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r: 59276
b: refs/heads/master
c: 4aabab2
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Linus Torvalds committed Jul 12, 2007
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: ca9ced7f6798868f9d2c81a59b49f8c2136685d8
refs/heads/master: 4aabab2181f20560948c2045ce1faaa9ac1507a8
16 changes: 16 additions & 0 deletions trunk/Documentation/ABI/removed/raw1394_legacy_isochronous
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What: legacy isochronous ABI of raw1394 (1st generation iso ABI)
Date: June 2007 (scheduled), removed in kernel v2.6.23
Contact: linux1394-devel@lists.sourceforge.net
Description:
The two request types RAW1394_REQ_ISO_SEND, RAW1394_REQ_ISO_LISTEN have
been deprecated for quite some time. They are very inefficient as they
come with high interrupt load and several layers of callbacks for each
packet. Because of these deficiencies, the video1394 and dv1394 drivers
and the 3rd-generation isochronous ABI in raw1394 (rawiso) were created.

Users:
libraw1394 users via the long deprecated API raw1394_iso_write,
raw1394_start_iso_write, raw1394_start_iso_rcv, raw1394_stop_iso_rcv

libdc1394, which optionally uses these old libraw1394 calls
alternatively to the more efficient video1394 ABI
103 changes: 0 additions & 103 deletions trunk/Documentation/DMA-mapping.txt
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Expand Up @@ -664,109 +664,6 @@ It is that simple.
Well, not for some odd devices. See the next section for information
about that.

DAC Addressing for Address Space Hungry Devices

There exists a class of devices which do not mesh well with the PCI
DMA mapping API. By definition these "mappings" are a finite
resource. The number of total available mappings per bus is platform
specific, but there will always be a reasonable amount.

What is "reasonable"? Reasonable means that networking and block I/O
devices need not worry about using too many mappings.

As an example of a problematic device, consider compute cluster cards.
They can potentially need to access gigabytes of memory at once via
DMA. Dynamic mappings are unsuitable for this kind of access pattern.

To this end we've provided a small API by which a device driver
may use DAC cycles to directly address all of physical memory.
Not all platforms support this, but most do. It is easy to determine
whether the platform will work properly at probe time.

First, understand that there may be a SEVERE performance penalty for
using these interfaces on some platforms. Therefore, you MUST only
use these interfaces if it is absolutely required. %99 of devices can
use the normal APIs without any problems.

Note that for streaming type mappings you must either use these
interfaces, or the dynamic mapping interfaces above. You may not mix
usage of both for the same device. Such an act is illegal and is
guaranteed to put a banana in your tailpipe.

However, consistent mappings may in fact be used in conjunction with
these interfaces. Remember that, as defined, consistent mappings are
always going to be SAC addressable.

The first thing your driver needs to do is query the PCI platform
layer if it is capable of handling your devices DAC addressing
capabilities:

int pci_dac_dma_supported(struct pci_dev *hwdev, u64 mask);

You may not use the following interfaces if this routine fails.

Next, DMA addresses using this API are kept track of using the
dma64_addr_t type. It is guaranteed to be big enough to hold any
DAC address the platform layer will give to you from the following
routines. If you have consistent mappings as well, you still
use plain dma_addr_t to keep track of those.

All mappings obtained here will be direct. The mappings are not
translated, and this is the purpose of this dialect of the DMA API.

All routines work with page/offset pairs. This is the _ONLY_ way to
portably refer to any piece of memory. If you have a cpu pointer
(which may be validly DMA'd too) you may easily obtain the page
and offset using something like this:

struct page *page = virt_to_page(ptr);
unsigned long offset = offset_in_page(ptr);

Here are the interfaces:

dma64_addr_t pci_dac_page_to_dma(struct pci_dev *pdev,
struct page *page,
unsigned long offset,
int direction);

The DAC address for the tuple PAGE/OFFSET are returned. The direction
argument is the same as for pci_{map,unmap}_single(). The same rules
for cpu/device access apply here as for the streaming mapping
interfaces. To reiterate:

The cpu may touch the buffer before pci_dac_page_to_dma.
The device may touch the buffer after pci_dac_page_to_dma
is made, but the cpu may NOT.

When the DMA transfer is complete, invoke:

void pci_dac_dma_sync_single_for_cpu(struct pci_dev *pdev,
dma64_addr_t dma_addr,
size_t len, int direction);

This must be done before the CPU looks at the buffer again.
This interface behaves identically to pci_dma_sync_{single,sg}_for_cpu().

And likewise, if you wish to let the device get back at the buffer after
the cpu has read/written it, invoke:

void pci_dac_dma_sync_single_for_device(struct pci_dev *pdev,
dma64_addr_t dma_addr,
size_t len, int direction);

before letting the device access the DMA area again.

