The console semaphore must be held while the OMAP UART devices are
disabled, lest a console write cause an ARM abort (and a kernel crash)
when the underlying console device is inaccessible. These crashes
only occur when the console is on one of the OMAP internal serial
ports.
While this problem has been latent in the PM idle loop for some time,
the crash was not triggerable with an unmodified kernel until commit
6f251e9db1 ("OMAP: UART: omap_device
conversions, remove implicit 8520 assumptions"). After this patch, a
console write often occurs after the console UART has been disabled in
the idle loop, crashing the system. Several users have encountered
this bug:
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38396.htmlhttp://www.mail-archive.com/linux-omap@vger.kernel.org/msg36602.html
The same commit also introduced new code that disabled the UARTs
during init, in omap_serial_init_port(). The kernel will also crash
in this code when earlyconsole and extra debugging is enabled:
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg36411.html
The minimal fix for the -rc series is to hold the console semaphore
while the OMAP UARTs are disabled. This is a somewhat overbroad fix,
since the console may not be located on an OMAP UART, as is the case
with the GPMC UART on Zoom3. While it is technically possible to
determine which devices the console or earlyconsole is actually
running on, it is not a trivial problem to solve, and the code to do
so is not really appropriate for the -rc series.
The right long-term fix is to ensure that no code outside of the OMAP
serial driver can disable an OMAP UART. As I understand it, code to
implement this is under development by TI.
This patch is a collaboration between Paul Walmsley <paul@pwsan.com>
and Tony Lindgren <tony@atomide.com>. Thanks to Ming Lei
<tom.leiming@gmail.com> and Pramod <pramod.gurav@ti.com> for their
feedback on earlier versions of this patch.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Pramod <pramod.gurav@ti.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Jean Pihet <jean.pihet@newoldbits.com>
Cc: Govindraj.R <govindraj.raja@ti.com>
Only OMAP2+ platforms have the System Control Module (SCM) IP block.
In the past, we've kept the SCM header file in plat-omap. This has
led to abuse - device drivers including it; includes being added that
create implicit dependencies on OMAP2+ builds; etc.
In response, move the SCM headers into mach-omap2/.
As part of this, remove the direct SCM access from the OMAP UDC
driver. It was clearly broken. The UDC code needs an indepth review for
use on OMAP2+ chips.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Cory Maccarrone <darkstar6262@gmail.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
As is done on OMAP3, check omap_uart_can_sleep() as one of the
pre-conditions for entering the idle loop. Without this check,
entering idle introduces large latencies on active UARTs, and is
especially noticable on serial console.
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Fix all of the remaining PRCM register shift/bitmask macros that did not
use the _SHIFT/_MASK suffixes to use them. This makes the use of these
macros consistent. It is intended to reduce error, as code can be inspected
visually by reviewers to ensure that bitshifts and bitmasks are used in
the appropriate places.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Fix all of the remaining OMAP2 PRCM register shift/bitmask macros that
did not use the _SHIFT/_MASK suffixes to use them. This makes the use
of these macros consistent. It is intended to reduce error, as code
can be inspected visually by reviewers to ensure that bitshifts and
bitmasks are used in the appropriate places.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Currently, the GPIO 'prepare' hook is only called when going to
off-mode, while the function is called 'prepare_for_retention.' This
patch renames the function to 'prepare_for_idle' and calls it for any
powersate != PWRDM_POWER_ON passing in the powerstate.
The hook itself is then responsible for doing various preparation
based on the powerstate.
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Add usecounting for wakeup and sleep dependencies. In the current
situation, if several functions add dependencies on the same
clockdomains, when the first dependency removal function is called,
the dependency will be incorrectly removed from the hardware.
Add clkdm_clear_all_wkdeps() and clkdm_clear_all_sleepdeps(), which
provide a fast and usecounting-consistent way to clear all hardware
clockdomain dependencies, since accesses to these registers can be
quite slow. pm{2,3}4xx.c has been updated to use these new functions.
