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Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

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Conflicts:

	arch/x86/kernel/io_apic.c
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Rusty Russell
2008-12-31 23:05:57 +10:30
parent e12f0102ac 6a94cb7306
commit 2ca1a61583
2084 changed files with 144487 additions and 50597 deletions
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2
Documentation/RCU/00-INDEX
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@@ -16,6 +16,8 @@ RTFP.txt
- List of RCU papers (bibliography) going back to 1980.
torture.txt
- RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
trace.txt
- CONFIG_RCU_TRACE debugfs files and formats
UP.txt
- RCU on Uniprocessor Systems
whatisRCU.txt

413
Documentation/RCU/trace.txt Normal file
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CONFIG_RCU_TRACE debugfs Files and Formats
The rcupreempt and rcutree implementations of RCU provide debugfs trace
output that summarizes counters and state. This information is useful for
debugging RCU itself, and can sometimes also help to debug abuses of RCU.
Note that the rcuclassic implementation of RCU does not provide debugfs
trace output.
The following sections describe the debugfs files and formats for
preemptable RCU (rcupreempt) and hierarchical RCU (rcutree).
Preemptable RCU debugfs Files and Formats
This implementation of RCU provides three debugfs files under the
top-level directory RCU: rcu/rcuctrs (which displays the per-CPU
counters used by preemptable RCU) rcu/rcugp (which displays grace-period
counters), and rcu/rcustats (which internal counters for debugging RCU).
The output of "cat rcu/rcuctrs" looks as follows:
CPU last cur F M
0 5 -5 0 0
1 -1 0 0 0
2 0 1 0 0
3 0 1 0 0
4 0 1 0 0
5 0 1 0 0
6 0 2 0 0
7 0 -1 0 0
8 0 1 0 0
ggp = 26226, state = waitzero
The per-CPU fields are as follows:
o "CPU" gives the CPU number. Offline CPUs are not displayed.
o "last" gives the value of the counter that is being decremented
for the current grace period phase. In the example above,
the counters sum to 4, indicating that there are still four
RCU read-side critical sections still running that started
before the last counter flip.
o "cur" gives the value of the counter that is currently being
both incremented (by rcu_read_lock()) and decremented (by
rcu_read_unlock()). In the example above, the counters sum to
1, indicating that there is only one RCU read-side critical section
still running that started after the last counter flip.
o "F" indicates whether RCU is waiting for this CPU to acknowledge
a counter flip. In the above example, RCU is not waiting on any,
which is consistent with the state being "waitzero" rather than
"waitack".
o "M" indicates whether RCU is waiting for this CPU to execute a
memory barrier. In the above example, RCU is not waiting on any,
which is consistent with the state being "waitzero" rather than
"waitmb".
o "ggp" is the global grace-period counter.
o "state" is the RCU state, which can be one of the following:
o "idle": there is no grace period in progress.
o "waitack": RCU just incremented the global grace-period
counter, which has the effect of reversing the roles of
the "last" and "cur" counters above, and is waiting for
all the CPUs to acknowledge the flip. Once the flip has
been acknowledged, CPUs will no longer be incrementing
what are now the "last" counters, so that their sum will
decrease monotonically down to zero.
o "waitzero": RCU is waiting for the sum of the "last" counters
to decrease to zero.
o "waitmb": RCU is waiting for each CPU to execute a memory
barrier, which ensures that instructions from a given CPU's
last RCU read-side critical section cannot be reordered
with instructions following the memory-barrier instruction.
The output of "cat rcu/rcugp" looks as follows:
oldggp=48870 newggp=48873
Note that reading from this file provokes a synchronize_rcu(). The
"oldggp" value is that of "ggp" from rcu/rcuctrs above, taken before
executing the synchronize_rcu(), and the "newggp" value is also the
"ggp" value, but taken after the synchronize_rcu() command returns.
The output of "cat rcu/rcugp" looks as follows:
na=1337955 nl=40 wa=1337915 wl=44 da=1337871 dl=0 dr=1337871 di=1337871
1=50989 e1=6138 i1=49722 ie1=82 g1=49640 a1=315203 ae1=265563 a2=49640
z1=1401244 ze1=1351605 z2=49639 m1=5661253 me1=5611614 m2=49639
These are counters tracking internal preemptable-RCU events, however,
some of them may be useful for debugging algorithms using RCU. In
particular, the "nl", "wl", and "dl" values track the number of RCU
callbacks in various states. The fields are as follows:
o "na" is the total number of RCU callbacks that have been enqueued
since boot.
o "nl" is the number of RCU callbacks waiting for the previous
grace period to end so that they can start waiting on the next
grace period.
o "wa" is the total number of RCU callbacks that have started waiting
for a grace period since boot. "na" should be roughly equal to
"nl" plus "wa".
o "wl" is the number of RCU callbacks currently waiting for their
grace period to end.
o "da" is the total number of RCU callbacks whose grace periods
have completed since boot. "wa" should be roughly equal to
"wl" plus "da".
o "dr" is the total number of RCU callbacks that have been removed
from the list of callbacks ready to invoke. "dr" should be roughly
equal to "da".
o "di" is the total number of RCU callbacks that have been invoked
since boot. "di" should be roughly equal to "da", though some
early versions of preemptable RCU had a bug so that only the
last CPU's count of invocations was displayed, rather than the
sum of all CPU's counts.
o "1" is the number of calls to rcu_try_flip(). This should be
roughly equal to the sum of "e1", "i1", "a1", "z1", and "m1"
described below. In other words, the number of times that
the state machine is visited should be equal to the sum of the
number of times that each state is visited plus the number of
times that the state-machine lock acquisition failed.
o "e1" is the number of times that rcu_try_flip() was unable to
acquire the fliplock.
o "i1" is the number of calls to rcu_try_flip_idle().
o "ie1" is the number of times rcu_try_flip_idle() exited early
due to the calling CPU having no work for RCU.
o "g1" is the number of times that rcu_try_flip_idle() decided
to start a new grace period. "i1" should be roughly equal to
"ie1" plus "g1".
o "a1" is the number of calls to rcu_try_flip_waitack().
o "ae1" is the number of times that rcu_try_flip_waitack() found
that at least one CPU had not yet acknowledge the new grace period
(AKA "counter flip").
o "a2" is the number of time rcu_try_flip_waitack() found that
all CPUs had acknowledged. "a1" should be roughly equal to
"ae1" plus "a2". (This particular output was collected on
a 128-CPU machine, hence the smaller-than-usual fraction of
calls to rcu_try_flip_waitack() finding all CPUs having already
acknowledged.)
o "z1" is the number of calls to rcu_try_flip_waitzero().
o "ze1" is the number of times that rcu_try_flip_waitzero() found
that not all of the old RCU read-side critical sections had
completed.
o "z2" is the number of times that rcu_try_flip_waitzero() finds
the sum of the counters equal to zero, in other words, that
all of the old RCU read-side critical sections had completed.
The value of "z1" should be roughly equal to "ze1" plus
"z2".
o "m1" is the number of calls to rcu_try_flip_waitmb().
o "me1" is the number of times that rcu_try_flip_waitmb() finds
that at least one CPU has not yet executed a memory barrier.
o "m2" is the number of times that rcu_try_flip_waitmb() finds that
all CPUs have executed a memory barrier.
Hierarchical RCU debugfs Files and Formats
This implementation of RCU provides three debugfs files under the
top-level directory RCU: rcu/rcudata (which displays fields in struct
rcu_data), rcu/rcugp (which displays grace-period counters), and
rcu/rcuhier (which displays the struct rcu_node hierarchy).
The output of "cat rcu/rcudata" looks as follows:
rcu:
0 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=1 rp=3c2a dt=23301/73 dn=2 df=1882 of=0 ri=2126 ql=2 b=10
1 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=3 rp=39a6 dt=78073/1 dn=2 df=1402 of=0 ri=1875 ql=46 b=10
2 c=4010 g=4010 pq=1 pqc=4010 qp=0 rpfq=-5 rp=1d12 dt=16646/0 dn=2 df=3140 of=0 ri=2080 ql=0 b=10
3 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=2b50 dt=21159/1 dn=2 df=2230 of=0 ri=1923 ql=72 b=10
4 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1644 dt=5783/1 dn=2 df=3348 of=0 ri=2805 ql=7 b=10
5 c=4012 g=4013 pq=0 pqc=4011 qp=1 rpfq=3 rp=1aac dt=5879/1 dn=2 df=3140 of=0 ri=2066 ql=10 b=10
6 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=ed8 dt=5847/1 dn=2 df=3797 of=0 ri=1266 ql=10 b=10
7 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1fa2 dt=6199/1 dn=2 df=2795 of=0 ri=2162 ql=28 b=10
rcu_bh:
0 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-145 rp=21d6 dt=23301/73 dn=2 df=0 of=0 ri=0 ql=0 b=10
1 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-170 rp=20ce dt=78073/1 dn=2 df=26 of=0 ri=5 ql=0 b=10
2 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-83 rp=fbd dt=16646/0 dn=2 df=28 of=0 ri=4 ql=0 b=10
3 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-105 rp=178c dt=21159/1 dn=2 df=28 of=0 ri=2 ql=0 b=10
4 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-30 rp=b54 dt=5783/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
