Richard Woodruff writes:
| The historic usage of this has been against single use leaf clocks
| (1st instance of gptimer).  When it was used it did:
|       clk_get()
|       clk_set_parent()
|       clk_enable()
|
| This usage was ok for that. Use on a disabled clock is needed.
|
| If there are multiple users on the clock or it is enabled there are
| problems.
|
| The call can still be unfriendly if 2 different drivers are using the
| clock with their own clock get/enable. It might be the function should
| return an error if usecount != 0 to stop surprises.  It is all around
| better if the parenting is done when the clock is off.

This is a good reason to ensure that the clock is not enabled when
clk_set_parent() is called.
Acked-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Use pr_err() for errors rather than pr_debug().  pr_debug() are
compiled away unless -DDEBUG is used.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Richard Woodruff writes that chip errata prevent USBTLL SAR from working
on OMAP3 ES levels before ES3.1:

http://marc.info/?l=linux-arm-kernel&m=123319614808833&w=2

Update the OMAP3 powerdomain structures appropriately.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Some OMAP3 chip behaviors change in ES levels after ES2.  Modify the
existing omap_chip flags to add options for ES3.0 and ES3.1.

Add a new macro, CHIP_GE_OMAP3430ES2, to cover ES levels from ES2
onwards - a common pattern for OMAP3 features.  Update all current
users of the omap_chip macros to use this new macro.

Also add CHIP_GE_OMAP3430ES3_1 to cover the USBTLL SAR errata case
(described and fixed in the following patch)
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This roughly corresponds with OMAP commits: 7d06c48d, 3241b19e,
88b5d9b6, 18a55008, 9c909ac9, 5c6497bc, 8b1f0bd4, 2ac1da8c.

For both OMAP2 and OMAP3, we note the reference and bypass clocks in
the DPLL data structure.  Whenever we modify the DPLL rate, we first
ensure that both the reference and bypass clocks are enabled.  Then,
we decide whether to use the reference and DPLL, or the bypass clock
if the desired rate is identical to the bypass rate, and program the
DPLL appropriately.  Finally, we update the clock's parent, and then
disable the unused clocks.

This keeps the parents correctly balanced, and more importantly ensures
that the bypass clock is running whenever we reprogram the DPLL.  This
is especially important because the procedure for reprogramming the DPLL
involves switching to the bypass clock.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

linux-omap source commit 33d000c9
introduces a way to "dry run" clock changes before they're committed.
However, this involves putting logic to handle this into each and
every recalc function, and unfortunately due to the caching, led to
some bugs.

Solve both of issues by making the recalc methods always return the
clock rate for the clock, which the caller decides what to do with.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Clock rate change code executes inside a spinlock with hardirqs
disabled.  The only code that should be messing around with the
hardirq state should be the plat-omap/clock.c code.  In the
omap2_reprogram_dpllcore() case, this probably just wastes cycles, but
in the omap3_core_dpll_m2_set_rate() case, this is a nasty bug.

linux-omap source commit is b9b6208d.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Based on a patch from Paul Walmsley <paul@pwsan.com>:

 omap2_clk_enable() should enable a clock's clockdomain before
 attempting to enable its parent clock's clockdomain.  Similarly, in
 the unlikely event that the parent clock enable fails, the clockdomain
 should be disabled.

 linux-omap source commit is 6d6e285e.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Based upon a patch from Paul Walmsley <paul@pwsan.com>:

 If _omap2_clk_enable() fails, the clock's usecount must be decremented
 by one no matter whether the clock has a parent or not.

but reorganised a bit.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This function is race-prone and mistakenly conveys the impression to
drivers that it is part of the clock interface.  Get rid of it: core
code that absolutely needs this can just check clk->usecount.  Drivers
should not use it at all.

linux-omap source commit is 5df9e4ad.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Several parts of the OMAP2/3 clock code use wmb() to try to ensure
that the hardware write completes before continuing.  This approach is
problematic: wmb() only ensures that the write leaves the ARM.  It
does not ensure that the write actually reaches the endpoint device.
The endpoint device in this case - either the PRM, CM, or SCM - is
three interconnects away from the ARM - and the final interconnect is
low-speed.  And the OCP interconnects will post the write, and who
knows how long that will take to complete.  So the wmb() is not what
we want.  Worse, the wmb() is indiscriminate; it causes the ARM to
flush any other unrelated buffered writes and wait for the local
interconnect to acknowledge them - potentially very expensive.

