From: Lucas Stach <l.stach@pengutronix.de>
To: Bjorn Helgaas <helgaas@kernel.org>, Stefan Agner <stefan@agner.ch>
Cc: lorenzo.pieralisi@arm.com, jingoohan1@gmail.com,
gustavo.pimentel@synopsys.com, tpiepho@impinj.com,
leonard.crestez@nxp.com, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] PCI: imx6: limit DBI register length
Date: Tue, 12 Feb 2019 09:54:54 +0100 [thread overview]
Message-ID: <1549961694.2546.18.camel@pengutronix.de> (raw)
In-Reply-To: <20190211213900.GA247873@google.com>
Hi Bjorn,
Am Montag, den 11.02.2019, 15:39 -0600 schrieb Bjorn Helgaas:
> On Wed, Feb 06, 2019 at 10:57:32AM +0100, Stefan Agner wrote:
> > Define the length of the DBI registers. This makes sure that
> > the kernel does not access registers beyond that point, avoiding
> > the following abort on a i.MX 6Quad:
> > # cat /sys/devices/soc0/soc/1ffc000.pcie/pci0000\:00/0000\:00\:00.0/config
> > [ 100.021433] Unhandled fault: imprecise external abort (0x1406) at 0xb6ea7000
> > ...
> > [ 100.056423] PC is at dw_pcie_read+0x50/0x84
> > [ 100.060790] LR is at dw_pcie_rd_own_conf+0x44/0x48
> > ...
>
> I assume this problem happens when using the pci_read_config() path or
> something similar?
>
> Could this be solved using pci_dev.cfg_size instead of building a new
> dwc-specific mechanism? There are some quirks that set dev->cfg_size
> to keep from reading past certain points in config space, e.g.,
> quirk_citrine(), quirk_nfp6000().
>
> I'm not necessarily opposed to doing it in dwc, but maybe there's some
> advantage in reducing the number of ways of doing the same thing.
This actually started out as a quirk changing the cfg size. But the
valid config space size seems to be different between root ports that
share the same (broken) device ID (Synopsys abcd), so I doubt that this
would be easier and/or any cleaner to implement as a quirk.
Regards,
Lucas
> > Signed-off-by: Stefan Agner <stefan@agner.ch>
> > > > Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> > ---
> > Changes in v3:
> > - Rebase on pci/dwc
> > Changes in v4:
> > - Rebase on pci/dwc
> > Changes in v5:
> > - Rebased ontop of pci/dwc
> > - Use DBI length of 0x200
> >
> > drivers/pci/controller/dwc/pci-imx6.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> > index c1d434ba3642..1ef7be1232f3 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -55,6 +55,7 @@ enum imx6_pcie_variants {
> > struct imx6_pcie_drvdata {
> > > > enum imx6_pcie_variants variant;
> > > > u32 flags;
> > > > + int dbi_length;
> > };
> >
> > struct imx6_pcie {
> > @@ -1087,6 +1088,8 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> > > > break;
> > > > }
> >
> > > > + pci->dbi_length = imx6_pcie->drvdata->dbi_length;
> > +
> > > > /* Grab turnoff reset */
> > > > imx6_pcie->turnoff_reset = devm_reset_control_get_optional_exclusive(dev, "turnoff");
> > > > if (IS_ERR(imx6_pcie->turnoff_reset)) {
> > @@ -1170,6 +1173,7 @@ static const struct imx6_pcie_drvdata drvdata[] = {
> > > > .variant = IMX6Q,
> > > > .flags = IMX6_PCIE_FLAG_IMX6_PHY |
> > > > IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE,
> > > > + .dbi_length = 0x200,
> > > > },
> > > > [IMX6SX] = {
> > > > .variant = IMX6SX,
> > --
> > 2.20.1
> >
next prev parent reply other threads:[~2019-02-12 8:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-06 9:57 [PATCH 1/2] PCI: dwc: allow to limit registers set length Stefan Agner
2019-02-06 9:57 ` [PATCH 2/2] PCI: imx6: limit DBI register length Stefan Agner
2019-02-11 21:39 ` Bjorn Helgaas
2019-02-12 8:54 ` Lucas Stach [this message]
2019-02-12 11:33 ` Lorenzo Pieralisi
2019-02-12 19:07 ` Stefan Agner
2019-02-06 18:02 ` [PATCH 1/2] PCI: dwc: allow to limit registers set length Lorenzo Pieralisi
2019-02-07 15:08 ` [PATCH 1/2] Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com> Gustavo Pimentel
2019-02-08 11:10 ` [PATCH 1/2] PCI: dwc: allow to limit registers set length Lorenzo Pieralisi
-- strict thread matches above, loose matches on Subject: below --
2018-11-19 9:41 Stefan Agner
2018-11-19 9:41 ` [PATCH 2/2] PCI: imx6: limit DBI register length Stefan Agner
2018-11-20 1:06 ` Trent Piepho
2018-11-20 1:33 ` Trent Piepho
2018-11-20 10:22 ` Leonard Crestez
2018-11-20 10:30 ` Stefan Agner
2018-11-20 13:03 ` Leonard Crestez
2018-11-20 13:12 ` Stefan Agner
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