5 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-29 rp=df5 dt=5879/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
6 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-28 rp=788 dt=5847/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
7 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-53 rp=1098 dt=6199/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
The first section lists the rcu_data structures for rcu, the second for
rcu_bh. Each section has one line per CPU, or eight for this 8-CPU system.
The fields are as follows:
o The number at the beginning of each line is the CPU number.
CPUs numbers followed by an exclamation mark are offline,
but have been online at least once since boot. There will be
no output for CPUs that have never been online, which can be
a good thing in the surprisingly common case where NR_CPUS is
substantially larger than the number of actual CPUs.
o "c" is the count of grace periods that this CPU believes have
completed. CPUs in dynticks idle mode may lag quite a ways
behind, for example, CPU 4 under "rcu" above, which has slept
through the past 25 RCU grace periods. It is not unusual to
see CPUs lagging by thousands of grace periods.
o "g" is the count of grace periods that this CPU believes have
started. Again, CPUs in dynticks idle mode may lag behind.
If the "c" and "g" values are equal, this CPU has already
reported a quiescent state for the last RCU grace period that
it is aware of, otherwise, the CPU believes that it owes RCU a
quiescent state.
o "pq" indicates that this CPU has passed through a quiescent state
for the current grace period. It is possible for "pq" to be
"1" and "c" different than "g", which indicates that although
the CPU has passed through a quiescent state, either (1) this
CPU has not yet reported that fact, (2) some other CPU has not
yet reported for this grace period, or (3) both.
o "pqc" indicates which grace period the last-observed quiescent
state for this CPU corresponds to. This is important for handling
the race between CPU 0 reporting an extended dynticks-idle
quiescent state for CPU 1 and CPU 1 suddenly waking up and
reporting its own quiescent state. If CPU 1 was the last CPU
for the current grace period, then the CPU that loses this race
will attempt to incorrectly mark CPU 1 as having checked in for
the next grace period!
o "qp" indicates that RCU still expects a quiescent state from
this CPU.
o "rpfq" is the number of rcu_pending() calls on this CPU required
to induce this CPU to invoke force_quiescent_state().
o "rp" is low-order four hex digits of the count of how many times
rcu_pending() has been invoked on this CPU.
o "dt" is the current value of the dyntick counter that is incremented
when entering or leaving dynticks idle state, either by the
scheduler or by irq. The number after the "/" is the interrupt
nesting depth when in dyntick-idle state, or one greater than
the interrupt-nesting depth otherwise.
This field is displayed only for CONFIG_NO_HZ kernels.
o "dn" is the current value of the dyntick counter that is incremented
when entering or leaving dynticks idle state via NMI. If both
the "dt" and "dn" values are even, then this CPU is in dynticks
idle mode and may be ignored by RCU. If either of these two
counters is odd, then RCU must be alert to the possibility of
an RCU read-side critical section running on this CPU.
This field is displayed only for CONFIG_NO_HZ kernels.
o "df" is the number of times that some other CPU has forced a
quiescent state on behalf of this CPU due to this CPU being in
dynticks-idle state.
This field is displayed only for CONFIG_NO_HZ kernels.
o "of" is the number of times that some other CPU has forced a
quiescent state on behalf of this CPU due to this CPU being
offline. In a perfect world, this might neve happen, but it
turns out that offlining and onlining a CPU can take several grace
periods, and so there is likely to be an extended period of time
when RCU believes that the CPU is online when it really is not.
Please note that erring in the other direction (RCU believing a
CPU is offline when it is really alive and kicking) is a fatal
error, so it makes sense to err conservatively.
o "ri" is the number of times that RCU has seen fit to send a
reschedule IPI to this CPU in order to get it to report a
quiescent state.
o "ql" is the number of RCU callbacks currently residing on
this CPU. This is the total number of callbacks, regardless
of what state they are in (new, waiting for grace period to
start, waiting for grace period to end, ready to invoke).
o "b" is the batch limit for this CPU. If more than this number
of RCU callbacks is ready to invoke, then the remainder will
be deferred.
The output of "cat rcu/rcugp" looks as follows:
rcu: completed=33062 gpnum=33063
rcu_bh: completed=464 gpnum=464
Again, this output is for both "rcu" and "rcu_bh". The fields are
taken from the rcu_state structure, and are as follows:
o "completed" is the number of grace periods that have completed.
It is comparable to the "c" field from rcu/rcudata in that a
CPU whose "c" field matches the value of "completed" is aware
that the corresponding RCU grace period has completed.
o "gpnum" is the number of grace periods that have started. It is
comparable to the "g" field from rcu/rcudata in that a CPU
whose "g" field matches the value of "gpnum" is aware that the
corresponding RCU grace period has started.
If these two fields are equal (as they are for "rcu_bh" above),
then there is no grace period in progress, in other words, RCU
is idle. On the other hand, if the two fields differ (as they
do for "rcu" above), then an RCU grace period is in progress.
The output of "cat rcu/rcuhier" looks as follows, with very long lines:
c=6902 g=6903 s=2 jfq=3 j=72c7 nfqs=13142/nfqsng=0(13142) fqlh=6
1/1 0:127 ^0
3/3 0:35 ^0 0/0 36:71 ^1 0/0 72:107 ^2 0/0 108:127 ^3
3/3f 0:5 ^0 2/3 6:11 ^1 0/0 12:17 ^2 0/0 18:23 ^3 0/0 24:29 ^4 0/0 30:35 ^5 0/0 36:41 ^0 0/0 42:47 ^1 0/0 48:53 ^2 0/0 54:59 ^3 0/0 60:65 ^4 0/0 66:71 ^5 0/0 72:77 ^0 0/0 78:83 ^1 0/0 84:89 ^2 0/0 90:95 ^3 0/0 96:101 ^4 0/0 102:107 ^5 0/0 108:113 ^0 0/0 114:119 ^1 0/0 120:125 ^2 0/0 126:127 ^3
rcu_bh:
c=-226 g=-226 s=1 jfq=-5701 j=72c7 nfqs=88/nfqsng=0(88) fqlh=0
0/1 0:127 ^0
0/3 0:35 ^0 0/0 36:71 ^1 0/0 72:107 ^2 0/0 108:127 ^3
0/3f 0:5 ^0 0/3 6:11 ^1 0/0 12:17 ^2 0/0 18:23 ^3 0/0 24:29 ^4 0/0 30:35 ^5 0/0 36:41 ^0 0/0 42:47 ^1 0/0 48:53 ^2 0/0 54:59 ^3 0/0 60:65 ^4 0/0 66:71 ^5 0/0 72:77 ^0 0/0 78:83 ^1 0/0 84:89 ^2 0/0 90:95 ^3 0/0 96:101 ^4 0/0 102:107 ^5 0/0 108:113 ^0 0/0 114:119 ^1 0/0 120:125 ^2 0/0 126:127 ^3
This is once again split into "rcu" and "rcu_bh" portions. The fields are
as follows:
o "c" is exactly the same as "completed" under rcu/rcugp.
o "g" is exactly the same as "gpnum" under rcu/rcugp.
o "s" is the "signaled" state that drives force_quiescent_state()'s
state machine.
o "jfq" is the number of jiffies remaining for this grace period
before force_quiescent_state() is invoked to help push things
along. Note that CPUs in dyntick-idle mode thoughout the grace
period will not report on their own, but rather must be check by
some other CPU via force_quiescent_state().
o "j" is the low-order four hex digits of the jiffies counter.
Yes, Paul did run into a number of problems that turned out to
be due to the jiffies counter no longer counting. Why do you ask?
o "nfqs" is the number of calls to force_quiescent_state() since
boot.
o "nfqsng" is the number of useless calls to force_quiescent_state(),
where there wasn't actually a grace period active. This can
happen due to races. The number in parentheses is the difference
between "nfqs" and "nfqsng", or the number of times that
force_quiescent_state() actually did some real work.
o "fqlh" is the number of calls to force_quiescent_state() that
exited immediately (without even being counted in nfqs above)
due to contention on ->fqslock.
o Each element of the form "1/1 0:127 ^0" represents one struct
rcu_node. Each line represents one level of the hierarchy, from
root to leaves. It is best to think of the rcu_data structures
as forming yet another level after the leaves. Note that there
might be either one, two, or three levels of rcu_node structures,
depending on the relationship between CONFIG_RCU_FANOUT and
CONFIG_NR_CPUS.
o The numbers separated by the "/" are the qsmask followed
by the qsmaskinit. The qsmask will have one bit
set for each entity in the next lower level that
has not yet checked in for the current grace period.
The qsmaskinit will have one bit for each entity that is
currently expected to check in during each grace period.
The value of qsmaskinit is assigned to that of qsmask
at the beginning of each grace period.
For example, for "rcu", the qsmask of the first entry
of the lowest level is 0x14, meaning that we are still
waiting for CPUs 2 and 4 to check in for the current
grace period.
o The numbers separated by the ":" are the range of CPUs
served by this struct rcu_node. This can be helpful
in working out how the hierarchy is wired together.
For example, the first entry at the lowest level shows
"0:5", indicating that it covers CPUs 0 through 5.
o The number after the "^" indicates the bit in the
next higher level rcu_node structure that this
rcu_node structure corresponds to.
For example, the first entry at the lowest level shows
"^0", indicating that it corresponds to bit zero in
the first entry at the middle level.

