Migrate cadence_ttc driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: NSören Brinkmann <soren.brinkmann@xilinx.com>

New TTCs support 32bit mode. Older versions support
only 16bit modes. Keep 16bit mode as default
and 32bit optional.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

For supporting ARM big-endian is necessary to use
proper IO endianess accessors.

Based on Ben Dooks BE guide.
Similar conversion is done here:
"mv_xor: use {readl, writel}_relaxed instead of __raw_{readl, writel}"
(sha1: 5733c38a)
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

The currently used method adjusting the clocksource to a changing input
frequency does not work on kernels from 3.11 on.
The new approach is to keep the timer frequency as constant as possible.
I.e.
 - due to the TTC's prescaler limitations, allow frequency changes
   only if the frequency scales by a power of 2
 - adjust the counter's divider on the fly when a frequency change
   occurs

This limits cpufreq to scale by certain factors only.
But we may keep the time base somewhat constant, so that sleep() & co
keep working as expected, while supporting cpufreq.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NMichal Simek <michal.simek@xilinx.com>

The timer core takes care of serialization and IRQs. Hence the driver is
no longer required to disable interrupts when calling
clockevents_update_freq().
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NMichal Simek <michal.simek@xilinx.com>

When the kernel is compiled with:
CONFIG_HIGH_RES_TIMERS=no
CONFIG_HZ_PERIODIC=yes
CONFIG_DEBUG_ATOMIC_SLEEP=yes

The following WARN appears:

WARNING: CPU: 1 PID: 0 at linux/kernel/mutex.c:856 mutex_trylock+0x70/0x1fc()
DEBUG_LOCKS_WARN_ON(in_interrupt())
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.12.0-xilinx-dirty #93
[<c0014a78>] (unwind_backtrace+0x0/0x11c) from [<c0011b6c>] (show_stack+0x10/0x14)
[<c0011b6c>] (show_stack+0x10/0x14) from [<c039120c>] (dump_stack+0x7c/0xc0)
[<c039120c>] (dump_stack+0x7c/0xc0) from [<c001fda4>] (warn_slowpath_common+0x60/0x84)
[<c001fda4>] (warn_slowpath_common+0x60/0x84) from [<c001fe48>] (warn_slowpath_fmt+0x2c/0x3c)
[<c001fe48>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0392658>] (mutex_trylock+0x70/0x1fc)
[<c0392658>] (mutex_trylock+0x70/0x1fc) from [<c02dfc08>] (clk_prepare_lock+0xc/0xe4)
[<c02dfc08>] (clk_prepare_lock+0xc/0xe4) from [<c02e099c>] (clk_get_rate+0xc/0x44)
[<c02e099c>] (clk_get_rate+0xc/0x44) from [<c02d0394>] (ttc_set_mode+0x34/0x78)
[<c02d0394>] (ttc_set_mode+0x34/0x78) from [<c005f794>] (clockevents_set_mode+0x28/0x5c)
[<c005f794>] (clockevents_set_mode+0x28/0x5c) from [<c00607fc>] (tick_broadcast_on_off+0x190/0x1c0)
[<c00607fc>] (tick_broadcast_on_off+0x190/0x1c0) from [<c005f168>] (clockevents_notify+0x58/0x1ac)
[<c005f168>] (clockevents_notify+0x58/0x1ac) from [<c02b99dc>] (cpuidle_setup_broadcast_timer+0x20/0x24)
[<c02b99dc>] (cpuidle_setup_broadcast_timer+0x20/0x24) from [<c006cd04>] (generic_smp_call_function_single_interrupt+0)
[<c006cd04>] (generic_smp_call_function_single_interrupt+0xe0/0x130) from [<c00138c8>] (handle_IPI+0x88/0x118)
[<c00138c8>] (handle_IPI+0x88/0x118) from [<c0008504>] (gic_handle_irq+0x58/0x60)
[<c0008504>] (gic_handle_irq+0x58/0x60) from [<c0012644>] (__irq_svc+0x44/0x78)
Exception stack(0xef099fa0 to 0xef099fe8)
9fa0: 00000001 ef092100 00000000 ef092100 ef098000 00000015 c0399f2c c0579d74
9fc0: 0000406a 413fc090 00000000 00000000 00000000 ef099fe8 c00666ec c000f46c
9fe0: 20000113 ffffffff
[<c0012644>] (__irq_svc+0x44/0x78) from [<c000f46c>] (arch_cpu_idle+0x34/0x3c)
[<c000f46c>] (arch_cpu_idle+0x34/0x3c) from [<c0053980>] (cpu_startup_entry+0xa8/0x10c)
[<c0053980>] (cpu_startup_entry+0xa8/0x10c) from [<000085a4>] (0x85a4)

We are in an interrupt context (IPI) and we are calling clk_get_rate in the
set_mode function which in turn ends up by getting a mutex... Even if that
does not hang, it is a potential kernel deadlock.

