The standard omap_hwmod.c _reset() code relies on an IP block's
OCP_SYSCONFIG.SOFTRESET register bit to reset the IP block. This
works for most IP blocks on the chip, but unfortunately not all. For
example, initiator-only IP blocks often don't have any MPU-accessible
OCP-header registers, and therefore the MPU can't write to any
OCP_SYSCONFIG registers in that block. Other IP blocks, such as the
IVA and I2C, require a specialized reset sequence.
Since we need to be able to reset these IP blocks as well, allow
custom IP block reset functions to be passed into the hwmod code via a
per-hwmod-class reset function pointer, struct omap_hwmod_class.reset.
If .reset is non-null, then the hwmod _reset() code will call the custom
function instead of the standard OCP SOFTRESET-based code.
As part of this change, rename most of the existing _reset() function
code to _ocp_softreset(), to indicate more clearly that it does not work
for all cases.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Paul Hunt <hunt@ti.com>
Cc: Stanley Liu <stanley_liu@ti.com>
Allow board files and OMAP core code to control the state that some or
all of the hwmods end up in at the end of _setup() (called by
omap_hwmod_late_init() ). Reimplement the old skip_setup_idle code in
terms of this new postsetup state code.
There are two use-cases for this patch: the !CONFIG_PM_RUNTIME case,
in which all IP blocks should stay enabled after _setup() finishes;
and the MPU watchdog case, in which the watchdog IP block should enter
idle if watchdog coverage of kernel initialization is desired, and
should be disabled otherwise.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Charulatha Varadarajan <charu@ti.com>
Some OMAP IP blocks, such as the watchdog timers, cannot be completely
shut down via the standard hwmod shutdown mechanism. This patch
enables the hwmod data files to supply a pointer to a custom
pre-shutdown function via the struct omap_hwmod_class.pre_shutdown
function pointer. If the struct omap_hwmod_class.pre_shutdown
function pointer is non-null, the function will be executed before the
existing hwmod shutdown code runs.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Split omap2_init_common_hw() into two functions. The first,
omap2_init_common_infrastructure(), initializes the hwmod code and
data, the OMAP PM code, and the clock code and data. The second,
omap2_init_common_devices(), handles any other early device
initialization that, for whatever reason, has not been or cannot be
moved to initcalls or early platform devices.
This patch is required for the hwmod postsetup patch, which allows
board files to change the state that hwmods should be placed into at
the conclusion of the hwmod _setup() function. For example, for a
board whose creators wish to ensure watchdog coverage across the
entire kernel boot process, code to change the watchdog's postsetup
state will be added in the board-*.c file between the
omap2_init_common_infrastructure() and omap2_init_common_devices() function
calls.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
The SRAM PA addresses are locally defined and used at
different places, i.e. SRAM management code and idle sleep code.
The macros are now defined at a centralized place, for
easier maintenance.
Tested on N900 and Beagleboard with full RET and OFF modes,
using cpuidle and suspend.
Signed-off-by: Jean Pihet <j-pihet@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Nishanth Menon<nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
With new OPP layer, OPP users will access OPP API directly instead of
using OMAP PM layer, so remove all notions of OPPs from the OMAP PM
layer.
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
No need to call this early from init_irq. Also recent changes
initialize GPIO now later, so calling gpio_request from init_irq
will make it fail.
While at it, also remove the unnecessary EXPORT_SYMBOL.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Convert DMA library into DMA platform driver and make use of
platform data provided by hwmod data base for OMAP2+ onwards.
For OMAP1 processors, the DMA driver in mach-omap uses resource
structures for getting platform data.
Thanks to Tony Lindgren <tony@atomide.com> for fixing various
omap1 issues and testing the same on OSK5912 board.
Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
Tested-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Add OMAP2430 DMA hwmod data and also add required
DMA device attributes.
Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Add OMAP2420 DMA hwmod data and also add required
DMA device attributes.
Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Implement errata handling to use flags instead of cpu_is_* and
cpu_class_* in the code.
The errata flags are initialized at init time and during runtime we are
using the errata variable (via the IS_DMA_ERRATA macro) to execute the
required errata workaround.
