ARM: OMAP2+: fix kernel-doc warnings

Use the correct function name in a comment.
Add the return value documentation for one function.

These changes prevent these warnings:

wd_timer.c:76: warning: expecting prototype for omap2_wdtimer_reset(). Prototype was for omap2_wd_timer_reset() instead
wd_timer.c:76: warning: No description found for return value of 'omap2_wd_timer_reset'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: linux-omap@vger.kernel.org
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: patches@armlinux.org.uk
Message-ID: <20240117011004.22669-14-rdunlap@infradead.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 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 as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ARM: OMAP2+: Remove unused legacy code for watchdog

We are now booting all mach-omap2 in device tree only mode.
Any code that is only called in legacy boot mode where
of_have_populated_dt() is not set is safe to remove now.

Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arm: mach-omap2: Convert pr_warning to pr_warn

Use the more common pr_warn.

Other miscellanea:

o Realign arguments

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

ARM: OMAP2+: raw read and write endian fix

All OMAP IP blocks expect LE data, but CPU may operate in BE mode.
Need to use endian neutral functions to read/write h/w registers.
I.e instead of __raw_read[lw] and __raw_write[lw] functions code
need to use read[lw]_relaxed and write[lw]_relaxed functions.
If the first simply reads/writes register, the second will byteswap
it if host operates in BE mode.

Changes are trivial sed like replacement of __raw_xxx functions
with xxx_relaxed variant.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Signed-off-by: Taras Kondratiuk <taras.kondratiuk@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

ARM: OMAP2+: omap_device: remove obsolete pm_lats and early_device code

Remove now-obsolete code from arch/arm/mach-omap2/omap_device.c. This
mostly consists of removing the first attempt at device PM latency
handling. This was never really used, has been replaced by the common
dev_pm_qos code, and needs to go away as part of the DT conversion.
Also, the early platform_device creation code has been removed, as it
appears to be unused.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

ARM: OMAP2+: Use omap initcalls

This way the initcalls don't run on other SoCs on multiplatform
kernels. Otherwise we'll get something like this when booting
on vexpress:

omap_hwmod: _ensure_mpu_hwmod_is_setup: MPU initiator hwmod mpu not yet registered
...
WARNING: at arch/arm/mach-omap2/pm.c:82 _init_omap_device+0x74/0x94()
_init_omap_device: could not find omap_hwmod for mpu
...
omap-dma-engine omap-dma-engine: OMAP DMA engine driver
...

Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

ARM: OMAP2+: PRCM: consolidate PRCM-related timeout macros

Consolidate all of the copies of MAX_MODULE_HARDRESET_WAIT and
MAX_MODULE_SOFTRESET_WAIT into one place, arch/arm/mach-omap2/prm.h.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>

ARM: OMAP2+: WDT: move init; add read_reset_sources pdata function pointer

The OMAP watchdog timer driver directly calls a function exported by
code in arch/arm/mach-omap2. This is not good; it tightly couples
this driver to the mach-omap2 integration code. Instead, add a
temporary platform_data function pointer to abstract this function
call. A subsequent patch will convert the watchdog driver to use this
function pointer.

This patch also moves the device creation code out of
arch/arm/mach-omap2/devices.c and into arch/arm/mach-omap2/wd_timer.c.
This is another step towards the removal of
arch/arm/mach-omap2/devices.c.

Cc: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
[paul@pwsan.com: skip wd_timer device creation when DT blob is present]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

ARM: OMAP: Make plat/omap_hwmod.h local to mach-omap2

Let's make omap_hwmod local to mach-omap2 for
ARM common zImage support.

Signed-off-by: Tony Lindgren <tony@atomide.com>

ARM: OMAP2+: WDTIMER integration: fix !PM boot crash, disarm timer after hwmod reset

Without runtime PM enabled, hwmod needs to leave all IP blocks in an
enabled state by default so any driver access to the HW will succeed.
This is accomplished by seting the postsetup_state to enabled for all
hwmods during init when runtime PM is disabled.

Currently, we have a special case for WDT in that its postsetup_state
is always set to disabled. This is done so that the WDT is disabled
and the timer is disarmed at boot in case there is no WDT driver.
This also means that when runtime PM is disabled, if a WDT driver *is*
built in the kernel, the kernel will crash on the first access to the
WDT hardware.

