From: Johan Hovold <johan@kernel.org>
To: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>
Cc: "Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
"Richard Zhu" <hongxing.zhu@nxp.com>,
"Lucas Stach" <l.stach@pengutronix.de>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Shawn Guo" <shawnguo@kernel.org>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
"Fabio Estevam" <festevam@gmail.com>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Chuanhua Lei" <lchuanhua@maxlinear.com>,
"Marek Vasut" <marek.vasut+renesas@gmail.com>,
"Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas.com>,
linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
imx@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org,
abel.vesa@linaro.org, johan+linaro@kernel.org
Subject: Re: [PATCH v6 3/4] PCI: qcom: Add equalization settings for 16.0 GT/s
Date: Thu, 5 Sep 2024 08:50:35 +0200 [thread overview]
Message-ID: <ZtlUu3uwl06E7LJF@hovoldconsulting.com> (raw)
In-Reply-To: <941d1bfb-965e-43e4-9f34-edaf2de5d661@quicinc.com>
On Wed, Sep 04, 2024 at 01:46:09PM -0700, Shashank Babu Chinta Venkata wrote:
> On 9/4/24 08:52, Manivannan Sadhasivam wrote:
> > On Wed, Sep 04, 2024 at 11:39:09AM +0200, Johan Hovold wrote:
> >> On Wed, Sep 04, 2024 at 12:41:59PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> >>> From: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>
> >>> + /*
> >>> + * GEN3_RELATED_OFF register is repurposed to apply equalization
> >>> + * settings at various data transmission rates through registers namely
> >>> + * GEN3_EQ_*. RATE_SHADOW_SEL bit field of GEN3_RELATED_OFF determines
> >>> + * data rate for which this equalization settings are applied.
> >>> + reg |= FIELD_PREP(GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK, 0x1);
> >>
> >> How does 0x1 map to gen4/16 GT?
> GEN3_RELATED_OFF has been repurposed to use with multiple data rates.
> RATE_SHADOW_SEL_MASK on GEN3_RELATED_OFF value decides the data rate
> of shadow registers namely GEN3_EQ_* registers. Per documentation 0x0
> maps to 8 GT/s, 0x1 maps to 16 GT/s and 0x2 maps to 32 GT/s.
Thanks for clarifying. Perhaps these should become defines eventually
(or the comment could be extended). There are a lot of "magic" constants
in here.
Johan
next prev parent reply other threads:[~2024-09-05 6:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-04 7:11 [PATCH v6 0/4] PCI: qcom: Add 16.0 GT/s equalization and margining settings Manivannan Sadhasivam via B4 Relay
2024-09-04 7:11 ` [PATCH v6 1/4] PCI: dwc: Rename 'dw_pcie::link_gen' to 'dw_pcie::max_link_speed' Manivannan Sadhasivam via B4 Relay
2024-09-04 9:21 ` Johan Hovold
2024-09-04 15:58 ` Frank Li
2024-09-04 16:12 ` Manivannan Sadhasivam
2024-09-05 8:36 ` kernel test robot
2024-09-05 16:11 ` kernel test robot
2024-09-04 7:11 ` [PATCH v6 2/4] PCI: dwc: Always cache the maximum link speed value in dw_pcie::max_link_speed Manivannan Sadhasivam via B4 Relay
2024-09-04 9:30 ` Johan Hovold
2024-09-04 15:49 ` Manivannan Sadhasivam
2024-09-05 6:45 ` Johan Hovold
2024-09-04 16:01 ` Frank Li
2024-09-04 7:11 ` [PATCH v6 3/4] PCI: qcom: Add equalization settings for 16.0 GT/s Manivannan Sadhasivam via B4 Relay
2024-09-04 9:39 ` Johan Hovold
2024-09-04 15:52 ` Manivannan Sadhasivam
2024-09-04 20:46 ` Shashank Babu Chinta Venkata
2024-09-05 6:50 ` Johan Hovold [this message]
2024-09-05 15:27 ` Manivannan Sadhasivam
2024-09-05 16:27 ` Johan Hovold
2024-09-05 17:34 ` Manivannan Sadhasivam
2024-09-06 6:49 ` Johan Hovold
2024-09-10 17:00 ` Manivannan Sadhasivam
2024-09-04 7:12 ` [PATCH v6 4/4] PCI: qcom: Add RX margining " Manivannan Sadhasivam via B4 Relay
2024-09-04 9:53 ` Johan Hovold
2024-09-04 16:04 ` Manivannan Sadhasivam
2024-09-04 20:48 ` Shashank Babu Chinta Venkata
2024-09-05 7:00 ` Johan Hovold
2024-09-04 9:56 ` [PATCH v6 0/4] PCI: qcom: Add 16.0 GT/s equalization and margining settings Johan Hovold
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