Re: [PATCH next v2 1/2] PCI: keystone: add pci error irq handler

[Murali Karicheri <m-karicheri2@ti.com>]

On 04/19/2016 09:03 PM, Bjorn Helgaas wrote:
> Hi Murali,
> 
> On Mon, Apr 11, 2016 at 10:50:30AM -0400, Murali Karicheri wrote:
>> Keystone PCI hardware generates error interrupts at RC using platform
>> irq instead of standard msi/legacy irq. Add a simple error handler that
>> logs the fatal interrupt status to the console.
>>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>> Acked-by: Rob Herring <robh@kernel.org>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Pawel Moll <pawel.moll@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
>> Cc: Kumar Gala <galak@codeaurora.org>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
> 
> I applied this with minor changes to pci/host-keystone for v4.7.
> See below:
> 
>> +bool ks_dw_pcie_handle_error_irq(struct device *dev, void __iomem *reg_base)
>> +{
>> +	u32 status;
>> +	bool ret = false;
>> +
>> +	status = readl(reg_base + ERR_IRQ_STATUS_RAW) & ERR_IRQ_ALL;
>> +	if (status) {
>> +		/* The PCIESS interrupt status buts are "write 1 to clear" */
>> +		if (status & ERR_FATAL_IRQ)
>> +			dev_err(dev, "PCIE fatal error detected\n");
>> +
>> +		/* ack the irq event. */
>> +		writel(status, reg_base + ERR_IRQ_STATUS);
>> +		ret = true;
>> +	}
>> +	return ret;
>> +}
> 
> It seems pointless to me to return true/false here and then:
> 
>> +static irqreturn_t pcie_err_irq_handler(int irq, void *priv)
>> +{
>> +	struct keystone_pcie *ks_pcie = priv;
>> +
>> +	if (ks_dw_pcie_handle_error_irq(ks_pcie->pp.dev, ks_pcie->va_app_base))
>> +		return IRQ_HANDLED;
>> +
>> +	return IRQ_NONE;
>> +}
> 
> convert the true/false to IRQ_HANDLED/IRQ_NONE here.  So I changed
> ks_dw_pcie_handle_error_irq() to return IRQ_HANDLED/IRQ_NONE directly,
> resulting in the patch below.

I think that should be fine. Only reason, i did that way was that the pcie-designware
code is kept as a library of functions to configure the designware hardware common to
all platforms that has the designware core h/w and keep all of the platform specific info
such as IRQ handler to the platform glue driver such as pci-keystone.c. But that is not
true today as there is msi irq handler in this driver. So this is fine.

I will pull these from your designware pci/host-keystone and let you know if I see
any issues or send a diff patch to the list.

Once again, thanks for pulling this to v4.7.

