Commit e200904b authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Bjorn Helgaas
Browse files

PCI/PM: Split pci_power_up() 

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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent f0881d38

drivers/pci/pci.c

+35 −6
Original line number Diff line number Diff line
@@ -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