Some boards might require to control a regulator to power the PCIe port.

Add support for an optional regulator defined in Device Tree linked in the
PCIe controller under `vpcie-supply`.  If present, the regulator will be
disabled and then enabled as part of the PCIe host initialization process
and will be disabled when shutting down.
Signed-off-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
[bhelgaas: use dev_err() instead of pr_err() in
imx6_pcie_assert_core_reset()]
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NRichard Zhu <hongxing.zhu@nxp.com>

Add various bits of code needed to support i.MX7D variant of the IP.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Cc: yurovsky@gmail.com
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Dong Aisheng <dongas86@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: devicetree@vger.kernel.org

I.MX6+ has a dedicated bit for resetting PCIe core, which should be used
instead of a regular reset sequence since using the latter will hang the
SoC.

This commit is based on c34068d48273e24d392d9a49a38be807954420ed from
http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.gitTested-by: NGary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NFabio Estevam <fabio.estevam@nxp.com>

Freescale has stated [1] that the LVDS clock source of the IMX6 does not
pass the PCI Gen2 clock jitter test, therefore unless an external Gen2
compliant external clock source is present and supplied back to the IMX6
PCIe core via LVDS CLK1/CLK2 you can not claim Gen2 compliance.

Add a DT property to specify Gen1 vs Gen2 and check this before allowing a
Gen2 link.

We default to Gen1 if the property is not present because at this time
there are no IMX6 boards in mainline that 'input' a clock on LVDS
CLK1/CLK2.

In order to be Gen2 compliant on IMX6 you need to:

 - Have a Gen2 compliant external clock generator and route that clock back
   to either LVDS CLK1 or LVDS CLK2 as an input (see IMX6SX-SabreSD
   reference design).

 - Specify this clock in the PCIe node in the DT (i.e.,
   IMX6QDL_CLK_LVDS1_IN or IMX6QDL_CLK_LVDS2_IN instead of
   IMX6QDL_CLK_LVDS1_GATE which configures it as a CLK output).

[1] https://community.freescale.com/message/453209Signed-off-by: NTim Harvey <tharvey@gateworks.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
CC: Fabio Estevam <fabio.estevam@freescale.com>
CC: Zhu Richard <Richard.Zhu@freescale.com>
CC: Akshay Bhat <akshay.bhat@timesys.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Shawn Guo <shawnguo@kernel.org>

Currently the reset-gpio DT property which controls the PCI bus device
reset signal defaults to active-low reset sequence (L=reset state,
H=operation state) plus the code in reset function isn't GPIO polarity
aware - it doesn't matter if the defined reset-gpio is active-low or
active-high, it will always result into active-low reset sequence.

I've tried to fix it properly and change the reset-gpio reset sequence to
be polarity-aware, but this patch has been accepted and then reverted as it
has introduced few backward incompatible issues:

1. Some DTBs, for example, imx6qdl-sabresd, don't define reset-gpio
polarity correctly:

  reset-gpio = <&gpio7 12 0>;

which means that it's defined as active-high, but in reality it's
active-low; thus it wouldn't work without a DTS fix.

2. The logic in the reset function is inverted:

	gpio_set_value_cansleep(imx6_pcie->reset_gpio, 0)
	msleep(100);
	gpio_set_value_cansleep(imx6_pcie->reset_gpio, 1);

so even if some of the i.MX6 boards had reset-gpio polarity defined
correctly in their DTSes, they would stop working.

As we can't break old DTBs, we can't fix them, so we need to introduce this
new DT reset-gpio-active-high boolean property so we can support boards
with active-high reset sequence.

This active-high reset sequence is for example needed on Apalis SoMs, where
GPIO1_IO28, used to PCIe reset is not connected directly to PERST# PCIe
signal, but it's ORed with RESETBMCU coming off the PMIC, and thus is
inverted, active-high.

Tested-by: Tim Harvey <tharvey@gateworks.com>	# Gateworks Ventana boards (which have active-low PERST#)
Signed-off-by: NPetr Štetiar <ynezz@true.cz>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NRob Herring <robh@kernel.org>

Add initial PCIe support for the imx6 SoC derivate imx6sx.  PCI MSI support
is untested as the necessary suspend/resume quirk is not included in this
patch.

This patch is heavily based on patches by Richard Zhu.

[bhelgaas: factor out refclk enable, fix adjacent typos in imx6q-pcie.txt]
Signed-off-by: NChristoph Fritz <chf.fritz@googlemail.com>
Acked-by: NRichard Zhu <Richard.Zhu@freescale.com>
Acked-by: NLucas Stach <l.stach@pengutronix.de>

The settings in GPR8 are dependent upon the particular layout of the
hardware platform.  As such, they should be configurable via the device
tree.

Look up PHY Tx driver settings from the device tree.  Fall back to the
original hard-coded values if they are not specified in the device tree.
Signed-off-by: NJustin Waters <justin.waters@timesys.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NLucas Stach <l.stach@pengutronix.de>

Fixes "imx6q-pcie 1ffc000.pcie: missing *config* reg space"
error exposed by new versions of the designware pcie driver.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>

The glue around the core designware IP is significantly different between
the Exynos and i.MX implementation, which is reflected in the DT bindings.

This changes the i.MX6 binding to reuse as much as possible from the common
designware binding and removes old cruft.

I removed the optional GPIOs with the following reasoning:
- disable-gpio: endpoint specific GPIO, not currently wired up in any code.
  Should be handled by the PCI device driver, not the host controller
  driver.
- wake-up-gpio: same as above.
- power-on-gpio: No user in any upstream DT.  This should be handled by a
  regulator which shouldn't be controlled by the host driver, but rather by
  the PCI device driver.

[bhelgaas: whitespace fixes]
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>