Murali
> 
> This is applied to pci/host-keystone for v4.7.
> 
> 
> commit 7be92716c1aa40f5690e6a5f01fc0d385dd72303
> Author: Murali Karicheri <m-karicheri2@ti.com>
> Date:   Mon Apr 11 10:50:30 2016 -0400
> 
>     PCI: keystone: Add error IRQ handler
>     
>     Keystone PCI hardware generates error interrupts at RC using a platform IRQ
>     instead of a standard MSI or legacy IRQ.  Add a simple error handler that
>     logs the fatal interrupt status to the console.
>     
>     [bhelgaas: tidy comments, return irqreturn_t directly]
>     Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>     Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
>     Acked-by: Rob Herring <robh@kernel.org>
>     CC: Pawel Moll <pawel.moll@arm.com>
>     CC: Mark Rutland <mark.rutland@arm.com>
>     CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
>     CC: Kumar Gala <galak@codeaurora.org>
> 
> diff --git a/Documentation/devicetree/bindings/pci/pci-keystone.txt b/Documentation/devicetree/bindings/pci/pci-keystone.txt
> index 54eae29..d08a4d5 100644
> --- a/Documentation/devicetree/bindings/pci/pci-keystone.txt
> +++ b/Documentation/devicetree/bindings/pci/pci-keystone.txt
> @@ -56,6 +56,7 @@ Optional properties:-
>  	phy-names: name of the Generic Keystine SerDes phy for PCI
>  	  - If boot loader already does PCI link establishment, then phys and
>  	    phy-names shouldn't be present.
> +	interrupts: platform interrupt for error interrupts.
>  
>  Designware DT Properties not applicable for Keystone PCI
>  
> diff --git a/drivers/pci/host/pci-keystone-dw.c b/drivers/pci/host/pci-keystone-dw.c
> index 6153853..4151509 100644
> --- a/drivers/pci/host/pci-keystone-dw.c
> +++ b/drivers/pci/host/pci-keystone-dw.c
> @@ -14,6 +14,7 @@
>  
>  #include <linux/irq.h>
>  #include <linux/irqdomain.h>
> +#include <linux/irqreturn.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_pci.h>
> @@ -53,6 +54,21 @@
>  #define IRQ_STATUS			0x184
>  #define MSI_IRQ_OFFSET			4
>  
> +/* Error IRQ bits */
> +#define ERR_AER		BIT(5)	/* ECRC error */
> +#define ERR_AXI		BIT(4)	/* AXI tag lookup fatal error */
> +#define ERR_CORR	BIT(3)	/* Correctable error */
> +#define ERR_NONFATAL	BIT(2)	/* Non-fatal error */
> +#define ERR_FATAL	BIT(1)	/* Fatal error */
> +#define ERR_SYS		BIT(0)	/* System (fatal, non-fatal, or correctable) */
> +#define ERR_IRQ_ALL	(ERR_AER | ERR_AXI | ERR_CORR | \
> +			 ERR_NONFATAL | ERR_FATAL | ERR_SYS)
> +#define ERR_FATAL_IRQ	(ERR_FATAL | ERR_AXI)
> +#define ERR_IRQ_STATUS_RAW		0x1c0
> +#define ERR_IRQ_STATUS			0x1c4
> +#define ERR_IRQ_ENABLE_SET		0x1c8
> +#define ERR_IRQ_ENABLE_CLR		0x1cc
> +
>  /* Config space registers */
>  #define DEBUG0				0x728
>  
> @@ -243,6 +259,28 @@ void ks_dw_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie, int offset)
>  	writel(offset, ks_pcie->va_app_base + IRQ_EOI);
>  }
>  
> +void ks_dw_pcie_enable_error_irq(void __iomem *reg_base)
> +{
> +	writel(ERR_IRQ_ALL, reg_base + ERR_IRQ_ENABLE_SET);
> +}
> +
> +irqreturn_t ks_dw_pcie_handle_error_irq(struct device *dev,
> +					void __iomem *reg_base)
> +{
> +	u32 status;
> +
> +	status = readl(reg_base + ERR_IRQ_STATUS_RAW) & ERR_IRQ_ALL;
> +	if (!status)
> +		return IRQ_NONE;
> +
> +	if (status & ERR_FATAL_IRQ)
> +		dev_err(dev, "fatal error (status %#010x)\n", status);
> +
> +	/* Ack the IRQ; status bits are RW1C */
> +	writel(status, reg_base + ERR_IRQ_STATUS);
