[PATCH 3.16 081/366] PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume

Ben Hutchings
2018-11-11T20:13:42Z

From: Mika Westerberg <mika.westerberg@linux.intel.com>

commit 13c65840feab8109194f9490c9870587173cb29d upstream.

After a suspend/resume cycle the Presence Detect or Data Link Layer Status
Changed bits might be set. If we don't clear them those events will not
fire anymore and nothing happens for instance when a device is now
hot-unplugged.

Fix this by clearing those bits in a newly introduced function
pcie_reenable_notification(). This should be fine because immediately
after, we check if the adapter is still present by reading directly from
the status register.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/pci/hotplug/pciehp.h | 2 +-
drivers/pci/hotplug/pciehp_core.c | 2 +-
drivers/pci/hotplug/pciehp_hpc.c | 13 ++++++++++++-
3 files changed, 14 insertions(+), 3 deletions(-)

--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -143,7 +143,7 @@ struct controller *pcie_init(struct pcie
int pcie_init_notification(struct controller *ctrl);
int pciehp_enable_slot(struct slot *p_slot);
int pciehp_disable_slot(struct slot *p_slot);
-void pcie_enable_notification(struct controller *ctrl);
+void pcie_reenable_notification(struct controller *ctrl);
int pciehp_power_on_slot(struct slot *slot);
void pciehp_power_off_slot(struct slot *slot);
void pciehp_get_power_status(struct slot *slot, u8 *status);
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -332,7 +332,7 @@ static int pciehp_resume(struct pcie_dev
ctrl = get_service_data(dev);

/* reinitialize the chipset's event detection logic */
- pcie_enable_notification(ctrl);
+ pcie_reenable_notification(ctrl);

slot = ctrl->slot;

--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -580,7 +580,7 @@ static irqreturn_t pcie_isr(int irq, voi
return IRQ_HANDLED;
}

-void pcie_enable_notification(struct controller *ctrl)
+static void pcie_enable_notification(struct controller *ctrl)
{
u16 cmd, mask;

@@ -618,6 +618,17 @@ void pcie_enable_notification(struct con
pcie_write_cmd(ctrl, cmd, mask);
}

+void pcie_reenable_notification(struct controller *ctrl)
+{
+ /*
+ * Clear both Presence and Data Link Layer Changed to make sure
+ * those events still fire after we have re-enabled them.
+ */
+ pcie_capability_write_word(ctrl->pcie->port, PCI_EXP_SLTSTA,
+ PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC);
+ pcie_enable_notification(ctrl);
+}
+
static void pcie_disable_notification(struct controller *ctrl)
{
u16 mask;