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MFP Configuration for PXA2xx/PXA3xx Processors
Eric Miao <eric.miao@marvell.com>
MFP stands for Multi-Function Pin, which is the pin-mux logic on PXA3xx and
later PXA series processors. This document describes the existing MFP API,
and how board/platform driver authors could make use of it.
Basic Concept
===============
Unlike the GPIO alternate function settings on PXA25x and PXA27x, a new MFP
mechanism is introduced from PXA3xx to completely move the pin-mux functions
out of the GPIO controller. In addition to pin-mux configurations, the MFP
also controls the low power state, driving strength, pull-up/down and event
detection of each pin. Below is a diagram of internal connections between
the MFP logic and the remaining SoC peripherals:
+--------+
| |--(GPIO19)--+
| GPIO | |
| |--(GPIO...) |
+--------+ |
| +---------+
+--------+ +------>| |
| PWM2 |--(PWM_OUT)-------->| MFP |
+--------+ +------>| |-------> to external PAD
| +---->| |
+--------+ | | +-->| |
| SSP2 |---(TXD)----+ | | +---------+
+--------+ | |
| |
+--------+ | |
| Keypad |--(MKOUT4)----+ |
+--------+ |
|
+--------+ |
| UART2 |---(TXD)--------+
+--------+
NOTE: the external pad is named as MFP_PIN_GPIO19, it doesn't necessarily
mean it's dedicated for GPIO19, only as a hint that internally this pin
can be routed from GPIO19 of the GPIO controller.
To better understand the change from PXA25x/PXA27x GPIO alternate function
to this new MFP mechanism, here are several key points:
1. GPIO controller on PXA3xx is now a dedicated controller, same as other
internal controllers like PWM, SSP and UART, with 128 internal signals
which can be routed to external through one or more MFPs (e.g. GPIO<0>
can be routed through either MFP_PIN_GPIO0 as well as MFP_PIN_GPIO0_2,
see arch/arm/mach-pxa/mach/include/mfp-pxa300.h)
2. Alternate function configuration is removed from this GPIO controller,
the remaining functions are pure GPIO-specific, i.e.
- GPIO signal level control
- GPIO direction control
- GPIO level change detection
3. Low power state for each pin is now controlled by MFP, this means the
PGSRx registers on PXA2xx are now useless on PXA3xx
4. Wakeup detection is now controlled by MFP, PWER does not control the
wakeup from GPIO(s) any more, depending on the sleeping state, ADxER
(as defined in pxa3xx-regs.h) controls the wakeup from MFP
NOTE: with such a clear separation of MFP and GPIO, by GPIO<xx> we normally
mean it is a GPIO signal, and by MFP<xxx> or pin xxx, we mean a physical
pad (or ball).
MFP API Usage
===============
For board code writers, here are some guidelines:
1. include ONE of the following header files in your <board>.c:
- #include <mach/mfp-pxa25x.h>
- #include <mach/mfp-pxa27x.h>
- #include <mach/mfp-pxa300.h>
- #include <mach/mfp-pxa320.h>
- #include <mach/mfp-pxa930.h>
NOTE: only one file in your <board>.c, depending on the processors used,
because pin configuration definitions may conflict in these file (i.e.
same name, different meaning and settings on different processors). E.g.
for zylonite platform, which support both PXA300/PXA310 and PXA320, two
separate files are introduced: zylonite_pxa300.c and zylonite_pxa320.c
(in addition to handle MFP configuration differences, they also handle
the other differences between the two combinations).
NOTE: PXA300 and PXA310 are almost identical in pin configurations (with
PXA310 supporting some additional ones), thus the difference is actually
covered in a single mfp-pxa300.h.
2. prepare an array for the initial pin configurations, e.g.:
static unsigned long mainstone_pin_config[] __initdata = {
/* Chip Select */
GPIO15_nCS_1,
/* LCD - 16bpp Active TFT */
GPIOxx_TFT_LCD_16BPP,
GPIO16_PWM0_OUT, /* Backlight */
/* MMC */
GPIO32_MMC_CLK,
GPIO112_MMC_CMD,
GPIO92_MMC_DAT_0,
GPIO109_MMC_DAT_1,
GPIO110_MMC_DAT_2,
GPIO111_MMC_DAT_3,
...
/* GPIO */
GPIO1_GPIO | WAKEUP_ON_EDGE_BOTH,
};
a) once the pin configurations are passed to pxa{2xx,3xx}_mfp_config(),
and written to the actual registers, they are useless and may discard,
adding '__initdata' will help save some additional bytes here.
b) when there is only one possible pin configurations for a component,
some simplified definitions can be used, e.g. GPIOxx_TFT_LCD_16BPP on
PXA25x and PXA27x processors
c) if by board design, a pin can be configured to wake up the system
from low power state, it can be 'OR'ed with any of:
WAKEUP_ON_EDGE_BOTH
WAKEUP_ON_EDGE_RISE
WAKEUP_ON_EDGE_FALL
WAKEUP_ON_LEVEL_HIGH - specifically for enabling of keypad GPIOs,
to indicate that this pin has the capability of wake-up the system,
and on which edge(s). This, however, doesn't necessarily mean the
pin _will_ wakeup the system, it will only when set_irq_wake() is
invoked with the corresponding GPIO IRQ (GPIO_IRQ(xx) or gpio_to_irq())
and eventually calls gpio_set_wake() for the actual register setting.
d) although PXA3xx MFP supports edge detection on each pin, the
internal logic will only wakeup the system when those specific bits
in ADxER registers are set, which can be well mapped to the
corresponding peripheral, thus set_irq_wake() can be called with
the peripheral IRQ to enable the wakeup.
MFP on PXA3xx
===============
Every external I/O pad on PXA3xx (excluding those for special purpose) has
one MFP logic associated, and is controlled by one MFP register (MFPR).
The MFPR has the following bit definitions (for PXA300/PXA310/PXA320):
31 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+-------------------------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RESERVED |PS|PU|PD| DRIVE |SS|SD|SO|EC|EF|ER|--| AF_SEL |
+-------------------------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Bit 3: RESERVED
Bit 4: EDGE_RISE_EN - enable detection of rising edge on this pin
Bit 5: EDGE_FALL_EN - enable detection of falling edge on this pin
Bit 6: EDGE_CLEAR - disable edge detection on this pin
Bit 7: SLEEP_OE_N - enable outputs during low power modes
Bit 8: SLEEP_DATA - output data on the pin during low power modes
Bit 9: SLEEP_SEL - selection control for low power modes signals
Bit 13: PULLDOWN_EN - enable the internal pull-down resistor on this pin
Bit 14: PULLUP_EN - enable the internal pull-up resistor on this pin
Bit 15: PULL_SEL - pull state controlled by selected alternate function
(0) or by PULL{UP,DOWN}_EN bits (1)
Bit 0 - 2: AF_SEL - alternate function selection, 8 possibilities, from 0-7
Bit 10-12: DRIVE - drive strength and slew rate
0b000 - fast 1mA
0b001 - fast 2mA
0b002 - fast 3mA
0b003 - fast 4mA
0b004 - slow 6mA
0b005 - fast 6mA
0b006 - slow 10mA
0b007 - fast 10mA
MFP Design for PXA2xx/PXA3xx
==============================
Due to the difference of pin-mux handling between PXA2xx and PXA3xx, a unified
MFP API is introduced to cover both series of processors.
The basic idea of this design is to introduce definitions for all possible pin
configurations, these definitions are processor and platform independent, and
the actual API invoked to convert these definitions into register settings and
make them effective there-after.
Files Involved
--------------
- arch/arm/mach-pxa/include/mach/mfp.h
for
1. Unified pin definitions - enum constants for all configurable pins
2. processor-neutral bit definitions for a possible MFP configuration
- arch/arm/mach-pxa/include/mach/mfp-pxa3xx.h
for PXA3xx specific MFPR register bit definitions and PXA3xx common pin
configurations
- arch/arm/mach-pxa/include/mach/mfp-pxa2xx.h
for PXA2xx specific definitions and PXA25x/PXA27x common pin configurations
- arch/arm/mach-pxa/include/mach/mfp-pxa25x.h
arch/arm/mach-pxa/include/mach/mfp-pxa27x.h
arch/arm/mach-pxa/include/mach/mfp-pxa300.h
arch/arm/mach-pxa/include/mach/mfp-pxa320.h
arch/arm/mach-pxa/include/mach/mfp-pxa930.h
for processor specific definitions
- arch/arm/mach-pxa/mfp-pxa3xx.c
- arch/arm/mach-pxa/mfp-pxa2xx.c
for implementation of the pin configuration to take effect for the actual
processor.
Pin Configuration
-----------------
The following comments are copied from mfp.h (see the actual source code
for most updated info)
/*
* a possible MFP configuration is represented by a 32-bit integer
*
* bit 0.. 9 - MFP Pin Number (1024 Pins Maximum)
* bit 10..12 - Alternate Function Selection
* bit 13..15 - Drive Strength
* bit 16..18 - Low Power Mode State
* bit 19..20 - Low Power Mode Edge Detection
* bit 21..22 - Run Mode Pull State
*
* to facilitate the definition, the following macros are provided
*
* MFP_CFG_DEFAULT - default MFP configuration value, with
* alternate function = 0,
* drive strength = fast 3mA (MFP_DS03X)
* low power mode = default
* edge detection = none
*
* MFP_CFG - default MFPR value with alternate function
* MFP_CFG_DRV - default MFPR value with alternate function and
* pin drive strength
* MFP_CFG_LPM - default MFPR value with alternate function and
* low power mode
* MFP_CFG_X - default MFPR value with alternate function,
* pin drive strength and low power mode
*/
Examples of pin configurations are:
#define GPIO94_SSP3_RXD MFP_CFG_X(GPIO94, AF1, DS08X, FLOAT)
which reads GPIO94 can be configured as SSP3_RXD, with alternate function
selection of 1, driving strength of 0b101, and a float state in low power
modes.
NOTE: this is the default setting of this pin being configured as SSP3_RXD
which can be modified a bit in board code, though it is not recommended to
do so, simply because this default setting is usually carefully encoded,
and is supposed to work in most cases.
Register Settings
-----------------
Register settings on PXA3xx for a pin configuration is actually very
straight-forward, most bits can be converted directly into MFPR value
in a easier way. Two sets of MFPR values are calculated: the run-time
ones and the low power mode ones, to allow different settings.
The conversion from a generic pin configuration to the actual register
settings on PXA2xx is a bit complicated: many registers are involved,
including GAFRx, GPDRx, PGSRx, PWER, PKWR, PFER and PRER. Please see
mfp-pxa2xx.c for how the conversion is made.

