Re: [PATCH v7 13/13] PCI: tegra194: Free resources during controller deinitialization

[Manikanta Maddireddy <mmaddireddy@nvidia.com>]

On 05/03/26 4:13 pm, Manivannan Sadhasivam wrote:
> On Tue, Mar 03, 2026 at 12:24:48PM +0530, Manikanta Maddireddy wrote:
>> From: Vidya Sagar <vidyas@nvidia.com>
>>
>> Call pci_epc_deinit_notify() during controller deinitialization to free the
>> resources allocated by Endpoint function driver. This is safe to call
>> during PCIe assert sequence because we don't expect Endpoint function
>> driver to touch hardware in deinit function.
>>
> 
> Are you sure? The epf-test driver itself touches DBI space during deinit.
> 
> - Mani
Ok, I see epf-test is doing clear_bar which access DBI space.
But, I think we should give give a chance to EPF drivers to clean up 
resources and stop using them in PERST# assert. Let me know your inputs 
on this.

- Manikanta

> 
>> Fixes: 40e2125381dc ("PCI: tegra194: Move controller cleanups to pex_ep_event_pex_rst_deassert()")
>> Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
>> Tested-by: Jon Hunter <jonathanh@nvidia.com>
>> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
>> ---
>> Changes V5 -> V7: None
>> Changes V4 -> V5: Remove pci_epc_deinit_notify() call from pex_ep_event_pex_rst_deassert()
>> Changes V1 -> V4: None
>>
>>   drivers/pci/controller/dwc/pcie-tegra194.c | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
>> index a311c31109e3..b1ae46761915 100644
>> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
>> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
>> @@ -1624,12 +1624,16 @@ static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
>>   
>>   static void pex_ep_event_pex_rst_assert(struct tegra_pcie_dw *pcie)
>>   {
>> +	struct dw_pcie *pci = &pcie->pci;
>> +	struct dw_pcie_ep *ep = &pci->ep;
>>   	u32 val;
>>   	int ret;
>>   
>>   	if (pcie->ep_state == EP_STATE_DISABLED)
>>   		return;
>>   
>> +	pci_epc_deinit_notify(ep->epc);
>> +
>>   	ret = readl_poll_timeout(pcie->appl_base + APPL_DEBUG, val,
>>   		((val & APPL_DEBUG_LTSSM_STATE_MASK) == LTSSM_STATE_DETECT_QUIET) ||
>>   		((val & APPL_DEBUG_LTSSM_STATE_MASK) == LTSSM_STATE_DETECT_ACT) ||
>> @@ -1796,7 +1800,6 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
>>   	reset_control_deassert(pcie->core_rst);
>>   
>>   	/* Perform cleanup that requires refclk and core reset deasserted */
>> -	pci_epc_deinit_notify(pcie->pci.ep.epc);
>>   	dw_pcie_ep_cleanup(&pcie->pci.ep);
>>   
>>   	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
>> -- 
>> 2.34.1
>>
> 

-- 
nvpublic