On omap4 control module is divided in four IP blocks.
- CTRL_MODULE_CORE			0x4a002000
- CTRL_MODULE_PAD_CORE		0x4a100000
- CTRL_MODULE_WKUP			0x4a30c000
- CTRL_MODULE_PAD_WKUP		0x4a31e000

Addressing all the modules with single base address is not possible
considering 16 bit offsets. The mux code manages the pad core and pad
wakeup related base address inside the mux framework. For other usage
only control core and control pad bases are necessary. So this patch
maps only needed pad control base address which is used by device drivers
and infrastructure code

The main control core base is still kept same in this patch to
keep git-bisect working. This will be fixed in the relevant patch
in this series.
Signed-off-by: NBenoit Cousson <b-cousson@ti.com>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

Fix a few OMAP4430 clock tree problems after the recent manual merge of the
various ES2 clock patches:

- usim optional clock and its parent had the same name, rename the parent
usim_fclk -> usim_ck

- OPTFCLKEN_CLK32K is not handled anymore by the USBPHYOCP2SCP module in ES2
Create a new clock that belongs to CM_ALWON_USBPHY_CLKCTRL register

This patch depends on some of the PRCM macro updates from Rajendra.
Signed-off-by: NBenoit Cousson <b-cousson@ti.com>
[paul@pwsan.com: tweaked patch description]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>

DSS on ES2 supports only OSWR, hence remove the support
for CSWR from the powerdomain framework.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NBenoît Cousson <b-cousson@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

4430 ES2 has a few new registers added and a few modified
from ES1. This patch adds all the register changes in PRM
and CM for OMAP4430 ES2.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NBenoît Cousson <b-cousson@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

This patch updates the PRM and CM register bitshifts and masks
for OMAP4430 ES2.0.

Replace as well the BITFIELD macro with the shift operator in order
to be consistent with the previous OMAP2 & 3 format.

Sort the register list in comments in order to have a consistent
register order and avoid futur change during code generation.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NBenoît Cousson <b-cousson@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

OMAP4 IP optional clocks require explicit enable in module CTRLCLK
register. In order to allow that we have to create artificial clock
nodes that represent this clock inputs in the IP.

Notes:
- Temporary use OMAP3 names for GPIO optional clocks until the GPIO hwmod
convertion is done. It will enforce the usage of OMAP4 names as the reference.
- Temporary use OMAP3 names for TIMER main clock (gptX_fck) until TIMER hwmod
convertion is done. During that convertion, the new name will have to be used.
Signed-off-by: NBenoit Cousson <b-cousson@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Rajendra Nayak <rnayak@ti.com>

The OMAP4 hwmod data introduced the new naming convention for TI
IPs (See patch OMAP4: hwmod: Add partial hwmod support for OMAP4430 ES1.0)

The leaf clock names are using the same IP name and thus must be
modified to match the clock populated in the hwmod data.

- Fix some leaf clocks nodes that were using a _iclk instead of the _fclk
prefix.
- Fix some wrong interface clock name for master IPs connected to
interconnect.

Please not that due to the fact that nodes are sorted by name, the name
change will introduce a quite ugly diff a little bit hard to follow.

Timers clock con_id is still using the old gptX_fck name until the
gptimer driver is updated to omap_device framework.
Timers entries in hwmods DB are still disabled until the migration
if timer to platform_driver + omap_hwmod.
Signed-off-by: NBenoit Cousson <b-cousson@ti.com>
[paul@pwsan.com: manually resolved conflicts with Rajendra's clock patch]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>

This patch updates the clock tree with all the
changes in OMAP4430 ES2.

clock nodes added
-1- tie_low_clock_ck
-2- abe_dpll_bypass_clk_mux_ck

clock nodes deleted
-1- dpll_sys_ref_clk
-2- per_sgx_fclk
-3- usbphyocp2scp_ick
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NBenoît Cousson <b-cousson@ti.com>
[paul@pwsan.com: added comment re ES1 clocks to top of file]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

We need to make sure that only the first do_signal() to be handled on
the way out syscall will bother with syscall restarts; additionally, the
check on the "signal has user handler" path had been wrong - compare
with restart prevention in sigreturn()...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

do_signal() should place the syscall number in gr7, not gr8 when
handling ERESTART_WOULDBLOCK.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use force_sigsegv() rather than force_sig(SIGSEGV, ...) as the former
resets the SEGV handler pointer which will kill the process, rather than
leaving it open to an infinite loop if the SEGV handler itself caused a
SEGV signal.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

a) sa_handler might be maliciously set to point to kernel memory;
   blindly dereferencing it in FDPIC case is a Bad Idea(tm).

b) I'm not sure you need that set_fs(USER_DS) there at all, but if you
   do, you'd better do it *before* checking the frame you've decided to
   use with access_ok(), lest sigaltstack() becomes a convenient
   roothole.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Reset restart_block.fn on executing a sigreturn such that any currently
pending system call restarts will be forced to return -EINTR.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Unlike the other targets, alpha sets _one_ sigframe and
buggers off until the next syscall/interrupt, even if
more signals are pending.  It leads to quite a few unpleasant
inconsistencies, starting with SIGSEGV potentially arriving
not where it should and including e.g. mess with sigsuspend();
consider two pending signals blocked until sigsuspend()
unblocks them.  We pick the first one; then, if we are hit
by interrupt while in the handler, we process the second one
as well.  If we are not, and if no syscalls had been made,
we get out of the first handler and leave the second signal
pending; normally sigreturn() would've picked it anyway, but
here it starts with restoring the original mask and voila -
the second signal is blocked again.  On everything else we
get both delivered consistently.

It's actually easy to fix; the only thing to watch out for
is prevention of double syscall restart.  Fortunately, the
idea I've nicked from arm fix by rmk works just fine...

Testcase demonstrating the behaviour in question; on alpha
we get one or both flags set (usually one), on everything
else both are always set.
	#include <signal.h>
	#include <stdio.h>
	int had1, had2;
	void f1(int sig) { had1 = 1; }
	void f2(int sig) { had2 = 1; }
	main()
	{
		sigset_t set1, set2;
		sigemptyset(&set1);
		sigemptyset(&set2);
		sigaddset(&set2, 1);
		sigaddset(&set2, 2);
		signal(1, f1);
		signal(2, f2);
		sigprocmask(SIG_SETMASK, &set2, NULL);
		raise(1);
		raise(2);
		sigsuspend(&set1);
		printf("had1:%d had2:%d\n", had1, had2);
	}
Tested-by: NMichael Cree <mcree@orcon.net.nz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

The way sigreturn() is implemented on alpha breaks PTRACE_SYSCALL,
all way back to 1.3.95 when alpha has grown PTRACE_SYSCALL support.

What happens is direct return to ret_from_syscall, in order to bypass
mangling of a3 (error indicator) and prevent other mutilations of
registers (e.g. by syscall restart).  That's fine, but... the entire
TIF_SYSCALL_TRACE codepath is kept separate on alpha and post-syscall
stopping/notifying the tracer is after the syscall.  And the normal
path we are forcibly switching to doesn't have it.

So we end up with *one* stop in traced sigreturn() vs. two in other
syscalls.  And yes, strace is visibly broken by that; try to strace
the following
	#include <signal.h>
	#include <stdio.h>
	void f(int sig) {}
	main()
	{
		signal(SIGHUP, f);
		raise(SIGHUP);
		write(1, "eeeek\n", 6);
	}
and watch the show.  The
	close(1)                                = 405
in the end of strace output is coming from return value of write() (6 ==
__NR_close on alpha) and syscall number of exit_group() (__NR_exit_group ==
405 there).

The fix is fairly simple - the only thing we end up missing is the call
of syscall_trace() and we can tell whether we'd been called from the
SYSCALL_TRACE path by checking ra value.  Since we are setting the
switch_stack up (that's what sys_sigreturn() does), we have the right
environment for calling syscall_trace() - just before we call
undo_switch_stack() and return.  Since undo_switch_stack() will overwrite
s0 anyway, we can use it to store the result of "has it been called from
SYSCALL_TRACE path?" check.  The same thing applies in rt_sigreturn().
Tested-by: NMichael Cree <mcree@orcon.net.nz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Old code used to set regs->r0 and regs->r19 to force the right
return value.  Leaving that after switch to ERESTARTNOHAND
was a Bad Idea(tm), since now that screws the restart - if we
hit the case when get_signal_to_deliver() returns 0, we will
step back to syscall insn, with v0 set to EINTR and a3 to 1.
The latter won't matter, since EINTR is 4, aka __NR_write.

