clk: tegra: fix error return case for recalc_rate

tegra-bpmp clocks driver makes implicit conversion of signed error
code to unsigned value in recalc_rate operation. The behavior for
recalc_rate, according to it's specification, should be that "If the
driver cannot figure out a rate for this clock, it must return 0."

Fixes: ca6f2796eef7 ("clk: tegra: Add BPMP clock driver")
Signed-off-by: Timo Alho <talho@nvidia.com>
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Link: https://lore.kernel.org/r/20230912112951.2330497-1-cyndis@kapsi.fi
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: tegra: bpmp: Add a determine_rate hook

The Tegra BPMP mux 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-v4-34-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: tegra: Support BPMP-FW ABI deny flags

Support BPMP_CLK_STATE_CHANGE_DENIED by not populating state changing
operations when the flag is set.

Support BPMP_CLK_RATE_PARENT_CHANGE_DENIED by not populating rate or
parent changing operations when the flag is set.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220818210000.6600-1-wsa+renesas@sang-engineering.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: tegra: Replace .round_rate() with .determine_rate()

Replace the .round_rate() callback with .determine_rate() which can
consider max_rate imposed by clk_set_max_rate() while rounding the clock
rate.

Note that if the .determine_rate() callback is defined it will be called
instead of the .round_rate() callback when calling clk_round_rate(). By
using .determine_rate(), the maximum rate returned when calling
clk_round_rate() is now limited by the current max_rate.

Signed-off-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
[jonathanh@nvidia.com: checkpatch fixes and commit message update]
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: tegra: Register clocks from root to leaf

Current clock initialization causes intermediate registering of orphan
clocks (i.e. a clock without a parent registered). CCF keeps track of
orphan clocks and any time a new clock is registered, it will loop
through the list of orphan and queries if the parent is now available.
This operation triggers one or more clock operations, which are IPCs
with BPMP-FW. Hence, due to the order in which the clocks appear
currently, this causes > 5000 IPC messages to be sent to BPMP-FW during
clock initialization.

Optimize the clock probing by registering clocks hierarchically from
root clock towards leafs.

Signed-off-by: Timo Alho <talho@nvidia.com>
[jonathanh@nvidia.com: checkpatch fixes]
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: tegra: bpmp: Clamp clock rates on requests

BPMP firmware ABI expects the rate inputs in int64_t. However,
tegra_bpmp_clk_round_rate() and tegra_bpmp_clk_set_rate() functions
directly assign 'unsigned long' inputs to a int64_t value causing
unexpected rounding errors.

Fix this by clipping the input rate to S64_MAX.

Signed-off-by: Sivaram Nair <sivaramn@nvidia.com>
[mperttunen: slight cleanup]
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Reviewed-by: Sivaram Nair <sivaramn@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

clk: tegra: bpmp: Don't crash when a clock fails to register

When registering clocks, we just skip any that fail to register
(leaving a NULL hole in the clock table). However, our of_xlate
function still tries to dereference each entry while looking for
the clock with the requested id, causing a crash if any clocks
failed to register. Add a check to of_xlate to skip any NULL
clocks.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: tegra: Check BPMP response return code

Check return code in BPMP response message(s). The typical error case is
when a clock operation is attempted with an invalid clock identifier.

Also remove error print from call to clk_get_info() as the
implementation loops through the range of all possible identifiers, yet
the operation is expected to error out when the clock ID is unused.

Signed-off-by: Timo Alho <talho@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

clk: tegra: Add BPMP clock driver

This driver uses the services provided by the BPMP firmware driver to
implement a clock driver based on the MRQ_CLK request. This part of the
BPMP ABI provides a means to enumerate and control clocks and should
allow the driver to work on any chip that supports this ABI.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>