Re: [PATCH v7 2/4] PCI: qcom-ep: Add support for D-state change notification

[Mayank Rana <quic_mrana@quicinc.com>]

On 7/10/2024 4:08 AM, Krishna chaitanya chundru wrote:
> Add support to pass D-state change notification to Endpoint
> function driver.
> Read perst value to determine if the link is in D3Cold/D3hot.
> 
> Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> ---
>   drivers/pci/controller/dwc/pcie-qcom-ep.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> index 236229f66c80..817fad805c51 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> @@ -648,6 +648,7 @@ static irqreturn_t qcom_pcie_ep_global_irq_thread(int irq, void *data)
>   	struct device *dev = pci->dev;
>   	u32 status = readl_relaxed(pcie_ep->parf + PARF_INT_ALL_STATUS);
>   	u32 mask = readl_relaxed(pcie_ep->parf + PARF_INT_ALL_MASK);
> +	pci_power_t state;
>   	u32 dstate, val;
>   
>   	writel_relaxed(status, pcie_ep->parf + PARF_INT_ALL_CLEAR);
> @@ -671,11 +672,16 @@ static irqreturn_t qcom_pcie_ep_global_irq_thread(int irq, void *data)
>   		dstate = dw_pcie_readl_dbi(pci, DBI_CON_STATUS) &
>   					   DBI_CON_STATUS_POWER_STATE_MASK;
>   		dev_dbg(dev, "Received D%d state event\n", dstate);
> -		if (dstate == 3) {
> +		state = dstate;
> +		if (dstate == PCI_D3hot) {
>   			val = readl_relaxed(pcie_ep->parf + PARF_PM_CTRL);
>   			val |= PARF_PM_CTRL_REQ_EXIT_L1;
>   			writel_relaxed(val, pcie_ep->parf + PARF_PM_CTRL);
Can you please also check that do we really need to bring link back out 
of L1/L1SS on receiving D3 hot ?
> +			if (gpiod_get_value(pcie_ep->reset))
> +				state = PCI_D3cold;
>   		}
> +		pci_epc_dstate_notify(pci->ep.epc, state);
>   	} else if (FIELD_GET(PARF_INT_ALL_LINK_UP, status)) {
>   		dev_dbg(dev, "Received Linkup event. Enumeration complete!\n");
>   		dw_pcie_ep_linkup(&pci->ep);
> 

Regards,
Mayank