[PATCH V3 1/6] IB/hfi1: Use pci_try_reset_bus() for initiating pci secondary bus reset

[PATCH V3 1/6] IB/hfi1: Use pci_try_reset_bus() for initiating pci secondary bus reset

[Sinan Kaya]

Getting ready to hide pci_reset_bridge_secondary_bus() from the drivers.
pci_reset_bridge_secondary_bus() should only be used internally by the
PCI code itself.

Other drivers should rely on higher level pci_try_reset_bus() API.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/infiniband/hw/hfi1/pcie.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/pcie.c b/drivers/infiniband/hw/hfi1/pcie.c
index 4d4371b..4570c4d 100644
--- a/drivers/infiniband/hw/hfi1/pcie.c
+++ b/drivers/infiniband/hw/hfi1/pcie.c
@@ -905,9 +905,7 @@ static int trigger_sbr(struct hfi1_devdata *dd)
 	 * delay after a reset is required.  Per spec requirements,
 	 * the link is either working or not after that point.
 	 */
-	pci_reset_bridge_secondary_bus(dev->bus->self);
-
-	return 0;
+	return pci_try_reset_bus(dev->bus);
 }
 
 /*
-- 
2.7.4


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[PATCH V3 2/6] PCI: Hide pci_reset_bridge_secondary_bus() from drivers

[Sinan Kaya]

Rename pci_reset_bridge_secondary_bus() to pci_bridge_secondary_bus_reset()
and move the declartation from linux/pci.h to drivers/pci.h to be used
internally in PCI directory only.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/hotplug/pciehp_hpc.c |  2 +-
 drivers/pci/pci.c                | 11 +++++------
 drivers/pci/pci.h                |  1 +
 drivers/pci/pcie/aer.c           |  2 +-
 drivers/pci/pcie/err.c           |  2 +-
 include/linux/pci.h              |  1 -
 6 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index bbaa211..8dae232 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -746,7 +746,7 @@ int pciehp_reset_slot(struct slot *slot, int probe)
 	if (pciehp_poll_mode)
 		del_timer_sync(&ctrl->poll_timer);
 
-	rc = pci_reset_bridge_secondary_bus(ctrl->pcie->port);
+	rc = pci_bridge_secondary_bus_reset(ctrl->pcie->port);
 
 	pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, stat_mask);
 	pcie_write_cmd_nowait(ctrl, ctrl_mask, ctrl_mask);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 98d1490..236220c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4224,19 +4224,18 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
 }
 
 /**
- * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge.
+ * pci_bridge_secondary_bus_reset - Reset the secondary bus on a PCI bridge.
  * @dev: Bridge device
  *
  * Use the bridge control register to assert reset on the secondary bus.
  * Devices on the secondary bus are left in power-on state.
  */
-int pci_reset_bridge_secondary_bus(struct pci_dev *dev)
+int pci_bridge_secondary_bus_reset(struct pci_dev *dev)
 {
 	pcibios_reset_secondary_bus(dev);
 
 	return pci_dev_wait(dev, "bus reset", PCIE_RESET_READY_POLL_MS);
 }
-EXPORT_SYMBOL_GPL(pci_reset_bridge_secondary_bus);
 
 static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
 {
@@ -4253,7 +4252,7 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
 	if (probe)
 		return 0;
 
-	return pci_reset_bridge_secondary_bus(dev->bus->self);
+	return pci_bridge_secondary_bus_reset(dev->bus->self);
 }
 
 static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, int probe)
@@ -4860,7 +4859,7 @@ static int pci_bus_reset(struct pci_bus *bus, int probe)
 
 	might_sleep();
 
-	ret = pci_reset_bridge_secondary_bus(bus->self);
+	ret = pci_bridge_secondary_bus_reset(bus->self);
 
 	pci_bus_unlock(bus);
 
@@ -4924,7 +4923,7 @@ int pci_try_reset_bus(struct pci_bus *bus)
 
 	if (pci_bus_trylock(bus)) {
 		might_sleep();
-		rc = pci_reset_bridge_secondary_bus(bus->self);
+		rc = pci_bridge_secondary_bus_reset(bus->self);
 		pci_bus_unlock(bus);
 	} else
 		rc = -EAGAIN;
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index c358e7a0..f784263 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -33,6 +33,7 @@ int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai,
 		  enum pci_mmap_api mmap_api);
 
 int pci_probe_reset_function(struct pci_dev *dev);
+int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
 
 /**
  * struct pci_platform_pm_ops - Firmware PM callbacks
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index f1d0f3e..74ea6ec 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1314,7 +1314,7 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 	reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
 	pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, reg32);
 
