linux-kernel - Re: [PATCH 2/2] firmware: arm_scmi: Add qcom hvc/shmem transport

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Message-ID: <e8399fcf-e0d8-cc31-d9a7-b0f4f7cc3e71@quicinc.com>
Date:   Tue, 18 Jul 2023 14:16:04 -0700
From:   Nikunj Kela <quic_nkela@...cinc.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        <sudeep.holla@....com>
CC:     <cristian.marussi@....com>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
        <agross@...nel.org>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <linux-arm-kernel@...ts.infradead.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH 2/2] firmware: arm_scmi: Add qcom hvc/shmem transport


On 7/18/2023 11:42 AM, Krzysztof Kozlowski wrote:
> On 18/07/2023 20:25, Nikunj Kela wrote:
>>>> +
>>>> +	scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
>>>> +	if (!scmi_info)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	np = of_parse_phandle(cdev->of_node, "shmem", 0);
>>>> +	if (!of_device_is_compatible(np, "arm,scmi-shmem"))
>>> You leak here reference.
>> Wouldn't the devm_* API take care of that implicitly? It is same in
>> smc.c as well.
> Thanks for bringing my attention to this. I sent a fix for smc.c. Fix
> your patch as well, please.
Thanks, I thought you were referring to kzalloc cleanup. Will include 
this fix. BTW, you may need to fix mailbox.c as well.
>
>>>> +		return -ENXIO;
>>>> +
>>>> +	ret = of_address_to_resource(np, 0, &res);
>>>> +	of_node_put(np);
>>>> +	if (ret) {
>>>> +		dev_err(cdev, "failed to get SCMI Tx shared memory\n");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	size = resource_size(&res);
>>>> +
>>>> +	/* let's map 2 additional ulong since
>>>> +	 * func-id & capability-id are kept after shmem.
>>>> +	 *     +-------+
>>>> +	 *     |       |
>>>> +	 *     | shmem |
>>>> +	 *     |       |
>>>> +	 *     |       |
>>>> +	 *     +-------+ <-- size
>>>> +	 *     | funcId|
>>>> +	 *     +-------+ <-- size + sizeof(ulong)
>>>> +	 *     | capId |
>>>> +	 *     +-------+ <-- size + 2*sizeof(ulong)
>>>> +	 */
>>>> +
>>>> +	scmi_info->shmem = devm_ioremap(dev, res.start,
>>>> +					size + 2 * sizeof(unsigned long));
>>>> +	if (!scmi_info->shmem) {
>>>> +		dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
>>>> +		return -EADDRNOTAVAIL;
>>>> +	}
>>>> +
>>>> +	func_id = readl((void *)(scmi_info->shmem) + size);
>>>> +
>>>> +#ifdef CONFIG_ARM64
>>>> +	cap_id = readq((void *)(scmi_info->shmem) + size +
>>>> +		       sizeof(unsigned long));
>>>> +#else
>>>> +	cap_id = readl((void *)(scmi_info->shmem) + size +
>>>> +		       sizeof(unsigned long));
>>>> +#endif
>>>> +
>>>> +	/*
>>>> +	 * If there is an interrupt named "a2p", then the service and
>>>> +	 * completion of a message is signaled by an interrupt rather than by
>>>> +	 * the return of the hvc call.
>>>> +	 */
>>>> +	irq = of_irq_get_byname(cdev->of_node, "a2p");
>>>> +	if (irq > 0) {
>>>> +		ret = devm_request_irq(dev, irq, qcom_hvc_msg_done_isr,
>>>> +				       IRQF_NO_SUSPEND,
>>>> +				       dev_name(dev), scmi_info);
>>>> +		if (ret) {
>>>> +			dev_err(dev, "failed to setup SCMI completion irq\n");
>>> return dev_err_probe, unless this is not called in probe... but then
>>> using devm-interface raises questions.
>> This is copied as is from existing smc.c
> I understand and I hope you understand the code you copied. If there is
> a bug in existing code, please do not copy it to new code (like leaking
> OF node reference).
>
> Best regards,
> Krzysztof
>