From: Konrad Dybcio <konrad.dybcio@linaro.org>
To: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>,
agross@kernel.org, andersson@kernel.org, mani@kernel.org
Cc: quic_msarkar@quicinc.com, quic_kraravin@quicinc.com,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Gustavo Pimentel" <gustavo.pimentel@synopsys.com>,
"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
"Serge Semin" <fancer.lancer@gmail.com>,
"Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas.com>,
"Conor Dooley" <conor.dooley@microchip.com>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v3 3/3] PCI: qcom: Add rx margining settings for 16GT/s
Date: Thu, 2 May 2024 01:13:45 +0200 [thread overview]
Message-ID: <5a9a0c90-d191-49e1-8cd5-1d45c82040ac@linaro.org> (raw)
In-Reply-To: <53c0e508-60fe-ee5d-cb2b-a5392c330377@quicinc.com>
[...]
>>> EXPORT_SYMBOL_GPL(qcom_pcie_common_set_16gt_eq_settings);
>>> +void qcom_pcie_common_set_16gt_rx_margining_settings(struct dw_pcie *pci)
>>> +{
>>> + u32 reg;
>>> +
>>> + reg = dw_pcie_readl_dbi(pci, GEN4_LANE_MARGINING_1_OFF);
>>> + reg = MARGINING_MAX_VOLTAGE_OFFSET(0x24) |
>>> + MARGINING_NUM_VOLTAGE_STEPS(0x78) |
>>> + MARGINING_MAX_TIMING_OFFSET(0x32) |
>>> + MARGINING_NUM_TIMING_STEPS(0x10);
>>> + dw_pcie_writel_dbi(pci, GEN4_LANE_MARGINING_1_OFF, reg);
>>
>> Since this is DW-common, why is this inside the qcom driver?
> Though this register space is in dw-common specific, these settings are purely vendor specific . These settings are determined by systems team on vendor hardware, as these settings are used as margin to compensate signal variance due to various physical factors(like connection length, retimers etc).
Okay, so:
1. is the register layout vendor-specific too? i.e. are the bitfields DW-common?
2. will these settings work on all Qualcomm devices, regardless of SoC/board/
retimers used etc.?
Konrad
next prev parent reply other threads:[~2024-05-01 23:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-19 0:09 [PATCH v3 0/3] Add 16GT/s equalization and margining settings Shashank Babu Chinta Venkata
2024-04-19 0:09 ` [PATCH v3 1/3] PCI: qcom: Refactor common code Shashank Babu Chinta Venkata
2024-04-22 14:58 ` Manivannan Sadhasivam
2024-04-19 0:09 ` [PATCH v3 2/3] PCI: qcom: Add equalization settings for 16GT/s Shashank Babu Chinta Venkata
2024-04-22 15:16 ` Manivannan Sadhasivam
2024-04-22 22:59 ` Konrad Dybcio
2024-04-19 0:09 ` [PATCH v3 3/3] PCI: qcom: Add rx margining " Shashank Babu Chinta Venkata
2024-04-22 15:20 ` Manivannan Sadhasivam
2024-04-22 22:58 ` Konrad Dybcio
2024-04-30 20:37 ` Shashank Babu Chinta Venkata
2024-05-01 23:13 ` Konrad Dybcio [this message]
2024-04-19 7:36 ` [PATCH v3 0/3] Add 16GT/s equalization and margining settings Niklas Cassel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5a9a0c90-d191-49e1-8cd5-1d45c82040ac@linaro.org \
--to=konrad.dybcio@linaro.org \
--cc=agross@kernel.org \
--cc=andersson@kernel.org \
--cc=bhelgaas@google.com \
--cc=conor.dooley@microchip.com \
--cc=fancer.lancer@gmail.com \
--cc=gustavo.pimentel@synopsys.com \
--cc=jingoohan1@gmail.com \
--cc=kw@linux.com \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=lpieralisi@kernel.org \
--cc=mani@kernel.org \
--cc=manivannan.sadhasivam@linaro.org \
--cc=quic_kraravin@quicinc.com \
--cc=quic_msarkar@quicinc.com \
--cc=quic_schintav@quicinc.com \
--cc=robh@kernel.org \
--cc=yoshihiro.shimoda.uh@renesas.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).