-	rc = pci_reset_bridge_secondary_bus(dev);
+	rc = pci_bridge_secondary_bus_reset(dev);
 	pci_printk(KERN_DEBUG, dev, "Root Port link has been reset\n");
 
 	/* Clear Root Error Status */
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 3a62a2e..a3a26f1 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -177,7 +177,7 @@ static pci_ers_result_t default_reset_link(struct pci_dev *dev)
 {
 	int rc;
 
-	rc = pci_reset_bridge_secondary_bus(dev);
+	rc = pci_bridge_secondary_bus_reset(dev);
 	pci_printk(KERN_DEBUG, dev, "downstream link has been reset\n");
 	return !rc ? PCI_ERS_RESULT_RECOVERED : PCI_ERS_RESULT_DISCONNECT;
 }
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 340029b..6b12ce2 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1102,7 +1102,6 @@ int pci_reset_bus(struct pci_bus *bus);
 int pci_try_reset_bus(struct pci_bus *bus);
 void pci_reset_secondary_bus(struct pci_dev *dev);
 void pcibios_reset_secondary_bus(struct pci_dev *dev);
-int pci_reset_bridge_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
 int __must_check pci_assign_resource(struct pci_dev *dev, int i);
 int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);
-- 
2.7.4


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[PATCH V3 3/6] PCI: Unify try slot and bus reset API

[Sinan Kaya]

Drivers are expected to call pci_try_reset_slot() or pci_try_reset_bus() by
querying if a system supports hotplug or not. A survey showed that most
drivers don't do this and we are leaking hotplug capability to the user.

Hide pci_try_slot_reset() from drivers and embed into pci_try_bus_reset().
Change pci_try_reset_bus() parameter from struct pci_bus to struct pci_dev.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pci.c           | 26 +++++++++++++++++++++-----
 drivers/vfio/pci/vfio_pci.c |  6 ++----
 include/linux/pci.h         |  3 +--
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 236220c..79a1566 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4817,12 +4817,12 @@ int pci_reset_slot(struct pci_slot *slot)
 EXPORT_SYMBOL_GPL(pci_reset_slot);
 
 /**
- * pci_try_reset_slot - Try to reset a PCI slot
+ * __pci_try_reset_slot - Try to reset a PCI slot
  * @slot: PCI slot to reset
  *
  * Same as above except return -EAGAIN if the slot cannot be locked
  */
-int pci_try_reset_slot(struct pci_slot *slot)
+static int __pci_try_reset_slot(struct pci_slot *slot)
 {
 	int rc;
 
@@ -4843,7 +4843,6 @@ int pci_try_reset_slot(struct pci_slot *slot)
 
 	return rc;
 }
-EXPORT_SYMBOL_GPL(pci_try_reset_slot);
 
 static int pci_bus_reset(struct pci_bus *bus, int probe)
 {
@@ -4906,12 +4905,12 @@ int pci_reset_bus(struct pci_bus *bus)
 EXPORT_SYMBOL_GPL(pci_reset_bus);
 
 /**
- * pci_try_reset_bus - Try to reset a PCI bus
+ * __pci_try_reset_bus - Try to reset a PCI bus
  * @bus: top level PCI bus to reset
  *
  * Same as above except return -EAGAIN if the bus cannot be locked
  */
-int pci_try_reset_bus(struct pci_bus *bus)
+static int __pci_try_reset_bus(struct pci_bus *bus)
 {
 	int rc;
 
@@ -4932,6 +4931,23 @@ int pci_try_reset_bus(struct pci_bus *bus)
 
 	return rc;
 }
+
+/**
+ * pci_try_reset_bus - Try to reset a PCI bus
+ * @pdev: top level PCI device to reset via slot/bus
+ *
+ * Same as above except return -EAGAIN if the bus cannot be locked
+ */
+int pci_try_reset_bus(struct pci_dev *pdev)
+{
+	bool slot = false;
+
+	if (!pci_probe_reset_slot(pdev->slot))
+		slot = true;
+
+	return slot ? __pci_try_reset_slot(pdev->slot) :
+			__pci_try_reset_bus(pdev->bus);
+}
 EXPORT_SYMBOL_GPL(pci_try_reset_bus);
 