6
Documentation/block/biodoc.txt
View File

@@ -914,7 +914,7 @@ I/O scheduler, a.k.a. elevator, is implemented in two layers. Generic dispatch
queue and specific I/O schedulers. Unless stated otherwise, elevator is used
to refer to both parts and I/O scheduler to specific I/O schedulers.
Block layer implements generic dispatch queue in ll_rw_blk.c and elevator.c.
Block layer implements generic dispatch queue in block/*.c.
The generic dispatch queue is responsible for properly ordering barrier
requests, requeueing, handling non-fs requests and all other subtleties.
@@ -926,8 +926,8 @@ be built inside the kernel. Each queue can choose different one and can also
change to another one dynamically.
A block layer call to the i/o scheduler follows the convention elv_xxx(). This
calls elevator_xxx_fn in the elevator switch (drivers/block/elevator.c). Oh,
xxx and xxx might not match exactly, but use your imagination. If an elevator
calls elevator_xxx_fn in the elevator switch (block/elevator.c). Oh, xxx
and xxx might not match exactly, but use your imagination. If an elevator
doesn't implement a function, the switch does nothing or some minimal house
keeping work.

69
Documentation/dvb/technisat.txt Normal file
View File

@@ -0,0 +1,69 @@
How to set up the Technisat devices
===================================
1) Find out what device you have
================================
First start your linux box with a shipped kernel:
lspci -vvv for a PCI device (lsusb -vvv for an USB device) will show you for example:
02:0b.0 Network controller: Techsan Electronics Co Ltd B2C2 FlexCopII DVB chip / Technisat SkyStar2 DVB card (rev 02)
dmesg | grep frontend may show you for example:
DVB: registering frontend 0 (Conexant CX24123/CX24109)...
2) Kernel compilation:
======================
If the Technisat is the only TV device in your box get rid of unnecessary modules and check this one:
"Multimedia devices" => "Customise analog and hybrid tuner modules to build"
In this directory uncheck every driver which is activated there.
Then please activate:
2a) Main module part:
a.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters"
b.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC PCI" in case of a PCI card OR
c.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC USB" in case of an USB 1.1 adapter
d.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Enable debug for the B2C2 FlexCop drivers"
Notice: d.) is helpful for troubleshooting
2b) Frontend module part:
1.) Revision 2.3:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink VP310/MT312/ZL10313 based"
2.) Revision 2.6:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0299 based"
3.) Revision 2.7:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Samsung S5H1420 based"
c.)"Multimedia devices" => "Customise DVB frontends" => "Integrant ITD1000 Zero IF tuner for DVB-S/DSS"
d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller"
4.) Revision 2.8:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24113/CX24128 tuner for DVB-S/DSS"
c.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24123 based"
d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller"
5.) DVB-T card:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink MT352 based"
6.) DVB-C card:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0297 based"
7.) ATSC card 1st generation:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Broadcom BCM3510"
8.) ATSC card 2nd generation:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "NxtWave Communications NXT2002/NXT2004 based"
c.)"Multimedia devices" => "Customise DVB frontends" => "LG Electronics LGDT3302/LGDT3303 based"
Author: Uwe Bugla <uwe.bugla@gmx.de> December 2008

92
Documentation/fb/pxafb.txt
View File

@@ -5,9 +5,13 @@ The driver supports the following options, either via
options=<OPTIONS> when modular or video=pxafb:<OPTIONS> when built in.
For example:
modprobe pxafb options=mode:640x480-8,passive
modprobe pxafb options=vmem:2M,mode:640x480-8,passive
or on the kernel command line
video=pxafb:mode:640x480-8,passive
video=pxafb:vmem:2M,mode:640x480-8,passive
vmem: VIDEO_MEM_SIZE
Amount of video memory to allocate (can be suffixed with K or M
for kilobytes or megabytes)
mode:XRESxYRES[-BPP]
XRES == LCCR1_PPL + 1
@@ -52,3 +56,87 @@ outputen:POLARITY
pixclockpol:POLARITY
pixel clock polarity
0 => falling edge, 1 => rising edge
Overlay Support for PXA27x and later LCD controllers
====================================================
PXA27x and later processors support overlay1 and overlay2 on-top of the
base framebuffer (although under-neath the base is also possible). They
support palette and no-palette RGB formats, as well as YUV formats (only
available on overlay2). These overlays have dedicated DMA channels and
behave in a similar way as a framebuffer.
However, there are some differences between these overlay framebuffers
and normal framebuffers, as listed below:
1. overlay can start at a 32-bit word aligned position within the base
framebuffer, which means they have a start (x, y). This information
is encoded into var->nonstd (no, var->xoffset and var->yoffset are
not for such purpose).
2. overlay framebuffer is allocated dynamically according to specified
'struct fb_var_screeninfo', the amount is decided by:
var->xres_virtual * var->yres_virtual * bpp
bpp = 16 -- for RGB565 or RGBT555
= 24 -- for YUV444 packed
= 24 -- for YUV444 planar
= 16 -- for YUV422 planar (1 pixel = 1 Y + 1/2 Cb + 1/2 Cr)
= 12 -- for YUV420 planar (1 pixel = 1 Y + 1/4 Cb + 1/4 Cr)
NOTE:
a. overlay does not support panning in x-direction, thus
var->xres_virtual will always be equal to var->xres
b. line length of overlay(s) must be on a 32-bit word boundary,
for YUV planar modes, it is a requirement for the component
with minimum bits per pixel, e.g. for YUV420, Cr component
for one pixel is actually 2-bits, it means the line length
should be a multiple of 16-pixels
c. starting horizontal position (XPOS) should start on a 32-bit
word boundary, otherwise the fb_check_var() will just fail.
d. the rectangle of the overlay should be within the base plane,
otherwise fail
Applications should follow the sequence below to operate an overlay
framebuffer:
a. open("/dev/fb[1-2]", ...)
b. ioctl(fd, FBIOGET_VSCREENINFO, ...)
c. modify 'var' with desired parameters:
1) var->xres and var->yres
2) larger var->yres_virtual if more memory is required,
usually for double-buffering
3) var->nonstd for starting (x, y) and color format
4) var->{red, green, blue, transp} if RGB mode is to be used
d. ioctl(fd, FBIOPUT_VSCREENINFO, ...)
e. ioctl(fd, FBIOGET_FSCREENINFO, ...)
f. mmap
g. ...
3. for YUV planar formats, these are actually not supported within the
framebuffer framework, application has to take care of the offsets
and lengths of each component within the framebuffer.
4. var->nonstd is used to pass starting (x, y) position and color format,
the detailed bit fields are shown below:
31 23 20 10 0
+-----------------+---+----------+----------+
| ... unused ... |FOR| XPOS | YPOS |
+-----------------+---+----------+----------+
FOR - color format, as defined by OVERLAY_FORMAT_* in pxafb.h
0 - RGB
1 - YUV444 PACKED
2 - YUV444 PLANAR
3 - YUV422 PLANAR
4 - YUR420 PLANAR
XPOS - starting horizontal position
YPOS - starting vertical position

4
Documentation/filesystems/xfs.txt
View File

@@ -229,10 +229,6 @@ The following sysctls are available for the XFS filesystem:
ISGID bit is cleared if the irix_sgid_inherit compatibility sysctl
is set.
fs.xfs.restrict_chown (Min: 0 Default: 1 Max: 1)
Controls whether unprivileged users can use chown to "give away"
a file to another user.
fs.xfs.inherit_sync (Min: 0 Default: 1 Max: 1)
Setting this to "1" will cause the "sync" flag set
by the xfs_io(8) chattr command on a directory to be

