45 lines
1.7 KiB
Diff
45 lines
1.7 KiB
Diff
From 94e89b145371b68fa0ea294855adebcd03e0522e Mon Sep 17 00:00:00 2001
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From: Marc Zyngier <maz@kernel.org>
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Date: Tue, 30 Mar 2021 16:11:41 +0100
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Subject: PCI/MSI: Let PCI host bridges declare their reliance on MSI domains
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There is a whole class of host bridges that cannot know whether
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MSIs will be provided or not, as they rely on other blocks
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to provide the MSI functionnality, using MSI domains. This is
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the case for example on systems that use the ARM GIC architecture.
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Introduce a new attribute ('msi_domain') indicating that implicit
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dependency, and use this property to set the NO_MSI flag when
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no MSI domain is found at probe time.
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Link: https://lore.kernel.org/r/20210330151145.997953-11-maz@kernel.org
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Signed-off-by: Marc Zyngier <maz@kernel.org>
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Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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Acked-by: Bjorn Helgaas <bhelgaas@google.com>
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---
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drivers/pci/probe.c | 2 ++
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include/linux/pci.h | 1 +
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2 files changed, 3 insertions(+)
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--- a/drivers/pci/probe.c
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+++ b/drivers/pci/probe.c
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@@ -925,6 +925,8 @@ static int pci_register_host_bridge(stru
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device_enable_async_suspend(bus->bridge);
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pci_set_bus_of_node(bus);
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pci_set_bus_msi_domain(bus);
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+ if (bridge->msi_domain && !dev_get_msi_domain(&bus->dev))
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+ bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
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if (!parent)
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set_dev_node(bus->bridge, pcibus_to_node(bus));
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--- a/include/linux/pci.h
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+++ b/include/linux/pci.h
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@@ -545,6 +545,7 @@ struct pci_host_bridge {
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unsigned int native_dpc:1; /* OS may use PCIe DPC */
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unsigned int preserve_config:1; /* Preserve FW resource setup */
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unsigned int size_windows:1; /* Enable root bus sizing */
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+ unsigned int msi_domain:1; /* Bridge wants MSI domain */
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/* Resource alignment requirements */
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resource_size_t (*align_resource)(struct pci_dev *dev,
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