 /**
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index b423a30..71018ec 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1010,8 +1010,7 @@ static long vfio_pci_ioctl(void *device_data,
 						    &info, slot);
 		if (!ret)
 			/* User has access, do the reset */
-			ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :
-				     pci_try_reset_bus(vdev->pdev->bus);
+			ret = pci_try_reset_bus(vdev->pdev);
 
 hot_reset_release:
 		for (i--; i >= 0; i--)
@@ -1373,8 +1372,7 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 	}
 
 	if (needs_reset)
-		ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :
-			     pci_try_reset_bus(vdev->pdev->bus);
+		ret = pci_try_reset_bus(vdev->pdev);
 
 put_devs:
 	for (i = 0; i < devs.cur_index; i++) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 6b12ce2..f5c85b6 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1096,10 +1096,9 @@ int pci_reset_function_locked(struct pci_dev *dev);
 int pci_try_reset_function(struct pci_dev *dev);
 int pci_probe_reset_slot(struct pci_slot *slot);
 int pci_reset_slot(struct pci_slot *slot);
-int pci_try_reset_slot(struct pci_slot *slot);
 int pci_probe_reset_bus(struct pci_bus *bus);
 int pci_reset_bus(struct pci_bus *bus);
-int pci_try_reset_bus(struct pci_bus *bus);
+int pci_try_reset_bus(struct pci_dev *dev);
 void pci_reset_secondary_bus(struct pci_dev *dev);
 void pcibios_reset_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
-- 
2.7.4


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[PATCH V3 4/6] PCI: Deprecate pci_reset_bus() and pci_reset_slot() functions

[Sinan Kaya]

pci_reset_bus() and pci_reset_slot() functions are not being used by
any code. Remove them from the kernel in favor of pci_try_reset_bus()
and pci_try_reset_slot() functions.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pci.c   | 55 ++---------------------------------------------------
 include/linux/pci.h |  2 --
 2 files changed, 2 insertions(+), 55 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 79a1566..6cec722 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4784,9 +4784,9 @@ int pci_probe_reset_slot(struct pci_slot *slot)
 EXPORT_SYMBOL_GPL(pci_probe_reset_slot);
 
 /**
- * pci_reset_slot - reset a PCI slot
+ * __pci_try_reset_slot - Try to reset a PCI slot
  * @slot: PCI slot to reset
- *
+ *`
  * A PCI bus may host multiple slots, each slot may support a reset mechanism
  * independent of other slots.  For instance, some slots may support slot power
  * control.  In the case of a 1:1 bus to slot architecture, this function may
@@ -4796,30 +4796,6 @@ EXPORT_SYMBOL_GPL(pci_probe_reset_slot);
  * through this function.  PCI config space of all devices in the slot and
  * behind the slot is saved before and restored after reset.
  *
- * Return 0 on success, non-zero on error.
- */
-int pci_reset_slot(struct pci_slot *slot)
-{
-	int rc;
-
-	rc = pci_slot_reset(slot, 1);
-	if (rc)
-		return rc;
-
-	pci_slot_save_and_disable(slot);
-
-	rc = pci_slot_reset(slot, 0);
-
-	pci_slot_restore(slot);
-
-	return rc;
-}
-EXPORT_SYMBOL_GPL(pci_reset_slot);
-
-/**
- * __pci_try_reset_slot - Try to reset a PCI slot
- * @slot: PCI slot to reset
- *
  * Same as above except return -EAGAIN if the slot cannot be locked
  */
 static int __pci_try_reset_slot(struct pci_slot *slot)
@@ -4878,33 +4854,6 @@ int pci_probe_reset_bus(struct pci_bus *bus)
 EXPORT_SYMBOL_GPL(pci_probe_reset_bus);
 
 /**
- * pci_reset_bus - reset a PCI bus
- * @bus: top level PCI bus to reset
- *
- * Do a bus reset on the given bus and any subordinate buses, saving
- * and restoring state of all devices.
- *
- * Return 0 on success, non-zero on error.
- */
-int pci_reset_bus(struct pci_bus *bus)
-{
-	int rc;
-
-	rc = pci_bus_reset(bus, 1);
-	if (rc)
-		return rc;
-
-	pci_bus_save_and_disable(bus);
-
-	rc = pci_bus_reset(bus, 0);
-
-	pci_bus_restore(bus);
-
-	return rc;
-}
-EXPORT_SYMBOL_GPL(pci_reset_bus);
-
-/**
  * __pci_try_reset_bus - Try to reset a PCI bus
  * @bus: top level PCI bus to reset
  *
diff --git a/include/linux/pci.h b/include/linux/pci.h
index f5c85b6..ad0c89a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1095,9 +1095,7 @@ int pci_reset_function(struct pci_dev *dev);
 int pci_reset_function_locked(struct pci_dev *dev);
 int pci_try_reset_function(struct pci_dev *dev);
 int pci_probe_reset_slot(struct pci_slot *slot);
-int pci_reset_slot(struct pci_slot *slot);
 int pci_probe_reset_bus(struct pci_bus *bus);
-int pci_reset_bus(struct pci_bus *bus);
 int pci_try_reset_bus(struct pci_dev *dev);
 void pci_reset_secondary_bus(struct pci_dev *dev);
 void pcibios_reset_secondary_bus(struct pci_dev *dev);
-- 
2.7.4


