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PCI: support PM D0hot->D3 transition reset

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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.

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Yu Zhao 2009-06-13 15:52:14 +08:00 committed by Jesse Barnes
parent 8c1c699fec
commit f85876ba82
1 changed files with 34 additions and 0 deletions
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34
drivers/pci/pci.c
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@ -2132,6 +2132,36 @@ 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;
@ -2149,6 +2179,10 @@ 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);