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PCI/PM: Split pci_power_up()

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One of the two callers of pci_power_up() invokes
pci_update_current_state() and pci_restore_state() right after calling
it, in which case running the part of it happening after the mandatory
transition delays is redundant, so move that part out of it into a new
function called pci_set_full_power_state() that will be invoked from
pci_set_power_state() which is the other caller of pci_power_up().

Link: https://lore.kernel.org/r/1942150.usQuhbGJ8B@kreacher
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Rafael J. Wysocki 2022-05-05 20:13:00 +02:00 committed by Bjorn Helgaas
parent f0881d38c7
commit e200904b27
1 changed files with 35 additions and 6 deletions
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41
drivers/pci/pci.c
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@ -1189,6 +1189,9 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
/**
* pci_power_up - Put the given device into D0
* @dev: PCI device to power up
*
* On success, return 0 or 1, depending on whether or not it is necessary to
* restore the device's BARs subsequently (1 is returned in that case).
*/
int pci_power_up(struct pci_dev *dev)
{
@ -1224,10 +1227,8 @@ int pci_power_up(struct pci_dev *dev)
need_restore = (state == PCI_D3hot || dev->current_state >= PCI_D3hot) &&
!(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET);
if (state == PCI_D0) {
dev->current_state = PCI_D0;
if (state == PCI_D0)
goto end;
}
/*
* Force the entire word to 0. This doesn't affect PME_Status, disables
@ -1241,13 +1242,41 @@ int pci_power_up(struct pci_dev *dev)
else if (state == PCI_D2)
udelay(PCI_PM_D2_DELAY);
end:
dev->current_state = PCI_D0;
if (need_restore)
return 1;
return 0;
}
/**
* pci_set_full_power_state - Put a PCI device into D0 and update its state
* @dev: PCI device to power up
*
* Call pci_power_up() to put @dev into D0, read from its PCI_PM_CTRL register
* to confirm the state change, restore its BARs if they might be lost and
* reconfigure ASPM in acordance with the new power state.
*
* If pci_restore_state() is going to be called right after a power state change
* to D0, it is more efficient to use pci_power_up() directly instead of this
* function.
*/
static int pci_set_full_power_state(struct pci_dev *dev)
{
u16 pmcsr;
int ret;
ret = pci_power_up(dev);
if (ret < 0)
return ret;
pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
dev->current_state = pmcsr & PCI_PM_CTRL_STATE_MASK;
if (dev->current_state != PCI_D0)
pci_info_ratelimited(dev, "Refused to change power state from %s to D0\n",
pci_power_name(dev->current_state));
end:
/*
* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
* INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
@ -1261,7 +1290,7 @@ int pci_power_up(struct pci_dev *dev)
* restore at least the BARs so that the device will be
* accessible to its driver.
*/
if (need_restore)
if (ret > 0)
pci_restore_bars(dev);
if (dev->bus->self)
@ -1415,7 +1444,7 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
return 0;
if (state == PCI_D0)
return pci_power_up(dev);
return pci_set_full_power_state(dev);
/*
* This device is quirked not to be put into D3, so don't put it in