Commit Graph

52174 Commits

Author SHA1 Message Date
Peter Oberparleiter
7039d3a11c [S390] dasd: Add ipldev parameter.
Specifying 'ipldev' in the dasd= kernel parameter will automatically
activate the boot device for use by the dasd driver.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:44 +02:00
Horst Hummel
4dfd5c4593 [S390] dasd: Add sysfs attribute status and generate uevents.
This patch adds a sysfs-attribute 'status' to make the DASD device-status
accessible from user-space. In addition, the DASD driver generates an
uevent(CHANGE) for the ccw-device on each device-status change.
This enables user-space applications (e.g. udev) to do related processing.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:44 +02:00
Martin Schwidefsky
be7962856d [S390] Improved kernel stack overflow checking.
Recent cvs versions of gcc have support for an improved stack overflow
checking that calculates the size of the guard size for each function.
If the compiler accepts -mstack-size without -mstack-guard then the
new stack check is available. We always want to use the new stack
checker.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-04-27 16:01:43 +02:00
Heiko Carstens
60691d3c2c [S390] Get rid of console setup functions.
We get this:

Section mismatch: reference to .init.text:con3270_consetup from .data
		  between 'con3270' (at offset 0x45c8) and 'con3270_fn'
Section mismatch: reference to .init.text:con3215_consetup from .data
		  between 'con3215' (at offset 0x4678) and
		  'raw3215_ccw_driver'

Since there is no difference between a non present console setup
function and one that returns only 0 remove them.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-04-27 16:01:43 +02:00
Martin Schwidefsky
be5ec363e9 [S390] No execute support cleanup.
Simplify the signal_return function that checks for the two special
system calls sigreturn and rt_sigreturn. No need to do a page table
walk, a call to copy_from_user while disabled page faults will work
as well.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-04-27 16:01:43 +02:00
Martin Schwidefsky
10c1031f70 [S390] Minor fault path optimization.
The minor fault path has grown a lot in terms of cycles. In particular
the kprobes hook is very costly. Optimize the path to save a couple of
cycles. If kprobes is enabled more than 300 cycles can be avoided if
kprobes_running() is false.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-04-27 16:01:43 +02:00
Heiko Carstens
c0007f1a65 [S390] Use generic bug.
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>
2007-04-27 16:01:42 +02:00
Martin Schwidefsky
bb11e3bdba [S390] Improved oops output.
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>
2007-04-27 16:01:42 +02:00
Martin Schwidefsky
03ff9a235a [S390] System call cleanup.
Remove system call glue for sys_clone, sys_fork, sys_vfork, sys_execve,
sys_sigreturn, sys_rt_sigreturn and sys_sigaltstack. Call do_execve from
kernel_execve directly, move pt_regs to the right place and branch to
sysc_return to start the user space program. This removes the last
in-kernel system call.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-04-27 16:01:42 +02:00
Cornelia Huck
ef99516c96 [S390] cio: Unregister ccw devices directly.
We used to unregister ccw devices not directly from the I/O
subchannel remove function in order to avoid lifelocks on the
css bus semaphore. This semaphore is gone, and there is no reason
to not unregister the ccw device directly (it is even better since
it is more in keeping with the goal of immediate disconnect).

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:42 +02:00
Cornelia Huck
8c4941c53b [S390] cio: cm_enable memory leak.
We allocage two pages when channel path measurements are enabled
via cm_enable. We must not forget to free them again when
channel path measurements are disabled again.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:41 +02:00
Cornelia Huck
d76123eb35 [S390] cio: ccwgroup register vs. unregister.
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>
2007-04-27 16:01:41 +02:00
Cornelia Huck
82b7ac058f [S390] cio: Dont call css_update_ssd_info from interrupt context.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:41 +02:00
Peter Oberparleiter
7ad6a24970 [S390] cio: fix subchannel channel-path data usage
Ensure that channel-path related subchannel data is only retrieved and
used when it is valid and that it is updated when it may have changed.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:40 +02:00
Peter Oberparleiter
83b3370c79 [S390] cio: replace subchannel evaluation queue with bitmap
Use a bitmap for indicating which subchannels require evaluation
instead of allocating memory for each evaluation request. This
approach reduces memory consumption during recovery in case of
massive evaluation request occurrence and removes the need for
memory allocation failure handling.

Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:40 +02:00
Stefan Bader
387b734fc2 [S390] cio: Re-start path verification after aborting internal I/O.
Path verification triggered by changes to the available CHPIDs will be
interrupted by another change but not re-started. This results in an
invalid path mask.
To solve this make sure to completely re-start path verification when
changing the available paths.

Signed-off-by: Stefan Bader <shbader@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:40 +02:00
Cornelia Huck
cfbe9bb2fb [S390] cio: Use add_uevent_var.
Convert ccw_uevent to use add_uevent_var and adapt snprint_alias.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:40 +02:00
Peter Oberparleiter
e5854a5839 [S390] cio: Channel-path configure function.
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>
2007-04-27 16:01:39 +02:00
Cornelia Huck
f5ba6c8636 [S390] cio: Clean up online_store.
Detangle the online_store code and make it more readable.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:39 +02:00
Peter Oberparleiter
c9182e0f42 [S390] cio: observe chpid valid flag
Check validity flag of CHPID description data before continuing with
channel-path initialization.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27 16:01:39 +02:00
Peter Oberparleiter
e6b6e10ac1 [S390] cio: Introduce separate files for channel-path related code.
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>
2007-04-27 16:01:38 +02:00
Peter Oberparleiter
d120b2a4e6 [S390] cio: Allow 0 and 1 as input for channel path status attribute.
Channel path status can now be modified by writing '0' and '1'
to the sysfs status attribute in addition to 'offline' and
'online' respectively.

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>
2007-04-27 16:01:38 +02:00
Peter Oberparleiter
f86635fad1 [S390] cio: Introduce struct chp_id.
Introduce data type for channel-path IDs.

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>
2007-04-27 16:01:38 +02:00
Heiko Carstens
6fc321fd7d [S390] cio/ipl: Clean interface between cio and ipl code.
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>
2007-04-27 16:01:38 +02:00
Heiko Carstens
29c380f5f0 [S390] memory detection: stop at first memory hole.
If both sclp and diag memory detection don't work stop at the first
memory hole. Otherwise the code might loop forever...

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-04-27 16:01:12 +02:00
Haavard Skinnemoen
8224ca1958 [AVR32] Fix compile error with gcc 4.1
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>
2007-04-27 14:21:47 +02:00
Artem Bityutskiy
d468a03002 UBI: remove unused variable
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-04-27 15:11:44 +03:00
Mathieu Desnoyers
a4022b0d60 avr32: remove unneeded cast in atomic.h
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>
2007-04-27 13:54:02 +02:00
Robert P. J. Day
0277b378c3 AVR32: Remove useless config option "GENERIC_BUST_SPINLOCK".
Remove the clearly useless config option GENERIC_BUST_SPINLOCK, which
is not used anywhere in the tree.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:45:26 +02:00
Haavard Skinnemoen
c0c3e81608 [AVR32] Optimize the TLB miss handler
Reorder some instructions and change the register usage to reduce
the number of pipeline stalls. Also use the bfextu and bfins
instructions for bitfield manipulations instead of shifting and
masking.

This makes gzipping a 80MB file approximately 2% faster.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:44:15 +02:00
Haavard Skinnemoen
9ca20a8366 [AVR32] Board code for ATNGW100
Add board code and defconfig for the ATNGW100 Network Gateway kit.
For more information about this board, see

http://www.atmel.com/dyn/products/tools_card.asp?tool_id=4102

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:44:15 +02:00
Haavard Skinnemoen
2c1a2a3441 [AVR32] Use memcpy/memset in memcpy_{from,to}_io and memset_io
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>
2007-04-27 13:44:15 +02:00
Haavard Skinnemoen
d80e2bb126 [AVR32] Get rid of board_setup_fbmem()
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>
2007-04-27 13:44:15 +02:00
Haavard Skinnemoen
f9692b9501 [AVR32] Reserve framebuffer memory in early_parse_fbmem()
With the current strategy of using the bootmem allocator to allocate
or reserve framebuffer memory, there's a slight chance that the
requested area has been taken by the boot allocator bitmap before we
get around to reserving it.

