clk: meson: change usleep_range() to udelay() for atomic context

The function meson_clk_pll_enable() can be invoked under the enable_lock
spinlock from the clk core logic, which risks a kernel panic during the
usleep_range() call:

BUG: scheduling while atomic: kworker/u4:2/36/0x00000002
Modules linked in: g_ffs usb_f_fs libcomposite
CPU: 1 PID: 36 Comm: kworker/u4:2 Not tainted 6.4.0-rc5 #273
Workqueue: events_unbound async_run_entry_fn
Call trace:
dump_backtrace+0x9c/0x128
show_stack+0x20/0x38
dump_stack_lvl+0x48/0x60
dump_stack+0x18/0x28
__schedule_bug+0x58/0x78
__schedule+0x828/0xa88
schedule+0x64/0xd8
schedule_hrtimeout_range_clock+0xd0/0x208
schedule_hrtimeout_range+0x1c/0x30
usleep_range_state+0x6c/0xa8
meson_clk_pll_enable+0x1f4/0x310
clk_core_enable+0x78/0x200
clk_core_enable+0x58/0x200
clk_core_enable+0x58/0x200
clk_core_enable+0x58/0x200
clk_enable+0x34/0x60

So it is required to use the udelay() function instead of usleep_range()
for the atomic context safety.

Fixes: b6ec400aa153 ("clk: meson: introduce new pll power-on sequence for A1 SoC family")
Reported-by: Jan Dakinevich <yvdakinevich@sberdevices.ru>
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Link: https://lore.kernel.org/r/20230704215404.11533-1-ddrokosov@sberdevices.ru
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: pll: remove unneeded semicolon

No functional modification involved.

./drivers/clk/meson/clk-pll.c:373:2-3: Unneeded semicolon.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20230614084808.98819-1-jiapeng.chong@linux.alibaba.com
Fixes: b6ec400aa153 ("clk: meson: introduce new pll power-on sequence for A1 SoC family")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: introduce new pll power-on sequence for A1 SoC family

Modern meson PLL IPs are a little bit different from early known PLLs.
The main difference is located in the init/enable/disable sequences; the
rate logic is the same.

In A1 PLL, the PLL enable sequence is different, so add new optional pll
reg bits and use the new power-on sequence to enable the PLL:
1. enable the pll, delay for 10us
2. enable the pll self-adaption current module, delay for 40us
3. enable the lock detect module

Signed-off-by: Jian Hu <jian.hu@amlogic.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Link: https://lore.kernel.org/r/20230523135351.19133-3-ddrokosov@sberdevices.ru
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: make pll rst bit as optional

Compared with the previous SoCs, self-adaption current module
is newly added for A1, and there is no reset parameter except the
fixed pll. Since we use clk-pll generic driver for A1 pll
implementation, rst bit should be optional to support new behavior.

Signed-off-by: Jian Hu <jian.hu@amlogic.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Link: https://lore.kernel.org/r/20230523135351.19133-2-ddrokosov@sberdevices.ru
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: Remove a useless include

<linux/rational.h> is not needed for these drivers. Remove the
corresponding #include.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/12dd5cb49efa7714f8e0389e4c7b3bc829e8a90e.1668289299.git.christophe.jaillet@wanadoo.fr
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: meson: pll: add pcie lock retry workaround

The PCIe PLL locking may be unreliable under some circumstance, such as
high or low temperature. If the PLL fails to lock, reset it a try again.

This helps on the S905X4

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
[commit message amend]
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/cc80cda0-4dda-2e3e-3fc8-afa97717479b@gmail.com

clk: meson: pll: adjust timeout in meson_clk_pll_wait_lock()

Currently we loop over meson_parm_read() up to 24mln times.
This results in a unpredictable timeout period. In my case
it's over 5s on a S905X4-based system. Make the timeout
period predictable and set it to 100ms.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/a801afc0-a8f2-a0a4-0f2b-a7201351d563@gmail.com

clk: meson: pll: switch to determine_rate for the PLL ops

This increases the maxmium supported frequency on 32-bit systems from
2^31 (signed long as used by clk_ops.round_rate, maximum value:
approx. 2.14GHz) to 2^32 (unsigned long as used by
clk_ops.determine_rate, maximum value: approx. 4.29GHz).
On Meson8/8b/8m2 the HDMI PLL and it's OD (post-dividers) are
capable of running at up to 2.97GHz. So switch the divider
implementation in clk-regmap to clk_ops.determine_rate to support these
higher frequencies on 32-bit systems.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20210517203724.1006254-4-martin.blumenstingl@googlemail.com

clk: meson: clk-pll: propagate the error from meson_clk_pll_set_rate()

Popagate the error code from meson_clk_pll_set_rate() when the PLL does
not lock with the new settings.