It is not allowed to call clk_get_rate() from interrupt context. To
avoid such calls the timer input frequency is stored in the driver's
data struct which makes it accessible to the driver in any context.

[dlezcano] completed the changelog with the WARN trace and added a more
detailed description. Tested on zync zc702.
Acked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

This patch removes the use of the IRQF_DISABLED flag

It's a NOOP since 2.6.35 and it will be removed one day.

[dlezcano] : slightly changed the changelog
Signed-off-by: NMichael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

The 32 bit sched_clock interface now supports 64 bits. Upgrade to
the 64 bit function to allow us to remove the 32 bit registration
interface.

Cc: Soren Brinkmann <soren.brinkmann@xilinx.com>
Cc: Michal Simek <monstr@monstr.eu>
Tested-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

Reuse the TTC clocksource timer as sched clock provider.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NMichal Simek <monstr@monstr.eu>

The clk-provider.h header is not required by this driver.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

Migrate the Zynq platform and its drivers to use the new clock
controller driver.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Acked-by: NMike Turquette <mturquette@linaro.org>

Move zynq timer out of mach folder to generic location
and enable it.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

Remove all xilinx specific names from the driver
because this is generic driver for cadence ttc.
xttc->ttc
ttcps->ttc
...

No functional changes in this driver.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

Use clocksource timer initialization.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

Use cdns,ttc because this driver is Cadence Rev06
Triple Timer Counter and everybody can use it
without xilinx specific function name or probing.

Also use standard dt description for timer
and also prepare for moving to clocksource
initialization.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

The timers are common to both A9 cores, so let's set the clock
event struct's cpumask accordingly, to all possible CPUs.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>

Fixing multi line comment style at two locations.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>

Some #includes are implicitly included through others, some are
just not needed.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>

Aligning the columns in a block of #defines, so that the values
are starting in the same colum on every line.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>

Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: NMichal Simek <michal.simek@xilinx.com>
Acked-by: NJohn Linn <john.linn@xilinx.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>

Acknowedging an interrupt requires to read the interrupt register
only. The write was only required to work around a bug in
the QEMU implementation of the TTC, which is fixed.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>

The acronym PSS is deprecated by Xilinx. The correct term, which is
also used in Xilinx documentation is PS (processing system).
This is just a search and replace:
 - s/PSS/PS/g
 - s/pss/ps/g
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>

Now that the TTC driver has proper support for DT bindings, it is not
necessary for the registers to be mapped early.  They will be mapped
during clock initialization using of_iomap().  Remove the early mapping.

In addition, remove the extraneous zynq_soc.h include from the timer
driver.
Signed-off-by: NJosh Cartwright <josh.cartwright@ni.com>
Tested-by: NMichal Simek <michal.simek@xilinx.com>

Add support for retrieving TTC configuration from device tree.  This
includes the ability to pull information about the driving clocks from
the of_clk bindings.
Signed-off-by: NJosh Cartwright <josh.cartwright@ni.com>
Acked-by: NMichal Simek <michal.simek@xilinx.com>

Move the sys_timer definition out of ttc driver and make it part of the
common zynq code.  This is preparation for renaming and COMMON_CLK
support.
Signed-off-by: NJosh Cartwright <josh.cartwright@ni.com>
Tested-by: NMichal Simek <michal.simek@xilinx.com>

The 1st board support is minimal to get a system up and running
on the Xilinx platform.

This platform reuses the clock implementation from plat-versatile, and
it depends entirely on CONFIG_OF support.  There is only one board
support file which obtains all device information from a device tree
dtb file which is passed to the kernel at boot time.
Signed-off-by: NJohn Linn <john.linn@xilinx.com>