66
Documentation/lguest/lguest.c
View File

@@ -481,51 +481,6 @@ static unsigned long load_initrd(const char *name, unsigned long mem)
/* We return the initrd size. */
return len;
}
/* Once we know how much memory we have we can construct simple linear page
* tables which set virtual == physical which will get the Guest far enough
* into the boot to create its own.
*
* We lay them out of the way, just below the initrd (which is why we need to
* know its size here). */
static unsigned long setup_pagetables(unsigned long mem,
unsigned long initrd_size)
{
unsigned long *pgdir, *linear;
unsigned int mapped_pages, i, linear_pages;
unsigned int ptes_per_page = getpagesize()/sizeof(void *);
mapped_pages = mem/getpagesize();
/* Each PTE page can map ptes_per_page pages: how many do we need? */
linear_pages = (mapped_pages + ptes_per_page-1)/ptes_per_page;
/* We put the toplevel page directory page at the top of memory. */
pgdir = from_guest_phys(mem) - initrd_size - getpagesize();
/* Now we use the next linear_pages pages as pte pages */
linear = (void *)pgdir - linear_pages*getpagesize();
/* Linear mapping is easy: put every page's address into the mapping in
* order. PAGE_PRESENT contains the flags Present, Writable and
* Executable. */
for (i = 0; i < mapped_pages; i++)
linear[i] = ((i * getpagesize()) | PAGE_PRESENT);
/* The top level points to the linear page table pages above. */
for (i = 0; i < mapped_pages; i += ptes_per_page) {
pgdir[i/ptes_per_page]
= ((to_guest_phys(linear) + i*sizeof(void *))
| PAGE_PRESENT);
}
verbose("Linear mapping of %u pages in %u pte pages at %#lx\n",
mapped_pages, linear_pages, to_guest_phys(linear));
/* We return the top level (guest-physical) address: the kernel needs
* to know where it is. */
return to_guest_phys(pgdir);
}
/*:*/
/* Simple routine to roll all the commandline arguments together with spaces
@@ -548,13 +503,13 @@ static void concat(char *dst, char *args[])
/*L:185 This is where we actually tell the kernel to initialize the Guest. We
* saw the arguments it expects when we looked at initialize() in lguest_user.c:
* the base of Guest "physical" memory, the top physical page to allow, the
* top level pagetable and the entry point for the Guest. */
static int tell_kernel(unsigned long pgdir, unsigned long start)
* the base of Guest "physical" memory, the top physical page to allow and the
* entry point for the Guest. */
static int tell_kernel(unsigned long start)
{
unsigned long args[] = { LHREQ_INITIALIZE,
(unsigned long)guest_base,
guest_limit / getpagesize(), pgdir, start };
guest_limit / getpagesize(), start };
int fd;
verbose("Guest: %p - %p (%#lx)\n",
@@ -1030,7 +985,7 @@ static void update_device_status(struct device *dev)
/* Zero out the virtqueues. */
for (vq = dev->vq; vq; vq = vq->next) {
memset(vq->vring.desc, 0,
vring_size(vq->config.num, getpagesize()));
vring_size(vq->config.num, LGUEST_VRING_ALIGN));
lg_last_avail(vq) = 0;
}
} else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
@@ -1211,7 +1166,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
void *p;
/* First we need some memory for this virtqueue. */
pages = (vring_size(num_descs, getpagesize()) + getpagesize() - 1)
pages = (vring_size(num_descs, LGUEST_VRING_ALIGN) + getpagesize() - 1)
/ getpagesize();
p = get_pages(pages);
@@ -1228,7 +1183,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
vq->config.pfn = to_guest_phys(p) / getpagesize();
/* Initialize the vring. */
vring_init(&vq->vring, num_descs, p, getpagesize());
vring_init(&vq->vring, num_descs, p, LGUEST_VRING_ALIGN);
/* Append virtqueue to this device's descriptor. We use
* device_config() to get the end of the device's current virtqueues;
@@ -1941,7 +1896,7 @@ int main(int argc, char *argv[])
{
/* Memory, top-level pagetable, code startpoint and size of the
* (optional) initrd. */
unsigned long mem = 0, pgdir, start, initrd_size = 0;
unsigned long mem = 0, start, initrd_size = 0;
/* Two temporaries and the /dev/lguest file descriptor. */
int i, c, lguest_fd;
/* The boot information for the Guest. */
@@ -2040,9 +1995,6 @@ int main(int argc, char *argv[])
boot->hdr.type_of_loader = 0xFF;
}
/* Set up the initial linear pagetables, starting below the initrd. */
pgdir = setup_pagetables(mem, initrd_size);
/* The Linux boot header contains an "E820" memory map: ours is a
* simple, single region. */
boot->e820_entries = 1;
@@ -2064,7 +2016,7 @@ int main(int argc, char *argv[])
/* We tell the kernel to initialize the Guest: this returns the open
* /dev/lguest file descriptor. */
lguest_fd = tell_kernel(pgdir, start);
lguest_fd = tell_kernel(start);
/* We clone off a thread, which wakes the Launcher whenever one of the
* input file descriptors needs attention. We call this the Waker, and

51
Documentation/lockstat.txt
View File

@@ -71,35 +71,50 @@ Look at the current lock statistics:
# less /proc/lock_stat
01 lock_stat version 0.2
01 lock_stat version 0.3
02 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
03 class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
04 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
05
06 &inode->i_data.tree_lock-W: 15 21657 0.18 1093295.30 11547131054.85 58 10415 0.16 87.51 6387.60
07 &inode->i_data.tree_lock-R: 0 0 0.00 0.00 0.00 23302 231198 0.25 8.45 98023.38
08 --------------------------
09 &inode->i_data.tree_lock 0 [<ffffffff8027c08f>] add_to_page_cache+0x5f/0x190
10
11 ...............................................................................................................................................................................................
12
13 dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24
14 -----------
15 dcache_lock 180 [<ffffffff802c0d7e>] sys_getcwd+0x11e/0x230
16 dcache_lock 165 [<ffffffff802c002a>] d_alloc+0x15a/0x210
17 dcache_lock 33 [<ffffffff8035818d>] _atomic_dec_and_lock+0x4d/0x70
18 dcache_lock 1 [<ffffffff802beef8>] shrink_dcache_parent+0x18/0x130
06 &mm->mmap_sem-W: 233 538 18446744073708 22924.27 607243.51 1342 45806 1.71 8595.89 1180582.34
07 &mm->mmap_sem-R: 205 587 18446744073708 28403.36 731975.00 1940 412426 0.58 187825.45 6307502.88
08 ---------------
09 &mm->mmap_sem 487 [<ffffffff8053491f>] do_page_fault+0x466/0x928
10 &mm->mmap_sem 179 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
11 &mm->mmap_sem 279 [<ffffffff80210a57>] sys_mmap+0x75/0xce
12 &mm->mmap_sem 76 [<ffffffff802a490b>] sys_munmap+0x32/0x59
13 ---------------
14 &mm->mmap_sem 270 [<ffffffff80210a57>] sys_mmap+0x75/0xce
15 &mm->mmap_sem 431 [<ffffffff8053491f>] do_page_fault+0x466/0x928
16 &mm->mmap_sem 138 [<ffffffff802a490b>] sys_munmap+0x32/0x59
17 &mm->mmap_sem 145 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
18
19 ...............................................................................................................................................................................................
20
21 dcache_lock: 621 623 0.52 118.26 1053.02 6745 91930 0.29 316.29 118423.41
22 -----------
23 dcache_lock 179 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
24 dcache_lock 113 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
25 dcache_lock 99 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
26 dcache_lock 104 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
27 -----------
28 dcache_lock 192 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
29 dcache_lock 98 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
30 dcache_lock 72 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
31 dcache_lock 112 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
This excerpt shows the first two lock class statistics. Line 01 shows the
output version - each time the format changes this will be updated. Line 02-04
show the header with column descriptions. Lines 05-10 and 13-18 show the actual
show the header with column descriptions. Lines 05-18 and 20-31 show the actual
statistics. These statistics come in two parts; the actual stats separated by a
short separator (line 08, 14) from the contention points.
short separator (line 08, 13) from the contention points.
The first lock (05-10) is a read/write lock, and shows two lines above the
The first lock (05-18) is a read/write lock, and shows two lines above the
short separator. The contention points don't match the column descriptors,
they have two: contentions and [<IP>] symbol.
they have two: contentions and [<IP>] symbol. The second set of contention
points are the points we're contending with.
The integer part of the time values is in us.
View the top contending locks:

85
Documentation/scsi/cxgb3i.txt Normal file
View File

@@ -0,0 +1,85 @@
Chelsio S3 iSCSI Driver for Linux
Introduction
============
The Chelsio T3 ASIC based Adapters (S310, S320, S302, S304, Mezz cards, etc.
series of products) supports iSCSI acceleration and iSCSI Direct Data Placement
(DDP) where the hardware handles the expensive byte touching operations, such
as CRC computation and verification, and direct DMA to the final host memory
destination:
- iSCSI PDU digest generation and verification
On transmitting, Chelsio S3 h/w computes and inserts the Header and
Data digest into the PDUs.
On receiving, Chelsio S3 h/w computes and verifies the Header and
Data digest of the PDUs.
- Direct Data Placement (DDP)
S3 h/w can directly place the iSCSI Data-In or Data-Out PDU's
payload into pre-posted final destination host-memory buffers based
on the Initiator Task Tag (ITT) in Data-In or Target Task Tag (TTT)
in Data-Out PDUs.
- PDU Transmit and Recovery
On transmitting, S3 h/w accepts the complete PDU (header + data)
from the host driver, computes and inserts the digests, decomposes
the PDU into multiple TCP segments if necessary, and transmit all
the TCP segments onto the wire. It handles TCP retransmission if
needed.
On receving, S3 h/w recovers the iSCSI PDU by reassembling TCP
segments, separating the header and data, calculating and verifying
the digests, then forwards the header to the host. The payload data,
if possible, will be directly placed into the pre-posted host DDP
buffer. Otherwise, the payload data will be sent to the host too.
The cxgb3i driver interfaces with open-iscsi initiator and provides the iSCSI
acceleration through Chelsio hardware wherever applicable.
Using the cxgb3i Driver
=======================
The following steps need to be taken to accelerates the open-iscsi initiator:
1. Load the cxgb3i driver: "modprobe cxgb3i"
The cxgb3i module registers a new transport class "cxgb3i" with open-iscsi.
* in the case of recompiling the kernel, the cxgb3i selection is located at
Device Drivers
SCSI device support --->
[*] SCSI low-level drivers --->
<M> Chelsio S3xx iSCSI support
2. Create an interface file located under /etc/iscsi/ifaces/ for the new
transport class "cxgb3i".
The content of the file should be in the following format:
iface.transport_name = cxgb3i
iface.net_ifacename = <ethX>
iface.ipaddress = <iscsi ip address>
* if iface.ipaddress is specified, <iscsi ip address> needs to be either the
same as the ethX's ip address or an address on the same subnet. Make
sure the ip address is unique in the network.
3. edit /etc/iscsi/iscsid.conf
The default setting for MaxRecvDataSegmentLength (131072) is too big,
replace "node.conn[0].iscsi.MaxRecvDataSegmentLength" to be a value no
bigger than 15360 (for example 8192):
node.conn[0].iscsi.MaxRecvDataSegmentLength = 8192
* The login would fail for a normal session if MaxRecvDataSegmentLength is
too big. A error message in the format of
"cxgb3i: ERR! MaxRecvSegmentLength <X> too big. Need to be <= <Y>."
would be logged to dmesg.
4. To direct open-iscsi traffic to go through cxgb3i's accelerated path,
"-I <iface file name>" option needs to be specified with most of the
iscsiadm command. <iface file name> is the transport interface file created
in step 2.