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[PATCH V3 5/6] PCI: Rename pci_try_reset_bus() to pci_reset_bus()

[Sinan Kaya]

Now that the old implementation of pci_reset_bus() is gone, replace
pci_try_reset_bus() with pci_reset_bus().

Compared to the old implementation, new code will fail immmediately with
-EAGAIN if object lock cannot be obtained.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/infiniband/hw/hfi1/pcie.c |  2 +-
 drivers/pci/pci.c                 | 18 +++++++++---------
 drivers/vfio/pci/vfio_pci.c       |  4 ++--
 include/linux/pci.h               |  2 +-
 4 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/pcie.c b/drivers/infiniband/hw/hfi1/pcie.c
index 4570c4d..a6d695a 100644
--- a/drivers/infiniband/hw/hfi1/pcie.c
+++ b/drivers/infiniband/hw/hfi1/pcie.c
@@ -905,7 +905,7 @@ static int trigger_sbr(struct hfi1_devdata *dd)
 	 * delay after a reset is required.  Per spec requirements,
 	 * the link is either working or not after that point.
 	 */
-	return pci_try_reset_bus(dev->bus);
+	return pci_reset_bus(dev->bus);
 }
 
 /*
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6cec722..28a071d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4784,7 +4784,7 @@ int pci_probe_reset_slot(struct pci_slot *slot)
 EXPORT_SYMBOL_GPL(pci_probe_reset_slot);
 
 /**
- * __pci_try_reset_slot - Try to reset a PCI slot
+ * __pci_reset_slot - Try to reset a PCI slot
  * @slot: PCI slot to reset
  *`
  * A PCI bus may host multiple slots, each slot may support a reset mechanism
@@ -4798,7 +4798,7 @@ EXPORT_SYMBOL_GPL(pci_probe_reset_slot);
  *
  * Same as above except return -EAGAIN if the slot cannot be locked
  */
-static int __pci_try_reset_slot(struct pci_slot *slot)
+static int __pci_reset_slot(struct pci_slot *slot)
 {
 	int rc;
 
@@ -4854,12 +4854,12 @@ int pci_probe_reset_bus(struct pci_bus *bus)
 EXPORT_SYMBOL_GPL(pci_probe_reset_bus);
 
 /**
- * __pci_try_reset_bus - Try to reset a PCI bus
+ * __pci_reset_bus - Try to reset a PCI bus
  * @bus: top level PCI bus to reset
  *
  * Same as above except return -EAGAIN if the bus cannot be locked
  */
-static int __pci_try_reset_bus(struct pci_bus *bus)
+static int __pci_reset_bus(struct pci_bus *bus)
 {
 	int rc;
 
@@ -4882,22 +4882,22 @@ static int __pci_try_reset_bus(struct pci_bus *bus)
 }
 
 /**
- * pci_try_reset_bus - Try to reset a PCI bus
+ * pci_reset_bus - Try to reset a PCI bus
  * @pdev: top level PCI device to reset via slot/bus
  *
  * Same as above except return -EAGAIN if the bus cannot be locked
  */
-int pci_try_reset_bus(struct pci_dev *pdev)
+int pci_reset_bus(struct pci_dev *pdev)
 {
 	bool slot = false;
 
 	if (!pci_probe_reset_slot(pdev->slot))
 		slot = true;
 
-	return slot ? __pci_try_reset_slot(pdev->slot) :
-			__pci_try_reset_bus(pdev->bus);
+	return slot ? __pci_reset_slot(pdev->slot) :
+			__pci_reset_bus(pdev->bus);
 }
-EXPORT_SYMBOL_GPL(pci_try_reset_bus);
+EXPORT_SYMBOL_GPL(pci_reset_bus);
 
