PCI-to-PCI Bridge 1.2 specifies that the Secondary Bus Reset bit can
force the assertion of RST# on the secondary interface, which can be
used to reset all devices including subordinates under this bus. This
can be used to reset a function if this function is the only device
under this bus.
Signed-off-by: Yu Zhao <yu.zhao@xxxxxxxxx>
---
drivers/pci/pci.c | 31 +++++++++++++++++++++++++++++++
1 files changed, 31 insertions(+), 0 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e459a0b..a77c33a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2115,6 +2115,33 @@ static int pci_pm_flr(struct pci_dev *dev, int probe)
return 0;
}
+static int pci_secondary_bus_reset(struct pci_dev *dev, int probe)
+{
+ u16 ctrl;
+ struct pci_dev *pdev;
+
+ if (dev->subordinate)
+ return -ENOTTY;
+
+ list_for_each_entry(pdev, &dev->bus->devices, bus_list)
+ if (pdev != dev)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, &ctrl);
+ ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
+ pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
+ msleep(100);
+
+ ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
+ pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
+ msleep(100);
+
+ return 0;
+}
+
static int pci_dev_reset(struct pci_dev *dev, int probe)
{
int rc;
@@ -2136,6 +2163,10 @@ static int pci_dev_reset(struct pci_dev *dev, int probe)
goto done;
rc = pci_pm_flr(dev, probe);
+ if (rc != -ENOTTY)
+ goto done;
+
+ rc = pci_secondary_bus_reset(dev, probe);
done:
up(&dev->dev.sem);
--
1.5.6.4
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