43
Documentation/video4linux/API.html
View File

@@ -1,16 +1,27 @@
<TITLE>V4L API</TITLE>
<H1>Video For Linux APIs</H1>
<table border=0>
<tr>
<td>
<A HREF=http://www.linuxtv.org/downloads/video4linux/API/V4L1_API.html>
V4L original API</a>
</td><td>
Obsoleted by V4L2 API
</td></tr><tr><td>
<A HREF=http://www.linuxtv.org/downloads/video4linux/API/V4L2_API>
V4L2 API</a>
</td><td>
Should be used for new projects
</td></tr>
</table>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<meta content="text/html;charset=ISO-8859-2" http-equiv="Content-Type" />
<title>V4L API</title>
</head>
<body>
<h1>Video For Linux APIs</h1>
<table border="0">
<tr>
<td>
<a href="http://www.linuxtv.org/downloads/video4linux/API/V4L1_API.html">V4L original API</a>
</td>
<td>
Obsoleted by V4L2 API
</td>
</tr>
<tr>
<td>
<a href="http://www.linuxtv.org/downloads/video4linux/API/V4L2_API">V4L2 API</a>
</td>
<td>Should be used for new projects
</td>
</tr>
</table>
</body>
</html>

7
Documentation/video4linux/CARDLIST.bttv
View File

@@ -104,8 +104,8 @@
103 -> Grand X-Guard / Trust 814PCI [0304:0102]
104 -> Nebula Electronics DigiTV [0071:0101]
105 -> ProVideo PV143 [aa00:1430,aa00:1431,aa00:1432,aa00:1433,aa03:1433]
106 -> PHYTEC VD-009-X1 MiniDIN (bt878)
107 -> PHYTEC VD-009-X1 Combi (bt878)
106 -> PHYTEC VD-009-X1 VD-011 MiniDIN (bt878)
107 -> PHYTEC VD-009-X1 VD-011 Combi (bt878)
108 -> PHYTEC VD-009 MiniDIN (bt878)
109 -> PHYTEC VD-009 Combi (bt878)
110 -> IVC-100 [ff00:a132]
@@ -151,3 +151,6 @@
150 -> Geovision GV-600 [008a:763c]
151 -> Kozumi KTV-01C
152 -> Encore ENL TV-FM-2 [1000:1801]
153 -> PHYTEC VD-012 (bt878)
154 -> PHYTEC VD-012-X1 (bt878)
155 -> PHYTEC VD-012-X2 (bt878)

1
Documentation/video4linux/CARDLIST.cx23885
View File

@@ -11,3 +11,4 @@
10 -> DViCO FusionHDTV7 Dual Express [18ac:d618]
11 -> DViCO FusionHDTV DVB-T Dual Express [18ac:db78]
12 -> Leadtek Winfast PxDVR3200 H [107d:6681]
13 -> Compro VideoMate E650F [185b:e800]

5
Documentation/video4linux/CARDLIST.cx88
View File

@@ -2,7 +2,7 @@
1 -> Hauppauge WinTV 34xxx models [0070:3400,0070:3401]
2 -> GDI Black Gold [14c7:0106,14c7:0107]
3 -> PixelView [1554:4811]
4 -> ATI TV Wonder Pro [1002:00f8]
4 -> ATI TV Wonder Pro [1002:00f8,1002:00f9]
5 -> Leadtek Winfast 2000XP Expert [107d:6611,107d:6613]
6 -> AverTV Studio 303 (M126) [1461:000b]
7 -> MSI TV-@nywhere Master [1462:8606]
@@ -74,3 +74,6 @@
73 -> TeVii S420 DVB-S [d420:9022]
74 -> Prolink Pixelview Global Extreme [1554:4976]
75 -> PROF 7300 DVB-S/S2 [B033:3033]
76 -> SATTRADE ST4200 DVB-S/S2 [b200:4200]
77 -> TBS 8910 DVB-S [8910:8888]
78 -> Prof 6200 DVB-S [b022:3022]

9
Documentation/video4linux/CARDLIST.em28xx
View File

@@ -1,5 +1,5 @@
0 -> Unknown EM2800 video grabber (em2800) [eb1a:2800]
1 -> Unknown EM2750/28xx video grabber (em2820/em2840) [eb1a:2820,eb1a:2860,eb1a:2861,eb1a:2870,eb1a:2881,eb1a:2883]
1 -> Unknown EM2750/28xx video grabber (em2820/em2840) [eb1a:2820,eb1a:2821,eb1a:2860,eb1a:2861,eb1a:2870,eb1a:2881,eb1a:2883]
2 -> Terratec Cinergy 250 USB (em2820/em2840) [0ccd:0036]
3 -> Pinnacle PCTV USB 2 (em2820/em2840) [2304:0208]
4 -> Hauppauge WinTV USB 2 (em2820/em2840) [2040:4200,2040:4201]
@@ -12,9 +12,9 @@
11 -> Terratec Hybrid XS (em2880) [0ccd:0042]
12 -> Kworld PVR TV 2800 RF (em2820/em2840)
13 -> Terratec Prodigy XS (em2880) [0ccd:0047]
14 -> Pixelview Prolink PlayTV USB 2.0 (em2820/em2840) [eb1a:2821]
14 -> Pixelview Prolink PlayTV USB 2.0 (em2820/em2840)
15 -> V-Gear PocketTV (em2800)
16 -> Hauppauge WinTV HVR 950 (em2883) [2040:6513,2040:6517,2040:651b,2040:651f]
16 -> Hauppauge WinTV HVR 950 (em2883) [2040:6513,2040:6517,2040:651b]
17 -> Pinnacle PCTV HD Pro Stick (em2880) [2304:0227]
18 -> Hauppauge WinTV HVR 900 (R2) (em2880) [2040:6502]
19 -> PointNix Intra-Oral Camera (em2860)
@@ -27,7 +27,6 @@
26 -> Hercules Smart TV USB 2.0 (em2820/em2840)
27 -> Pinnacle PCTV USB 2 (Philips FM1216ME) (em2820/em2840)
28 -> Leadtek Winfast USB II Deluxe (em2820/em2840)
29 -> Pinnacle Dazzle DVC 100 (em2820/em2840)
30 -> Videology 20K14XUSB USB2.0 (em2820/em2840)
31 -> Usbgear VD204v9 (em2821)
32 -> Supercomp USB 2.0 TV (em2821)
@@ -57,3 +56,5 @@
56 -> Pinnacle Hybrid Pro (2) (em2882) [2304:0226]
57 -> Kworld PlusTV HD Hybrid 330 (em2883) [eb1a:a316]
58 -> Compro VideoMate ForYou/Stereo (em2820/em2840) [185b:2041]
60 -> Hauppauge WinTV HVR 850 (em2883) [2040:651f]
61 -> Pixelview PlayTV Box 4 USB 2.0 (em2820/em2840)

3
Documentation/video4linux/CARDLIST.saa7134
View File

@@ -10,7 +10,7 @@
9 -> Medion 5044
10 -> Kworld/KuroutoShikou SAA7130-TVPCI
11 -> Terratec Cinergy 600 TV [153b:1143]
12 -> Medion 7134 [16be:0003]
12 -> Medion 7134 [16be:0003,16be:5000]
13 -> Typhoon TV+Radio 90031
14 -> ELSA EX-VISION 300TV [1048:226b]
15 -> ELSA EX-VISION 500TV [1048:226a]
@@ -151,3 +151,4 @@
150 -> Zogis Real Angel 220
151 -> ADS Tech Instant HDTV [1421:0380]
152 -> Asus Tiger Rev:1.00 [1043:4857]
153 -> Kworld Plus TV Analog Lite PCI [17de:7128]

8
Documentation/video4linux/README.cx88
View File

@@ -1,4 +1,3 @@
cx8800 release notes
====================
@@ -10,21 +9,20 @@ current status
video
- Basically works.
- Some minor image quality glitches.
- For now only capture, overlay support isn't completed yet.
- For now, only capture and read(). Overlay isn't supported.
audio
- The chip specs for the on-chip TV sound decoder are next
to useless :-/
- Neverless the builtin TV sound decoder starts working now,
at least for PAL-BG. Other TV norms need other code ...
at least for some standards.
FOR ANY REPORTS ON THIS PLEASE MENTION THE TV NORM YOU ARE
USING.
- Most tuner chips do provide mono sound, which may or may not
be useable depending on the board design. With the Hauppauge
cards it works, so there is mono sound available as fallback.
- audio data dma (i.e. recording without loopback cable to the
sound card) should be possible, but there is no code yet ...
sound card) is supported via cx88-alsa.
vbi
- Code present. Works for NTSC closed caption. PAL and other

