From: Niklas Cassel <cassel@kernel.org>
To: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
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>,
"Frank Li" <Frank.Li@nxp.com>,
"Serge Semin" <Sergey.Semin@baikalelectronics.ru>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
macro@orcam.me.uk, stable@vger.kernel.org
Subject: Re: [PATCH v2 1/3] PCI: dwc: Fix skipped index 0 in outbound ATU setup
Date: Thu, 22 Jan 2026 16:02:31 +0100 [thread overview]
Message-ID: <aXI8ByG3RlLpIRRa@ryzen> (raw)
In-Reply-To: <20251229-ecam_io_fix-v2-1-41a0e56a6faa@oss.qualcomm.com>
On Mon, Dec 29, 2025 at 04:12:41PM +0530, Krishna Chaitanya Chundru wrote:
> In dw_pcie_iatu_setup(), the outbound ATU loop uses a pre-increment
> on the index and starts programming from 1, effectively skipping
> index 0. This results in the first outbound window never being
> configured.
This in not true.
outbound iatu at index 0 is used for CFG IOs, see dw_pcie_other_conf_map_bus()
and:
https://github.com/torvalds/linux/blob/v6.19-rc6/drivers/pci/controller/dwc/pcie-designware-host.c#L888
Also see my series here:
https://lore.kernel.org/linux-pci/20260122145411.453291-4-cassel@kernel.org/T/
That tries to clean up this mess.
Kind regards,
Niklas
next prev parent reply other threads:[~2026-01-22 15:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-29 10:42 [PATCH v2 0/3] PCI: dwc: Fix missing iATU setup when ECAM is enabled Krishna Chaitanya Chundru
2025-12-29 10:42 ` [PATCH v2 1/3] PCI: dwc: Fix skipped index 0 in outbound ATU setup Krishna Chaitanya Chundru
2026-01-22 15:02 ` Niklas Cassel [this message]
2026-01-22 18:16 ` Maciej W. Rozycki
2026-01-22 21:19 ` Niklas Cassel
2026-01-23 20:35 ` Maciej W. Rozycki
2025-12-29 10:42 ` [PATCH v2 2/3] PCI: dwc: Correct iATU index increment for MSG TLP region Krishna Chaitanya Chundru
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