Testcase:

	#include <signal.h>
	#define _GNU_SOURCE
	#include <unistd.h>
	#include <sys/syscall.h>

	main()
	{
		sigset_t mask;
		sigemptyset(&mask);
		sigaddset(&mask, SIGCONT);
		sigprocmask(SIG_SETMASK, &mask, NULL);
		kill(0, SIGCONT);
		syscall(__NR_sigsuspend, 1, "b0rken\n", 7);
	}

results on alpha in immediate message to stdout...

Fix is obvious; moreover, since we don't need regs anymore, we can
switch to normal prototypes for these guys and lose the wrappers.
Even better, rt_sigsuspend() is identical to generic version in
kernel/signal.c now.
Tested-by: NMichael Cree <mcree@orcon.net.nz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

same thing as had been done on other targets back in 2003 -
move setting ->restart_block.fn into {rt_,}sigreturn().
Tested-by: NMichael Cree <mcree@orcon.net.nz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Pending work from the performance event subsystem is executed in
the timer interrupt.  This patch shifts the call to
perf_event_do_pending() before the call to update_process_times()
as the latter may call back into the perf event subsystem and it
is prudent to have the pending work executed first.
Signed-off-by: NMichael Cree <mcree@orcon.net.nz>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

The 2.6.36-rc kernel added three new system calls:
fanotify_init, fanotify_mark, and prlimit64.  This
patch wires them up on Alpha.

Built and booted on an XP900.  Untested beyond that.
Signed-off-by: NMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

All uses of the BKL on alpha are totally bogus, nothing
is really protected by this. Remove the remaining users
so we don't have to mark alpha as 'depends on BKL'.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: linux-alpha@vger.kernel.org
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Alpha SMP flush_icache_user_range() is implemented as an inline
function inside include/asm/cacheflush.h.  It dereferences @current
but doesn't include linux/sched.h and thus causes build failure if
linux/sched.h wasn't included previously.  Fix it by including the
needed header file explicitly.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Acked-by: NJan-Benedict Glaw <jbglaw@lug-owl.de>
Signed-off-by: Nmatt mooney <mfm@muteddisk.com>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Acked-by: NRichard Henderson  <rth@twiddle.net>
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Add IORESOURCE_IRQ_HIGHLEVEL irq flag to dm9000 driver
platform data in board mach-real6410.
Signed-off-by: NDarius Augulis <augulis.darius@gmail.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

Fix errors reported by checkpatch.pl script
Signed-off-by: NDarius Augulis <augulis.darius@gmail.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

Avoids build warnings due to the undeclared non-statics.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

If a signal hits us outside of a syscall and another gets delivered
when we are in sigreturn (e.g. because it had been in sa_mask for
the first one and got sent to us while we'd been in the first handler),
we have a chance of returning from the second handler to location one
insn prior to where we ought to return.  If r0 happens to contain -513
(-ERESTARTNOINTR), sigreturn will get confused into doing restart
syscall song and dance.

Incredible joy to debug, since it manifests as random, infrequent and
very hard to reproduce double execution of instructions in userland
code...

The fix is simple - mark it "don't bother with restarts" in wrapper,
i.e. set r8 to 0 in sys_sigreturn and sys_rt_sigreturn wrappers,
suppressing the syscall restart handling on return from these guys.
They can't legitimately return a restart-worthy error anyway.

Testcase:
	#include <unistd.h>
	#include <signal.h>
	#include <stdlib.h>
	#include <sys/time.h>
	#include <errno.h>

	void f(int n)
	{
		__asm__ __volatile__(
			"ldr r0, [%0]\n"
			"b 1f\n"
			"b 2f\n"
			"1:b .\n"
			"2:\n" : : "r"(&n));
	}

	void handler1(int sig) { }
	void handler2(int sig) { raise(1); }
	void handler3(int sig) { exit(0); }

	main()
	{
		struct sigaction s = {.sa_handler = handler2};
		struct itimerval t1 = { .it_value = {1} };
		struct itimerval t2 = { .it_value = {2} };

		signal(1, handler1);

		sigemptyset(&s.sa_mask);
		sigaddset(&s.sa_mask, 1);
		sigaction(SIGALRM, &s, NULL);

		signal(SIGVTALRM, handler3);

		setitimer(ITIMER_REAL, &t1, NULL);
		setitimer(ITIMER_VIRTUAL, &t2, NULL);

		f(-513); /* -ERESTARTNOINTR */

		write(1, "buggered\n", 9);
		return 1;
	}
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Tony's fix (f574c843) has a small bug,
it incorrectly uses "r3" as a scratch register in the first of the two
unlock paths ... it is also inefficient.  Optimize the fast path again.
Signed-off-by: NPetr Tesarik <ptesarik@suse.cz>
Signed-off-by: NTony Luck <tony.luck@intel.com>

This cut-and-paste bug was caused by rewriting the register dump
code to use only a single printk per line of output.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

This tripped up a driver (not yet committed to git).  Fix it now.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

During context switch, save and restore a couple of additional bits of
tilegx user state that can be persistently modified by userspace.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

Rather than just using pt_regs, it now contains the actual saved
state explicitly, similar to pt_regs.  By doing it this way, we
provide a cleaner API for userspace (or equivalently, we avoid the
need for libc to provide its own definition of sigcontext).