Reused errata handling patch from: Peter Ujfalusi
<peter.ujfalusi@nokia.com>
https://patchwork.kernel.org/patch/231191/
Changes to above patch:
1. Changes are done for converting all the existing errata work arounds
to use this feature.
2. Detailed description for each errata is added.
3. Fixed bug in SET_DMA_ERRATA macro
4. Bit shifting in macro definitions are replaced with BIT() macro
Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
Tested-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Prepare DMA library to get converted into DMA driver using platform
device model and hwmod infrastucture(for omap2+, resource structures
for omap1)
The low level read/write macros are replaced with static inline
functions and register offsets are handled through static register
offset tables mapped through enumeration constants.
These low level read/write functions along with static register offset
tables will be moved to respective mach-omap dma files in the later
patches of this series.
There are no functionality changes with these changes except change in
logic for handling 16bit registers of OMAP1.
Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
Tested-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
The naming convention for omap_device is omap_XXX.
Rename the device and driver name in order to stick
to this naming convention.
Remove the hs prefix that is implicit for every OMAP uarts.
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Govindraj Raja <govindraj.raja@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Add minimal support for Nokia RM-680 board.
Tested with omap2plus_defconfig.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
[tony@atomide.com: updated to remove omap_gpio_init
Signed-off-by: Tony Lindgren <tony@atomide.com>
Some IOMMUs cannot use the whole 0x0 - 0xFFFFFFFF range.
With this new API the valid range can be set.
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Acked-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
Initialize asm_irq_flags in omap_init_irq and use it in
get_irqnr_and_base to detect between omap7xx and omap15xx/16xx.
Note that both INT_1510_IH2_IRQ and INT_1510_IH2_IRQ are defined
as 0, so use INT_1510_IH2_IRQ for both of them.
Tested-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Defining iounmap() with arguments prevents it from being used as a
function pointer, causing platforms to work around this. Instead,
define it to be a simple macro.
Do the same for __arch_io(re|un)map too.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We need to divide the 15xx/16xx offset by 2 for 7xx. Use bank->stride
for that. This allows us to get rid of the duplicate defines for the
MPUIO registers.
Note that this will cause omap-keypad.c driver to not work on 7xx.
However, the right fix there is to move over to matrix_keypad instead
as suggested by Cory Maccarrone <darkstar6262@gmail.com> and
Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>.
Cc: Cory Maccarrone <darkstar6262@gmail.com>
Acked-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Implement GPIO as a platform device.
GPIO APIs are used in machine_init functions. Hence it is
required to complete GPIO probe before board_init. Therefore
GPIO device register and driver register are implemented as
postcore_initcalls.
omap_gpio_init() does nothing now and this function would be
removed in the next patch as it's usage is spread across most
of the board files.
Inorder to convert GPIO as platform device, modifications are
required in clockxxxx_data.c file for OMAP1 so that device names
can be used to obtain clock instead of getting clocks by
name/NULL ptr.
Use runtime pm APIs (pm_runtime_put*/pm_runtime_get*) for enabling
or disabling the clocks, modify sysconfig settings and remove usage
of clock FW APIs.
Note 1: Converting GPIO driver to use runtime PM APIs is not done as a
separate patch because GPIO clock names are different for various OMAPs
and are different for some of the banks in the same CPU. This would need
usage of cpu_is checks and bank id checks while using clock FW APIs in
the gpio driver. Hence while making GPIO a platform driver framework,
PM runtime APIs are used directly.
Note 2: While implementing GPIO as a platform device, pm runtime APIs
are used as mentioned above and modification is not done in gpio's
prepare for idle/ resume after idle functions. This would be done
in the next patch series and GPIO driver would be made to use dev_pm_ops
instead of sysdev_class in that series only.
Due to the above, the GPIO driver implicitly relies on
CM_AUTOIDLE = 1 on its iclk for power management to work, since the
driver never disables its iclk.
This would be taken care in the next patch series (see Note 3 below).
Refer to
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg39112.html
for more details.
Note 3: only pm_runtime_get_sync is called in gpio's probe() and
pm_runtime_put* is never called. This is to make the implementation
similar to the existing GPIO code. Another patch series would be sent
to correct this.