By inserting the framebuffer region as a reserved region as early as
possible, we improve our chances for success and we make the region
visible as a reserved region in dmesg and /proc/iomem without any
extra work.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:44:14 +02:00
Haavard Skinnemoen
d8011768e6 [AVR32] Simplify early handling of memory regions
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>
2007-04-27 13:44:14 +02:00
Haavard Skinnemoen
5539f59ac4 [AVR32] Move setup_bootmem() from mm/init.c to kernel/setup.c
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:44:14 +02:00
Haavard Skinnemoen
e3e7d8d4ea [AVR32] Make I/O access macros work with external devices
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>
2007-04-27 13:44:14 +02:00
Haavard Skinnemoen
92b728c147 [AVR32] Fix NMI handler
Fix a problem with the NMI handler entry code related to the NMI handler
sharing some code with the exception handlers. This is not a good idea
because the RSR and RAR registers are not the same, and the NMI handler
runs with interrupts masked the whole time so there's no need to check
for pending work.

Open-code the low-level NMI handling logic instead so that the pt_regs
layout is actually correct when the higher-level handler is called.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:44:13 +02:00
Haavard Skinnemoen
623b0355d5 [AVR32] Clean up exception handling code
* 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>
2007-04-27 13:44:13 +02:00
Haavard Skinnemoen
3b328c9809 [AVR32] Clean up cpu identification and add features bitmap
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>
2007-04-27 13:44:13 +02:00
Haavard Skinnemoen
535c806c26 [AVR32] Clean up asm/sysreg.h
Fix indentation and remove spurious comments in asm-avr32/sysreg.h

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:44:13 +02:00
Haavard Skinnemoen
188ff65d49 [AVR32] Don't enable clocks with no users
Bring the code that sets the initial PM clock masks in line with the
comment preceding it by only enabling clocks that have users != 0.
Fix SM clock definition and avr32_hpt_init() so that the SM and TC0
clocks keep ticking.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:44:13 +02:00
Hans-Christian Egtvedt
19b7ce8bad [AVR32] Put cpu in sleep 0 when idle.
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>
2007-04-27 13:44:12 +02:00
Hans-Christian Egtvedt
7760989e5e [AVR32] Change system timer from count-compare to Timer/Counter 0
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>
2007-04-27 13:44:12 +02:00
Haavard Skinnemoen
228e845fd2 [AVR32] Add mach-specific Kconfig
Include at32ap-specific Kconfig file from top-level Kconfig file. The
at32ap Kconfig is currently empty, but it will grow some machine-
specific options soon.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 13:43:27 +02:00
Hans-Christian Egtvedt
068d9f6eb9 [AVR32] Add nwait and tdf parameters to SMC configuration
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>
2007-04-27 13:43:27 +02:00
Artem Bityutskiy
485764016d UBI: add me to MAINTAINERS
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-04-27 14:24:35 +03:00
Artem Bityutskiy
0029da3bf4 JFFS2: add UBI support
This patch make JFFS2 able to work with UBI volumes via the emulated MTD
devices which are directly mapped to these volumes.

Signed-off-by: Artem Bityutskiy <dedekind@infradead.org>
2007-04-27 14:24:08 +03:00
Artem B. Bityutskiy
801c135ce7 UBI: Unsorted Block Images
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>
2007-04-27 14:23:33 +03:00
Haavard Skinnemoen
9c8f8e7524 [AVR32] Add basic HMATRIX support
This adds register and clock definitions for the High-speed bus Matrix
(HMATRIX) as well as a function that can be used to configure special
EBI functionality like CompactFlash and NAND flash support.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-27 12:58:50 +02:00