The imx6 PCI host controller suffers from a HW integration bug whereby
the MSI enable bit in the root port MSI capability enables/disables MSIs
interrupts for all downstream components in the PCI tree.
This requires, as implemented in
75cb8d20c1 ("PCI: imx: Enable MSI from downstream components")
that the root port MSI enable bit should be set in order for downstream
PCI devices MSIs to function.
The MSI enable bit programming might be lost during the suspend and
should be re-stored during resume.
Save the MSI control during suspend and restore it in resume.
Link: https://lore.kernel.org/r/1670479534-22154-1-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
[lpieralisi@kernel.org: commit log]
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
commit bb38919ec5 ("PCI: imx6: Add support for i.MX6 PCIe controller")
added a fault hook to this driver in the probe function. So it was only
installed if needed.
commit bde4a5a00e ("PCI: imx6: Allow probe deferral by reset GPIO")
moved it from probe to driver init which installs the hook unconditionally
as soon as the driver is compiled into a kernel.
When this driver is compiled as a module, the hook is not registered
until after the driver has been matched with a .compatible and
loaded.
commit 415b6185c5 ("PCI: imx6: Fix config read timeout handling")
extended the fault handling code.
commit 2d8ed461db ("PCI: imx6: Add support for i.MX8MQ")
added some protection for non-ARM architectures, but this does not
protect non-i.MX ARM architectures.
Since fault handlers can be triggered on any architecture for different
reasons, there is no guarantee that they will be triggered only for the
assumed situation, leading to improper error handling (i.MX6-specific
imx6q_pcie_abort_handler) on foreign systems.
I had seen strange L3 imprecise external abort messages several times on
OMAP4 and OMAP5 devices and couldn't make sense of them until I realized
they were related to this unused imx6q driver because I had
CONFIG_PCI_IMX6=y.
Note that CONFIG_PCI_IMX6=y is useful for kernel binaries that are designed
to run on different ARM SoC and be differentiated only by device tree
binaries. So turning off CONFIG_PCI_IMX6 is not a solution.
Therefore we check the compatible in the init function before registering
the fault handler.
Link: https://lore.kernel.org/r/e1bcfc3078c82b53aa9b78077a89955abe4ea009.1678380991.git.hns@goldelico.com
Fixes: bde4a5a00e ("PCI: imx6: Allow probe deferral by reset GPIO")
Fixes: 415b6185c5 ("PCI: imx6: Fix config read timeout handling")
Fixes: 2d8ed461db ("PCI: imx6: Add support for i.MX8MQ")
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
When the PHY is the reference clock provider then it must be initialized
and powered on before the reset on the client is deasserted, otherwise
the link will never come up. The order was changed in cf236e0c0d.
Restore the correct order to make the driver work again on boards where
the PHY provides the reference clock. This also changes the order for
boards where the Soc is the PHY reference clock divider, but this
shouldn't do any harm.
Link: https://lore.kernel.org/r/20221101095714.440001-1-s.hauer@pengutronix.de
Fixes: cf236e0c0d ("PCI: imx6: Do not hide PHY driver callbacks and refine the error handling")
Tested-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Create imx6_pcie_stop_link() and imx6_pcie_host_exit() functions.
Encapsulate clocks, regulators disables and PHY uninitialization into
imx6_pcie_host_exit().
To keep suspend/resume symmetric as much as possible, invoke these two
new created functions in suspend callback.
To be symmetric with imx6_pcie_host_exit(), move imx6_pcie_clk_enable()
to imx6_pcie_host_init() from imx6_pcie_deassert_core_reset().
Link: https://lore.kernel.org/r/1657783869-19194-18-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
The PCIe ref clocks are specific to different variants. The enables are
already split out into imx6_pcie_enable_ref_clk(), but the disables were
combined with the more generic bus/phy/pcie clock disables in
imx6_pcie_clk_disable().
Split out the variant-specific disables into imx6_pcie_disable_ref_clk() to
match imx6_pcie_enable_ref_clk().
No functional change intended.
Link: https://lore.kernel.org/r/1657783869-19194-6-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
Replace SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() with NOIRQ_SYSTEM_SLEEP_PM_OPS(),
which has the advantage that the compiler always sees the PM callbacks as
referenced, so they don't need to be wrapped with "#ifdef CONFIG_PM_SLEEP"
or tagged with "__maybe_unused" to avoid "defined but not used" warnings.
See 1a3c7bb088 ("PM: core: Add new *_PM_OPS macros, deprecate old ones").
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
According to the PCIe standard the PERST# signal (reset-gpio in
fsl,imx* compatible dts) should be kept asserted for at least 100 usec
before the PCIe refclock is stable, should be kept asserted for at
least 100 msec after the power rails are stable and the host should wait
at least 100 msec after it is de-asserted before accessing the
configuration space of any attached device.
