diff mbox

[3/3] PCI/AER: Provide reset_link for firmware first root port

Message ID 1369766929-4386-4-git-send-email-betty.dall@hp.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Betty Dall May 28, 2013, 6:48 p.m. UTC
The firmware first path does not install the aerdrv root port
service driver, so the firmware first root port does not have
a reset_link callback. When a firmware first root port does not have
a reset_link callback, use a new default reset_link similar to what
we already do for the default_downstream_reset_link(). The firmware
first default reset_link brings the root port out of SBR if firmware
left it in SBR.

Signed-off-by: Betty Dall <betty.dall@hp.com>
---

 drivers/pci/pcie/aer/aerdrv_core.c |   37 ++++++++++++++++++++++++++++++++++++
 1 files changed, 37 insertions(+), 0 deletions(-)


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Comments

Greg Pearson May 29, 2013, 3:42 p.m. UTC | #1
On 05/28/2013 12:48 PM, Betty Dall wrote:
> The firmware first path does not install the aerdrv root port
> service driver, so the firmware first root port does not have
> a reset_link callback. When a firmware first root port does not have
> a reset_link callback, use a new default reset_link similar to what
> we already do for the default_downstream_reset_link(). The firmware
> first default reset_link brings the root port out of SBR if firmware
> left it in SBR.
>
> Signed-off-by: Betty Dall <betty.dall@hp.com>
> ---
>
>   drivers/pci/pcie/aer/aerdrv_core.c |   37 ++++++++++++++++++++++++++++++++++++
>   1 files changed, 37 insertions(+), 0 deletions(-)
>
>
> diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
> index 8ec8b4f..6862fe3 100644
> --- a/drivers/pci/pcie/aer/aerdrv_core.c
> +++ b/drivers/pci/pcie/aer/aerdrv_core.c
> @@ -413,6 +413,40 @@ static pci_ers_result_t default_downstream_reset_link(struct pci_dev *dev)
>   	return PCI_ERS_RESULT_RECOVERED;
>   }
>   
> +/**
> + * default_ff_root_port_reset_link - default reset function for firmware
> + *		first Root Port
> + * @dev: pointer to root port's pci_dev data structure
> + *
> + * Invoked when performing link reset at Root Port w/ no aer driver.
> + * This happens through the firmware first path. Firmware may leave
> + * the Root Port in SBR and it is the OS responsiblity to bring it out
> + * of SBR.
> + */
> +static pci_ers_result_t default_ff_root_port_reset_link(struct pci_dev *dev)
> +{
> +	u16 p2p_ctrl;
> +
> +	/* Read Secondary Bus Reset */
> +	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &p2p_ctrl);
> +	p2p_ctrl |= PCI_BRIDGE_CTL_BUS_RESET;

Remove "p2p_ctrl |= PCI_BRIDGE_CTL_BUS_RESET;" otherwise the following 
conditional is always taken.

--
Greg

> +
> +	/* De-assert Secondary Bus Reset, if it is set */
> +	if (p2p_ctrl & PCI_BRIDGE_CTL_BUS_RESET) {
> +		p2p_ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
> +		pci_write_config_word(dev, PCI_BRIDGE_CONTROL, p2p_ctrl);
> +
> +		/*
> +		 * System software must wait for at least 100ms from the end
> +		 * of a reset of one or more device before it is permitted
> +		 * to issue Configuration Requests to those devices.
> +		 */
> +		msleep(200);
> +		dev_dbg(&dev->dev, "Root Port link has been reset\n");
> +	}
> +	return PCI_ERS_RESULT_RECOVERED;
> +}
> +
>   static int find_aer_service_iter(struct device *device, void *data)
>   {
>   	struct pcie_port_service_driver *service_driver, **drv;
> @@ -460,6 +494,9 @@ static pci_ers_result_t reset_link(struct pci_dev *dev)
>   		status = driver->reset_link(udev);
>   	} else if (pci_pcie_type(udev) == PCI_EXP_TYPE_DOWNSTREAM) {
>   		status = default_downstream_reset_link(udev);
> +	} else if (pci_pcie_type(udev) == PCI_EXP_TYPE_ROOT_PORT &&
> +		pcie_aer_get_firmware_first(udev)) {
> +		status = default_ff_root_port_reset_link(udev);
>   	} else {
>   		dev_printk(KERN_DEBUG, &dev->dev,
>   			"no link-reset support at upstream device %s\n",
> --
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Betty Dall May 29, 2013, 4:16 p.m. UTC | #2
On Wed, 2013-05-29 at 09:42 -0600, Pearson, Greg wrote:
> On 05/28/2013 12:48 PM, Betty Dall wrote:
> > The firmware first path does not install the aerdrv root port
> > service driver, so the firmware first root port does not have
> > a reset_link callback. When a firmware first root port does not have
> > a reset_link callback, use a new default reset_link similar to what
> > we already do for the default_downstream_reset_link(). The firmware
> > first default reset_link brings the root port out of SBR if firmware
> > left it in SBR.
> >
> > Signed-off-by: Betty Dall <betty.dall@hp.com>
> > ---
> >
> >   drivers/pci/pcie/aer/aerdrv_core.c |   37 ++++++++++++++++++++++++++++++++++++
> >   1 files changed, 37 insertions(+), 0 deletions(-)
> >
> >
> > diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
> > index 8ec8b4f..6862fe3 100644
> > --- a/drivers/pci/pcie/aer/aerdrv_core.c
> > +++ b/drivers/pci/pcie/aer/aerdrv_core.c
> > @@ -413,6 +413,40 @@ static pci_ers_result_t default_downstream_reset_link(struct pci_dev *dev)
> >   	return PCI_ERS_RESULT_RECOVERED;
> >   }
> >   
> > +/**
> > + * default_ff_root_port_reset_link - default reset function for firmware
> > + *		first Root Port
> > + * @dev: pointer to root port's pci_dev data structure
> > + *
> > + * Invoked when performing link reset at Root Port w/ no aer driver.
> > + * This happens through the firmware first path. Firmware may leave
> > + * the Root Port in SBR and it is the OS responsiblity to bring it out
> > + * of SBR.
> > + */
> > +static pci_ers_result_t default_ff_root_port_reset_link(struct pci_dev *dev)
> > +{
> > +	u16 p2p_ctrl;
> > +
> > +	/* Read Secondary Bus Reset */
> > +	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &p2p_ctrl);
> > +	p2p_ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
> 
> Remove "p2p_ctrl |= PCI_BRIDGE_CTL_BUS_RESET;" otherwise the following 
> conditional is always taken.
> 
> --
> Greg