19
Documentation/video4linux/gspca.txt
View File

@@ -50,9 +50,14 @@ ov519 045e:028c Micro$oft xbox cam
spca508 0461:0815 Micro Innovation IC200
sunplus 0461:0821 Fujifilm MV-1
zc3xx 0461:0a00 MicroInnovation WebCam320
stv06xx 046d:0840 QuickCam Express
stv06xx 046d:0850 LEGO cam / QuickCam Web
stv06xx 046d:0870 Dexxa WebCam USB
spca500 046d:0890 Logitech QuickCam traveler
vc032x 046d:0892 Logitech Orbicam
vc032x 046d:0896 Logitech Orbicam
vc032x 046d:0897 Logitech QuickCam for Dell notebooks
zc3xx 046d:089d Logitech QuickCam E2500
zc3xx 046d:08a0 Logitech QC IM
zc3xx 046d:08a1 Logitech QC IM 0x08A1 +sound
zc3xx 046d:08a2 Labtec Webcam Pro
@@ -169,6 +174,9 @@ spca500 06bd:0404 Agfa CL20
spca500 06be:0800 Optimedia
sunplus 06d6:0031 Trust 610 LCD PowerC@m Zoom
spca506 06e1:a190 ADS Instant VCD
ov534 06f8:3002 Hercules Blog Webcam
ov534 06f8:3003 Hercules Dualpix HD Weblog
sonixj 06f8:3004 Hercules Classic Silver
spca508 0733:0110 ViewQuest VQ110
spca508 0130:0130 Clone Digital Webcam 11043
spca501 0733:0401 Intel Create and Share
@@ -199,7 +207,8 @@ sunplus 08ca:2050 Medion MD 41437
sunplus 08ca:2060 Aiptek PocketDV5300
tv8532 0923:010f ICM532 cams
mars 093a:050f Mars-Semi Pc-Camera
pac207 093a:2460 PAC207 Qtec Webcam 100
pac207 093a:2460 Qtec Webcam 100
pac207 093a:2461 HP Webcam
pac207 093a:2463 Philips SPC 220 NC
pac207 093a:2464 Labtec Webcam 1200
pac207 093a:2468 PAC207
@@ -213,10 +222,13 @@ pac7311 093a:2603 PAC7312
pac7311 093a:2608 Trust WB-3300p
pac7311 093a:260e Gigaware VGA PC Camera, Trust WB-3350p, SIGMA cam 2350
pac7311 093a:260f SnakeCam
pac7311 093a:2620 Apollo AC-905
pac7311 093a:2621 PAC731x
pac7311 093a:2622 Genius Eye 312
pac7311 093a:2624 PAC7302
pac7311 093a:2626 Labtec 2200
pac7311 093a:262a Webcam 300k
pac7311 093a:262c Philips SPC 230 NC
zc3xx 0ac8:0302 Z-star Vimicro zc0302
vc032x 0ac8:0321 Vimicro generic vc0321
vc032x 0ac8:0323 Vimicro Vc0323
@@ -249,11 +261,13 @@ sonixj 0c45:60c0 Sangha Sn535
sonixj 0c45:60ec SN9C105+MO4000
sonixj 0c45:60fb Surfer NoName
sonixj 0c45:60fc LG-LIC300
sonixj 0c45:60fe Microdia Audio
sonixj 0c45:6128 Microdia/Sonix SNP325
sonixj 0c45:612a Avant Camera
sonixj 0c45:612c Typhoon Rasy Cam 1.3MPix
sonixj 0c45:6130 Sonix Pccam
sonixj 0c45:6138 Sn9c120 Mo4000
sonixj 0c45:613a Microdia Sonix PC Camera
sonixj 0c45:613b Surfer SN-206
sonixj 0c45:613c Sonix Pccam168
sonixj 0c45:6143 Sonix Pccam168
@@ -263,6 +277,9 @@ etoms 102c:6251 Qcam xxxxxx VGA
zc3xx 10fd:0128 Typhoon Webshot II USB 300k 0x0128
spca561 10fd:7e50 FlyCam Usb 100
zc3xx 10fd:8050 Typhoon Webshot II USB 300k
ov534 1415:2000 Sony HD Eye for PS3 (SLEH 00201)
pac207 145f:013a Trust WB-1300N
vc032x 15b8:6002 HP 2.0 Megapixel rz406aa
spca501 1776:501c Arowana 300K CMOS Camera
t613 17a1:0128 TASCORP JPEG Webcam, NGS Cyclops
vc032x 17ef:4802 Lenovo Vc0323+MI1310_SOC