Fix this by converting the wmb()s into readbacks of the same PRM/CM/SCM
register.  Since the PRM/CM/SCM devices use a single OCP thread, this
will cause the MPU to block while waiting for posted writes to that device
to complete.

linux-omap source commit is 260f5487.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Consolidate the commit code for DELAYED_APP clocks into a subroutine,
_omap2xxx_clk_commit().  Also convert the MPU barrier wmb() into an
OCP barrier, since with an MPU barrier, we have no guarantee that the
write actually reached the endpoint device.

linux-omap source commit is 0f5bdb73.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

clk_disable() previously used an ARM barrier, wmb(), to try to ensure
that the hardware write completed before continuing.  There are some
problems with this approach.

The first problem is that wmb() only ensures that the write leaves the
ARM -- not that it actually reaches the endpoint device.  In this
case, the endpoint device - either the PRM, CM, or SCM - is three
interconnects away from the ARM, and the final interconnect is
low-speed.  And the OCP interconnects will post the write, who knows
how long that will take to complete.  So the wmb() is not really what
we want.

Worse, the wmb() is indiscriminate; it will cause the ARM to flush any
other unrelated buffered writes and wait for the local interconnect to
acknowledge them - potentially very expensive.

This first problem could be fixed by doing a readback of the same PRM/CM/SCM
register.  Since these devices use a single OCP thread, this will cause the
MPU to wait for the write to complete.

But the primary problem is a conceptual one: clk_disable() should not
need any kind of barrier.  clk_enable() needs one since device driver
code must not access a device until its clocks are known to be
enabled.  But clk_disable() has no such restriction.

Since blocking the MPU on a PRM/CM/SCM write can be a very
high-latency operation - several hundred MPU cycles - it's worth
avoiding this barrier if possible.

linux-omap source commit is f4aacad2.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Traditionally, we've tracked the parent/child relationships between
clk structures by setting the child's parent member to point at the
upstream clock.  As a result, when decending the tree, we have had
to scan all clocks to find the children.

Avoid this wasteful scanning by keeping a list of the clock's children.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This implements the remainder of:
  OMAP clock: move rate recalc, propagation code up to plat-omap/clock.c
from Paul Walmsley which is not covered by the previous:
  [ARM] omap: move clock propagation into core omap clock code
  [ARM] omap: remove unnecessary calls to propagate_rate()
  [ARM] omap: move propagate_rate() calls into generic omap clock code
commits.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Use the standard clk_set_rate() function in omap2_clk_arch_init()
rather than omap2_select_table_rate() -- this will ensure that clock
rates are recalculated and propagated correctly after those operations
are consolidated into clk_set_rate().

linux-omap source commit is 03c03330.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Current implementation will disable clocks in the order defined in clock34xx.h,
at least DPLL4_M2X2 will hang in certain cases (and prevent retention / off)
if clocks are not disabled in correct order. This patch makes sure the parent
clocks will be active when disabling a clock.

linux-omap source commit is 67268006.
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Add the omap3_core_dpll_m2_set_rate() function to the OMAP3 clock code,
which calls into the SRAM function omap3_sram_configure_core_dpll() to
change the CORE DPLL M2 divider.  (SRAM code is necessary since rate changes
on clocks upstream from the SDRC can glitch SDRAM accesses.)

Use this function for the set_rate function pointer in the dpll3_m2_ck
struct clk.  With this function in place, PM/OPP code should be able to
alter SDRAM speed via code similar to:

      clk_set_rate(&dpll3_m2_ck, target_rate).

linux-omap source commit is 7f8b2b0f.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

For a given SDRAM clock rate, SDRAM chips require memory controllers
to use a specific set of timing minimums and maximums to transfer data
reliably.  These parameters can be different for different memory chips
and can also potentially vary by board.