We can't simply leave the WDT module enabled, because the timer is
armed by default after reset. That means that if there is no WDT
driver initialzed or loaded before the timer expires, the kernel will
reboot.

To fix this, a custom reset method is added to the watchdog class of
omap_hwmod. This method will *always* disarm the timer after hwmod
reset. The WDT timer then will only be rearmed when/if the driver is
loaded for the WDT. With the timer disarmed by default, we no longer
need a special-case for the postsetup_state of WDT during init, so it
is removed.

Any platforms wishing to ensure the watchdog remains armed across the
entire boot boot can simply disable the reset-on-init feature of the
watchdog hwmod using omap_hwmod_no_setup_reset().

Tested on 3530/Overo, 4430/Panda.

NOTE: on 4430, the hwmod OCP reset does not seem to rearm the timer as
documented in the TRM (and what happens on OMAP3.) I noticed this
because testing the HWMOD_INIT_NO_RESET feature with no driver loaded,
I expected a reboot part way through the boot, but did not see a
reboot. Adding some debug to read the counter, I verified that right
after OCP softreset, the counter is not firing. After writing the
magic start sequence, the timer starts counting. This means that the
timer disarm sequence added here does not seem to be needed for 4430,
but is technically the correct way to ensure the timer is disarmed, so
it is left in for OMAP4.

Special thanks to Paul Walmsley for helping brainstorm ideas to fix
this problem.

Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[paul@pwsan.com: updated the omap2_wd_timer_reset() function in the
wake of commit 3c55c1baffa5f719eb2ae9729088bc867f972f53 ("ARM:
OMAP2+: hwmod: Revert "ARM: OMAP2+: hwmod: Make omap_hwmod_softreset
wait for reset status""); added kerneldoc; rolled in warning fix from Kevin]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

omap2+: wdt: trivial sparse fixes

omap2_wd_timer_disable is declared in wdtimer.h and used by hwmod
function pointers for usage, the header inclusion is necessary
to ensure that the prototype and function remains consistent.
omap_wdt_latency is passed as a pointer and does not need global scope

Fixes sparse warnings:
arch/arm/mach-omap2/devices.c:981:31: warning: symbol 'omap_wdt_latency' was not declared. Should it be static?
arch/arm/mach-omap2/wd_timer.c:27:5: warning: symbol 'omap2_wd_timer_disable' was not declared. Should it be static?

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

OMAP2+: wd_timer: disable on boot via hwmod postsetup mechanism

The OMAP watchdog timer IP blocks require a specific set of register
writes to occur before they will be disabled[1], even if the device
clocks appear to be disabled in the CM_*CLKEN registers. In the MPU
watchdog case, failure to execute this reset sequence will eventually
cause the watchdog to reset the OMAP unexpectedly.

Previously, the code to disable this watchdog was manually called from
mach-omap2/devices.c during device initialization. This causes the
watchdog to be unconditionally disabled for a portion of kernel
initialization. This should be controllable by the board-*.c files,
since some system integrators will want full watchdog coverage of
kernel initialization. Also, the watchdog disable code was not
connected to the hwmod shutdown code. This means that calling
omap_hwmod_shutdown() will not, in fact, disable the watchdog, and the
goal of omap_hwmod_shutdown() is to be able to shutdown any on-chip
OMAP device.

To resolve the latter problem, populate the pre_shutdown pointer in
the watchdog timer hwmod classes with a function that executes the
watchdog shutdown sequence. This allows the hwmod code to fully
disable the watchdog.

Then, to allow some board files to support watchdog coverage
throughout kernel initialization, add common code to mach-omap2/io.c
to cause the MPU watchdog to be disabled on boot unless a board file
specifically requests it to remain enabled. Board files can do this
by changing the watchdog timer hwmod's postsetup state between the
omap2_init_common_infrastructure() and omap2_init_common_devices()
function calls.

1. OMAP34xx Multimedia Device Silicon Revision 3.1.x Rev. ZH
[SWPU222H], Section 16.4.3.6, "Start/Stop Sequence for WDTs (Using
WDTi.WSPR Register)"

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Charulatha Varadarajan <charu@ti.com>

OMAP2+: wd_timer: separate watchdog disable code from the rest of mach-omap2/devices.c

Split the wd_timer disable code out into its own file,
mach-omap2/wd_timer.c; it belongs in its own file rather than
cluttering up devices.c.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Charulatha Varadarajan <charu@ti.com>