[PATCH] PCI: qcom: Skip wait for link up if global IRQ handler is present

[PATCH] PCI: qcom: Skip wait for link up if global IRQ handler is present

[Krishna chaitanya chundru]

In cases where a global IRQ handler is present to manage link up
interrupts, it may not be necessary to wait for the link to be up
during PCI initialization which optimizes the bootup time.

Move platform_get_irq_byname_optional() above to set bypass_link_up_wait
before dw_pcie_host_init() as this flag is used in this function only.

And also as part of the PCIe link up event, update ICC and OPP values.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 drivers/pci/controller/dwc/pcie-designware-host.c | 3 ++-
 drivers/pci/controller/dwc/pcie-designware.h      | 1 +
 drivers/pci/controller/dwc/pcie-qcom.c            | 7 ++++++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 3e41865c7290..e0ddfaf9f87a 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -531,7 +531,8 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 	}
 
 	/* Ignore errors, the link may come up later */
-	dw_pcie_wait_for_link(pci);
+	if (!pp->bypass_link_up_wait)
+		dw_pcie_wait_for_link(pci);
 
 	bridge->sysdata = pp;
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index e518f81ea80c..7fe0e9b1b095 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -348,6 +348,7 @@ struct dw_pcie_rp {
 	bool			use_atu_msg;
 	int			msg_atu_index;
 	struct resource		*msg_res;
+	bool			bypass_link_up_wait;
 };
 
 struct dw_pcie_ep_ops {
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 88a98be930e3..bcb8c60453ba 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1552,6 +1552,8 @@ static irqreturn_t qcom_pcie_global_irq_thread(int irq, void *data)
 		pci_lock_rescan_remove();
 		pci_rescan_bus(pp->bridge->bus);
 		pci_unlock_rescan_remove();
+
+		qcom_pcie_icc_opp_update(pcie);
 	} else {
 		dev_WARN_ONCE(dev, 1, "Received unknown event. INT_STATUS: 0x%08x\n",
 			      status);
@@ -1686,6 +1688,10 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, pcie);
 
+	irq = platform_get_irq_byname_optional(pdev, "global");
+	if (irq > 0)
+		pp->bypass_link_up_wait = true;
+
 	ret = dw_pcie_host_init(pp);
 	if (ret) {
 		dev_err(dev, "cannot initialize host\n");
@@ -1699,7 +1705,6 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 		goto err_host_deinit;
 	}
 
-	irq = platform_get_irq_byname_optional(pdev, "global");
 	if (irq > 0) {
 		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 						qcom_pcie_global_irq_thread,

---
base-commit: 9aaeb87ce1e966169a57f53a02ba05b30880ffb8
change-id: 20240911-remove_wait-ad46248dc9f0

Best regards,
-- 
Krishna chaitanya chundru <quic_krichai@quicinc.com>

Re: [PATCH] PCI: qcom: Skip wait for link up if global IRQ handler is present

[Manivannan Sadhasivam]

On Tue, Sep 17, 2024 at 04:16:20PM +0530, Krishna chaitanya chundru wrote:
> In cases where a global IRQ handler is present to manage link up
> interrupts, it may not be necessary to wait for the link to be up
> during PCI initialization which optimizes the bootup time.
> 
> Move platform_get_irq_byname_optional() above to set bypass_link_up_wait
> before dw_pcie_host_init() as this flag is used in this function only.
> 
> And also as part of the PCIe link up event, update ICC and OPP values.
> 

This has to be a separate patch.

> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 3 ++-
>  drivers/pci/controller/dwc/pcie-designware.h      | 1 +
>  drivers/pci/controller/dwc/pcie-qcom.c            | 7 ++++++-
>  3 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 3e41865c7290..e0ddfaf9f87a 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -531,7 +531,8 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
>  	}
>  
>  	/* Ignore errors, the link may come up later */
> -	dw_pcie_wait_for_link(pci);

Add a comment to clarify that the link up delay is skipped in the presence of
Link up IRQ.

This flag is not a way to just skip the link up delay for arbitrary reasons as
attempted before.

> +	if (!pp->bypass_link_up_wait)
> +		dw_pcie_wait_for_link(pci);
>  
>  	bridge->sysdata = pp;
>  
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index e518f81ea80c..7fe0e9b1b095 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -348,6 +348,7 @@ struct dw_pcie_rp {
>  	bool			use_atu_msg;
>  	int			msg_atu_index;
>  	struct resource		*msg_res;
> +	bool			bypass_link_up_wait;

How about, 'linkup_irq'?

- Mani

>  };
>  
>  struct dw_pcie_ep_ops {
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 88a98be930e3..bcb8c60453ba 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1552,6 +1552,8 @@ static irqreturn_t qcom_pcie_global_irq_thread(int irq, void *data)
>  		pci_lock_rescan_remove();
>  		pci_rescan_bus(pp->bridge->bus);
>  		pci_unlock_rescan_remove();
> +
> +		qcom_pcie_icc_opp_update(pcie);
>  	} else {
>  		dev_WARN_ONCE(dev, 1, "Received unknown event. INT_STATUS: 0x%08x\n",
>  			      status);
> @@ -1686,6 +1688,10 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, pcie);
>  
> +	irq = platform_get_irq_byname_optional(pdev, "global");
> +	if (irq > 0)
> +		pp->bypass_link_up_wait = true;
> +
>  	ret = dw_pcie_host_init(pp);
>  	if (ret) {
>  		dev_err(dev, "cannot initialize host\n");
> @@ -1699,7 +1705,6 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  		goto err_host_deinit;
>  	}
>  
> -	irq = platform_get_irq_byname_optional(pdev, "global");
>  	if (irq > 0) {
>  		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
>  						qcom_pcie_global_irq_thread,
> 
> ---
> base-commit: 9aaeb87ce1e966169a57f53a02ba05b30880ffb8
> change-id: 20240911-remove_wait-ad46248dc9f0
> 
> Best regards,
> -- 
> Krishna chaitanya chundru <quic_krichai@quicinc.com>
> 

-- 
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