This patch adds the infrastructure for board-*.c files to pass this
timing data to the SDRAM controller init function.  The timing data is
specified in an 'omap_sdrc_params' structure, in terms of SDRC
controller register values.  An array of these structs, one per SDRC
target clock rate, is passed by the board-*.c file to
omap2_init_common_hw().

This patch does not define the values for different memory chips, nor
does it use the values for anything; those will come in subsequent patches.

linux-omap source commit is bc84ecfc.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Separate SDRC code common to OMAP2/3 from mach-omap2/sdrc2xxx.c to
mach-omap2/sdrc.c.  Rename the OMAP2xxx-specific functions to use an
'omap2xxx' prefix rather than an 'omap2' prefix, and use "sdrc" in the
function names rather than "memory."  Mark several functions
as static that should not be used outside the sdrc2xxx.c file.

linux-omap source commit is bf1612b9.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Rename arch/arm/mach-omap2/memory.c to arch/arm/mach-omap2/sdrc2xxx.c, since
it contains exclusively SDRAM-related functions.  Most of the functions
are also OMAP2xxx-specific - those which are common will be separated out
in a following patch.

linux-omap source commit is fe212f79.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Move the contents of the arch/arm/mach-omap2/memory.h file to the
existing mach/sdrc.h file, and remove memory.h.  Modify files which
include memory.h to include asm/arch/sdrc.h instead.

linux-omap source commit is e7ae2d89.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This fixes booting, and is a step toward fixing things properly:

- Make enable_reg u32 instead of u16
  [rmk: virtual addresses are void __iomem *, not u32]
- Get rid of VIRTUAL_IO_ADDRESS for clocks
- Use __raw_read/write instead of omap_read/write for clock registers

This patch adds a bunch of compile warnings until omap1 clock
also uses offsets.

linux-omap source commit is 9d1dff86.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch fixes a few OMAP2xxx CM_IDLEST bits that were incorrectly
marked as being OMAP2xxx-wide, when they were actually 2420-specific.

Also, originally when the PRCM register macros were defined, bit shift
macros used a "_SHIFT" suffix, and mask macros used none.  This became
a source of bugs and confusion, as the mask macros were mistakenly
used for shift values.  Gradually, the mask macros have been updated,
piece by piece, to add a "_MASK" suffix on the end to clarify.  This
patch applies this change to the CM_IDLEST_* register bits.

The patch also adds a few bits that were missing, mostly from the 3430ES1
to ES2 revisions.

linux-omap source commits are d18eff5b,
e1f1a5cc, and part of
9fe6b6cfSigned-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch rolls up several cleanup patches.

1. Some unnecessarily verbose variable names are used in several clock.c
functions; clean these up per CodingStyle.

2. Remove omap2_get_clksel() and just use clk->clksel_reg and
clk->clksel_mask directly.

3. Get rid of void __iomem * usage in omap2_clksel_get_src_field.
Prepend the function name with an underscore to highlight that it is a
static function.

linux-omap source commits are 7fa95e00,
af0ea23f, and
91c0c979.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

During _omap3_noncore_dpll_lock(), if a DPLL has no active downstream
clocks and DPLL autoidle is enabled, the DPLL may never lock, since it
will enter autoidle immediately.  To resolve this, disable DPLL
autoidle while locking the DPLL, and unconditionally wait for the DPLL
to lock.  This fixes some bugs where the kernel would hang when returning
from retention or return the wrong rate for the DPLL.

This patch is a collaboration with Peter de Schrijver
<peter.de-schrijver@nokia.com> and Kevin Hilman
<khilman@deeprootsystems.com>.

linux-omap source commit is 3b7de4be.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Peter de Schrijver <peter.de-schrijver@nokia.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The DPLL FREQSEL jitter correction bits are set based on a table in
the 34xx TRM, Table 4-38, according to the DPLL's internal clock
frequency "Fint."  Several Fint frequency ranges are missing from this
table.  Previously, we allowed these Fint frequency ranges to be
selected in the rate rounding code, but did not change the FREQSEL bits.
Correspondence with the OMAP hardware team indicates that Fint values
not in the table should not be used.  So, prevent them from being
selected during DPLL rate rounding.  This removes warnings and also
can prevent the chip from locking up.