520
Documentation/video4linux/v4l2-framework.txt Normal file
View File

@@ -0,0 +1,520 @@
Overview of the V4L2 driver framework
=====================================
This text documents the various structures provided by the V4L2 framework and
their relationships.
Introduction
------------
The V4L2 drivers tend to be very complex due to the complexity of the
hardware: most devices have multiple ICs, export multiple device nodes in
/dev, and create also non-V4L2 devices such as DVB, ALSA, FB, I2C and input
(IR) devices.
Especially the fact that V4L2 drivers have to setup supporting ICs to
do audio/video muxing/encoding/decoding makes it more complex than most.
Usually these ICs are connected to the main bridge driver through one or
more I2C busses, but other busses can also be used. Such devices are
called 'sub-devices'.
For a long time the framework was limited to the video_device struct for
creating V4L device nodes and video_buf for handling the video buffers
(note that this document does not discuss the video_buf framework).
This meant that all drivers had to do the setup of device instances and
connecting to sub-devices themselves. Some of this is quite complicated
to do right and many drivers never did do it correctly.
There is also a lot of common code that could never be refactored due to
the lack of a framework.
So this framework sets up the basic building blocks that all drivers
need and this same framework should make it much easier to refactor
common code into utility functions shared by all drivers.
Structure of a driver
---------------------
All drivers have the following structure:
1) A struct for each device instance containing the device state.
2) A way of initializing and commanding sub-devices (if any).
3) Creating V4L2 device nodes (/dev/videoX, /dev/vbiX, /dev/radioX and
/dev/vtxX) and keeping track of device-node specific data.
4) Filehandle-specific structs containing per-filehandle data.
This is a rough schematic of how it all relates:
device instances
|
+-sub-device instances
|
\-V4L2 device nodes
|
\-filehandle instances
Structure of the framework
--------------------------
The framework closely resembles the driver structure: it has a v4l2_device
struct for the device instance data, a v4l2_subdev struct to refer to
sub-device instances, the video_device struct stores V4L2 device node data
and in the future a v4l2_fh struct will keep track of filehandle instances
(this is not yet implemented).
struct v4l2_device
------------------
Each device instance is represented by a struct v4l2_device (v4l2-device.h).
Very simple devices can just allocate this struct, but most of the time you
would embed this struct inside a larger struct.
You must register the device instance:
v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
Registration will initialize the v4l2_device struct and link dev->driver_data
to v4l2_dev. Registration will also set v4l2_dev->name to a value derived from
dev (driver name followed by the bus_id, to be precise). You may change the
name after registration if you want.
The first 'dev' argument is normally the struct device pointer of a pci_dev,
usb_device or platform_device.
You unregister with:
v4l2_device_unregister(struct v4l2_device *v4l2_dev);
Unregistering will also automatically unregister all subdevs from the device.
Sometimes you need to iterate over all devices registered by a specific
driver. This is usually the case if multiple device drivers use the same
hardware. E.g. the ivtvfb driver is a framebuffer driver that uses the ivtv
hardware. The same is true for alsa drivers for example.
You can iterate over all registered devices as follows:
static int callback(struct device *dev, void *p)
{
struct v4l2_device *v4l2_dev = dev_get_drvdata(dev);
/* test if this device was inited */
if (v4l2_dev == NULL)
return 0;
...
return 0;
}
int iterate(void *p)
{
struct device_driver *drv;
int err;
/* Find driver 'ivtv' on the PCI bus.
pci_bus_type is a global. For USB busses use usb_bus_type. */
drv = driver_find("ivtv", &pci_bus_type);
/* iterate over all ivtv device instances */
err = driver_for_each_device(drv, NULL, p, callback);
put_driver(drv);
return err;
}
Sometimes you need to keep a running counter of the device instance. This is
commonly used to map a device instance to an index of a module option array.
The recommended approach is as follows:
static atomic_t drv_instance = ATOMIC_INIT(0);
static int __devinit drv_probe(struct pci_dev *dev,
const struct pci_device_id *pci_id)
{
...
state->instance = atomic_inc_return(&drv_instance) - 1;
}
struct v4l2_subdev
------------------
Many drivers need to communicate with sub-devices. These devices can do all
sort of tasks, but most commonly they handle audio and/or video muxing,
encoding or decoding. For webcams common sub-devices are sensors and camera
controllers.
Usually these are I2C devices, but not necessarily. In order to provide the
driver with a consistent interface to these sub-devices the v4l2_subdev struct
(v4l2-subdev.h) was created.
Each sub-device driver must have a v4l2_subdev struct. This struct can be
stand-alone for simple sub-devices or it might be embedded in a larger struct
if more state information needs to be stored. Usually there is a low-level
device struct (e.g. i2c_client) that contains the device data as setup
by the kernel. It is recommended to store that pointer in the private
data of v4l2_subdev using v4l2_set_subdevdata(). That makes it easy to go
from a v4l2_subdev to the actual low-level bus-specific device data.
You also need a way to go from the low-level struct to v4l2_subdev. For the
common i2c_client struct the i2c_set_clientdata() call is used to store a
v4l2_subdev pointer, for other busses you may have to use other methods.
From the bridge driver perspective you load the sub-device module and somehow
obtain the v4l2_subdev pointer. For i2c devices this is easy: you call
i2c_get_clientdata(). For other busses something similar needs to be done.
Helper functions exists for sub-devices on an I2C bus that do most of this
tricky work for you.
Each v4l2_subdev contains function pointers that sub-device drivers can
implement (or leave NULL if it is not applicable). Since sub-devices can do
so many different things and you do not want to end up with a huge ops struct
of which only a handful of ops are commonly implemented, the function pointers
are sorted according to category and each category has its own ops struct.
The top-level ops struct contains pointers to the category ops structs, which
may be NULL if the subdev driver does not support anything from that category.
It looks like this:
struct v4l2_subdev_core_ops {
int (*g_chip_ident)(struct v4l2_subdev *sd, struct v4l2_chip_ident *chip);
int (*log_status)(struct v4l2_subdev *sd);
int (*init)(struct v4l2_subdev *sd, u32 val);
...
};
struct v4l2_subdev_tuner_ops {
...
};
struct v4l2_subdev_audio_ops {
...
};
struct v4l2_subdev_video_ops {
...
};
struct v4l2_subdev_ops {
const struct v4l2_subdev_core_ops *core;
const struct v4l2_subdev_tuner_ops *tuner;
const struct v4l2_subdev_audio_ops *audio;
const struct v4l2_subdev_video_ops *video;
};
The core ops are common to all subdevs, the other categories are implemented
depending on the sub-device. E.g. a video device is unlikely to support the
audio ops and vice versa.
This setup limits the number of function pointers while still making it easy
to add new ops and categories.
A sub-device driver initializes the v4l2_subdev struct using:
v4l2_subdev_init(subdev, &ops);
Afterwards you need to initialize subdev->name with a unique name and set the
module owner. This is done for you if you use the i2c helper functions.
A device (bridge) driver needs to register the v4l2_subdev with the
v4l2_device:
int err = v4l2_device_register_subdev(device, subdev);
This can fail if the subdev module disappeared before it could be registered.
After this function was called successfully the subdev->dev field points to
the v4l2_device.
You can unregister a sub-device using:
v4l2_device_unregister_subdev(subdev);
Afterwards the subdev module can be unloaded and subdev->dev == NULL.
You can call an ops function either directly:
err = subdev->ops->core->g_chip_ident(subdev, &chip);
but it is better and easier to use this macro:
err = v4l2_subdev_call(subdev, core, g_chip_ident, &chip);
The macro will to the right NULL pointer checks and returns -ENODEV if subdev
is NULL, -ENOIOCTLCMD if either subdev->core or subdev->core->g_chip_ident is
NULL, or the actual result of the subdev->ops->core->g_chip_ident ops.
It is also possible to call all or a subset of the sub-devices:
v4l2_device_call_all(dev, 0, core, g_chip_ident, &chip);
Any subdev that does not support this ops is skipped and error results are
ignored. If you want to check for errors use this:
err = v4l2_device_call_until_err(dev, 0, core, g_chip_ident, &chip);
Any error except -ENOIOCTLCMD will exit the loop with that error. If no
errors (except -ENOIOCTLCMD) occured, then 0 is returned.
The second argument to both calls is a group ID. If 0, then all subdevs are
called. If non-zero, then only those whose group ID match that value will
be called. Before a bridge driver registers a subdev it can set subdev->grp_id
to whatever value it wants (it's 0 by default). This value is owned by the
bridge driver and the sub-device driver will never modify or use it.
The group ID gives the bridge driver more control how callbacks are called.
For example, there may be multiple audio chips on a board, each capable of
changing the volume. But usually only one will actually be used when the
user want to change the volume. You can set the group ID for that subdev to
e.g. AUDIO_CONTROLLER and specify that as the group ID value when calling
v4l2_device_call_all(). That ensures that it will only go to the subdev
that needs it.
The advantage of using v4l2_subdev is that it is a generic struct and does
not contain any knowledge about the underlying hardware. So a driver might
contain several subdevs that use an I2C bus, but also a subdev that is
controlled through GPIO pins. This distinction is only relevant when setting
up the device, but once the subdev is registered it is completely transparent.
I2C sub-device drivers
----------------------
Since these drivers are so common, special helper functions are available to
ease the use of these drivers (v4l2-common.h).
The recommended method of adding v4l2_subdev support to an I2C driver is to
embed the v4l2_subdev struct into the state struct that is created for each
I2C device instance. Very simple devices have no state struct and in that case
you can just create a v4l2_subdev directly.
A typical state struct would look like this (where 'chipname' is replaced by
the name of the chip):
struct chipname_state {
struct v4l2_subdev sd;
... /* additional state fields */
};
Initialize the v4l2_subdev struct as follows:
v4l2_i2c_subdev_init(&state->sd, client, subdev_ops);
This function will fill in all the fields of v4l2_subdev and ensure that the
v4l2_subdev and i2c_client both point to one another.
You should also add a helper inline function to go from a v4l2_subdev pointer
to a chipname_state struct:
static inline struct chipname_state *to_state(struct v4l2_subdev *sd)
{
return container_of(sd, struct chipname_state, sd);
}
Use this to go from the v4l2_subdev struct to the i2c_client struct:
struct i2c_client *client = v4l2_get_subdevdata(sd);
And this to go from an i2c_client to a v4l2_subdev struct:
struct v4l2_subdev *sd = i2c_get_clientdata(client);
Finally you need to make a command function to make driver->command()
call the right subdev_ops functions:
static int subdev_command(struct i2c_client *client, unsigned cmd, void *arg)
{
return v4l2_subdev_command(i2c_get_clientdata(client), cmd, arg);
}
If driver->command is never used then you can leave this out. Eventually the
driver->command usage should be removed from v4l.
Make sure to call v4l2_device_unregister_subdev(sd) when the remove() callback
is called. This will unregister the sub-device from the bridge driver. It is
safe to call this even if the sub-device was never registered.
The bridge driver also has some helper functions it can use:
struct v4l2_subdev *sd = v4l2_i2c_new_subdev(adapter, "module_foo", "chipid", 0x36);
This loads the given module (can be NULL if no module needs to be loaded) and
calls i2c_new_device() with the given i2c_adapter and chip/address arguments.
If all goes well, then it registers the subdev with the v4l2_device. It gets
the v4l2_device by calling i2c_get_adapdata(adapter), so you should make sure
that adapdata is set to v4l2_device when you setup the i2c_adapter in your
driver.
You can also use v4l2_i2c_new_probed_subdev() which is very similar to
v4l2_i2c_new_subdev(), except that it has an array of possible I2C addresses
that it should probe. Internally it calls i2c_new_probed_device().
Both functions return NULL if something went wrong.
struct video_device
-------------------
The actual device nodes in the /dev directory are created using the
video_device struct (v4l2-dev.h). This struct can either be allocated
dynamically or embedded in a larger struct.
To allocate it dynamically use:
struct video_device *vdev = video_device_alloc();
if (vdev == NULL)
return -ENOMEM;
vdev->release = video_device_release;
If you embed it in a larger struct, then you must set the release()
callback to your own function:
struct video_device *vdev = &my_vdev->vdev;
vdev->release = my_vdev_release;
The release callback must be set and it is called when the last user
of the video device exits.
The default video_device_release() callback just calls kfree to free the
allocated memory.
You should also set these fields:
- parent: set to the parent device (same device as was used to register
v4l2_device).
- name: set to something descriptive and unique.
- fops: set to the file_operations struct.
- ioctl_ops: if you use the v4l2_ioctl_ops to simplify ioctl maintenance
(highly recommended to use this and it might become compulsory in the
future!), then set this to your v4l2_ioctl_ops struct.
If you use v4l2_ioctl_ops, then you should set .unlocked_ioctl to
__video_ioctl2 or .ioctl to video_ioctl2 in your file_operations struct.
video_device registration
-------------------------
Next you register the video device: this will create the character device
for you.
err = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
if (err) {
video_device_release(vdev); // or kfree(my_vdev);
return err;
}
Which device is registered depends on the type argument. The following
types exist:
VFL_TYPE_GRABBER: videoX for video input/output devices
VFL_TYPE_VBI: vbiX for vertical blank data (i.e. closed captions, teletext)
VFL_TYPE_RADIO: radioX for radio tuners
VFL_TYPE_VTX: vtxX for teletext devices (deprecated, don't use)
The last argument gives you a certain amount of control over the device
kernel number used (i.e. the X in videoX). Normally you will pass -1 to
let the v4l2 framework pick the first free number. But if a driver creates
many devices, then it can be useful to have different video devices in
separate ranges. For example, video capture devices start at 0, video
output devices start at 16.
So you can use the last argument to specify a minimum kernel number and
the v4l2 framework will try to pick the first free number that is equal
or higher to what you passed. If that fails, then it will just pick the
first free number.
Whenever a device node is created some attributes are also created for you.
If you look in /sys/class/video4linux you see the devices. Go into e.g.
video0 and you will see 'name' and 'index' attributes. The 'name' attribute
is the 'name' field of the video_device struct. The 'index' attribute is
a device node index that can be assigned by the driver, or that is calculated
for you.
If you call video_register_device(), then the index is just increased by
1 for each device node you register. The first video device node you register
always starts off with 0.
Alternatively you can call video_register_device_index() which is identical
to video_register_device(), but with an extra index argument. Here you can
pass a specific index value (between 0 and 31) that should be used.
Users can setup udev rules that utilize the index attribute to make fancy
device names (e.g. 'mpegX' for MPEG video capture device nodes).
After the device was successfully registered, then you can use these fields:
- vfl_type: the device type passed to video_register_device.
- minor: the assigned device minor number.
- num: the device kernel number (i.e. the X in videoX).
- index: the device index number (calculated or set explicitly using
video_register_device_index).
If the registration failed, then you need to call video_device_release()
to free the allocated video_device struct, or free your own struct if the
video_device was embedded in it. The vdev->release() callback will never
be called if the registration failed, nor should you ever attempt to
unregister the device if the registration failed.
video_device cleanup
--------------------
When the video device nodes have to be removed, either during the unload
of the driver or because the USB device was disconnected, then you should
unregister them:
video_unregister_device(vdev);
This will remove the device nodes from sysfs (causing udev to remove them
from /dev).
After video_unregister_device() returns no new opens can be done.
However, in the case of USB devices some application might still have one
of these device nodes open. You should block all new accesses to read,
write, poll, etc. except possibly for certain ioctl operations like
queueing buffers.
When the last user of the video device node exits, then the vdev->release()
callback is called and you can do the final cleanup there.
video_device helper functions
-----------------------------
There are a few useful helper functions:
You can set/get driver private data in the video_device struct using:
void *video_get_drvdata(struct video_device *dev);
void video_set_drvdata(struct video_device *dev, void *data);
Note that you can safely call video_set_drvdata() before calling
video_register_device().
And this function:
struct video_device *video_devdata(struct file *file);
returns the video_device belonging to the file struct.
The final helper function combines video_get_drvdata with
video_devdata:
void *video_drvdata(struct file *file);
You can go from a video_device struct to the v4l2_device struct using:
struct v4l2_device *v4l2_dev = dev_get_drvdata(vdev->parent);