From: Abhishek Sahu abhsahu@nvidia.com
[ Upstream commit a17beb1a0882a544523dcb5d0da4801272dfd43a ]
Although not allowed by the PCI specs, some multi-function devices have power dependencies between the functions. For example, function 1 may not work unless function 0 is in the D0 power state.
The existing quirk_gpu_hda() adds a device link to express this dependency for GPU and HDA devices, but it really is not specific to those device types.
Generalize it and rename it to pci_create_device_link() so we can create dependencies between any "consumer" and "producer" functions of a multi-function device, where the consumer is only functional if the producer is in D0. This reorganization should not affect any functionality.
Link: https://lore.kernel.org/lkml/20190606092225.17960-2-abhsahu@nvidia.com Signed-off-by: Abhishek Sahu abhsahu@nvidia.com [bhelgaas: commit log, reword diagnostic] Signed-off-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/quirks.c | 54 ++++++++++++++++++++++++++++---------------- 1 file changed, 34 insertions(+), 20 deletions(-)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 6af7fc0be21d..3e1a0a207734 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4955,35 +4955,49 @@ static void quirk_fsl_no_msi(struct pci_dev *pdev) DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_FREESCALE, PCI_ANY_ID, quirk_fsl_no_msi);
/* - * GPUs with integrated HDA controller for streaming audio to attached displays - * need a device link from the HDA controller (consumer) to the GPU (supplier) - * so that the GPU is powered up whenever the HDA controller is accessed. - * The GPU and HDA controller are functions 0 and 1 of the same PCI device. - * The device link stays in place until shutdown (or removal of the PCI device - * if it's hotplugged). Runtime PM is allowed by default on the HDA controller - * to prevent it from permanently keeping the GPU awake. + * Although not allowed by the spec, some multi-function devices have + * dependencies of one function (consumer) on another (supplier). For the + * consumer to work in D0, the supplier must also be in D0. Create a + * device link from the consumer to the supplier to enforce this + * dependency. Runtime PM is allowed by default on the consumer to prevent + * it from permanently keeping the supplier awake. */ -static void quirk_gpu_hda(struct pci_dev *hda) +static void pci_create_device_link(struct pci_dev *pdev, unsigned int consumer, + unsigned int supplier, unsigned int class, + unsigned int class_shift) { - struct pci_dev *gpu; + struct pci_dev *supplier_pdev;
- if (PCI_FUNC(hda->devfn) != 1) + if (PCI_FUNC(pdev->devfn) != consumer) return;
- gpu = pci_get_domain_bus_and_slot(pci_domain_nr(hda->bus), - hda->bus->number, - PCI_DEVFN(PCI_SLOT(hda->devfn), 0)); - if (!gpu || (gpu->class >> 16) != PCI_BASE_CLASS_DISPLAY) { - pci_dev_put(gpu); + supplier_pdev = pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus), + pdev->bus->number, + PCI_DEVFN(PCI_SLOT(pdev->devfn), supplier)); + if (!supplier_pdev || (supplier_pdev->class >> class_shift) != class) { + pci_dev_put(supplier_pdev); return; }
- if (!device_link_add(&hda->dev, &gpu->dev, - DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME)) - pci_err(hda, "cannot link HDA to GPU %s\n", pci_name(gpu)); + if (device_link_add(&pdev->dev, &supplier_pdev->dev, + DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME)) + pci_info(pdev, "D0 power state depends on %s\n", + pci_name(supplier_pdev)); + else + pci_err(pdev, "Cannot enforce power dependency on %s\n", + pci_name(supplier_pdev)); + + pm_runtime_allow(&pdev->dev); + pci_dev_put(supplier_pdev); +}
- pm_runtime_allow(&hda->dev); - pci_dev_put(gpu); +/* + * Create device link for GPUs with integrated HDA controller for streaming + * audio to attached displays. + */ +static void quirk_gpu_hda(struct pci_dev *hda) +{ + pci_create_device_link(hda, 1, 0, PCI_BASE_CLASS_DISPLAY, 16); } DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_ATI, PCI_ANY_ID, PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda);