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VIDEO_EVENT_VSYNC
VIDEO_EVENT_VSYNC needs to tell the application which field it was that
received a VSYNC (odd/even/progressive). The vsync_field was added to the
union in video_event for this purpose.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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It took three core maintainers, over four years of work, eight new i2c
modules, eleven new V4L2 ioctls, three new DVB video ioctls, a Sliced
VBI API, a new MPEG encoder API, an enhanced DVB video MPEG decoding
API, major YUV/OSD contributions from Ian and John, web/wiki/svn/trac
support from Axel Thimm, (hardware) support from Hauppauge, support and
assistance from the v4l-dvb people and the many, many users of ivtv to
finally make it possible to merge this driver into the kernel.
Thank you all!
Signed-off-by: Kevin Thayer <nufan_wfk@yahoo.com>
Signed-off-by: Chris Kennedy <c@groovy.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: John P Harvey <john.p.harvey@btinternet.com>
Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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The documentation of Several miscellaneous commands was updated.
As a result of which the CX2341X_ENC_UNKNOWN command was renamed to
CX2341X_ENC_SET_VERT_CROP_LINE.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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This change supplies a more generic version of the tuner callback.
The tuner struct now has a function pointer
int (*tuner_callback) (void *dev, int command, int arg)
additionally to a int config parameter.
both can be set through the TUNER_SET_TYPE_ADDR client call.
Note that the meaning of the parameters depend on the tuner type.
Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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These entries mainly are to support configurations of the tda827x
silicon tuner with a preamplifier.
The values can be set throgh the attach inform or through
the extended TUNER_SET_TYPE_ADDR client call. The function pointer
will only be updated if the parameter is not NULL.
Since a typecast is necessary to set the pointer, i added a typedef for
this pointer (tuner_gpio_func_t) in tuner.h
Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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The cx23415 adds some extra features that this DVB decoding API did
not support. This API has been expanded to support the required
features. Both source and binary backwards compatibility is kept
intact by these changes. So existing applications are not affected.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Ralph Metzler <rjkm@metzlerbros.de>
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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VIDIOC_G_CHIP_IDENT improves debugging of card problems: it can be
used to detect which chips are on the board and based on that information
selected register dumps can be made, making it easy to debug complicated
media chips containing tens or hundreds of registers.
This ioctl replaces the internal VIDIOC_INT_G_CHIP_IDENT ioctl.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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Added VIDIOC_INT_G_STD_OUTPUT and VIDIOC_INT_S_STD_OUTPUT to allow drivers
to set the TV standard for video output separately from the video capture.
This is needed for cx23415 support where the decoder is separate from the
encoder and can have a different TV standard.
Modified the saa7127 module to listen to VIDIOC_INT_G/S_STD_OUTPUT instead
of VIDIOC_G/S_STD.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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Add V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY support.
Also add support for local and global alpha overlays.
Add new field enums V4L2_FIELD_INTERLACED_TB and V4L2_FIELD_INTERLACED_BT.
These changes are needed to support the ivtv On Screen Display features.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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Add V4L2_CAP_VIDEO_OUTPUT_POS capability and x, y position coordinates
to struct v4l2_pix_format.
This is needed to support positioning the MPEG/YUV output of the cx23415.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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Added V4L2_CID_MPEG_AUDIO_MUTE, V4L2_CID_MPEG_VIDEO_MUTE and
V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS controls together with
their implementation in the cx2341x module.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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show_state() (SysRq-T) developed the buggy habbit of not showing
TASK_RUNNING tasks. This was due to the mistaken belief that state_filter
== -1 would be a pass-through filter - while in reality it did not let
TASK_RUNNING == 0 p->state values through.
Fix this by restoring the original '!state_filter means all tasks'
special-case i had in the original version. Test-built and test-booted on
i686, SysRq-T now works as intended.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* 'for-linus' of git://git.infradead.org/ubi-2.6:
UBI: remove unused variable
UBI: add me to MAINTAINERS
JFFS2: add UBI support
UBI: Unsorted Block Images
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git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2: (27 commits)
ocfs2: Cache extent records
ocfs2: Remember rw lock level during direct io
ocfs2: Fix up i_blocks calculation to know about holes
ocfs2: Fix extent lookup to return true size of holes
ocfs2: Read from an unwritten extent returns zeros
ocfs2: make room for unwritten extents flag
ocfs2: Use own splice write actor
ocfs2: Use do_sync_mapping_range() in ocfs2_zero_tail_for_truncate()
[PATCH] Turn do_sync_file_range() into do_sync_mapping_range()
ocfs2: zero tail of sparse files on truncate
ocfs2: Teach ocfs2_get_block() about holes
ocfs2: remove ocfs2_prepare_write() and ocfs2_commit_write()
ocfs2: teach ocfs2_file_aio_write() about sparse files
ocfs2: Turn off shared writeable mmap for local files systems with holes.
ocfs2: abstract out allocation locking
ocfs2: teach extend/truncate about sparse files
ocfs2: temporarily remove extent map caching
ocfs2: sparse b-tree support
ocfs2: small cleanup of ocfs2_request_delete()
ocfs2: remove unused code
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* master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6: (67 commits)
[SCSI] SUNESP: Complete driver rewrite to version 2.0
[SPARC64]: Convert PCI over to generic struct iommu/strbuf.
[SPARC]: device_node name constification fallout
[SPARC64]: Convert SBUS over to generic iommu/strbuf structs.
[SPARC64]: Add generic iommu and strbuf structs to iommu.h
[SPARC64]: Consolidate {sbus,pci}_iommu_arena.
[SPARC]: Make device_node name and type const
[SPARC64]: constify some paramaters of OF routines
[TIGON3]: of_get_property() returns const.
[SPARC64]: Fix PCI rework to adhere to of_get_property() const return.
[SPARC64]: Document and fix calculation of pages_avail.
[SPARC64]: Make sure pbm->prom_node is setup easly enough in psycho.c
[SPARC64]: Use bootmem_bootmap_pages() in choose_bootmap_pfn().
[SPARC64]: Add proper header file extern for cmdline_memory_size.
[SPARC64]: Kill sparc_ultra_dump_{i,d}tlb()
[SPARC64]: Use DECLARE_BITMAP and BITS_TO_LONGS in mm/init.c
[SPARC64]: Give move verbose show_mem() output just like i386.
[SPARC64]: Mark show_mem() printk's with KERN_INFO.
[SPARC64]: Kill kvaddr_to_phys() and friends.
[SPARC64]: Privatize sun4u_get_pte() and fix name.
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* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: (448 commits)
[IPV4] nl_fib_lookup: Initialise res.r before fib_res_put(&res)
[IPV6]: Fix thinko in ipv6_rthdr_rcv() changes.
[IPV4]: Add multipath cached to feature-removal-schedule.txt
[WIRELESS] cfg80211: Clarify locking comment.
[WIRELESS] cfg80211: Fix locking in wiphy_new.
[WEXT] net_device: Don't include wext bits if not required.
[WEXT]: Misc code cleanups.
[WEXT]: Reduce inline abuse.
[WEXT]: Move EXPORT_SYMBOL statements where they belong.
[WEXT]: Cleanup early ioctl call path.
[WEXT]: Remove options.
[WEXT]: Remove dead debug code.
[WEXT]: Clean up how wext is called.
[WEXT]: Move to net/wireless
[AFS]: Eliminate cmpxchg() usage in vlocation code.
[RXRPC]: Fix pointers passed to bitops.
[RXRPC]: Remove bogus atomic_* overrides.
[AFS]: Fix u64 printing in debug logging.
[AFS]: Add "directory write" support.
[AFS]: Implement the CB.InitCallBackState3 operation.
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* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (22 commits)
[MIPS] Don't force frame pointers for lockdep on MIPS
[MIPS] update vr41xx Kconfig
[MIPS] remove 2 select entries for VR41xx
[MIPS] rename VR41XX to VR4100 series
[MIPS] Use DEFINE_SPINLOCK instead of SPIN_LOCK_UNLOCKED.
[MIPS] Replace old fashioned "__typeof" with "__typeof__".
[MIPS] Remove unused _THREAD_SIZE_ORDER from asm-offset.c.
[MIPS] Change PCI host bridge setup/resources
[MIPS] Register PCI host bridge resource earlier
[MIPS] Remove pnx8550-v2pci_defconfig
[MIPS] Add bcm1480 ZBus trace support, fix wait related bugs
[MIPS] Updated Sibyte headers
[MIPS] Remove unused argument from kunmap_coherent().
[MIPS] Malta: Delete unused prototype of mips_timer_interrupt.
[MIPS] Select ZONE_DMA only if GENERIC_ISA_DMA selected
[MIPS] MIPS Tech: Get rid of volatile in core code.
[MIPS] IP22: Get rid of volatile in IP22 core code.
[MIPS] JMR3927 cleanup
[MIPS] merge GT64111 PCI routines and GT64120 PCI_0 routines
[MIPS] Cobalt: Split PCI codes from setup.c
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* 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6: (38 commits)
[S390] SPIN_LOCK_UNLOCKED cleanup in drivers/s390
[S390] Clean up smp code in preparation for some larger changes.
[S390] Remove debugging junk.
[S390] Switch etr from tasklet to workqueue.
[S390] split page_test_and_clear_dirty.
[S390] Processor degradation notification.
[S390] vtime: cleanup per_cpu usage.
[S390] crypto: cleanup.
[S390] sclp: fix coding style.
[S390] vmlogrdr: stop IUCV connection in vmlogrdr_release.
[S390] sclp: initialize early.
[S390] ctc: kmalloc->kzalloc/casting cleanups.
[S390] zfcpdump support.
[S390] dasd: Add ipldev parameter.
[S390] dasd: Add sysfs attribute status and generate uevents.
[S390] Improved kernel stack overflow checking.
[S390] Get rid of console setup functions.
[S390] No execute support cleanup.
[S390] Minor fault path optimization.
[S390] Use generic bug.
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[Robert's original log message said this was a bug but it isn't, it's
just very old fashioned syntax that is not (no longer?) documented in the
gcc documentation. So for the sake of uniformity I'm applying his
patch but with a modified log message. -- Ralf]
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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This is an update to the earlier patch for the sibyte headers, and superceeds
the previous patch. Changes were necessary to get the tbprof driver working
on the bcm1480.
Patch to update Sibyte header files to match master versions maintained
at Broadcom. This patch also corrects some whitespace problems, and
(hopefully) shouldn't introduce any new ones.
Signed-off-by: Mark Mason <mason@broadcom.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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* Kill dead codes
* Rearrange irq chip handlers
* Minimize defconfig
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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The page_test_and_clear_dirty primitive really consists of two
operations, page_test_dirty and the page_clear_dirty. The combination
of the two is not an atomic operation, so it makes more sense to have
two separate operations instead of one.
In addition to the improved readability of the s390 version of
SetPageUptodate, it now avoids the page_test_dirty operation which is
an insert-storage-key-extended (iske) instruction which is an expensive
operation.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Generate uevents for all cpus if cpu capability changes. This can
happen e.g. because the cpus are overheating. The cpu capability can
be read via /sys/devices/system/cpu/cpuN/capability.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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s390 machines provide hardware support for creating Linux dumps on SCSI
disks. For creating a dump a special purpose dump Linux is used. The first
32 MB of memory are saved by the hardware before the dump Linux is
booted. Via an SCLP interface, the saved memory can be accessed from
Linux. This patch exports memory and registers of the crashed Linux to
userspace via a debugfs file. For more information refer to
Documentation/s390/zfcpdump.txt, which is included in this patch.
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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Generic bug implementation for s390. Will increase the value of the
console output on BUG() statements since registers r0-r5,r14 will
not be clobbered by a printk() call that was previously done before
the illegal instruction of BUG() was hit.
Also implements an architecture specific WARN_ON(). Output of that
could be increased but requires common code change.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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This patch adds two improvements to the oops output. First it adds an
additional line after the PSW which decodes the different fields of it.
Second a disassembler is added that decodes the instructions surrounding
the faulting PSW. The output of a test oops now looks like this:
kernel BUG at init/main.c:419
illegal operation: 0001 [#1]
CPU: 0 Not tainted
Process swapper (pid: 0, task: 0000000000464968, ksp: 00000000004be000)
Krnl PSW : 0700000180000000 00000000000120b6 (rest_init+0x36/0x38)
R:0 T:1 IO:1 EX:1 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 EA:3
Krnl GPRS: 0000000000000003 00000000004ba017 0000000000000022 0000000000000001
000000000003a5f6 0000000000000000 00000000004be6a8 0000000000000000
0000000000000000 00000000004b8200 0000000000003a50 0000000000008000
0000000000516368 000000000033d008 00000000000120b2 00000000004bdee0
Krnl Code: 00000000000120a6: e3e0f0980024 stg %r14,152(%r15)
00000000000120ac: c0e500014296 brasl %r14,3a5d8
00000000000120b2: a7f40001 brc 15,120b4
>00000000000120b6: 0707 bcr 0,%r7
00000000000120b8: eb7ff0500024 stmg %r7,%r15,80(%r15)
00000000000120be: c0d000195825 larl %r13,33d108
00000000000120c4: a7f13f00 tmll %r15,16128
00000000000120c8: a7840001 brc 8,120ca
Call Trace:
([<00000000000120b2>] rest_init+0x32/0x38)
[<00000000004be614>] start_kernel+0x37c/0x410
[<0000000000012020>] _ehead+0x20/0x80
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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Introduce a mutex for struct ccwgroup to prevent simuntaneous
register/unregister on the same ccwgroup device.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Add a new attribute to the channel-path sysfs directory through which
channel-path configure operations can be triggered. Also listen for
hardware events requesting channel-path configure operations and
process them accordingly.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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Clean interface between cio and ipl code, so Peter stops complaining.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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gcc 4.1 doesn't seem to like const variables as inline assembly
outputs. Drop support for reading 64-bit values using get_user() so
that we can use an unsigned long to hold the result regardless of the
actual size. This should be safe since many architectures, including
i386, doesn't support reading 64-bit values with get_user().
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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This int cast is superfluous since system.h cmpxchg already casts it in
(typeof(*(ptr))).
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Using readb/writeb to implement these breaks NOR flash support. I
can't see any reason why regular memcpy and memset shouldn't work.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Since the core setup code takes care of both allocation and
reservation of framebuffer memory, there's no need for this board-
specific hook anymore. Replace it with two global variables,
fbmem_start and fbmem_size, which can be used directly.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Use struct resource to specify both physical memory regions and
reserved regions and push everything into the same framework,
including kernel code/data and initrd memory. This allows us to get
rid of many special cases in the bootmem initialization and will also
make it easier to implement more robust handling of framebuffer
memory later.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Fix the I/O access macros so that they work with externally connected
devices accessed in little-endian mode over any bus width:
* Use a set of macros to define I/O port- and memory operations
borrowed from MIPS.
* Allow subarchitecture to specify address- and data-mangling
* Implement at32ap-specific port mangling (with build-time
configurable bus width. Only one bus width at a time supported
for now.)
* Rewrite iowriteN and friends to use write[bwl] and friends
(not the __raw counterparts.)
This has been tested using pata_pcmcia to access a CompactFlash card
connected to the EBI (16-bit bus width.)
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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* Use generic BUG() handling
* Remove some useless debug statements
* Use a common function _exception() to send signals or oops when
an exception can't be handled. This makes sure init doesn't
enter an infinite exception loop as well. Borrowed from powerpc.
* Add some basic exception tracing support to the page fault code.
* Rework dump_stack(), show_regs() and friends and move everything
into process.c
* Print information about configuration options and chip type when
oopsing
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Clean up the cpu identification code, using definitions from
<asm/sysreg.h> instead of hardcoded constants. Also, add a features
bitmap to struct avr32_cpuinfo to allow other code to make decisions
based upon what the running cpu is actually capable of.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Fix indentation and remove spurious comments in asm-avr32/sysreg.h
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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This patch puts the CPU in sleep 0 when doing nothing, idle. This will
turn of the CPU clock and thus save power. The CPU is waken again when
an interrupt occurs.
Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Due to limitation of the count-compare system timer (not able to
count when CPU is in sleep), the system timer had to be changed to
use a peripheral timer/counter.
The old COUNT-COMPARE code is still present in time.c as weak
functions. The new timer is added to the architecture directory.
This patch sets up TC0 as system timer The new timer has been tested
on AT32AP7000/ATSTK1000 at 100 Hz, 250 Hz, 300 Hz and 1000 Hz.
For more details about the timer/counter see the datasheet for
AT32AP700x available at
http://www.atmel.com/dyn/products/product_card.asp?part_id=3903
Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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Complete the SMC configuration code by adding nwait and tdf
parameter. After this change, we support the same parameters as the
hardware.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
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UBI (Latin: "where?") manages multiple logical volumes on a single
flash device, specifically supporting NAND flash devices. UBI provides
a flexible partitioning concept which still allows for wear-levelling
across the whole flash device.
In a sense, UBI may be compared to the Logical Volume Manager
(LVM). Whereas LVM maps logical sector numbers to physical HDD sector
numbers, UBI maps logical eraseblocks to physical eraseblocks.
More information may be found at
http://www.linux-mtd.infradead.org/doc/ubi.html
Partitioning/Re-partitioning
An UBI volume occupies a certain number of erase blocks. This is
limited by a configured maximum volume size, which could also be
viewed as the partition size. Each individual UBI volume's size can
be changed independently of the other UBI volumes, provided that the
sum of all volume sizes doesn't exceed a certain limit.
UBI supports dynamic volumes and static volumes. Static volumes are
read-only and their contents are protected by CRC check sums.
Bad eraseblocks handling
UBI transparently handles bad eraseblocks. When a physical
eraseblock becomes bad, it is substituted by a good physical
eraseblock, and the user does not even notice this.
Scrubbing
On a NAND flash bit flips can occur on any write operation,
sometimes also on read. If bit flips persist on the device, at first
they can still be corrected by ECC, but once they accumulate,
correction will become impossible. Thus it is best to actively scrub
the affected eraseblock, by first copying it to a free eraseblock
and then erasing the original. The UBI layer performs this type of
scrubbing under the covers, transparently to the UBI volume users.
Erase Counts
UBI maintains an erase count header per eraseblock. This frees
higher-level layers (like file systems) from doing this and allows
for centralized erase count management instead. The erase counts are
used by the wear-levelling algorithm in the UBI layer. The algorithm
itself is exchangeable.
Booting from NAND
For booting directly from NAND flash the hardware must at least be
capable of fetching and executing a small portion of the NAND
flash. Some NAND flash controllers have this kind of support. They
usually limit the window to a few kilobytes in erase block 0. This
"initial program loader" (IPL) must then contain sufficient logic to
load and execute the next boot phase.
Due to bad eraseblocks, which may be randomly scattered over the
flash device, it is problematic to store the "secondary program
loader" (SPL) statically. Also, due to bit-flips it may become
corrupted over time. UBI allows to solve this problem gracefully by
storing the SPL in a small static UBI volume.
UBI volumes vs. static partitions
UBI volumes are still very similar to static MTD partitions:
* both consist of eraseblocks (logical eraseblocks in case of UBI
volumes, and physical eraseblocks in case of static partitions;
* both support three basic operations - read, write, erase.
But UBI volumes have the following advantages over traditional
static MTD partitions:
* there are no eraseblock wear-leveling constraints in case of UBI
volumes, so the user should not care about this;
* there are no bit-flips and bad eraseblocks in case of UBI volumes.
So, UBI volumes may be considered as flash devices with relaxed
restrictions.
Where can it be found?
Documentation, kernel code and applications can be found in the MTD
gits.
What are the applications for?
The applications help to create binary flash images for two purposes: pfi
files (partial flash images) for in-system update of UBI volumes, and plain
binary images, with or without OOB data in case of NAND, for a manufacturing
step. Furthermore some tools are/and will be created that allow flash content
analysis after a system has crashed..
Who did UBI?
The original ideas, where UBI is based on, were developed by Andreas
Arnez, Frank Haverkamp and Thomas Gleixner. Josh W. Boyer and some others
were involved too. The implementation of the kernel layer was done by Artem
B. Bityutskiy. The user-space applications and tools were written by Oliver
Lohmann with contributions from Frank Haverkamp, Andreas Arnez, and Artem.
Joern Engel contributed a patch which modifies JFFS2 so that it can be run on
a UBI volume. Thomas Gleixner did modifications to the NAND layer. Alexander
Schmidt made some testing work as well as core functionality improvements.
Signed-off-by: Artem B. Bityutskiy <dedekind@linutronix.de>
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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