From PCIe CEM r2.0, sec 2.6.2
T-PVPERL: Power stable to PERST# inactive - 100 msec
T-PERST-CLK: REFCLK stable before PERST# inactive - 100 usec.
From PCIe r5.0, sec 6.6.1
With a Downstream Port that does not support Link speeds greater than
5.0 GT/s, software must wait a minimum of 100 ms before sending a
Configuration Request to the device immediately below that Port.
Failure to do so could prevent PCIe devices to be working correctly,
and this was experienced with real devices.
Move reset assert to imx6_pcie_assert_core_reset(), this way we ensure
that PERST# is asserted before enabling any clock, move de-assert to the
end of imx6_pcie_deassert_core_reset() after the clock is enabled and
deemed stable and add a new delay of 100 msec just afterward.
Link: https://lore.kernel.org/all/20220211152550.286821-1-francesco.dolcini@toradex.com
Link: https://lore.kernel.org/r/20220404081509.94356-1-francesco.dolcini@toradex.com
Fixes: bb38919ec5 ("PCI: imx6: Add support for i.MX6 PCIe controller")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
The CLKREQ# signal is an open drain, active low signal that is driven
low by the remote Endpoint device. But it might not be driven low if no
Endpoint device is connected.
On i.MX8MM PCIe, phy_init() may fail and system boot may hang if no
Endpoint is connected to assert CLKREQ#.
Handle this as on i.MX8MQ, where we explicitly assert CLKREQ# so the
PHY can be initialized.
Link: https://lore.kernel.org/r/1645672013-8949-1-git-send-email-hongxing.zhu@nxp.com
Fixes: 178e244cb6 ("PCI: imx: Add the imx8mm pcie support")
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
The intention of commit 886a9c1347 ("PCI: dwc: Move link handling into
common code") was to standardize the behavior of link down as explained
in its commit log:
"The behavior for a link down was inconsistent as some drivers would fail
probe in that case while others succeed. Let's standardize this to
succeed as there are usecases where devices (and the link) appear later
even without hotplug. For example, a reconfigured FPGA device."
The pci-imx6 still fails to probe when the link is not present, which
causes the following warning:
imx6q-pcie 8ffc000.pcie: Phy link never came up
imx6q-pcie: probe of 8ffc000.pcie failed with error -110
------------[ cut here ]------------
WARNING: CPU: 0 PID: 30 at drivers/regulator/core.c:2257 _regulator_put.part.0+0x1b8/0x1dc
Modules linked in:
CPU: 0 PID: 30 Comm: kworker/u2:2 Not tainted 5.15.0-next-20211103 #1
Hardware name: Freescale i.MX6 SoloX (Device Tree)
Workqueue: events_unbound async_run_entry_fn
[<c0111730>] (unwind_backtrace) from [<c010bb74>] (show_stack+0x10/0x14)
[<c010bb74>] (show_stack) from [<c0f90290>] (dump_stack_lvl+0x58/0x70)
[<c0f90290>] (dump_stack_lvl) from [<c012631c>] (__warn+0xd4/0x154)
[<c012631c>] (__warn) from [<c0f87b00>] (warn_slowpath_fmt+0x74/0xa8)
[<c0f87b00>] (warn_slowpath_fmt) from [<c076b4bc>] (_regulator_put.part.0+0x1b8/0x1dc)
[<c076b4bc>] (_regulator_put.part.0) from [<c076b574>] (regulator_put+0x2c/0x3c)
[<c076b574>] (regulator_put) from [<c08c3740>] (release_nodes+0x50/0x178)
Fix this problem by ignoring the dw_pcie_wait_for_link() error like
it is done on the other dwc drivers.
Tested on imx6sx-sdb and imx6q-sabresd boards.
Link: https://lore.kernel.org/r/20220106103645.2790803-1-festevam@gmail.com
Fixes: 886a9c1347 ("PCI: dwc: Move link handling into common code")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
Cc: <stable@vger.kernel.org>
Previously, the maximum link speed was set following an "fsl,max-link-speed"
property read, and should the read failed, then the PCIe generation was
manually set to PCIe Gen1 and thus limiting the link speed to 2.5 GT/s.
Code refactoring completed in the commit 39bc500650 ("PCI: dwc:
Centralize link gen setting") changed to the logic that was previously
used to limit the maximum link speed leaving behind an unused assignment
to a variable "ret".
Since the value returned from the of_property_read_u32() and stored in
the variable "ret" is never used in any meaningful way, and it's also
immediately reassigned in the code that follows, the assignment can be
removed.
Link: https://lore.kernel.org/r/20211003025439.84783-1-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
- Use "fallthrough" pseudo-keyword (Gustavo A. R. Silva)
- Drop redundant error messages after devm_clk_get() (Anson Huang)
* remotes/lorenzo/pci/imx6:
PCI: imx6: Do not output error message when devm_clk_get() failed with -EPROBE_DEFER
PCI: imx6: Use fallthrough pseudo-keyword
