From: Johan Hovold <johan@kernel.org>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Robert Marko <robimarko@gmail.com>,
svarbanov@mm-sol.com, agross@kernel.org,
bjorn.andersson@linaro.org, lpieralisi@kernel.org,
robh@kernel.org, kw@linux.com, bhelgaas@google.com,
p.zabel@pengutronix.de, jingoohan1@gmail.com,
linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, johan+linaro@kernel.org
Subject: Re: [PATCH v2] PCI: qcom: fix IPQ8074 Gen2 support
Date: Wed, 22 Jun 2022 16:52:20 +0200 [thread overview]
Message-ID: <YrMspGTROJUFYQrN@hovoldconsulting.com> (raw)
In-Reply-To: <YrK7b1GaEMuANGtR@hovoldconsulting.com>
On Wed, Jun 22, 2022 at 08:49:19AM +0200, Johan Hovold wrote:
> On Tue, Jun 21, 2022 at 03:32:11PM -0500, Bjorn Helgaas wrote:
> > On Tue, Jun 21, 2022 at 01:23:30PM +0200, Robert Marko wrote:
> > > IPQ8074 has one Gen2 and one Gen3 port, currently the Gen2 port will
> > > cause the system to hang as its using DBI registers in the .init
> > > and those are only accesible after phy_power_on().
> >
> > Is the fact that IPQ8074 has both a Gen2 and a Gen3 port relevant to
> > this patch? I don't see the connection.
> >
> > I see that qcom_pcie_host_init() does:
> >
> > qcom_pcie_host_init
> > pcie->cfg->ops->init(pcie)
> > phy_power_on(pcie->phy)
> > pcie->cfg->ops->post_init(pcie)
> >
> > and that you're moving DBI register accesses from
> > qcom_pcie_init_2_3_3() to qcom_pcie_post_init_2_3_3().
> >
> > But I also see DBI register accesses in other .init() functions:
> >
> > qcom_pcie_init_2_1_0
> > qcom_pcie_init_1_0_0 (oddly out of order)
> > qcom_pcie_init_2_3_2
> > qcom_pcie_init_2_4_0
> >
> > Why do these accesses not need to be moved? I assume it's because
> > pcie->phy is an optional PHY and phy_power_on() does nothing on those
> > controllers?
>
> At least the QMP PHY driver does not implement the PHY power_on op and
> instead fires everything up already at phy_init(). That may explain the
> difference in behaviour here.
That was due to a bug in -next which as since been fixed by commit
5bef2838f1a0 ("phy: qcom-qmp: fix PCIe PHY support")
which again do all PHY init at phy_power_on() instead of at phy_init().
Note also that before commit cc1e06f033af ("phy: qcom: qmp: Use
power_on/off ops for PCIe") everything was done at init.
Johan
prev parent reply other threads:[~2022-06-22 14:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-21 11:23 [PATCH v2] PCI: qcom: fix IPQ8074 Gen2 support Robert Marko
2022-06-21 17:29 ` Dmitry Baryshkov
2022-06-21 18:53 ` Robert Marko
2022-06-21 19:10 ` Dmitry Baryshkov
2022-06-21 20:32 ` Bjorn Helgaas
2022-06-21 20:45 ` Dmitry Baryshkov
2022-06-21 21:16 ` Bjorn Helgaas
2022-06-22 7:03 ` Dmitry Baryshkov
2022-06-21 21:05 ` Robert Marko
2022-06-21 21:43 ` Bjorn Helgaas
2022-06-22 14:23 ` Robert Marko
2022-06-22 20:26 ` Bjorn Helgaas
2022-06-22 6:49 ` Johan Hovold
2022-06-22 7:33 ` Johan Hovold
2022-06-22 14:52 ` Johan Hovold [this message]
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