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

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>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e7982af9a5d86efd738640fbe08dba01e4704155..1df99d9e350e988621a6a2242d443a28c3972bad 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5856,6 +5856,24 @@ 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 f9088c89a534737049463cc024e40db803422cb5..1d15c5d49cdd74a75a8605017b60b8d01a61227d 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2310,9 +2310,11 @@ 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