PCI PM 1.2 specifies that the device will perform an internal reset upon
transitioning from D3hot to D0 when the NO_SOFT_RESET bit is clear. This
method can be used to reset a function if neither PCIe FLR nor PCI AF FLR
are supported.
Signed-off-by: Yu Zhao <yu.zhao@xxxxxxxxx>
---
drivers/pci/pci.c | 34 ++++++++++++++++++++++++++++++++++
1 files changed, 34 insertions(+), 0 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index eebb50f..19a5479 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2130,6 +2130,36 @@ clear:
return 0;
}
+static int pci_pm_reset(struct pci_dev *dev, int probe)
+{
+ u16 csr;
+
+ if (!dev->pm_cap)
+ return -ENOTTY;
+
+ pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &csr);
+ if (csr & PCI_PM_CTRL_NO_SOFT_RESET)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ if (dev->current_state != PCI_D0)
+ return -EINVAL;
+
+ csr &= ~PCI_PM_CTRL_STATE_MASK;
+ csr |= PCI_D3hot;
+ pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
+ msleep(pci_pm_d3_delay);
+
+ csr &= ~PCI_PM_CTRL_STATE_MASK;
+ csr |= PCI_D0;
+ pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
+ msleep(pci_pm_d3_delay);
+
+ return 0;
+}
+
static int pci_dev_reset(struct pci_dev *dev, int probe)
{
int rc;
@@ -2147,6 +2177,10 @@ static int pci_dev_reset(struct pci_dev *dev, int probe)
goto done;
rc = pci_af_flr(dev, probe);
+ if (rc != -ENOTTY)
+ goto done;
+
+ rc = pci_pm_reset(dev, probe);
done:
if (!probe) {
up(&dev->dev.sem);
--
1.6.3.1
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