Re: [PATCH v6 3/3] PCI: qcom: Implement shutdown() callback

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 9/9/26 2:40 PM, Krishna Chaitanya Chundru wrote:
> 
> 
> On 9/9/2026 6:06 PM, Konrad Dybcio wrote:
>> On 9/9/26 2:24 PM, Krishna Chaitanya Chundru wrote:
>>> From: Manivannan Sadhasivam <mani@kernel.org>
>>>
>>> PCIe host controllers should bring the link down cleanly before system
>>> shutdown/reboot proceeds to remove power/clocks from the controller.
>>> Without this, the link may still be up and endpoints still have
>>> transactions in flight when power/clocks are cut, which can trip SMMU
>>> translation faults or NoC protocol errors.
>>>
>>> Reuse dw_pcie_suspend_noirq() in the shutdown path to force the link
>>> into L2, putting it into D3cold.
>>>
>>> device_shutdown() runs with interrupts enabled, unlike suspend_noirq().
>>> Mask the chained MSI IRQ(s) and the Global IRQ before tearing down the
>>> link and clocks/PHY, since a late/spurious interrupt could otherwise
>>> reach a handler that touches now-unclocked PARF/DBI registers.
>>>
>>> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
>>> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
>>> ---
>> [...]
>>
>>> +static void qcom_pcie_shutdown(struct platform_device *pdev)
>>> +{
>>> +	const struct qcom_pcie_cfg *pcie_cfg = of_device_get_match_data(&pdev->dev);
>>> +	struct qcom_pcie *pcie;
>>> +	struct dw_pcie *pci;
>>> +
>>> +	if (pcie_cfg && pcie_cfg->firmware_managed) {
>>> +		/*
>>> +		 * Firmware owns the link teardown and clock/PHY shutdown in
>>> +		 * this mode; Linux only owns the chained MSI IRQ(s), which
>>> +		 * still need to be masked off before shutdown proceeds.
>>> +		 */
>>> +		pci = platform_get_drvdata(pdev);
>>> +	} else {
>>> +		pcie = platform_get_drvdata(pdev);
>> This is no less than an intriguing choice.. please store the same
>> element in both cases so we don't have to do this
> for firmware_managed solutions struct qcom_pcie *pcie is not being
> used/allocated at all. it will waste of memory if we allocate memory for just
> this use case. - Krishna Chaitanya.

Should we move it to a separate file/driver then, perhaps?
We could share the ECAM ops in e.g. pcie-qcom-common.c

Konrad