If you need to get back to the PAGE/OFFSET tuple from a dma64_addr_t
the following interfaces are provided:

struct page *pci_dac_dma_to_page(struct pci_dev *pdev,
dma64_addr_t dma_addr);
unsigned long pci_dac_dma_to_offset(struct pci_dev *pdev,
dma64_addr_t dma_addr);

This is possible with the DAC interfaces purely because they are
not translated in any way.

Optimizing Unmap State Space Consumption

On many platforms, pci_unmap_{single,page}() is simply a nop.
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66 changes: 66 additions & 0 deletions trunk/Documentation/DocBook/kernel-api.tmpl
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Expand Up @@ -643,4 +643,70 @@ X!Idrivers/video/console/fonts.c
!Edrivers/spi/spi.c
</chapter>

<chapter id="i2c">
<title>I<superscript>2</superscript>C and SMBus Subsystem</title>

<para>
I<superscript>2</superscript>C (or without fancy typography, "I2C")
is an acronym for the "Inter-IC" bus, a simple bus protocol which is
widely used where low data rate communications suffice.
Since it's also a licensed trademark, some vendors use another
name (such as "Two-Wire Interface", TWI) for the same bus.
I2C only needs two signals (SCL for clock, SDA for data), conserving
board real estate and minimizing signal quality issues.
Most I2C devices use seven bit addresses, and bus speeds of up
to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
found wide use.
I2C is a multi-master bus; open drain signaling is used to
arbitrate between masters, as well as to handshake and to
synchronize clocks from slower clients.
</para>

<para>
The Linux I2C programming interfaces support only the master
side of bus interactions, not the slave side.
The programming interface is structured around two kinds of driver,
and two kinds of device.
An I2C "Adapter Driver" abstracts the controller hardware; it binds
to a physical device (perhaps a PCI device or platform_device) and
exposes a <structname>struct i2c_adapter</structname> representing
each I2C bus segment it manages.
On each I2C bus segment will be I2C devices represented by a
<structname>struct i2c_client</structname>. Those devices will
be bound to a <structname>struct i2c_driver</structname>,
which should follow the standard Linux driver model.
(At this writing, a legacy model is more widely used.)
There are functions to perform various I2C protocol operations; at
this writing all such functions are usable only from task context.
</para>

<para>
The System Management Bus (SMBus) is a sibling protocol. Most SMBus
systems are also I2C conformant. The electrical constraints are
tighter for SMBus, and it standardizes particular protocol messages
and idioms. Controllers that support I2C can also support most
SMBus operations, but SMBus controllers don't support all the protocol
options that an I2C controller will.
There are functions to perform various SMBus protocol operations,
either using I2C primitives or by issuing SMBus commands to
i2c_adapter devices which don't support those I2C operations.
</para>

!Iinclude/linux/i2c.h
!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
!Edrivers/i2c/i2c-core.c
</chapter>

<chapter id="splice">
<title>splice API</title>
<para>)
splice is a method for moving blocks of data around inside the
kernel, without continually transferring it between the kernel
and user space.
</para>
!Iinclude/linux/splice.h
!Ffs/splice.c
</chapter>


</book>
155 changes: 155 additions & 0 deletions trunk/Documentation/blackfin/kgdb.txt
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A Simple Guide to Configure KGDB

Sonic Zhang <sonic.zhang@analog.com>
Aug. 24th 2006


This KGDB patch enables the kernel developer to do source level debugging on
the kernel for the Blackfin architecture. The debugging works over either the
ethernet interface or one of the uarts. Both software breakpoints and
hardware breakpoints are supported in this version.
http://docs.blackfin.uclinux.org/doku.php?id=kgdb


2 known issues:
1. This bug:
http://blackfin.uclinux.org/tracker/index.php?func=detail&aid=544&group_id=18&atid=145
The GDB client for Blackfin uClinux causes incorrect values of local
variables to be displayed when the user breaks the running of kernel in GDB.
2. Because of a hardware bug in Blackfin 533 v1.0.3:
05000067 - Watchpoints (Hardware Breakpoints) are not supported
Hardware breakpoints cannot be set properly.


Debug over Ethernet:

1. Compile and install the cross platform version of gdb for blackfin, which
can be found at $(BINROOT)/bfin-elf-gdb.

2. Apply this patch to the 2.6.x kernel. Select the menuconfig option under
"Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
With this selected, option "Full Symbolic/Source Debugging support" and
"Compile the kernel with frame pointers" are also selected.

3. Select option "KGDB: connect over (Ethernet)". Add "kgdboe=@target-IP/,@host-IP/" to
the option "Compiled-in Kernel Boot Parameter" under "Kernel hacking".

