Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
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 12/13] PCI: MSI: Document the various ways of ending up with NO_MSI
Date: Thu, 25 Feb 2021 15:10:22 +0000
Message-ID: <20210225151023.3642391-13-maz@kernel.org> (raw)
In-Reply-To: <20210225151023.3642391-1-maz@kernel.org>

We have now 4 ways of ending up with NO_MSI being set.
Document them.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pci/msi.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index d9c73c173c14..425abcdfcaca 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -871,8 +871,16 @@ static int pci_msi_supported(struct pci_dev *dev, int nvec)
 	 * Any bridge which does NOT route MSI transactions from its
 	 * secondary bus to its primary bus must set NO_MSI flag on
 	 * the secondary pci_bus.
-	 * We expect only arch-specific PCI host bus controller driver
-	 * or quirks for specific PCI bridges to be setting NO_MSI.
+	 *
+	 * The NO_MSI flag can either be set directly by:
+	 * - arch-specific PCI host bus controller drivers (deprecated)
+	 * - quirks for specific PCI bridges
+	 *
+	 * or indirectly by platform-specific PCI host bridge drivers by:
+	 * - unconditionally advertising the 'no_msi' property
+	 * - advertising the 'msi_domain' property, which results in
+	 *   the NO_MSI flag when no MSI domain is found for this bridge
+	 *   at probe time.
 	 */
 	for (bus = dev->bus; bus; bus = bus->parent)
 		if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
-- 
2.29.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  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 ` [PATCH 10/13] PCI: MSI: Let PCI host bridges declare their reliance on MSI domains Marc Zyngier
2021-02-25 15:10 ` [PATCH 11/13] PCI: Make pci_host_common_probe() declare its " Marc Zyngier
2021-02-25 15:10 ` Marc Zyngier [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210225151023.3642391-13-maz@kernel.org \
    --to=maz@kernel.org \
    --cc=bhelgaas@google.com \
    --cc=frank-w@public-files.de \
    --cc=haiyangz@microsoft.com \
    --cc=jonathanh@nvidia.com \
    --cc=kys@microsoft.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-hyperv@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=linux-renesas-soc@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=lorenzo.pieralisi@arm.com \
    --cc=marek.vasut+renesas@gmail.com \
    --cc=michal.simek@xilinx.com \
    --cc=paul.walmsley@sifive.com \
    --cc=robh@kernel.org \
    --cc=ryder.lee@mediatek.com \
    --cc=sthemmin@microsoft.com \
    --cc=tglx@linutronix.de \
    --cc=thierry.reding@gmail.com \
    --cc=treding@nvidia.com \
    --cc=wei.liu@kernel.org \
    --cc=will@kernel.org \
    --cc=yoshihiro.shimoda.uh@renesas.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org
	public-inbox-index linux-arm-kernel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git