PCI: Add a helper to check Power Resource Requirements _PR3 existence

BugLink: https://bugs.launchpad.net/bugs/1840835
A driver may want to know the existence of _PR3, to choose different
runtime suspend behavior. A user will be add in next patch.

This is mostly the same as nouveau_pr3_present().

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20191018073848.14590-1-kai.heng.feng@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
(cherry picked from commit 52525b7a3cf82adec5c6cf0ecbd23ff228badc94 linux-next)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 57f15a7e6f0bbe9a6c10bf61038a99e54781c094..980dc798ee8b332621de93beb79141e7166bfa73 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5854,6 +5854,24 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode,
        return 0;
 }
 
+#ifdef CONFIG_ACPI
+bool pci_pr3_present(struct pci_dev *pdev)
+{
+       struct acpi_device *adev;
+
+       if (acpi_disabled)
+               return false;
+
+       adev = ACPI_COMPANION(&pdev->dev);
+       if (!adev)
+               return false;
+
+       return adev->power.flags.power_resources &&
+               acpi_has_method(adev->handle, "_PR3");
+}
+EXPORT_SYMBOL_GPL(pci_pr3_present);
+#endif
+
 /**
  * pci_add_dma_alias - Add a DMA devfn alias for a device
  * @dev: the PCI device for which alias is added

diff --git a/include/linux/pci.h b/include/linux/pci.h
index ac8a6c4e17923d477dac5edf19ad71147dc25e48..92a8d44322d6e311f06e51be7c5dbfeea5aa9caa 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2348,9 +2348,11 @@ struct irq_domain *pci_host_bridge_acpi_msi_domain(struct pci_bus *bus);
 
 void
 pci_msi_register_fwnode_provider(struct fwnode_handle *(*fn)(struct device *));
+bool pci_pr3_present(struct pci_dev *pdev);
 #else
 static inline struct irq_domain *
 pci_host_bridge_acpi_msi_domain(struct pci_bus *bus) { return NULL; }
+static bool pci_pr3_present(struct pci_dev *pdev) { return false; }
 #endif
 
 #ifdef CONFIG_EEH