Re: [PATCH v3 6/7] phy: qcom-qmp-pcie: add support for ipq9574 gen3x2 PHY

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Varadarajan Narayanan <quic_varada@quicinc.com>
Cc: "Alex G." <mr.nuke.me@gmail.com>,
	"Bjorn Andersson" <andersson@kernel.org>,
	"Konrad Dybcio" <konrad.dybcio@linaro.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Vinod Koul" <vkoul@kernel.org>,
	"Kishon Vijay Abraham I" <kishon@kernel.org>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
	linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-phy@lists.infradead.org, linux-clk@vger.kernel.org
Subject: Re: [PATCH v3 6/7] phy: qcom-qmp-pcie: add support for ipq9574 gen3x2 PHY
Date: Mon, 29 Apr 2024 13:55:32 +0300	[thread overview]
Message-ID: <CAA8EJpq+Bbws8yH5Xq7rHyA+-=DaCcfEcgUa5RUt2+LWQW0kKg@mail.gmail.com> (raw)
In-Reply-To: <Zi88Hdx6UgBo/gti@hu-varada-blr.qualcomm.com>

On Mon, 29 Apr 2024 at 09:20, Varadarajan Narayanan
<quic_varada@quicinc.com> wrote:
>
> On Wed, Apr 17, 2024 at 12:50:49AM +0300, Dmitry Baryshkov wrote:
> > On Wed, 17 Apr 2024 at 00:25, Alex G. <mr.nuke.me@gmail.com> wrote:
> > >
> > > Hi Dmitry,
> > >
> > > On 4/15/24 16:25, mr.nuke.me@gmail.com wrote:
> > > >
> > > >
> > > > On 4/15/24 15:10, Dmitry Baryshkov wrote:
> > > >> On Mon, 15 Apr 2024 at 21:23, Alexandru Gagniuc <mr.nuke.me@gmail.com>
> > > >> wrote:
> > > >>>
> > > >>> Add support for the gen3x2 PCIe PHY on IPQ9574, ported form downstream
> > > >>> 5.4 kernel. Only the serdes and pcs_misc tables are new, the others
> > > >>> being reused from IPQ8074 and IPQ6018 PHYs.
> > > >>>
> > > >>> Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
> > > >>> ---
> > > >>>   drivers/phy/qualcomm/phy-qcom-qmp-pcie.c      | 136 +++++++++++++++++-
> > > >>>   .../phy/qualcomm/phy-qcom-qmp-pcs-pcie-v5.h   |  14 ++
> > > >>>   2 files changed, 149 insertions(+), 1 deletion(-)
> > > >>>
> > > >>
> > > >> [skipped]
> > > >>
> > > >>> @@ -2448,7 +2542,7 @@ static inline void qphy_clrbits(void __iomem
> > > >>> *base, u32 offset, u32 val)
> > > >>>
> > > >>>   /* list of clocks required by phy */
> > > >>>   static const char * const qmp_pciephy_clk_l[] = {
> > > >>> -       "aux", "cfg_ahb", "ref", "refgen", "rchng", "phy_aux",
> > > >>> +       "aux", "cfg_ahb", "ref", "refgen", "rchng", "phy_aux",
> > > >>> "anoc", "snoc"
> > > >>
> > > >> Are the NoC clocks really necessary to drive the PHY? I think they are
> > > >> usually connected to the controllers, not the PHYs.
> > > >
> > > > The system will hang if these clocks are not enabled. They are also
> > > > attached to the PHY in the QCA 5.4 downstream kernel.
> >
> > Interesting.
> > I see that Varadarajan is converting these clocks into interconnects.
> > Maybe it's better to wait for those patches to land and use
> > interconnects instead. I think it would better suit the
> > infrastructure.
> >
> > Varadarajan, could you please comment, are these interconnects
> > connected to the PHY too or just to the PCIe controller?
>
> Sorry for the late response. Missed this e-mail.
>
> These 2 clks are related to AXI port clk on Aggnoc/SNOC, not
> directly connected to PCIE wrapper, but it should be enabled to
> generate pcie traffic.

So, are they required for the PHY or are they required for the PCIe
controller only?

>
> Thanks
> Varada
>
> > > They are named "anoc_lane", and "snoc_lane" in the downstream kernel.
> > > Would you like me to use these names instead?
> >
> > I'm fine either way.
> >

-- 
With best wishes
Dmitry