Fixes: 722825dcd54b2e ("clk: meson: migrate plls clocks to clk_regmap")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20201226121556.975418-4-martin.blumenstingl@googlemail.com

clk: meson: clk-pll: make "ret" a signed integer

The error codes returned by meson_clk_get_pll_settings() are all
negative. Make "ret" a signed integer in meson_clk_pll_set_rate() to
make it match with the clk_ops.set_rate API as well as the data type
returned by meson_clk_get_pll_settings().

Fixes: 8eed1db1adec6a ("clk: meson: pll: update driver for the g12a")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20201226121556.975418-3-martin.blumenstingl@googlemail.com

clk: meson: clk-pll: fix initializing the old rate (fallback) for a PLL

The "rate" parameter in meson_clk_pll_set_rate() contains the new rate.
Retrieve the old rate with clk_hw_get_rate() so we don't inifinitely try
to switch from the new rate to the same rate again.

Fixes: 7a29a869434e8b ("clk: meson: Add support for Meson clock controller")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20201226121556.975418-2-martin.blumenstingl@googlemail.com

clk: let init callback return an error code

If the init callback is allowed to request resources, it needs a return
value to report the outcome of such a request.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lkml.kernel.org/r/20190924123954.31561-3-jbrunet@baylibre.com
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: meson: pll: Fix by 0 division in __pll_params_to_rate()

Some meson pll registers can be initialized with 0 as N value, introducing
the following division by 0 when computing rate :

UBSAN: Undefined behaviour in drivers/clk/meson/clk-pll.c:75:9
division by zero
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc3-608075-g86c9af8630e1-dirty #400
Call trace:
dump_backtrace+0x0/0x1c0
show_stack+0x14/0x20
dump_stack+0xc4/0x100
ubsan_epilogue+0x14/0x68
__ubsan_handle_divrem_overflow+0x98/0xb8
__pll_params_to_rate+0xdc/0x140
meson_clk_pll_recalc_rate+0x278/0x3a0
__clk_register+0x7c8/0xbb0
devm_clk_hw_register+0x54/0xc0
meson_eeclkc_probe+0xf4/0x1a0
platform_drv_probe+0x54/0xd8
really_probe+0x16c/0x438
driver_probe_device+0xb0/0xf0
device_driver_attach+0x94/0xa0
__driver_attach+0x70/0x108
bus_for_each_dev+0xd8/0x128
driver_attach+0x30/0x40
bus_add_driver+0x1b0/0x2d8
driver_register+0xbc/0x1d0
__platform_driver_register+0x78/0x88
axg_driver_init+0x18/0x20
do_one_initcall+0xc8/0x24c
kernel_init_freeable+0x2b0/0x344
kernel_init+0x10/0x128
ret_from_fork+0x10/0x18

This checks if N is null before doing the division.

Fixes: 7a29a869434e ("clk: meson: Add support for Meson clock controller")
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
[jbrunet@baylibre.com: update the comment in above the fix]
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson-pll: add reduced specific clk_ops for G12A PCIe PLL

The Meson G12A PCIE PLL is fined tuned to deliver a very precise
100MHz reference clock for the PCIe Analog PHY, and thus requires
a strict register sequence to enable the PLL.
To simplify, use the _init() op to enable the PLL and keep
the other ops except set_rate since the rate is fixed.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lkml.kernel.org/r/20190307141455.23879-2-narmstrong@baylibre.com

clk: meson: pll: fix rounding and setting a rate that matches precisely

Make meson_clk_pll_is_better() consider a rate that precisely matches
the requested rate to be better than any previous rate (which was
smaller than the current).

Prior to commit 8eed1db1adec6a ("clk: meson: pll: update driver for the
g12a") meson_clk_get_pll_settings() returned early (before calling
meson_clk_pll_is_better()) if the rate from the current iteration
matches the requested rate precisely. After this commit
meson_clk_pll_is_better() is called unconditionally. This requires
meson_clk_pll_is_better() to work with the case where "now == rate".