The first pass through the rate rounding code will update the DPLL max
and min dividers appropriately, so later rate rounding passes will run
faster than the first.

Peter de Schrijver <peter.de-schrijver@nokia.com> put up with several
test cycles of this patch - thanks Peter.

linux-omap source commit is f9c1b82f.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Peter de Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The previous DPLL rate rounding algorithm counted the divider (N) down
from the maximum to 1.  Since we currently use a broad DPLL rate
tolerance, and lower N values are more power-efficient, we can often
bypass several iterations through the loop by counting N upwards from
1.

Peter de Schrijver <peter.de-schrijver@nokia.com> put up with several
test cycles of this patch - thanks Peter.

linux-omap source commit is 6f6d82bb.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Peter de Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Remove some clutter from omap2_dpll_round_rate().

linux-omap source commit is 4625dceb.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Convert struct dpll_data.idlest_bit field to idlest_mask.  Needed since
OMAP2 uses two bits for DPLL IDLEST rather than one.

While here, add the missing idlest_* fields for DPLL3.

linux-omap source commits are 25bab0f1
and b0f7fd17.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

OMAP34xx ES2 TRM Delta G to H states that the divider for DPLL1_FCLK and
DPLL2_FCLK can divide by 4 in addition to dividing by 1 and 2. Encode this
into the OMAP3 clock framework.

linux-omap source commit is 050684c1.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Fix DPLL jitter correction programming.  Previously,
omap3_noncore_dpll_program() stored the FREQSEL jitter correction
parameter to the wrong register.  This caused jitter correction to be set
incorrectly and also caused the DPLL divider to be programmed incorrectly.

Also, fix DPLL divider programming.  An off-by-one error existed in
omap3_noncore_dpll_program(), causing DPLLs to be programmed with a higher
divider than intended.

linux-omap source commit is 5c0ec88a.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Using sdti doesn't keep emu_pwrdm on if hardware supervised pwrdm
transitions are used. This causes sdti stop to work when power
management is initialized and hardware supervised pwrdm control is
enabled. This patch disables hardware supervised pwrdm control for
emu_pwrdm. Now emu_pwrdm is switched off on boot by software when it
is not used.
Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Fix the clockdomain autodep code to respect omap_chip platform flags.

Resolves "Unable to handle kernel paging request at virtual address
5f75706d" panic during power management initialization on OMAP2.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Enabling clock in a disabled power domain causes the power domain to be
turned on. However, the power transition is not always finished when
clk_enable() returns and this randomly crashes the kernel when an
interrupt happens right after the clk_enable, and the kernel tries to
read the irq status register for that domain.

Why the irq status register is inaccessible, I don't know. Also it
doesn't seem to be related to the module being not powered up, but to
the transition itself.

The same could perhaps happen after clk_disable also, but I have not
witnessed that.

The problem affects at least dss, cam and sgx clocks.

This change waits for the transition to be finished before returning
from omap2_clkdm_clk_enable().
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The SGX device on OMAP3 does not support retention, so remove RET from the
list of possible SGX power states.  Problem debugged by Richard Woodruff
<r-woodruff2@ti.com>.
Signed-off-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Each DPLL exists in its own powerdomain (cf 34xx TRM figure 4-18) and
clockdomain; so, create powerdomain and clockdomain structures for them.
Mark each DPLL clock as belonging to their respective DPLL clockdomain.
cf. 34xx TRM Table 4-27 (among other references).

linux-omap source commits are acdb6158 and
a8798a48.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

sys_clkout2 belongs in the core_clkdm (3430 TRM section 4.7.2.2).
It's not clear whether it actually is in the CORE clockdomain, or whether
it is technically in a different clockdomain; but this is closer to
reality than the present configuration.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Add clockdomains for the CM and PRM.  These will ultimately replace the
"wkup_clkdm", which appears to not actually exist on the hardware.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>