diff mbox series

[v3,2/5] PCI: tegra194: Move dw_pcie_ep_linkup() to threaded IRQ handler

Message ID 20221006134927.41437-3-manivannan.sadhasivam@linaro.org (mailing list archive)
State Superseded
Delegated to: Lorenzo Pieralisi
Headers show
Series PCI: endpoint: Rework the EPC to EPF notification | expand

Commit Message

Manivannan Sadhasivam Oct. 6, 2022, 1:49 p.m. UTC 
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 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

Vidya Sagar Oct. 10, 2022, 2:23 p.m. UTC | #1 
Hi Mani,
Thanks for your change. One comment though.

On 10/6/2022 7:19 PM, Manivannan Sadhasivam wrote:
> External email: Use caution opening links or attachments
> 
> 
> 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 | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index 1b6b437823d2..6a487f52e1fb 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 +519,7 @@ 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);

irq thread needs to be woken up at this point. So, please add
return IRQ_WAKE_THREAD;

Thanks,
Vidya Sagar

>                          }
>                  }
> 
> --
> 2.25.1
>
Manivannan Sadhasivam Oct. 25, 2022, 2:32 p.m. UTC | #2 
Hi Vidya,

On Mon, Oct 10, 2022 at 07:53:52PM +0530, Vidya Sagar wrote:
> Hi Mani,
> Thanks for your change. One comment though.
> 
> On 10/6/2022 7:19 PM, Manivannan Sadhasivam wrote:
> > External email: Use caution opening links or attachments
> > 
> > 
> > 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 | 8 ++++++--
> >   1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> > index 1b6b437823d2..6a487f52e1fb 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 +519,7 @@ 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);
> 
> irq thread needs to be woken up at this point. So, please add
> return IRQ_WAKE_THREAD;
> 

Ah, missed that. Will add it in next version.

Thanks,
Mani

> Thanks,
> Vidya Sagar
> 
> >                          }
> >                  }
> > 
> > --
> > 2.25.1
> >
diff mbox series

Patch

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 1b6b437823d2..6a487f52e1fb 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 +519,7 @@  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);
 			}
 		}