From: Niklas Cassel <cassel@kernel.org>
To: Koichiro Den <den@valinux.co.jp>
Cc: "Jingoo Han" <jingoohan1@gmail.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Kishon Vijay Abraham I" <kishon@kernel.org>,
"Jon Mason" <jdmason@kudzu.us>,
"Dave Jiang" <dave.jiang@intel.com>,
"Allen Hubbe" <allenbh@gmail.com>, "Frank Li" <Frank.Li@nxp.com>,
"Bhanu Seshu Kumar Valluri" <bhanuseshukumar@gmail.com>,
"Marco Crivellari" <marco.crivellari@suse.com>,
"Shin'ichiro Kawasaki" <shinichiro.kawasaki@wdc.com>,
"Manikanta Maddireddy" <mmaddireddy@nvidia.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
ntb@lists.linux.dev
Subject: Re: [PATCH v10 7/7] PCI: endpoint: pci-ep-msi: Add embedded doorbell fallback
Date: Mon, 2 Mar 2026 11:07:17 +0100 [thread overview]
Message-ID: <aaVhVc-teEeglUxJ@ryzen> (raw)
In-Reply-To: <20260302071427.534158-8-den@valinux.co.jp>
On Mon, Mar 02, 2026 at 04:14:27PM +0900, Koichiro Den wrote:
> Some endpoint platforms cannot use platform MSI / GIC ITS to implement
> EP-side doorbells. In those cases, EPF drivers cannot provide an
> interrupt-driven doorbell and often fall back to polling.
>
> Add an "embedded" doorbell backend that uses a controller-integrated
> doorbell target (e.g. DesignWare integrated eDMA interrupt-emulation
> doorbell).
>
> The backend locates the doorbell register and a corresponding Linux IRQ
> via the EPC aux-resource API. If the doorbell register is already
> exposed via a fixed BAR mapping, provide BAR+offset. Otherwise provide
> the DMA address returned by dma_map_resource() (which may be an IOVA
> when an IOMMU is enabled) so EPF drivers can map it into BAR space.
>
> When MSI doorbell allocation fails with -ENODEV,
> pci_epf_alloc_doorbell() falls back to this embedded backend.
>
> Signed-off-by: Koichiro Den <den@valinux.co.jp>
> ---
Tested-by: Niklas Cassel <cassel@kernel.org>
next prev parent reply other threads:[~2026-03-02 10:07 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-02 7:14 [PATCH v10 0/7] PCI: endpoint: pci-ep-msi: Add embedded doorbell fallback Koichiro Den
2026-03-02 7:14 ` [PATCH v10 1/7] PCI: endpoint: Add auxiliary resource query API Koichiro Den
2026-03-21 14:17 ` Manivannan Sadhasivam
2026-03-23 1:34 ` Koichiro Den
2026-03-02 7:14 ` [PATCH v10 2/7] PCI: dwc: Record integrated eDMA register window Koichiro Den
2026-03-21 14:21 ` Manivannan Sadhasivam
2026-03-23 1:46 ` Koichiro Den
2026-03-24 8:06 ` Koichiro Den
2026-03-02 7:14 ` [PATCH v10 3/7] PCI: dwc: ep: Expose integrated eDMA resources via EPC aux-resource API Koichiro Den
2026-03-23 18:36 ` Frank Li
2026-03-24 8:45 ` Koichiro Den
2026-03-02 7:14 ` [PATCH v10 4/7] PCI: endpoint: pci-ep-msi: Refactor doorbell allocation for new backends Koichiro Den
2026-03-02 7:14 ` [PATCH v10 5/7] PCI: endpoint: pci-epf-vntb: Reuse pre-exposed doorbells and IRQ flags Koichiro Den
2026-03-23 18:39 ` Frank Li
2026-03-02 7:14 ` [PATCH v10 6/7] PCI: endpoint: pci-epf-test: Reuse pre-exposed doorbell targets Koichiro Den
2026-03-23 18:41 ` Frank Li
2026-03-02 7:14 ` [PATCH v10 7/7] PCI: endpoint: pci-ep-msi: Add embedded doorbell fallback Koichiro Den
2026-03-02 10:07 ` Niklas Cassel [this message]
2026-03-23 18:48 ` Frank Li
2026-03-24 1:40 ` Koichiro Den
2026-03-25 7:06 ` Niklas Cassel
2026-03-25 8:43 ` Koichiro Den
2026-03-25 16:56 ` Niklas Cassel
2026-03-26 8:49 ` Koichiro Den
2026-03-26 9:59 ` Niklas Cassel
2026-03-26 10:25 ` Niklas Cassel
2026-03-26 12:12 ` Robin Murphy
2026-03-26 14:38 ` Koichiro Den
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