clk: tegra: periph: Switch to determine_rate

The Tegra periph clocks implements a mux with a set_parent hook, but
doesn't provide a determine_rate implementation.

This is a bit odd, since set_parent() is there to, as its name implies,
change the parent of a clock. However, the most likely candidate to
trigger that parent change is a call to clk_set_rate(), with
determine_rate() figuring out which parent is the best suited for a
given rate.

The other trigger would be a call to clk_set_parent(), but it's far less
used, and it doesn't look like there's any obvious user for that clock.

So, the set_parent hook is effectively unused, possibly because of an
oversight. However, it could also be an explicit decision by the
original author to avoid any reparenting but through an explicit call to
clk_set_parent().

The driver does implement round_rate() though, which means that we can
change the rate of the clock, but we will never get to change the
parent.

However, It's hard to tell whether it's been done on purpose or not.

Since we'll start mandating a determine_rate() implementation, let's
convert the round_rate() implementation to a determine_rate(), which
will also make the current behavior explicit. And if it was an
oversight, the clock behaviour can be adjusted later on.

Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: Prashant Gaikwad <pgaikwad@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-64-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: tegra: periph: Add a determine_rate hook

The Tegra periph nodiv clock implements a mux with a set_parent hook, but
doesn't provide a determine_rate implementation.

This is a bit odd, since set_parent() is there to, as its name implies,
change the parent of a clock. However, the most likely candidates to
trigger that parent change are either the assigned-clock-parents device
tree property or a call to clk_set_rate(), with determine_rate()
figuring out which parent is the best suited for a given rate.

The other trigger would be a call to clk_set_parent(), but it's far less
used, and it doesn't look like there's any obvious user for that clock.

However, the upstream device trees seem to use assigned-clock-parents on
that clock to force the parent at boot time, so it's likely that the
author intent was to force the parent through the device tree and
prevent any reparenting but through an explicit call to
clk_set_parent().

This case would be equivalent to setting the determine_rate
implementation to clk_hw_determine_rate_no_reparent(). Indeed, if no
determine_rate implementation is provided, clk_round_rate() (through
clk_core_round_rate_nolock()) will call itself on the parent if
CLK_SET_RATE_PARENT is set, and will not change the clock rate
otherwise.

Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: Prashant Gaikwad <pgaikwad@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-36-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: tegra: Fix refcounting of gate clocks

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>

clk: tegra: periph: Add restore_context support

This patch implements restore_context support for clk-periph and
clk-sdmmc-mux clock operations to restore clock parent and rates
on system resume.

During system suspend, core power goes off and looses the context
of the Tegra clock controller registers.

So on system resume, clocks parent and rate are restored back to
the context before suspend based on cached data.

Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201

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
public license along with this program if not see http www gnu org
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>

clk: tegra: Add peripheral clock registration helper

There is a common pattern that registers individual peripheral clocks
from an initialization table. Add a common implementation to remove the
duplication from various call sites.

Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: tegra: Fix build warnings on Tegra20/Tegra30

The recent conversion of proper const usage was only partial and didn't
include Tegra20 and Tegra30 support. Fix that up.

Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: tegra: Fix constness for peripheral clocks

checkpatch now warns for const ** and expects const * const * to be used
instead. This means we have to update the prototypes and function
declarations to handle this change.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Tested-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: tegra: Constify peripheral clock registers

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>

clk: tegra: Properly include clk.h

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>

clk: Replace explicit clk assignment with __clk_hw_set_clk

The change in the clk API to return a per-user clock instance, moved
the clock state to struct clk_core so now the struct clk_hw .core field
is used instead of .clk for most operations.

So for hardware clocks that needs to share the same clock state, both
the .core and .clk pointers have to be assigned but currently only the
.clk is set. This leads to NULL pointer dereference when the operations
try to access the hw clock .core. For example, the composite clock rate
and mux components didn't have a .core set which leads to this error:

Unable to handle kernel NULL pointer dereference at virtual address 00000034
pgd = c0004000
[00000034] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-next-20150211-00002-g1fb7f0e1150d #423
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
task: ee480000 ti: ee488000 task.ti: ee488000
PC is at clk_mux_determine_rate_flags+0x14/0x19c
LR is at __clk_mux_determine_rate+0x24/0x2c
pc : [<c03a355c>] lr : [<c03a3734>] psr: a0000113
sp : ee489ce8 ip : ee489d84 fp : ee489d84
r10: 0000005c r9 : 00000001 r8 : 016e3600
r7 : 00000000 r6 : 00000000 r5 : ee442200 r4 : ee440c98
r3 : ffffffff r2 : 00000000 r1 : 016e3600 r0 : ee440c98
Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 4000406a DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0xee488210)
Stack: (0xee489ce8 to 0xee48a000)
9ce0: 00000000 ffffffff 60000113 ee440c98 ee442200 00000000
9d00: 016e3600 ffffffff 00000001 0000005c ee489d84 c03a3734 ee489d80 ee489d84
9d20: 00000000 c048b130 00000400 c03a5798 ee489d80 ee489d84 c0607f60 ffffffea
9d40: 00000001 00000001 ee489d5c c003f844 c06e3340 ee402680 ee440d0c ed935000
9d60: 016e3600 00000003 00000001 0000005c eded3700 c03a11a0 ee489d80 ee489d84
9d80: 016e3600 ee402680 c05b413a eddc9900 016e3600 c03a1228 00000000 ffffffff
9da0: ffffffff eddc9900 016e3600 c03a1c1c ffffffff 016e3600 ed8c6710 c03d6ce4
9dc0: eded3400 00000000 00000000 c03c797c 00000001 0000005c eded3700 eded3700
9de0: 000005e0 00000001 0000005c c03db8ac c06e7e54 c03c8f08 00000000 c06e7e64
9e00: c06b6e74 c06e7f64 000005e0 c06e7df8 c06e5100 00000000 c06e7e6c c06e7f54
9e20: 00000000 00000000 eebd9550 00000000 c06e7da0 c06e7e54 ee7b5010 c06e7da0
9e40: eddc9690 c06e7db4 c06b6e74 00000097 00000000 c03d4398 00000000 ee7b5010
9e60: eebd9550 c06e7da0 00000000 c03db824 ee7b5010 fffffffe c06e7db4 c0299c7c
9e80: ee7b5010 c072a05c 00000000 c0298858 ee7b5010 c06e7db4 ee7b5044 00000000
9ea0: eddc9580 c0298a04 c06e7db4 00000000 c0298978 c02971d4 ee405c78 ee732b40
9ec0: c06e7db4 eded3800 c06d6738 c0298044 c0608300 c06e7db4 00000000 c06e7db4
9ee0: 00000000 c06beb58 c06beb58 c0299024 00000000 c068dd00 00000000 c0008944
9f00: 00000038 c049013c ee462200 c0711920 ee480000 60000113 c06c2cb0 00000000
9f20: 00000000 c06c2cb0 60000113 00000000 ef7fcafc 00000000 c0640194 c00389ec
9f40: c05ec3a8 c063f824 00000006 00000006 c06c2c50 c0696444 00000006 c0696424
9f60: c06ee1c0 c066b588 c06b6e74 00000097 00000000 c066bd44 00000006 00000006
9f80: c066b588 c003d684 00000000 c0481938 00000000 00000000 00000000 00000000
9fa0: 00000000 c0481940 00000000 c000e680 00000000 00000000 00000000 00000000
9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[<c03a355c>] (clk_mux_determine_rate_flags) from [<c03a3734>] (__clk_mux_determine_rate+0x24/0x2c)
[<c03a3734>] (__clk_mux_determine_rate) from [<c03a5798>] (clk_composite_determine_rate+0xbc/0x238)
[<c03a5798>] (clk_composite_determine_rate) from [<c03a11a0>] (clk_core_round_rate_nolock+0x5c/0x9c)
[<c03a11a0>] (clk_core_round_rate_nolock) from [<c03a1228>] (__clk_round_rate+0x38/0x40)
[<c03a1228>] (__clk_round_rate) from [<c03a1c1c>] (clk_round_rate+0x20/0x38)
[<c03a1c1c>] (clk_round_rate) from [<c03d6ce4>] (max98090_dai_set_sysclk+0x34/0x118)
[<c03d6ce4>] (max98090_dai_set_sysclk) from [<c03c797c>] (snd_soc_dai_set_sysclk+0x38/0x80)
[<c03c797c>] (snd_soc_dai_set_sysclk) from [<c03db8ac>] (snow_late_probe+0x24/0x48)
[<c03db8ac>] (snow_late_probe) from [<c03c8f08>] (snd_soc_register_card+0xf04/0x1070)
[<c03c8f08>] (snd_soc_register_card) from [<c03d4398>] (devm_snd_soc_register_card+0x30/0x64)
[<c03d4398>] (devm_snd_soc_register_card) from [<c03db824>] (snow_probe+0x68/0xcc)
[<c03db824>] (snow_probe) from [<c0299c7c>] (platform_drv_probe+0x48/0x98)
[<c0299c7c>] (platform_drv_probe) from [<c0298858>] (driver_probe_device+0x114/0x234)
[<c0298858>] (driver_probe_device) from [<c0298a04>] (__driver_attach+0x8c/0x90)
[<c0298a04>] (__driver_attach) from [<c02971d4>] (bus_for_each_dev+0x54/0x88)
[<c02971d4>] (bus_for_each_dev) from [<c0298044>] (bus_add_driver+0xd8/0x1cc)
[<c0298044>] (bus_add_driver) from [<c0299024>] (driver_register+0x78/0xf4)
[<c0299024>] (driver_register) from [<c0008944>] (do_one_initcall+0x80/0x1d0)
[<c0008944>] (do_one_initcall) from [<c066bd44>] (kernel_init_freeable+0x10c/0x1d8)
[<c066bd44>] (kernel_init_freeable) from [<c0481940>] (kernel_init+0x8/0xe4)
[<c0481940>] (kernel_init) from [<c000e680>] (ret_from_fork+0x14/0x34)
Code: e24dd00c e5907000 e1a08001 e88d000c (e5970034)

