diff options
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index c8b4dbdd1bdd..9ff7183e25a2 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -9,6 +9,7 @@ #include <linux/kernel.h> #include <linux/delay.h> +#include <linux/dmi.h> #include <linux/init.h> #include <linux/of.h> #include <linux/of_pci.h> @@ -101,6 +102,21 @@ unsigned int pcibios_max_latency = 255; /* If set, the PCIe ARI capability will not be used. */ static bool pcie_ari_disabled; +/* Disable bridge_d3 for all PCIe ports */ +static bool pci_bridge_d3_disable; +/* Force bridge_d3 for all PCIe ports */ +static bool pci_bridge_d3_force; + +static int __init pcie_port_pm_setup(char *str) +{ + if (!strcmp(str, "off")) + pci_bridge_d3_disable = true; + else if (!strcmp(str, "force")) + pci_bridge_d3_force = true; + return 1; +} +__setup("pcie_port_pm=", pcie_port_pm_setup); + /** * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children * @bus: pointer to PCI bus structure to search @@ -2156,6 +2172,164 @@ void pci_config_pm_runtime_put(struct pci_dev *pdev) } /** + * pci_bridge_d3_possible - Is it possible to put the bridge into D3 + * @bridge: Bridge to check + * + * This function checks if it is possible to move the bridge to D3. + * Currently we only allow D3 for recent enough PCIe ports. + */ +static bool pci_bridge_d3_possible(struct pci_dev *bridge) +{ + unsigned int year; + + if (!pci_is_pcie(bridge)) + return false; + + switch (pci_pcie_type(bridge)) { + case PCI_EXP_TYPE_ROOT_PORT: + case PCI_EXP_TYPE_UPSTREAM: + case PCI_EXP_TYPE_DOWNSTREAM: + if (pci_bridge_d3_disable) + return false; + if (pci_bridge_d3_force) + return true; + + /* + * It should be safe to put PCIe ports from 2015 or newer + * to D3. + */ + if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && + year >= 2015) { + return true; + } + break; + } + + return false; +} + +static int pci_dev_check_d3cold(struct pci_dev *dev, void *data) +{ + bool *d3cold_ok = data; + bool no_d3cold; + + /* + * The device needs to be allowed to go D3cold and if it is wake + * capable to do so from D3cold. + */ + no_d3cold = dev->no_d3cold || !dev->d3cold_allowed || + (device_may_wakeup(&dev->dev) && !pci_pme_capable(dev, PCI_D3cold)) || + !pci_power_manageable(dev); + + *d3cold_ok = !no_d3cold; + + return no_d3cold; +} + +/* + * pci_bridge_d3_update - Update bridge D3 capabilities + * @dev: PCI device which is changed + * @remove: Is the device being removed + * + * Update upstream bridge PM capabilities accordingly depending on if the + * device PM configuration was changed or the device is being removed. The + * change is also propagated upstream. + */ +static void pci_bridge_d3_update(struct pci_dev *dev, bool remove) +{ + struct pci_dev *bridge; + bool d3cold_ok = true; + + bridge = pci_upstream_bridge(dev); + if (!bridge || !pci_bridge_d3_possible(bridge)) + return; + + pci_dev_get(bridge); + /* + * If the device is removed we do not care about its D3cold + * capabilities. + */ + if (!remove) + pci_dev_check_d3cold(dev, &d3cold_ok); + + if (d3cold_ok) { + /* + * We need to go through all children to find out if all of + * them can still go to D3cold. + */ + pci_walk_bus(bridge->subordinate, pci_dev_check_d3cold, + &d3cold_ok); + } + + if (bridge->bridge_d3 != d3cold_ok) { + bridge->bridge_d3 = d3cold_ok; + /* Propagate change to upstream bridges */ + pci_bridge_d3_update(bridge, false); + } + + pci_dev_put(bridge); +} + +/** + * pci_bridge_d3_device_changed - Update bridge D3 capabilities on change + * @dev: PCI device that was changed + * + * If a device is added or its PM configuration, such as is it allowed to + * enter D3cold, is changed this function updates upstream bridge PM + * capabilities accordingly. + */ +void pci_bridge_d3_device_changed(struct pci_dev *dev) +{ + pci_bridge_d3_update(dev, false); +} + +/** + * pci_bridge_d3_device_removed - Update bridge D3 capabilities on remove + * @dev: PCI device being removed + * + * Function updates upstream bridge PM capabilities based on other devices + * still left on the bus. + */ +void pci_bridge_d3_device_removed(struct pci_dev *dev) +{ + pci_bridge_d3_update(dev, true); +} + +/** + * pci_d3cold_enable - Enable D3cold for device + * @dev: PCI device to handle + * + * This function can be used in drivers to enable D3cold from the device + * they handle. It also updates upstream PCI bridge PM capabilities + * accordingly. + */ +void pci_d3cold_enable(struct pci_dev *dev) +{ + if (dev->no_d3cold) { + dev->no_d3cold = false; + pci_bridge_d3_device_changed(dev); + } +} +EXPORT_SYMBOL_GPL(pci_d3cold_enable); + +/** + * pci_d3cold_disable - Disable D3cold for device + * @dev: PCI device to handle + * + * This function can be used in drivers to disable D3cold from the device + * they handle. It also updates upstream PCI bridge PM capabilities + * accordingly. + */ +void pci_d3cold_disable(struct pci_dev *dev) +{ + if (!dev->no_d3cold) { + dev->no_d3cold = true; + pci_bridge_d3_device_changed(dev); + } +} +EXPORT_SYMBOL_GPL(pci_d3cold_disable); + +/** * pci_pm_init - Initialize PM functions of given PCI device * @dev: PCI device to handle. */ @@ -2189,6 +2363,7 @@ void pci_pm_init(struct pci_dev *dev) dev->pm_cap = pm; dev->d3_delay = PCI_PM_D3_WAIT; dev->d3cold_delay = PCI_PM_D3COLD_WAIT; + dev->bridge_d3 = pci_bridge_d3_possible(dev); dev->d3cold_allowed = true; dev->d1_support = false; |