In OMAP3 and OMAP4 gpio's debounce clocks are optional clocks. They
are enabled/ disabled whenever required using clock framework APIs
TODO:
1. Cleanup the GPIO driver. Use function pointers and register
offest pointers instead of using hardcoded values
2. Remove all cpu_is_ checks and OMAP specific macros
3. Remove usage of gpio_bank array so that only
instance specific information is used in driver code
4. Rename 'method'/ avoid it's usage
5. Fix the non-wakeup gpios handling for OMAP2430, OMAP3 & OMAP4
6. Modify gpio's prepare for idle/ resume after idle functions
to use runtime pm implentation.
Signed-off-by: Charulatha V <charu@ti.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Reviewed-by: Basak, Partha <p-basak2@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
[tony@atomide.com: updated for bank specific revision and updated boards]
Signed-off-by: Tony Lindgren <tony@atomide.com>
Add GPIO hwmod data for OMAP2420 and add the required
GPIO device attributes in the gpio header file
Also remove "omap24xx.h" header file as it is not required
anymore.
Signed-off-by: Charulatha V <charu@ti.com>
Acked-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Add support for handling OMAP15xx specific gpio_init by
providing platform device data and doing device registration.
Signed-off-by: Charulatha V <charu@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
In the current mailbox driver, the mailbox internal pointer for
callback can be directly manipulated by the Users, so a second
User can easily corrupt the first user's callback pointer.
The initial effort to correct this issue can be referred here:
https://patchwork.kernel.org/patch/107520/
Along with fixing the above stated issue, this patch adds the
flexibility option to register notifications from
multiple readers to the events received on a mailbox instance.
The discussion regarding this can be referred here.
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg30671.html
Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Acked-by: Hiroshi Doyu <hiroshi.doyu@nokia.com>
The variable rq_full flag is a global variable, so if there are multiple
mailbox users there will be conflicts. Now there is a full flag per
mailbox queue.
Reported-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Acked-by: Hiroshi Doyu <hiroshi.doyu@nokia.com>
Access to some registers depends on register access mode
Three different modes are available for OMAP (at least)
• Operational mode LCR_REG[7] = 0x0
• Configuration mode A LCR_REG[7] = 0x1 and LCR_REG[7:0]! = 0xBF
• Configuration mode B LCR_REG[7] = 0x1 and LCR_REG[7:0] = 0xBF
Define access modes and remove redefinitions and magic numbers
in serial drivers (and later in bluetooth driver).
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@nokia.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Define MDR1 register serial definitions used in serial and
bluetooth drivers.
Change magic number to ones defined in serial_reg for omap1/2
serial driver.
Remove redefined MDR1 register definitions in omap-serial driver.
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@nokia.com>
Acked-by: G, Manjunath Kondaiah <manjugk@ti.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Craneboard is a hardware development platform based on the
Sitara AM3517 ARM Cortex - A8 microprocessor device. This is a
low cost reference design.
This patch adds basic board file. Detailed support will follow in
subsequent patches.
[1] http://www.ti.com/arm
[2] http://www.mistralsolutions.com/products/craneboard.php
Signed-off-by: Srinath <srinath@mistralsolutions.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Add hwmod structures for I2C controllers on OMAP3430.
This patch was developed in collaboration with Paul Walmsley
<paul@pwsan.com>.
OMAP3 fixes for correct IDLEST bit monitoring from
G, Manjunath Kondaiah <manjugk@ti.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: G, Manjunath Kondaiah <manjugk@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
This merges the staging-next tree to Linus's tree and resolves
some conflicts that were present due to changes in other trees that were
affected by files here.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'for-linus' of git://gitorious.org/linux-omap-dss2/linux:
OMAP: DSS2: don't power off a panel twice
OMAP: DSS2: OMAPFB: Allow usage of def_vrfb only for omap2,3
OMAP: DSS2: OMAPFB: make VRFB depends on OMAP2,3
OMAP: DSS2: OMAPFB: Allow FB_OMAP2 to build without VRFB
arm/omap: simplify conditional
OMAP: DSS2: DSI: Remove extra iounmap in error path
OMAP: DSS2: Use dss_features framework on DSS2 code
OMAP: DSS2: Introduce dss_features files
video/omap: remove mux.h include
ARM: omap/fb: move get_fbmem_region() to .init.text
ARM: omap/fb: move omapfb_reserve_sram to .init.text
ARM: omap/fb: move omap_init_fb to .init.text
OMAP: DSS2: OMAPFB: swap front and back porches for both hsync and vsync
OMAP: DSS2: make filter coefficient tables human readable
OMAP: DSS2: Add SPI dependency to Kconfig of ACX565AKM panel
* 'omap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6: (163 commits)
omap: complete removal of machine_desc.io_pg_offst and .phys_io
omap: UART: fix wakeup registers for OMAP24xx UART2
omap: Fix spotty MMC voltages
ASoC: OMAP4: MCPDM: Remove unnecessary include of plat/control.h
serial: omap-serial: fix signess error
OMAP3: DMA: Errata i541: sDMA FIFO draining does not finish
omap: dma: Fix buffering disable bit setting for omap24xx
omap: serial: Fix the boot-up crash/reboot without CONFIG_PM
OMAP3: PM: fix scratchpad memory accesses for off-mode
omap4: pandaboard: enable the ehci port on pandaboard
omap4: pandaboard: Fix the init if CONFIG_MMC_OMAP_HS is not set
omap4: pandaboard: remove unused hsmmc definition
OMAP: McBSP: Remove null omap44xx ops comment
OMAP: McBSP: Swap CLKS source definition
OMAP: McBSP: Fix CLKR and FSR signal muxing
OMAP2+: clock: reduce the amount of standard debugging while disabling unused clocks
OMAP: control: move plat-omap/control.h to mach-omap2/control.h
OMAP: split plat-omap/common.c
OMAP: McBSP: implement functional clock switching via clock framework
OMAP: McBSP: implement McBSP CLKR and FSR signal muxing via mach-omap2/mcbsp.c
...
Fixed up trivial conflicts in arch/arm/mach-omap2/
{board-zoom-peripherals.c,devices.c} as per Tony
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6: (365 commits)
ALSA: hda - Disable sticky PCM stream assignment for AD codecs
ALSA: usb - Creative USB X-Fi volume knob support
ALSA: ca0106: Use card specific dac id for mute controls.
ALSA: ca0106: Allow different sound cards to use different SPI channel mappings.
ALSA: ca0106: Create a nice spot for mapping channels to dacs.
ALSA: ca0106: Move enabling of front dac out of hardcoded setup sequence.
ALSA: ca0106: Pull out dac powering routine into separate function.
ALSA: ca0106 - add Sound Blaster 5.1vx info.
ASoC: tlv320dac33: Use usleep_range for delays
ALSA: usb-audio: add Novation Launchpad support
ALSA: hda - Add workarounds for CT-IBG controllers
ALSA: hda - Fix wrong TLV mute bit for STAC/IDT codecs
ASoC: tpa6130a2: Error handling for broken chip
ASoC: max98088: Staticise m98088_eq_band
ASoC: soc-core: Fix codec->name memory leak
ALSA: hda - Apply ideapad quirk to Acer laptops with Cxt5066
ALSA: hda - Add some workarounds for Creative IBG
ALSA: hda - Fix wrong SPDIF NID assignment for CA0110
ALSA: hda - Fix codec rename rules for ALC662-compatible codecs
ALSA: hda - Add alc_init_jacks() call to other codecs
...
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (141 commits)
USB: mct_u232: fix broken close
USB: gadget: amd5536udc.c: fix error path
USB: imx21-hcd - fix off by one resource size calculation
usb: gadget: fix Kconfig warning
usb: r8a66597-udc: Add processing when USB was removed.
mxc_udc: add workaround for ENGcm09152 for i.MX35
USB: ftdi_sio: add device ids for ScienceScope
USB: musb: AM35x: Workaround for fifo read issue
USB: musb: add musb support for AM35x
USB: AM35x: Add musb support
usb: Fix linker errors with CONFIG_PM=n
USB: ohci-sh - use resource_size instead of defining its own resource_len macro
USB: isp1362-hcd - use resource_size instead of defining its own resource_len macro
USB: isp116x-hcd - use resource_size instead of defining its own resource_len macro
USB: xhci: Fix compile error when CONFIG_PM=n
USB: accept some invalid ep0-maxpacket values
USB: xHCI: PCI power management implementation
USB: xHCI: bus power management implementation
USB: xHCI: port remote wakeup implementation
USB: xHCI: port power management implementation
...