The original version of this patch did not touch these files, which
previously wrote directly to the wkdep registers, and thus confused
the usecounting code. This problem was found by Kevin Hilman
<khilman@deeprootsystems.com>.
N.B.: This patch introduces one significant functional difference over
the previous pm34xx.c code: sleepdeps are now cleared during
clockdomain initialization, whereas previously they were left
untouched. This has been tested by Kevin and confirmed to work.
The original version of this patch also did not take into
consideration that some clockdomains do not have sleep or wakeup
dependency sources, which caused NULL pointer dereferences. This
problem was debugged and fixed by Kevin Hilman
<khilman@deeprootsystems.com>.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Jouni Högander <jouni.hogander@nokia.com>
Module offsets were same for OMAP2 and OMAP3 while they differ for OMAP4.
Hence we need different macros for identifying platform specific offsets.
Signed-off-by: Abhijit Pagare <abhijitpagare@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Move the remaining headers under plat-omap/include/mach
to plat-omap/include/plat. Also search and replace the
files using these headers to include using the right path.
This was done with:
#!/bin/bash
mach_dir_old="arch/arm/plat-omap/include/mach"
plat_dir_new="arch/arm/plat-omap/include/plat"
headers=$(cd $mach_dir_old && ls *.h)
omap_dirs="arch/arm/*omap*/ \
drivers/video/omap \
sound/soc/omap"
other_files="drivers/leds/leds-ams-delta.c \
drivers/mfd/menelaus.c \
drivers/mfd/twl4030-core.c \
drivers/mtd/nand/ams-delta.c"
for header in $headers; do
old="#include <mach\/$header"
new="#include <plat\/$header"
for dir in $omap_dirs; do
find $dir -type f -name \*.[chS] | \
xargs sed -i "s/$old/$new/"
done
find drivers/ -type f -name \*omap*.[chS] | \
xargs sed -i "s/$old/$new/"
for file in $other_files; do
sed -i "s/$old/$new/" $file
done
done
for header in $(ls $mach_dir_old/*.h); do
git mv $header $plat_dir_new/
done
Signed-off-by: Tony Lindgren <tony@atomide.com>
Add some infrastructure to easily iterate over clock and power
domains.
Signed-off-by: Peter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
This patch allows the UART clocks to be disabled when the OMAP UARTs
are inactive, thus permitting the chip to hit retention in idle.
After the expiration of an activity timer, each UART is allowed to
disable its clocks so the system can enter retention. The activity
timer is (re)activated on any UART interrupt, UART wake event or any
IO pad wakeup. The actual disable of the UART clocks is done in the
'prepare_idle' hook called from the OMAP idle loop.
While the activity timer is active, the smart-idle mode of the UART is
also disabled. This is due to a "feature" of the UART module that
after a UART wakeup, the smart-idle mode may be entered before the
UART has communicated the interrupt, or upon TX, an idle mode may be
entered before the TX FIFOs are emptied.
Upon suspend, the 'prepare_suspend' hook cancels any pending activity
timers and allows the clocks to be disabled immediately.
In addition, upon disabling clocks the UART state is saved in case
of an off-mode transition while clocks are off.
Special thanks to Tero Kristo for the initial ideas and first versions
of UART idle support, and to Jouni Hogander for extra testing and
bugfixes.
Tested on OMAP3 (Beagle, RX51, SDP, EVM) and OMAP2 (n810)
Cc: Tero Kristo <tero.kristo@nokia.com>
Cc: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Add common omap2/3 function to check wether there is irq pending.
Switch to use it in omap2 pm code instead of its own.
Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
This patch is to sync the core linux-omap PM code with mainline. This
code has evolved and been used for a while the linux-omap tree, but
the attempt here is to finally get this into mainline.
Following this will be a series of patches from the 'PM branch' of the
linux-omap tree to add full PM hardware support from the linux-omap
tree.
Much of this PM core code was written by Jouni Hogander with
significant contributions from Paul Walmsley as well as many others
from Nokia, Texas Instruments and linux-omap community.
Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
