watchdog: xilinx_wwdt: Use div_u64() in xilinx_wwdt_start()

After commit f1a43aadb5a6 ("watchdog: Enable COMPILE_TEST for more
drivers"), it is possible to enable this driver on 32-bit architectures.
When building for those architectures with clang, there is an error due
to a 64-bit division in xilinx_wwdt_start():

ERROR: modpost: "__aeabi_uldivmod" [drivers/watchdog/xilinx_wwdt.ko] undefined!

Use div_u64() to fix this, which takes a 64-bit dividend and 32-bit
divisor. GCC likely avoids the same error due to optimizations it
employs to transform division by a constant into other equivalent
operations, which may be different than what is implemented in clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/1915
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230815-watchdog-xilinx-div_u64-v1-1-20b0b5a65c2e@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it was merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230726233302.3812749-1-robh@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: xilinx_wwdt: Add Versal window watchdog support

Versal watchdog driver uses window watchdog mode. Window watchdog
timer(WWDT) contains closed(first) and open(second) window with
32 bit width. Write to the watchdog timer within predefined window
periods of time. This means a period that is not too soon and a
period that is not too late. The WWDT has to be restarted within
the open window time. If software tries to restart WWDT outside of
the open window time period, it generates a reset.

Signed-off-by: Srinivas Neeli <srinivas.neeli@amd.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lkml.kernel.org/r/20230420104231.2243079-4-srinivas.neeli@amd.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>