This fixes a hang during boot on Meson8b / Odroid-C1 for me.

Fixes: 8eed1db1adec6a ("clk: meson: pll: update driver for the g12a")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20190324164327.22590-2-martin.blumenstingl@googlemail.com

clk: meson: pll: update driver for the g12a

The g12a use fractional parameter of 17 useful bits. At the moment, this
parameter in encoded using u16 value. Use this opportunity to switch all
the pll to parameter to unsigned int. This should save us some annoying
trouble shooting when and m and n field eventually grow as well.

This patch also introduce pll multiplier range. On the g12a, the hifi and
gp0 plls are able to lock as long as the following condition is met:
55 <= m/n <= 255.

The param table describing this would be huge which is a waste of memory.
Using ranges, we can save memory. Ranges also help find the best pll
parameter significantly faster since we don't have to try all the possible
settings.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[jbrunet: fixed fix pll settings calculation with arm32]
Link: https://lkml.kernel.org/r/20190201145345.6795-2-jbrunet@baylibre.com

clk: meson: rework and clean drivers dependencies

Initially, the meson clock directory only hosted 2 controllers drivers,
for meson8 and gxbb. At the time, both used the same set of clock drivers
so managing the dependencies was not a big concern.

Since this ancient time, entropy did its job, controllers with different
requirement and specific clock drivers have been added. Unfortunately, we
did not do a great job at managing the dependencies between the
controllers and the different clock drivers. Some drivers, such as
clk-phase or vid-pll-div, are compiled even if they are useless on the
target (meson8). As we are adding new controllers, we need to be able to
pick a driver w/o pulling the whole thing.

The patch aims to clean things up by:
* providing a dedicated CONFIG_ for each clock drivers
* allowing clock drivers to be compiled as a modules, if possible
* stating explicitly which drivers are required by each controller.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20190201125841.26785-5-jbrunet@baylibre.com

clk: meson: clk-pll: check if the clock is already enabled

Since commit 6f888e7bc7bd58 ("clk: meson: clk-pll: add enable bit") our
PLLs also support the "enable" bit. Currently meson_clk_pll_enable
unconditionally resets the PLL, enables it, takes it out of reset and
waits until it is locked.

This works fine for our current clock trees. However, there will be a
problem once we allow modifications to sys_pll on Meson8, Meson8b and
Meson8m2 (which will be required for CPU frequency scaling):
the CPU clock is derived from the sys_pll clock. Once clk_enable is
called on the CPU clock this will be propagated by the common clock
framework up until the sys_pll clock. If we reset the PLL
unconditionally in meson_clk_pll_enable the CPU will be stopped (on
Meson8, Meson8b and Meson8m2).
To prevent this we simply check if the PLL is already enabled and do
reset the PLL if it's already enabled and locked.

Now that we have a utility function to check whether the PLL is enabled
we can also pass that to our clk_ops to let the common clock framework
know about the status of the hardware clock.
For now this is of limited use since the only common clock framework's
internal "disabled unused clocks" mechanism checks for this. Everything
else still uses the ref-counting (internal to the common clock
framework) when clk_enable is called.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20181115224048.13511-2-martin.blumenstingl@googlemail.com

clk: meson: clk-pll: drop hard-coded rates from pll tables

Putting hard-coded rates inside the parameter tables assumes that
the parent is known and will never change. That's a big assumption
we should not make.

We have everything we need to recalculate the output rate using
the parent rate and the rest of the parameters. Let's do so and
drop the rates from the tables.

Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: clk-pll: remove od parameters

Remove od parameters from pll clocks and add post dividers clocks
instead. Some clock, especially the one which feature several ods,
may provide output between those ods. Also, some drivers, such
as the hdmi driver, may require a more detailed control of the
clock dividers, compared to what CCF would perform automatically.

One added benefit of removing ods is that it also greatly reduce the
size of the rate parameter tables.

In the future, we could possibly take the predivider 'n' out of this
driver as well. To do so, we will need to understand the constraints
for the PLL to lock and whether or not it depends on the input clock
rate.

Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: clk-pll: add enable bit

Add the enable the bit of the pll clocks.
These pll clocks may be disabled but we can't model this as an external
gate since the pll needs to lock when enabled.