> +	return IRQ_HANDLED;
> +}
> +
>  static void ks_dw_pcie_ack_legacy_irq(struct irq_data *d)
>  {
>  }
> diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
> index b71f55b..6868918 100644
> --- a/drivers/pci/host/pci-keystone.c
> +++ b/drivers/pci/host/pci-keystone.c
> @@ -15,6 +15,7 @@
>  #include <linux/irqchip/chained_irq.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
> +#include <linux/interrupt.h>
>  #include <linux/irqdomain.h>
>  #include <linux/module.h>
>  #include <linux/msi.h>
> @@ -226,6 +227,9 @@ static void ks_pcie_setup_interrupts(struct keystone_pcie *ks_pcie)
>  							 ks_pcie);
>  		}
>  	}
> +
> +	if (ks_pcie->error_irq > 0)
> +		ks_dw_pcie_enable_error_irq(ks_pcie->va_app_base);
>  }
>  
>  /*
> @@ -289,6 +293,14 @@ static struct pcie_host_ops keystone_pcie_host_ops = {
>  	.scan_bus = ks_dw_pcie_v3_65_scan_bus,
>  };
>  
> +static irqreturn_t pcie_err_irq_handler(int irq, void *priv)
> +{
> +	struct keystone_pcie *ks_pcie = priv;
> +
> +	return ks_dw_pcie_handle_error_irq(ks_pcie->pp.dev,
> +					   ks_pcie->va_app_base);
> +}
> +
>  static int __init ks_add_pcie_port(struct keystone_pcie *ks_pcie,
>  			 struct platform_device *pdev)
>  {
> @@ -309,6 +321,22 @@ static int __init ks_add_pcie_port(struct keystone_pcie *ks_pcie,
>  			return ret;
>  	}
>  
> +	/*
> +	 * Index 0 is the platform interrupt for error interrupt
> +	 * from RC.  This is optional.
> +	 */
> +	ks_pcie->error_irq = irq_of_parse_and_map(ks_pcie->np, 0);
> +	if (ks_pcie->error_irq <= 0)
> +		dev_info(&pdev->dev, "no error IRQ defined\n");
> +	else {
> +		if (request_irq(ks_pcie->error_irq, pcie_err_irq_handler,
> +				IRQF_SHARED, "pcie-error-irq", ks_pcie) < 0) {
> +			dev_err(&pdev->dev, "failed to request error IRQ %d\n",
> +				ks_pcie->error_irq);
> +			return ret;
> +		}
> +	}
> +
>  	pp->root_bus_nr = -1;
>  	pp->ops = &keystone_pcie_host_ops;
>  	ret = ks_dw_pcie_host_init(ks_pcie, ks_pcie->msi_intc_np);
> @@ -376,6 +404,7 @@ static int __init ks_pcie_probe(struct platform_device *pdev)
>  	devm_release_mem_region(dev, res->start, resource_size(res));
>  
>  	pp->dev = dev;
> +	ks_pcie->np = node;
>  	platform_set_drvdata(pdev, ks_pcie);
>  	ks_pcie->clk = devm_clk_get(dev, "pcie");
>  	if (IS_ERR(ks_pcie->clk)) {
> diff --git a/drivers/pci/host/pci-keystone.h b/drivers/pci/host/pci-keystone.h
> index f0944e8..a5b0cb2 100644
> --- a/drivers/pci/host/pci-keystone.h
> +++ b/drivers/pci/host/pci-keystone.h
> @@ -29,6 +29,9 @@ struct keystone_pcie {
>  	int			msi_host_irqs[MAX_MSI_HOST_IRQS];
>  	struct			device_node *msi_intc_np;
>  	struct irq_domain	*legacy_irq_domain;
> +	struct device_node	*np;
> +
> +	int error_irq;
>  
>  	/* Application register space */
>  	void __iomem		*va_app_base;
> @@ -42,6 +45,9 @@ phys_addr_t ks_dw_pcie_get_msi_addr(struct pcie_port *pp);
>  /* Keystone specific PCI controller APIs */
>  void ks_dw_pcie_enable_legacy_irqs(struct keystone_pcie *ks_pcie);
>  void ks_dw_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie, int offset);
> +void ks_dw_pcie_enable_error_irq(void __iomem *reg_base);
> +irqreturn_t ks_dw_pcie_handle_error_irq(struct device *dev,
> +					void __iomem *reg_base);
>  int  ks_dw_pcie_host_init(struct keystone_pcie *ks_pcie,
>  			struct device_node *msi_intc_np);
>  int ks_dw_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
> 


-- 
Murali Karicheri
Linux Kernel, Keystone