The Tegra clock driver contains legacy code which deasserts hardware reset
when peripheral clocks are enabled. This behaviour comes from a pre-CCF
era of the Tegra drivers. This is unacceptable for modern kernel drivers
which use generic CCF and reset-control APIs because it breaks assumptions
of the drivers about clk/reset sequences and about reset-propagation
delays. Hence remove the awkward legacy behaviour from the clk driver.
In particular PMC driver assumes that hardware blocks remains in reset
while power domain is turning on, but the clk driver deasserts the reset
before power clamp is removed, hence breaking the driver's assumption.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
The refcounting of the gate clocks has a bug causing the enable_refcnt
to underflow when unused clocks are disabled. This happens because clk
provider erroneously bumps the refcount if clock is enabled at a boot
time, which it shouldn't be doing, and it does this only for the gate
clocks, while peripheral clocks are using the same gate ops and the
peripheral clocks are missing the initial bump. Hence the refcount of
the peripheral clocks is 0 when unused clocks are disabled and then the
counter is decremented further by the gate ops, causing the integer
underflow.
Fix this problem by removing the erroneous bump and by implementing the
disable_unused() callback, which disables the unused gates properly.
The visible effect of the bug is such that the unused clocks are never
gated if a loaded kernel module grabs the unused clocks and starts to use
them. In practice this shouldn't cause any real problems for the drivers
and boards supported by the kernel today.
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
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licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 228 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171438.107155473@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In case 2 clocks share an enable bit and one of them is enabled by a
driver and the other one is not, CCF will think it's enabled because it
will only look at the HW state. Therefore it will disable the clock and
thus also disable the other clock which was enabled. Solve this by
reading the initial state of the enable bit and incrementing the
refcount if it's set.
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
The peripheral clock registers are defined in static tables. These
tables never need to be modified at runtime, so they can reside in
read-only memory.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Clock provider drivers generally shouldn't include clk.h because
it's the consumer API. Only include clk.h in files that are using
it. Also add in a clkdev.h include that was missing in a file
using clkdev APIs.
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
In order to not clutter the include/linux directory with SoC specific
headers, move the Tegra-specific headers out into a separate directory.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Now that no code uses the custom Tegra module reset API, we can remove
its implementation.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Acked-By: Peter De Schrijver <pdeschrijver@nvidia.com>
This patch determines the register bank for clock enable/disable and reset
based on the clock ID instead of hardcoding it in the tables describing the
clocks. This results in less data to be maintained in the tables, making the
code easier to understand. The full benefit of the change will be realized once
also other clocktypes will be table based.
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Workaround a hardware bug in MSENC during clock enable.
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
The parameter name should be "gate", not "periph". This worked, however,
because it happens that everywhere periph_clk_to_bit is called, "gate" was
in the local scope.
Signed-off-by: Yen Lin <yelin@nvidia.com>
Signed-off-by: Andrew Chew <achew@nvidia.com>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Add Tegra specific clocks, pll, pll_out, peripheral, frac_divider, super.
Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
[swarren: alloc sizeof(*foo) not sizeof(struct foo), add comments re:
storing pointers to stack variables, make a timeout loop more idiomatic,
use _clk_pll_disable() not clk_disable_pll() from _program_pll() to
avoid redundant lock operations, unified tegra_clk_periph() and
tegra_clk_periph_nodiv(), unified tegra_clk_pll{,e}, rename all clock
registration functions so they don't have the same name as the clock
structs, return -EINVAL from clk_plle_enable when matching table rate
not found, pass ops to _tegra_clk_register_pll rather than a bool.]
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Dmitry Osipenko
Thomas Gleixner
Peter De Schrijver
Thierry Reding
Stephen Boyd
Stephen Warren
Yen Lin
Prashant Gaikwad