Re: [PATCH v4 2/5] PCI: tegra194: Move dw_pcie_ep_linkup() to threaded IRQ handler

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Tue, Oct 25, 2022 at 08:20:58PM +0530, Manivannan Sadhasivam wrote:
> dw_pcie_ep_linkup() may take more time to execute depending on the EPF
> driver implementation. Calling this API in the hard IRQ handler is not
> encouraged since the hard IRQ handlers are supposed to complete quickly.
> 
> So move the dw_pcie_ep_linkup() call to threaded IRQ handler.
> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/controller/dwc/pcie-tegra194.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index 1b6b437823d2..a0d231b7a435 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -287,6 +287,7 @@ struct tegra_pcie_dw {
>  	struct gpio_desc *pex_refclk_sel_gpiod;
>  	unsigned int pex_rst_irq;
>  	int ep_state;
> +	long link_status;
>  };
>  
>  static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
> @@ -450,9 +451,13 @@ static void pex_ep_event_hot_rst_done(struct tegra_pcie_dw *pcie)
>  static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
>  {
>  	struct tegra_pcie_dw *pcie = arg;
> +	struct dw_pcie_ep *ep = &pcie->pci.ep;
>  	struct dw_pcie *pci = &pcie->pci;
>  	u32 val, speed;
>  
> +	if (test_and_clear_bit(0, &pcie->link_status))
> +		dw_pcie_ep_linkup(ep);
> +
>  	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
>  		PCI_EXP_LNKSTA_CLS;
>  	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
> @@ -499,7 +504,6 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
>  static irqreturn_t tegra_pcie_ep_hard_irq(int irq, void *arg)
>  {
>  	struct tegra_pcie_dw *pcie = arg;
> -	struct dw_pcie_ep *ep = &pcie->pci.ep;
>  	int spurious = 1;
>  	u32 status_l0, status_l1, link_status;
>  
> @@ -515,7 +519,8 @@ static irqreturn_t tegra_pcie_ep_hard_irq(int irq, void *arg)
>  			link_status = appl_readl(pcie, APPL_LINK_STATUS);
>  			if (link_status & APPL_LINK_STATUS_RDLH_LINK_UP) {
>  				dev_dbg(pcie->dev, "Link is up with Host\n");
> -				dw_pcie_ep_linkup(ep);
> +				set_bit(0, &pcie->link_status);
> +				return IRQ_WAKE_THREAD;
>  			}
>  		}
>  
> -- 
> 2.25.1
> 

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