>  
> -	return ice;
> +	ice_handle = ice;
> +	kref_init(&ice_handle->refcount);
> +
> +	return ice_handle;
>  }
>  
> -static void qcom_ice_put(const struct qcom_ice *ice)
> +static void qcom_ice_put(struct kref *kref)
>  {
> -	struct platform_device *pdev = to_platform_device(ice->dev);
> -
> -	if (!platform_get_resource_byname(pdev, IORESOURCE_MEM, "ice"))
> -		platform_device_put(pdev);
> +	platform_device_put(to_platform_device(ice_handle->dev));
> +	ice_handle = NULL;
>  }
>  
>  static void devm_of_qcom_ice_put(struct device *dev, void *res)
>  {
> -	qcom_ice_put(*(struct qcom_ice **)res);
> +	const struct qcom_ice *ice = *(struct qcom_ice **)res;
> +	struct platform_device *pdev = to_platform_device(ice->dev);
> +
> +	if (!platform_get_resource_byname(pdev, IORESOURCE_MEM, "ice"))
> +		kref_put(&ice_handle->refcount, qcom_ice_put);
>  }
>  
>  /**
> @@ -713,42 +730,3 @@ struct qcom_ice *devm_of_qcom_ice_get(struct device *dev)
>  	return ice;
>  }
>  EXPORT_SYMBOL_GPL(devm_of_qcom_ice_get);
> -
> -static int qcom_ice_probe(struct platform_device *pdev)
> -{
> -	struct qcom_ice *engine;
> -	void __iomem *base;
> -
> -	base = devm_platform_ioremap_resource(pdev, 0);
> -	if (IS_ERR(base)) {
> -		dev_warn(&pdev->dev, "ICE registers not found\n");
> -		return PTR_ERR(base);
> -	}
> -
> -	engine = qcom_ice_create(&pdev->dev, base);
> -	if (IS_ERR(engine))
> -		return PTR_ERR(engine);
> -
> -	platform_set_drvdata(pdev, engine);
> -
> -	return 0;
> -}
> -
> -static const struct of_device_id qcom_ice_of_match_table[] = {
> -	{ .compatible = "qcom,inline-crypto-engine" },
> -	{ },
> -};
> -MODULE_DEVICE_TABLE(of, qcom_ice_of_match_table);
> -
> -static struct platform_driver qcom_ice_driver = {
> -	.probe	= qcom_ice_probe,
> -	.driver = {
> -		.name = "qcom-ice",
> -		.of_match_table = qcom_ice_of_match_table,
> -	},
> -};
> -
> -module_platform_driver(qcom_ice_driver);
> -
> -MODULE_DESCRIPTION("Qualcomm Inline Crypto Engine driver");
> -MODULE_LICENSE("GPL");
> -- 
> 2.51.0
> 

-- 
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