This adds a device-model driver for the timer block in the RK3368 (and
similar devices that share the same timer block, such as the RK3288) for
the down-counting (i.e. non-secure) timers.

This allows us to configure U-Boot for the RK3368 in such a way that
we can run with the secure timer inaccessible or uninitialised (note
that the ARMv8 generic timer does not count, if the secure timer is
not enabled).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

To fully support DM timer in SPL and TPL, we need a few things cleaned
up and normalised:
- inclusion of the uclass and drivers should be an all-or-nothing
  decision for each stage and under control of $(SPL_TPL_)TIMER
  instead of having the two-level configuration with TIMER and
  $(SPL_TPL_)TIMER_SUPPORT
- when $(SPL_TPL_)TIMER is enabled, the ARMv8 generic timer code can
  not be compiled in

This normalises configuration to $(SPL_TPL_)TIMER and moves the config
options to drivers/timer/Kconfig (and cleans up the collateral damage
to some defconfigs that had SPL_TIMER_SUPPORT enabled).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

The timer-uclass depends on full OF_CONTROL through its interrogation
of /chosen and the code to determine the clock-frequency.

For the OF_PLATDATA case, these code-paths are disabled and it becomes
the timer driver's responsibility to correctly set the clock-frequency
in the uclass priv-data.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Without a timer, U-Boot just doesn't boot. This is not something
we can turn off.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Rename try_msr_calibrate_tsc() to cpu_mhz_from_msr(), as that
better describes what the routine does.

This keeps in sync with Linux kernel commit:
  02c0cd2: x86/tsc_msr: Remove irqoff around MSR-based TSC enumeration

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Atom processors use a 19.2 MHz crystal oscillator.

Early processors generate 100 MHz via 19.2 MHz * 26 / 5 = 99.84 MHz.

Later processors generate 100 MHz via 19.2 MHz * 125 / 24 = 100 MHz.

Update the Silvermont-based tables accordingly, matching the Software
Developers Manual.

Also, correct a 166 MHz entry that should have been 116 MHz, and add
a missing 80 MHz entry for VLV2.

This keeps in sync with Linux kernel commit:
  05680e7: x86/tsc_msr: Correct Silvermont reference clock values

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Some processor abbreviations in the comments of freq_desc_tables[]
are obscure. This updates part of these to mention processors
that are known to us. Also expand frequency definitions.

This keeps in sync with Linux kernel commit:
  9e0cae9: x86/tsc_msr: Update comments, expand definitions

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

If either ratio or freq is zero, the return value is zero. There
is no need to create a fail branch and return zero there.

This keeps in sync with Linux kernel commit:
  14bb4e3: x86/tsc_msr: Remove debugging messages

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

try_msr_calibrate_tsc() is currently Intel-specific, and should not
execute on any other vendor's parts.

This keeps in sync with Linux kernel commit:
  ba82683: x86/tsc_msr: Identify Intel-specific code

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Currently we read the tsc radio like this:

	ratio = (MSR_PLATFORM_INFO >> 8) & 0x1f;

Thus we get bit 8-12 of MSR_PLATFORM_INFO, however according to the
Intel manual, the ratio bits are bit 8-15.

Fix this problem by masking 0xff instead.

This keeps in sync with Linux kernel commit:
  886123f: x86/tsc: Read all ratio bits from MSR_PLATFORM_INFO

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>