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From: Marc Zyngier <maz@kernel.org>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Will Deacon <will@kernel.org>,
	Marek Vasut <marek.vasut+renesas@gmail.com>,
	Rob Herring <robh@kernel.org>, Wei Liu <wei.liu@kernel.org>,
	Ryder Lee <ryder.lee@mediatek.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Thierry Reding <treding@nvidia.com>,
	Frank Wunderlich <frank-w@public-files.de>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	linux-mediatek@lists.infradead.org,
	Paul Walmsley <paul.walmsley@sifive.com>,
	linux-tegra@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	linux-arm-kernel@lists.infradead.org,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org
Subject: [PATCH 10/13] PCI: MSI: Let PCI host bridges declare their reliance on MSI domains
Date: Thu, 25 Feb 2021 15:10:20 +0000
Message-ID: <20210225151023.3642391-11-maz@kernel.org> (raw)
In-Reply-To: <20210225151023.3642391-1-maz@kernel.org>

The new 'no_msi' attribute solves the problem of advertising the lack
of MSI capability for host bridges that know for sure that there will
be no MSI for their end-points.

However, there is a whole class of host bridges that cannot know
whether MSIs will be provided or not, as they rely on other blocks
to provide the MSI functionnality, using MSI domains.  This is
the case for example on systems that use the ARM GIC architecture.

Introduce a new attribute ('msi_domain') indicating that implicit
dependency, and use this property to set the NO_MSI flag when
no MSI domain is found at probe time.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pci/probe.c | 2 +-
 include/linux/pci.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 146bd85c037e..bac9f69a06a8 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -925,7 +925,7 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
 	device_enable_async_suspend(bus->bridge);
 	pci_set_bus_of_node(bus);
 	pci_set_bus_msi_domain(bus);
-	if (bridge->no_msi)
+	if (bridge->no_msi || (bridge->msi_domain && !bus->dev.msi_domain))
 		bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
 
 	if (!parent)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9db3abf9fd90..accc2454eab0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -551,6 +551,7 @@ struct pci_host_bridge {
 	unsigned int	preserve_config:1;	/* Preserve FW resource setup */
 	unsigned int	size_windows:1;		/* Enable root bus sizing */
 	unsigned int	no_msi:1;		/* Bridge has no MSI support */
+	unsigned int	msi_domain:1;		/* Bridge wants MSI domain */
 
 	/* Resource alignment requirements */
 	resource_size_t (*align_resource)(struct pci_dev *dev,
-- 
2.29.2


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  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-25 15:10 [PATCH 00/13] PCI: MSI: Getting rid of msi_controller, and other cleanups Marc Zyngier
2021-02-25 15:10 ` [PATCH 01/13] PCI: tegra: Convert to MSI domains Marc Zyngier
2021-02-25 15:10 ` [PATCH 02/13] PCI: rcar: " Marc Zyngier
2021-02-28 18:48   ` Marek Vasut
2021-02-25 15:10 ` [PATCH 03/13] PCI: xilinx: " Marc Zyngier
2021-03-22 12:21   ` Lorenzo Pieralisi
2021-03-22 12:33     ` Michal Simek
2021-03-22 14:04       ` Marc Zyngier
2021-03-22 12:23   ` Lorenzo Pieralisi
2021-03-22 12:33     ` Michal Simek
2021-03-22 14:04     ` Marc Zyngier
2021-02-25 15:10 ` [PATCH 04/13] PCI: hyperv: Drop msi_controller structure Marc Zyngier
2021-03-01  4:24   ` Michael Kelley
2021-02-25 15:10 ` [PATCH 05/13] PCI: MSI: Drop use of msi_controller from core code Marc Zyngier
2021-02-25 15:10 ` [PATCH 06/13] PCI: MSI: Kill msi_controller structure Marc Zyngier
2021-02-25 15:10 ` [PATCH 07/13] PCI: MSI: Kill default_teardown_msi_irqs() Marc Zyngier
2021-02-25 15:10 ` [PATCH 08/13] PCI: MSI: Let PCI host bridges declare their lack of MSI handling Marc Zyngier
2021-02-25 15:10 ` [PATCH 09/13] PCI: mediatek: Advertise " Marc Zyngier
2021-03-01 10:43   ` Aw: " Frank Wunderlich
2021-03-01 11:49     ` Marc Zyngier
2021-03-01 12:16       ` Aw: " Frank Wunderlich
2021-03-01 13:31         ` Marc Zyngier
2021-03-01 14:06           ` Aw: " Frank Wunderlich
2021-03-02 10:35             ` Robin Murphy
2021-02-25 15:10 ` Marc Zyngier [this message]
2021-02-25 15:10 ` [PATCH 11/13] PCI: Make pci_host_common_probe() declare its reliance on MSI domains Marc Zyngier
2021-02-25 15:10 ` [PATCH 12/13] PCI: MSI: Document the various ways of ending up with NO_MSI Marc Zyngier
2021-02-25 15:10 ` [PATCH 13/13] PCI: quirks: Refactor advertising of the NO_MSI flag Marc Zyngier
2021-03-10 19:29 ` [PATCH 00/13] PCI: MSI: Getting rid of msi_controller, and other cleanups Bjorn Helgaas

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