Manually fix up (non-data) conflict: the SCSI merge gad renamed the
'hw_sector_size' member to 'physical_block_size', and the USB tree
brought a new use of it.
FB_OMAP2 can work without VRFB, but currently does not build. Fix this.
Signed-off-by: Senthilvadivu Guruswamy <svadivu@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
Calls init functions of dss_features during dss_probe, and the following
features are made omapxxxx independent:
- number of managers, overlays
- supported color modes for each overlay
- supported displays for each manager
- global aplha, and restriction of global alpha for video1 pipeline
- The register field ranges : FIRHINC, FIRVINC, FIFOHIGHTHRESHOLD
FIFOLOWTHRESHOLD and FIFOSIZE
Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
AM35x has musb interface (version 1.8) and uses CPPI41 DMA engine.
It has USB phy built inside the IP itself.
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Get mem and irq resources using platform helpers
- platform_get_base
- platform_get_irq
Signed-off-by: Abraham Arce <x0066660@ti.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Implement the suggested workaround for OMAP3 regarding to sDMA draining
issue, when the channel is disabled on the fly.
This errata affects the following configuration:
sDMA transfer is source synchronized
Buffering is enabled
SmartStandby is selected.
The issue can be easily reproduced by creating overrun situation while
recording audio.
Either introduce load to the CPU:
nice -19 arecord -D hw:0 -M -B 10000 -F 5000 -f dat > /dev/null & \
dd if=/dev/urandom of=/dev/null
or suspending the arecord, and resuming it:
arecord -D hw:0 -M -B 10000 -F 5000 -f dat > /dev/null
CTRL+Z; fg; CTRL+Z; fg; ...
In case of overrun audio stops DMA, and restarts it (without reseting
the sDMA channel). When we hit this errata in stop case (sDMA drain did
not complete), at the coming start the sDMA will not going to be
operational (it is still draining).
This leads to DMA stall condition.
On OMAP3 we can recover with sDMA channel reset, it has been observed
that by introducing unrelated sDMA activity might also help (reading
from MMC for example).
The same errata exists for OMAP2, where the suggestion is to disable the
buffering to avoid this type of error.
On OMAP3 the suggestion is to set sDMA to NoStandby before disabling
the channel, and wait for the drain to finish, than configure sDMA to
SmartStandby again.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by : Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by : Manjunath Kondaiah G <manjugk@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
An errata workaround for omap24xx is not setting the buffering disable bit
25 what is the purpose but channel enable bit 7 instead.
Background for this fix is the DMA stalling issue with ASoC omap-mcbsp
driver. Peter Ujfalusi <peter.ujfalusi@nokia.com> has found an issue in
recording that the DMA stall could happen if there were a buffer overrun
detected by ALSA and the DMA was stopped and restarted due that. This
problem is known to occur on both OMAP2420 and OMAP3. It can recover on
OMAP3 after dma free, dma request and reconfiguration cycle. However, on
OMAP2420 it seems that only way to recover is a reset.
Problem was not visible before the commit c12abc0. That commit changed that
the McBSP transmitter/receiver is released from reset only when needed. That
is, only enabled McBSP transmitter without transmission was able to prevent
this DMA stall problem in receiving side and underlying problem did not show
up until now. McBSP transmitter itself seems to no be reason since DMA
stall does not recover by enabling the transmission after stall.
Debugging showed that there were a DMA write active during DMA stop time and
it never completed even when restarting the DMA. Experimenting showed that
the DMA buffering disable bit could be used to avoid stalling when using
source synchronized transfers. However that could have performance hit and
OMAP3 TRM states that buffering disable is not allowed for destination
synchronized transfers so subsequent patch will implement a method to
complete DMA writes when stopping.
This patch is based on assumtion that complete lock-up on OMAP2420 is
different but related problem. I don't have access to OMAP2420 errata but
I believe this old workaround here is put for a reason but unfortunately
a wrong bit was typed and problem showed up only now.
Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Manjunath Kondaiah G <manjugk@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