Adding this bit allows to drop the poke of the first register of PLL.
This will be useful to model the different components of the pll using
generic clocks elements

Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: use SPDX license identifiers consistently

Replace every license notices in drivers/clk/meson by SPDX license
identifiers, as described in license-rules.rst

Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: add ROUND_CLOSEST to the pll driver

Provide an option for the pll driver to round to the rate closest to the
requested rate, instead of systematically rounding down.

This may allow the provided rate to be closer to the requested rate when
rounding up is not an issue

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

clk: meson: improve pll driver results with frac

Finding the appropriate settings of meson plls is too tricky to be done
entirely at runtime, using calculation only. Many combination of m, n
and od won't lock which is why we are using a table for this. However,
for plls having a fractional parameters, it is possible to improve on
the result provided by the table by calculating the frac parameter.

This change adds the calculation of frac when the parameter is available
and the rate provided by the table is not an exact match for the
requested rate.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

clk: meson: remove special gp0 lock loop

After testing, it appears that the gxl (and axg) does not require the
special locking/reset loop which was initially added for it.

All the values present in the gxl table can locked with the simple lock
checking loop.

The change switches the gxl and axg gp0 back to the simple lock checking
loop and removes the code no longer required.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

clk: meson: migrate plls clocks to clk_regmap

Rework meson pll driver to use clk_regmap and move meson8b, gxbb and
axg's clock using meson_clk_pll to clk_regmap.

This rework is not just about clk_regmap, there a serious clean-up of
the driver code:
* Add lock and reset field: Previously inferred from the n field.
* Simplify the reset logic: Code seemed to apply reset differently but
in fact it was always the same -> assert reset, apply params,
de-assert reset. The 2 lock checking loops have been kept for now, as
they seem to be necessary.
* Do the sequence of init register pokes only at .init() instead of in
.set_rate(). Redoing the init on every set_rate() is not necessary

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

clk: meson: fix rate calculation of plls with a fractional part

The rate of the parent should not be multiplied by 2 when the pll has a
fractional part. This is making the rate calculation of the gxl_hdmi_pll
wrong (and others as well). This multiplication is specific
to the hdmi_pll of gxbb and is most likely due to a multiplier sitting
in front of this particular pll.

Add a fixed factor clock in front on the gxbb pll and remove this constant
from the calculation to fix the problem

Fixes: 4a47295144dd ("clk: meson: fractional pll support")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: add od3 to the pll driver

Some meson plls, such as the hdmi pll, are using a 3rd od parameter,
which is yet another "power of 2" post divider. Add it to fix the
calculation of the hdmi_pll rate

Fixes: 738f66d3211d ("clk: gxbb: add AmLogic GXBB clk controller driver")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: use the frac parameter width instead of a constant

Use the fractional part width in the calculation instead of 12, which
happens to be the witdh right now. This is safer in case the field width
ever change in the future

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: remove unnecessary rounding in the pll clock

The pll driver performs the rate calculation in Mhz, which adds an
unnecessary rounding down to the Mhz of the rate. Use 64bits long
integers to perform this calculation safely on meson8b and perform the
calculation in Hz instead

Fixes: 7a29a869434e ("clk: meson: Add support for Meson clock controller")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: check pll rate param table before using it

Make sure the rate param table is available before using it.
Some read-only plls don't provide it, which is ok since the
table is not used by read-only clocks. R/W clocks are supposed
to provide it, but it does not hurt check it.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

clk: meson: Add support for parameters for specific PLLs

In recent Amlogic GXBB, GXL and GXM SoCs, the GP0 PLL needs some specific
parameters in order to initialize and lock correctly.

This patch adds an optional PARAM table used to initialize the PLL to a
default value with it's parameters in order to achieve to desired frequency.

The GP0 PLL in GXBB, GXL/GXM also needs some tweaks in the initialization
steps, and these are exposed along the PARAM table.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/1490178747-14837-2-git-send-email-narmstrong@baylibre.com

clk: meson: fractional pll support

Fractional MPLLs are a superset of the existing AmLogic MPLLs. They add
in a couple of new bitfields for further dividing the clock rate to
achieve rates with fractional hertz.

Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>

clk: meson8b: clean up pll clocks

Remove the pll registration function and helpers. Replace unnecessary
configuration struct with static initialization of the desired clock
type.

Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>

clk: meson: Add support for Meson clock controller

This patchset adds the infrastructure for registering and managing the
core clocks found on Amlogic MesonX SoCs. In particular:

- PLLs
- CPU clock
- Fixed rate clocks, fixed factor clocks, ...

Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>