The changes were made using the following cocinelle semantic patch:

@i@
@@

@depends on i@
identifier dst;
@@

- dst->clk = hw->clk;
+ __clk_hw_set_clk(dst, hw);

@depends on i@
identifier dst;
@@

- dst->hw.clk = hw->clk;
+ __clk_hw_set_clk(&dst->hw, hw);

Fixes: 035a61c314eb3 ("clk: Make clk API return per-user struct clk instances")
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>

clk: tegra: Staticize tegra_clk_periph_no_gate_ops

tegra_clk_periph_no_gate_ops is a local symbol.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

clk: tegra: Staticize tegra_clk_periph_nodiv_ops

tegra_clk_periph_nodiv_ops is used only in this file. Make it static.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

clk: tegra: remove legacy reset APIs

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>

clk: tegra: add TEGRA_PERIPH_NO_GATE

Tegra124 has a clock which consists of a mux and a fractional divider.
Add support for this.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: tegra: Add TEGRA_PERIPH_NO_DIV flag

This flag indicates the peripheral clock does not have a divider. It will
simplify the initialization tables and avoids some very similar code.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>

clk: tegra: common periph_clk_enb_refcnt and clks

This patch makes periph_clk_enb_refcnt a global array, dynamically allocated
at boottime. It simplifies the macros somewhat and allows clocks common to
several Tegra SoCs to be defined in a separate files. Also the clks array
becomes global and dynamically allocated which allows the DT registration to
be moved to a generic funcion.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>

clk: tegra: simplify periph clock data

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>

clk: tegra: Add flags to tegra_clk_periph()

We will need some tegra peripheral clocks with the CLK_IGNORE_UNUSED flag,
most notably mselect, which is a bridge between AXI and most peripherals.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

clk: tegra: Export peripheral reset functions

The tegra_periph_reset_assert() and tegra_periph_reset_deassert()
functions can be used by drivers to reset peripherals. In order to allow
such drivers to be built as modules, export the functions.

Note that this restores the status quo as the functions were exported
before the move to the drivers/clk tree.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

ARM: tegra: migrate to new clock code

Migrate Tegra clock support to drivers/clk/tegra, this involves
moving:
1. definition of tegra_cpu_car_ops to clk.c
2. definition of reset functions to clk-peripheral.c
3. change parent of cpu clock.
4. Remove legacy clock initialization.
5. Initialize clocks using DT.
6. Remove all instance of mach/clk.h

Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
[swarren: use to_clk_periph_gate().]
Signed-off-by: Stephen Warren <swarren@nvidia.com>

clk: tegra: add Tegra specific clocks

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>