While we're at it, move PT_FLAGS_xxx to where they are not visible
from userspace.  And always pass siginfo and mcontext to signal
handlers, even if they claim they don't need it, since sometimes
they actually try to use it anyway in practice.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

The sys_execve() implementation was properly const-ified but not
the declaration, the syscall wrappers, or the compat version.
This change completes the constification process.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

Fix up the IRQ names for the MN10300 on-chip serial ports in the driver as
request_interrupt() no longer allows names containing slashes, giving a warning
like the following if one is encountered:

	------------[ cut here ]------------
	WARNING: at fs/proc/generic.c:323 __xlate_proc_name+0x62/0x7c()
	name 'ttySM0/Rx'
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit d4d67150, we reopened an old hole for a 64-bit ptracer touching a
32-bit tracee in system call entry.  A %rax value set via ptrace at the
entry tracing stop gets used whole as a 32-bit syscall number, while we
only check the low 32 bits for validity.

Fix it by truncating %rax back to 32 bits after syscall_trace_enter,
in addition to testing the full 64 bits as has already been added.
Reported-by: NBen Hawkes <hawkes@sota.gen.nz>
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

On 64 bits, we always, by necessity, jump through the system call
table via %rax.  For 32-bit system calls, in theory the system call
number is stored in %eax, and the code was testing %eax for a valid
system call number.  At one point we loaded the stored value back from
the stack to enforce zero-extension, but that was removed in checkin
d4d67150.  An actual 32-bit process
will not be able to introduce a non-zero-extended number, but it can
happen via ptrace.

Instead of re-introducing the zero-extension, test what we are
actually going to use, i.e. %rax.  This only adds a handful of REX
prefixes to the code.
Reported-by: NBen Hawkes <hawkes@sota.gen.nz>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@kernel.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>

compat_alloc_user_space() expects the caller to independently call
access_ok() to verify the returned area.  A missing call could
introduce problems on some architectures.

This patch incorporates the access_ok() check into
compat_alloc_user_space() and also adds a sanity check on the length.
The existing compat_alloc_user_space() implementations are renamed
arch_compat_alloc_user_space() and are used as part of the
implementation of the new global function.

This patch assumes NULL will cause __get_user()/__put_user() to either
fail or access userspace on all architectures.  This should be
followed by checking the return value of compat_access_user_space()
for NULL in the callers, at which time the access_ok() in the callers
can also be removed.
Reported-by: NBen Hawkes <hawkes@sota.gen.nz>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NTony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: James Bottomley <jejb@parisc-linux.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: <stable@kernel.org>

This more or less reverts commits 08be9796 (x86: Force HPET
readback_cmp for all ATI chipsets) and 30a564be (x86, hpet: Restrict
read back to affected ATI chipsets) to the status of commit 8da854cb
(x86, hpet: Erratum workaround for read after write of HPET
comparator).

The delta to commit 8da854cb is mostly comments and the change from
WARN_ONCE to printk_once as we know the call path of this function
already.

This needs really in depth explanation:

First of all the HPET design is a complete failure. Having a counter
compare register which generates an interrupt on matching values
forces the software to do at least one superfluous readback of the
counter register.

While it is nice in theory to program "absolute" time events it is
practically useless because the timer runs at some absurd frequency
which can never be matched to real world units. So we are forced to
calculate a relative delta and this forces a readout of the actual
counter value, adding the delta and programming the compare
register. When the delta is small enough we run into the danger that
we program a compare value which is already in the past. Due to the
compare for equal nature of HPET we need to read back the counter
value after writing the compare rehgister (btw. this is necessary for
absolute timeouts as well) to make sure that we did not miss the timer
event. We try to work around that by setting the minimum delta to a
value which is larger than the theoretical time which elapses between
the counter readout and the compare register write, but that's only
true in theory. A NMI or SMI which hits between the readout and the
write can easily push us beyond that limit. This would result in
waiting for the next HPET timer interrupt until the 32bit wraparound
of the counter happens which takes about 306 seconds.