 /**
  * pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 71018ec..345c0dc 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1010,7 +1010,7 @@ static long vfio_pci_ioctl(void *device_data,
 						    &info, slot);
 		if (!ret)
 			/* User has access, do the reset */
-			ret = pci_try_reset_bus(vdev->pdev);
+			ret = pci_reset_bus(vdev->pdev);
 
 hot_reset_release:
 		for (i--; i >= 0; i--)
@@ -1372,7 +1372,7 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 	}
 
 	if (needs_reset)
-		ret = pci_try_reset_bus(vdev->pdev);
+		ret = pci_reset_bus(vdev->pdev);
 
 put_devs:
 	for (i = 0; i < devs.cur_index; i++) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index ad0c89a..79a2c27 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1096,7 +1096,7 @@ int pci_reset_function_locked(struct pci_dev *dev);
 int pci_try_reset_function(struct pci_dev *dev);
 int pci_probe_reset_slot(struct pci_slot *slot);
 int pci_probe_reset_bus(struct pci_bus *bus);
-int pci_try_reset_bus(struct pci_dev *dev);
+int pci_reset_bus(struct pci_dev *dev);
 void pci_reset_secondary_bus(struct pci_dev *dev);
 void pcibios_reset_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
-- 
2.7.4


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Re: [PATCH V3 5/6] PCI: Rename pci_try_reset_bus() to pci_reset_bus()

[Sinan Kaya]

On 6/28/2018 2:28 PM, Sinan Kaya wrote:
> --- a/drivers/infiniband/hw/hfi1/pcie.c
> +++ b/drivers/infiniband/hw/hfi1/pcie.c
> @@ -905,7 +905,7 @@ static int trigger_sbr(struct hfi1_devdata *dd)
>  	 * delay after a reset is required.  Per spec requirements,
>  	 * the link is either working or not after that point.
>  	 */
> -	return pci_try_reset_bus(dev->bus);
> +	return pci_reset_bus(dev->bus);
>  }
>  

This should have been 

return pci_reset_bus(dev);

I'll wait until I hear more feedback.

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

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[PATCH V3 6/6] PCI: Handle link reset via hotplug if supported

[Sinan Kaya]

If a bridge supports hotplug and observes a PCIe fatal error, the following
events happen:

1. AER driver removes the devices from PCI tree on fatal error
2. AER driver brings down the link by issuing a secondary bus reset waits
for the link to come up.
3. Hotplug driver observes a link down interrupt
4. Hotplug driver tries to remove the devices waiting for the rescan lock
but devices are already removed by the AER driver and AER driver is waiting
for the link to come back up.
5. AER driver tries to re-enumerate devices after polling for the link
state to go up.
6. Hotplug driver obtains the lock and tries to remove the devices again.

If a bridge is a hotplug capable bridge, bounce the error handling to the
hotplug driver so that hotplug driver can mask link up/down interrupts
while performing a secondary bus reset.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/hotplug/pciehp_core.c | 20 ++++++++++++++++++++
 drivers/pci/pcie/err.c            |  5 +++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 44a6a63..43a49cc 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -299,6 +299,24 @@ static int pciehp_resume(struct pcie_device *dev)
 }
 #endif /* PM */
 
+static pci_ers_result_t pciehp_reset_link(struct pci_dev *pdev)
+{
+	struct pcie_device *pciedev;
+	struct controller *ctrl;
+	struct device *devhp;
+	struct slot *slot;
+	int rc;
+
+	devhp = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_HP);
+	pciedev = to_pcie_device(devhp);
+	ctrl = get_service_data(pciedev);
+	slot = ctrl->slot;
+
+	rc = reset_slot(slot->hotplug_slot, 0);
+
+	return !rc ? PCI_ERS_RESULT_RECOVERED : PCI_ERS_RESULT_DISCONNECT;
+}
+
 static struct pcie_port_service_driver hpdriver_portdrv = {
 	.name		= PCIE_MODULE_NAME,
 	.port_type	= PCIE_ANY_PORT,
@@ -311,6 +329,8 @@ static struct pcie_port_service_driver hpdriver_portdrv = {
 	.suspend	= pciehp_suspend,
 	.resume		= pciehp_resume,
 #endif	/* PM */
+
+	.reset_link	= pciehp_reset_link,
 };
 
 static int __init pcied_init(void)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index a3a26f1..0b66779 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -308,6 +308,11 @@ void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service)
 		pci_dev_put(pdev);
 	}
 
+	/* handle link reset via hotplug driver if supported */
+	if (dev->is_hotplug_bridge &&
+		pcie_port_find_device(dev, PCIE_PORT_SERVICE_HP))
+		service = PCIE_PORT_SERVICE_HP;
+
 	result = reset_link(udev, service);
 
 	if ((service == PCIE_PORT_SERVICE_AER) &&
-- 
2.7.4


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