From: ALOK TIWARI <alok.a.tiwari@oracle.com>
To: "Manivannan Sadhasivam" <mani@kernel.org>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Krzysztof Kozlowski" <krzk@kernel.org>,
"Alim Akhtar" <alim.akhtar@samsung.com>,
"Jonathan Chocron" <jonnyc@amazon.com>
Cc: linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org,
Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Subject: Re: [PATCH v9 4/4] PCI: dwc: Support ECAM mechanism by enabling iATU 'CFG Shift Feature'
Date: Mon, 15 Sep 2025 20:44:10 +0530 [thread overview]
Message-ID: <74ccc612-beee-42a3-9ce3-947e59988f90@oracle.com> (raw)
In-Reply-To: <20250909-controller-dwc-ecam-v9-4-7d5b651840dd@kernel.org>
On 9/9/2025 12:37 PM, Manivannan Sadhasivam wrote:
> Currently, the driver is not making use of this CFG shift feature, thereby
> creating the iATU outbound map for each config access to the devices,
> causing latency and wasting CPU cycles.
>
> So to avoid this, configure the controller to enable CFG shift feature by
> enabling the 'CFG Shift' bit of the 'iATU Control 2 Register'.
>
> As a result of enabling CFG shift (ECAM), there is longer a need to map the
> DBI register space separately as the DBI region falls under the 'config'
> space used for ECAM (as DBI is used to access the Root Port).
nit : there is no longer a need
Thanks,
Alok
next prev parent reply other threads:[~2025-09-15 15:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-09 7:07 [PATCH v9 0/4] PCI: dwc: Add ECAM support with iATU configuration Manivannan Sadhasivam
2025-09-09 7:07 ` [PATCH v9 1/4] PCI: dwc: Add support for ELBI resource mapping Manivannan Sadhasivam
2025-09-09 7:07 ` [PATCH v9 2/4] PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature' Manivannan Sadhasivam
2025-09-09 7:07 ` [PATCH v9 3/4] PCI: qcom: Prepare for the DWC ECAM enablement Manivannan Sadhasivam
2025-09-12 21:44 ` Bjorn Helgaas
2025-09-15 14:32 ` Manivannan Sadhasivam
2025-09-12 21:50 ` Bjorn Helgaas
2025-09-15 14:34 ` Manivannan Sadhasivam
2025-09-09 7:07 ` [PATCH v9 4/4] PCI: dwc: Support ECAM mechanism by enabling iATU 'CFG Shift Feature' Manivannan Sadhasivam
2025-09-15 15:14 ` ALOK TIWARI [this message]
2025-11-28 3:17 ` Maciej W. Rozycki
2025-11-28 5:14 ` Krishna Chaitanya Chundru
2025-11-28 8:37 ` Maciej W. Rozycki
2025-11-28 13:44 ` Krishna Chaitanya Chundru
2025-11-28 17:16 ` Maciej W. Rozycki
2025-11-29 2:24 ` Krishna Chaitanya Chundru
2025-11-29 6:04 ` Maciej W. Rozycki
2025-12-01 11:51 ` Manivannan Sadhasivam
2025-12-01 14:38 ` Manivannan Sadhasivam
2025-12-01 16:42 ` Maciej W. Rozycki
2025-12-02 11:44 ` Manivannan Sadhasivam
2025-12-02 13:39 ` Maciej W. Rozycki
2025-12-02 13:45 ` Manivannan Sadhasivam
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