So we designed the next event function to look like:

   match = read_cnt() + delta;
   write_compare_ref(match);
   return read_cnt() < match ? 0 : -ETIME;

At some point we got into trouble with certain ATI chipsets. Even the
above "safe" procedure failed. The reason was that the write to the
compare register was delayed probably for performance reasons. The
theory was that they wanted to avoid the synchronization of the write
with the HPET clock, which is understandable. So the write does not
hit the compare register directly instead it goes to some intermediate
register which is copied to the real compare register in sync with the
HPET clock. That opens another window for hitting the dreaded "wait
for a wraparound" problem.

To work around that "optimization" we added a read back of the compare
register which either enforced the update of the just written value or
just delayed the readout of the counter enough to avoid the issue. We
unfortunately never got any affirmative info from ATI/AMD about this.

One thing is sure, that we nuked the performance "optimization" that
way completely and I'm pretty sure that the result is worse than
before some HW folks came up with those.

Just for paranoia reasons I added a check whether the read back
compare register value was the same as the value we wrote right
before. That paranoia check triggered a couple of years after it was
added on an Intel ICH9 chipset. Venki added a workaround (commit
8da854cb) which was reading the compare register twice when the first
check failed. We considered this to be a penalty in general and
restricted the readback (thus the wasted CPU cycles) to the known to
be affected ATI chipsets.

This turned out to be a utterly wrong decision. 2.6.35 testers
experienced massive problems and finally one of them bisected it down
to commit 30a564be which spured some further investigation.

Finally we got confirmation that the write to the compare register can
be delayed by up to two HPET clock cycles which explains the problems
nicely. All we can do about this is to go back to Venki's initial
workaround in a slightly modified version.

Just for the record I need to say, that all of this could have been
avoided if hardware designers and of course the HPET committee would
have thought about the consequences for a split second. It's out of my
comprehension why designing a working timer is so hard. There are two
ways to achieve it:

 1) Use a counter wrap around aware compare_reg <= counter_reg
    implementation instead of the easy compare_reg == counter_reg

    Downsides:

	- It needs more silicon.

	- It needs a readout of the counter to apply a relative
	  timeout. This is necessary as the counter does not run in
	  any useful (and adjustable) frequency and there is no
	  guarantee that the counter which is used for timer events is
	  the same which is used for reading the actual time (and
	  therefor for calculating the delta)

    Upsides:

	- None

  2) Use a simple down counter for relative timer events

    Downsides:

	- Absolute timeouts are not possible, which is not a problem
	  at all in the context of an OS and the expected
	  max. latencies/jitter (also see Downsides of #1)

   Upsides:

	- It needs less or equal silicon.

	- It works ALWAYS

	- It is way faster than a compare register based solution (One
	  write versus one write plus at least one and up to four
	  reads)

I would not be so grumpy about all of this, if I would not have been
ignored for many years when pointing out these flaws to various
hardware folks. I really hate timers (at least those which seem to be
designed by janitors).

Though finally we got a reasonable explanation plus a solution and I
want to thank all the folks involved in chasing it down and providing
valuable input to this.
Bisected-by: NNix <nix@esperi.org.uk>
Reported-by: NArtur Skawina <art.08.09@gmail.com>
Reported-by: NDamien Wyart <damien.wyart@free.fr>
Reported-by: NJohn Drescher <drescherjm@gmail.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: stable@kernel.org
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The irqs.h usage here got missed in the Samsung platform reorganisation.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NJassi Brar <jassi.brar@samsung.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

This patch fixes bug on gpio drive strength helper function.

The offset should be like follwoing.
-       off = chip->chip.base - pin;
+       off = pin - chip->chip.base;

In the s5p_gpio_get_drvstr(),
the second line is unnecessary, because overwrite drvstr.
        drvstr = __raw_readl(reg);
-       drvstr = 0xffff & (0x3 << shift);

And need 2bit masking before return the drvstr value.
        drvstr = drvstr >> shift;
+       drvstr &= 0x3;

In the s5p_gpio_set_drvstr(), need relevant bit clear.
        tmp = __raw_readl(reg);
+       tmp &= ~(0x3 << shift);
        tmp |= drvstr << shift;
Reported-by: NJaecheol Lee <jc.lee@samsung.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>