On Thursday, December 12, 2013 at 07:16:18 PM, Tim Harvey wrote:
> On Thu, Dec 12, 2013 at 2:22 AM, Marek Vasut <marex@xxxxxxx> wrote:
> > On Thursday, December 12, 2013 at 06:10:31 AM, Tim Harvey wrote:
> > > On Wed, Dec 11, 2013 at 2:30 AM, Marek Vasut <marex@xxxxxxx> wrote:
> > > > Some boards do not have a PCIe reset GPIO. To avoid probe
> > > > failure on these boards, make the reset GPIO optional as
> > > > well.
> > > >
> > > > Signed-off-by: Marek Vasut <marex@xxxxxxx>
> > > > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > > > Cc: Frank Li <lznuaa@xxxxxxxxx>
> > > > Cc: Harro Haan <hrhaan@xxxxxxxxx>
> > > > Cc: Jingoo Han <jg1.han@xxxxxxxxxxx>
> > > > Cc: Mohit KUMAR <Mohit.KUMAR@xxxxxx>
> > > > Cc: Pratyush Anand <pratyush.anand@xxxxxx>
> > > > Cc: Richard Zhu <r65037@xxxxxxxxxxxxx>
> > > > Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> > > > Cc: Sean Cross <xobs@xxxxxxxxxx>
> > > > Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
> > > > Cc: Siva Reddy Kallam <siva.kallam@xxxxxxxxxxx>
> > > > Cc: Srikanth T Shivanand <ts.srikanth@xxxxxxxxxxx>
> > > > Cc: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> > > > Cc: Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx>
> > > > Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
> > > > ---
> > > >
> > > > .../devicetree/bindings/pci/designware-pcie.txt | 2 +-
> > > > drivers/pci/host/pci-imx6.c | 29
> > > > +++++++++++----------- 2 files changed, 16 insertions(+), 15
> > > > deletions(-)
> > > >
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/pci/designware-pcie.txt
> > > > b/Documentation/devicetree/bindings/pci/designware-pcie.txt index
> > > > d5d26d4..b7a2279 100644
> > > > --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
> > > > +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
> > > >
> > > > @@ -19,9 +19,9 @@ Required properties:
> > > > to define the mapping of the PCIe interface to interrupt
> > > > numbers.
> > > >
> > > > - num-lanes: number of lanes to use
> > > >
> > > > -- reset-gpio: gpio pin number of power good signal
> > > >
> > > > Optional properties for fsl,imx6q-pcie
> > > >
> > > > +- reset-gpio: gpio pin number of power good signal
> > > >
> > > > - power-on-gpio: gpio pin number of power-enable signal
> > > > - wake-up-gpio: gpio pin number of incoming wakeup signal
> > > > - disable-gpio: gpio pin number of outgoing rfkill/endpoint disable
> > > > signal
> > > >
> > > > diff --git a/drivers/pci/host/pci-imx6.c
> > > > b/drivers/pci/host/pci-imx6.c index bd70af8..52027ad 100644
> > > > --- a/drivers/pci/host/pci-imx6.c
> > > > +++ b/drivers/pci/host/pci-imx6.c
> > > > @@ -214,9 +214,12 @@ static int imx6_pcie_assert_core_reset(struct
> > > > pcie_port *pp)
> > > >
> > > > regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> > > >
> > > > IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
> > > >
> > > > - gpio_set_value(imx6_pcie->reset_gpio, 0);
> > > > - msleep(100);
> > > > - gpio_set_value(imx6_pcie->reset_gpio, 1);
> > > > + /* Some boards don't have PCIe reset GPIO. */
> > > > + if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> > > > + gpio_set_value(imx6_pcie->reset_gpio, 0);
> > > > + msleep(100);
> > > > + gpio_set_value(imx6_pcie->reset_gpio, 1);
> > > > + }
> > > >
> > > > return 0;
> > > >
> > > > }
> > >
> > > Marek,
> > >
> > > Though not the fault of your patch, I noticed while looking at this
> > > that the PCI Express specification is not being properly met with
> > > regards to PERST# and the reference clock. The spec states that
> > > PERST# must be kept asserted until after the reference clock is stable
> > > (I'm not entirely clear how long of a delay is needed for the clock to
> > > become stable but I think the value is typically the 100ms). I see in
> > > the current pci-imx6.c code that imx6_pcie_host_init calls
> > > imx6_pcie_assert_core_reset first, then imx6_pcie_init_phy, followed
> > > by imx6_pcie_deassert_core_reset. Despite the function names,
> > > imx6_pcie_assert_core_reset as shown above asserts then de-asserts
> > > PERST# before the clock is enabled in imx6_pcie_deassert_core_reset.
> > > This seems to me to be a violation of the spec and I believe the
> > > msleep(100) and de-assertion of the option reset_gpio should be done
> > > in imx6_pcie_deassert_core reset after the clock is brought up.
> > >
> > > If you agree with my assessment, would you mind resolving this issue
> > > at the same time? If not, I'm happy to follow-up with a patch to
> > > resolve it after your patch is accepted.
> >
> > Is this not resolved by patch 0006 in this series please?
>
> Marek,
>
> Yes it is addressed there. Sorry - I missed that.
No problem, thanks for checking it :)
Bjorn, would you mind picking 2/7...6/7 of this series so we are done with
those? I will re-post 1/7 as a self-standing patch afterwards, it has no impact
on the rest of the series.
Shawn, can you please pick 7/7 ?
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