From: Brian Masney <bmasney@redhat.com>
To: Johan Hovold <johan+linaro@kernel.org>
Cc: "Stanimir Varbanov" <svarbanov@mm-sol.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Andy Gross" <agross@kernel.org>,
"Bjorn Andersson" <andersson@kernel.org>,
"Konrad Dybcio" <konrad.dybcio@somainline.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Krishna chaitanya chundru" <quic_krichai@quicinc.com>,
quic_vbadigan@quicinc.com, linux-arm-msm@vger.kernel.org,
linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] PCI: qcom: Add basic interconnect support
Date: Wed, 19 Oct 2022 10:32:41 -0400 [thread overview]
Message-ID: <Y1AKiTkLa23idaf2@x1> (raw)
In-Reply-To: <20221017112449.2146-3-johan+linaro@kernel.org>
On Mon, Oct 17, 2022 at 01:24:49PM +0200, Johan Hovold wrote:
> + /*
> + * Some Qualcomm platforms require interconnect bandwidth constraints
> + * to be set before enabling interconnect clocks.
> + *
> + * Set an initial peak bandwidth corresponding to single-lane Gen 1
> + * for the pcie-mem path.
> + */
> + ret = icc_set_bw(pcie->icc_mem, 0, MBps_to_icc(250));
[snip]
> + speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status);
> + width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status);
> +
> + switch (speed) {
> + case 1:
> + bw = MBps_to_icc(250);
> + break;
> + case 2:
> + bw = MBps_to_icc(500);
> + break;
> + default:
> + case 3:
> + bw = MBps_to_icc(985);
> + break;
> + }
Just curious: These platforms have a 4 lane PCIe bus. Why use 985
instead of 1000 for the maximum?
Brian
next prev parent reply other threads:[~2022-10-19 14:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-17 11:24 [PATCH 0/2] PCI: qcom: Add basic interconnect support Johan Hovold
2022-10-17 11:24 ` [PATCH 1/2] dt-bindings: PCI: qcom: Add SC8280XP/SA8540P interconnects Johan Hovold
2022-10-19 14:37 ` Krzysztof Kozlowski
2022-10-20 7:57 ` Johan Hovold
2022-10-20 12:29 ` Krzysztof Kozlowski
2022-10-21 6:40 ` Johan Hovold
2022-10-17 11:24 ` [PATCH 2/2] PCI: qcom: Add basic interconnect support Johan Hovold
2022-10-19 14:32 ` Brian Masney [this message]
2022-10-19 14:45 ` Johan Hovold
2022-10-20 16:49 ` Brian Masney
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