Agreed. That was a copy and paste mistake. I will fix and retest.

-Betty

> > +
> > +	/* De-assert Secondary Bus Reset, if it is set */
> > +	if (p2p_ctrl & PCI_BRIDGE_CTL_BUS_RESET) {
> > +		p2p_ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
> > +		pci_write_config_word(dev, PCI_BRIDGE_CONTROL, p2p_ctrl);
> > +
> > +		/*
> > +		 * System software must wait for at least 100ms from the end
> > +		 * of a reset of one or more device before it is permitted
> > +		 * to issue Configuration Requests to those devices.
> > +		 */
> > +		msleep(200);
> > +		dev_dbg(&dev->dev, "Root Port link has been reset\n");
> > +	}
> > +	return PCI_ERS_RESULT_RECOVERED;
> > +}
> > +
> >   static int find_aer_service_iter(struct device *device, void *data)
> >   {
> >   	struct pcie_port_service_driver *service_driver, **drv;
> > @@ -460,6 +494,9 @@ static pci_ers_result_t reset_link(struct pci_dev *dev)
> >   		status = driver->reset_link(udev);
> >   	} else if (pci_pcie_type(udev) == PCI_EXP_TYPE_DOWNSTREAM) {
> >   		status = default_downstream_reset_link(udev);
> > +	} else if (pci_pcie_type(udev) == PCI_EXP_TYPE_ROOT_PORT &&
> > +		pcie_aer_get_firmware_first(udev)) {
> > +		status = default_ff_root_port_reset_link(udev);
> >   	} else {
> >   		dev_printk(KERN_DEBUG, &dev->dev,
> >   			"no link-reset support at upstream device %s\n",
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >


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diff mbox

Patch

diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
index 8ec8b4f..6862fe3 100644
--- a/drivers/pci/pcie/aer/aerdrv_core.c
+++ b/drivers/pci/pcie/aer/aerdrv_core.c
@@ -413,6 +413,40 @@  static pci_ers_result_t default_downstream_reset_link(struct pci_dev *dev)
 	return PCI_ERS_RESULT_RECOVERED;
 }
 
+/**
+ * default_ff_root_port_reset_link - default reset function for firmware
+ *		first Root Port
+ * @dev: pointer to root port's pci_dev data structure
+ *
+ * Invoked when performing link reset at Root Port w/ no aer driver.
+ * This happens through the firmware first path. Firmware may leave
+ * the Root Port in SBR and it is the OS responsiblity to bring it out
+ * of SBR.
+ */
+static pci_ers_result_t default_ff_root_port_reset_link(struct pci_dev *dev)
+{
+	u16 p2p_ctrl;
+
+	/* Read Secondary Bus Reset */
+	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &p2p_ctrl);
+	p2p_ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
+
+	/* De-assert Secondary Bus Reset, if it is set */
+	if (p2p_ctrl & PCI_BRIDGE_CTL_BUS_RESET) {
+		p2p_ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
+		pci_write_config_word(dev, PCI_BRIDGE_CONTROL, p2p_ctrl);
+
+		/*
+		 * System software must wait for at least 100ms from the end
+		 * of a reset of one or more device before it is permitted
+		 * to issue Configuration Requests to those devices.
+		 */
+		msleep(200);
+		dev_dbg(&dev->dev, "Root Port link has been reset\n");
+	}
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
 static int find_aer_service_iter(struct device *device, void *data)
 {
 	struct pcie_port_service_driver *service_driver, **drv;
@@ -460,6 +494,9 @@  static pci_ers_result_t reset_link(struct pci_dev *dev)
 		status = driver->reset_link(udev);
 	} else if (pci_pcie_type(udev) == PCI_EXP_TYPE_DOWNSTREAM) {
 		status = default_downstream_reset_link(udev);
+	} else if (pci_pcie_type(udev) == PCI_EXP_TYPE_ROOT_PORT &&
+		pcie_aer_get_firmware_first(udev)) {
+		status = default_ff_root_port_reset_link(udev);
 	} else {
 		dev_printk(KERN_DEBUG, &dev->dev,
 			"no link-reset support at upstream device %s\n",