Linux PCI subsystem development
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From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
To: Bjorn Helgaas <helgaas@kernel.org>,
	Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Cc: "Vinod Koul" <vkoul@kernel.org>,
	"Neil Armstrong" <neil.armstrong@linaro.org>,
	"Philipp Zabel" <p.zabel@pengutronix.de>,
	"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>,
	linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 2/5] PCI: dwc: Add support for retaining link during host init
Date: Mon, 12 Jan 2026 12:29:26 +0100	[thread overview]
Message-ID: <816456c5-ad32-4829-ae0d-a0d09f468863@oss.qualcomm.com> (raw)
In-Reply-To: <20260109155350.GA546142@bhelgaas>

On 1/9/26 4:53 PM, Bjorn Helgaas wrote:
> On Fri, Jan 09, 2026 at 12:51:07PM +0530, Krishna Chaitanya Chundru wrote:
>> Some platforms keep the PCIe link up across bootloader and kernel
>> handoff. In such cases, reinitializing the root complex is unnecessary
>> if the DWC glue drivers wants to retain the PCIe link.
>>
>> Introduce a link_retain flag in struct dw_pcie_rp to indicate that
>> the link should be preserved. When this flag is set by DWC glue drivers,
>> skip dw_pcie_setup_rc() and only initialize MSI, avoiding redundant
>> configuration steps.
> 
> It sounds like this adds an assumption that the bootloader
> initialization is the same as what dw_pcie_setup_rc() would do.  This
> assumption also applies to future changes in dw_pcie_setup_rc().
> 
> It looks like you mention an issue like this in [PATCH 4/5]; DBI & ATU
> base being different than "HLOS" (whatever that is).  This sounds like

FYI, "HLOS" is a Qualcomm term for "High-Level OS".. which is a very
pedantic way to say "OS"

Konrad

  reply	other threads:[~2026-01-12 11:29 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-09  7:21 [PATCH 0/5] PCI: qcom: Add link retention support Krishna Chaitanya Chundru
2026-01-09  7:21 ` [PATCH 1/5] phy: qcom: qmp-pcie: Skip PHY reset if already up Krishna Chaitanya Chundru
2026-01-09  9:23   ` Abel Vesa
2026-01-09 13:08   ` Dmitry Baryshkov
2026-01-09 13:10     ` Neil Armstrong
2026-01-09 14:03       ` Dmitry Baryshkov
2026-01-14  9:36         ` Vinod Koul
2026-02-16 14:53         ` Manivannan Sadhasivam
2026-02-16 14:56           ` Konrad Dybcio
2026-01-09  7:21 ` [PATCH 2/5] PCI: dwc: Add support for retaining link during host init Krishna Chaitanya Chundru
2026-01-09 15:53   ` Bjorn Helgaas
2026-01-12 11:29     ` Konrad Dybcio [this message]
2026-01-22  8:55     ` Krishna Chaitanya Chundru
2026-01-09  7:21 ` [PATCH 3/5] PCI: qcom: Keep PERST# GPIO state as-is during probe Krishna Chaitanya Chundru
2026-01-09 11:14   ` Konrad Dybcio
2026-02-16 14:58   ` Manivannan Sadhasivam
2026-01-09  7:21 ` [PATCH 4/5] PCI: qcom: Add link retention support Krishna Chaitanya Chundru
2026-02-16 15:08   ` Manivannan Sadhasivam
2026-01-09  7:21 ` [PATCH 5/5] PCI: qcom: enable Link retain logic for Hamoa Krishna Chaitanya Chundru
2026-01-09 13:09   ` Dmitry Baryshkov
2026-01-22  8:59     ` Krishna Chaitanya Chundru
2026-01-15  2:16 ` [PATCH 0/5] PCI: qcom: Add link retention support Qiang Yu

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