4. Connect minicom to the serial port and boot the kernel image.

5. Configure the IP "/> ifconfig eth0 target-IP"

6. Start GDB client "bfin-elf-gdb vmlinux".

7. Connect to the target "(gdb) target remote udp:target-IP:6443".

8. Set software breakpoint "(gdb) break sys_open".

9. Continue "(gdb) c".

10. Run ls in the target console "/> ls".

11. Breakpoint hits. "Breakpoint 1: sys_open(..."

12. Display local variables and function paramters.
(*) This operation gives wrong results, see known issue 1.

13. Single stepping "(gdb) si".

14. Remove breakpoint 1. "(gdb) del 1"

15. Set hardware breakpoint "(gdb) hbreak sys_open".

16. Continue "(gdb) c".

17. Run ls in the target console "/> ls".

18. Hardware breakpoint hits. "Breakpoint 1: sys_open(...".
(*) This hardware breakpoint will not be hit, see known issue 2.

19. Continue "(gdb) c".

20. Interrupt the target in GDB "Ctrl+C".

21. Detach from the target "(gdb) detach".

22. Exit GDB "(gdb) quit".


Debug over the UART:

1. Compile and install the cross platform version of gdb for blackfin, which
can be found at $(BINROOT)/bfin-elf-gdb.

2. Apply this patch to the 2.6.x kernel. Select the menuconfig option under
"Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
With this selected, option "Full Symbolic/Source Debugging support" and
"Compile the kernel with frame pointers" are also selected.

3. Select option "KGDB: connect over (UART)". Set "KGDB: UART port number" to be
a different one from the console. Don't forget to change the mode of
blackfin serial driver to PIO. Otherwise kgdb works incorrectly on UART.

4. If you want connect to kgdb when the kernel boots, enable
"KGDB: Wait for gdb connection early"

5. Compile kernel.

6. Connect minicom to the serial port of the console and boot the kernel image.

7. Start GDB client "bfin-elf-gdb vmlinux".

8. Set the baud rate in GDB "(gdb) set remotebaud 57600".

9. Connect to the target on the second serial port "(gdb) target remote /dev/ttyS1".

10. Set software breakpoint "(gdb) break sys_open".

11. Continue "(gdb) c".

12. Run ls in the target console "/> ls".

13. A breakpoint is hit. "Breakpoint 1: sys_open(..."

14. All other operations are the same as that in KGDB over Ethernet.


Debug over the same UART as console:

1. Compile and install the cross platform version of gdb for blackfin, which
can be found at $(BINROOT)/bfin-elf-gdb.

2. Apply this patch to the 2.6.x kernel. Select the menuconfig option under
"Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
With this selected, option "Full Symbolic/Source Debugging support" and
"Compile the kernel with frame pointers" are also selected.

3. Select option "KGDB: connect over UART". Set "KGDB: UART port number" to console.
Don't forget to change the mode of blackfin serial driver to PIO.
Otherwise kgdb works incorrectly on UART.

4. If you want connect to kgdb when the kernel boots, enable
"KGDB: Wait for gdb connection early"

5. Connect minicom to the serial port and boot the kernel image.

6. (Optional) Ask target to wait for gdb connection by entering Ctrl+A. In minicom, you should enter Ctrl+A+A.

7. Start GDB client "bfin-elf-gdb vmlinux".

8. Set the baud rate in GDB "(gdb) set remotebaud 57600".

9. Connect to the target "(gdb) target remote /dev/ttyS0".

10. Set software breakpoint "(gdb) break sys_open".

11. Continue "(gdb) c". Then enter Ctrl+C twice to stop GDB connection.

12. Run ls in the target console "/> ls". Dummy string can be seen on the console.

13. Then connect the gdb to target again. "(gdb) target remote /dev/ttyS0".
Now you will find a breakpoint is hit. "Breakpoint 1: sys_open(..."

14. All other operations are the same as that in KGDB over Ethernet. The only
difference is that after continue command in GDB, please stop GDB
connection by 2 "Ctrl+C"s and connect again after breakpoints are hit or
Ctrl+A is entered.
16 changes: 3 additions & 13 deletions trunk/Documentation/block/barrier.txt
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Expand Up @@ -82,33 +82,23 @@ including draining and flushing.
typedef void (prepare_flush_fn)(request_queue_t *q, struct request *rq);

int blk_queue_ordered(request_queue_t *q, unsigned ordered,
prepare_flush_fn *prepare_flush_fn,
unsigned gfp_mask);

int blk_queue_ordered_locked(request_queue_t *q, unsigned ordered,
prepare_flush_fn *prepare_flush_fn,
unsigned gfp_mask);

The only difference between the two functions is whether or not the
caller is holding q->queue_lock on entry. The latter expects the
caller is holding the lock.
prepare_flush_fn *prepare_flush_fn);

@q : the queue in question
@ordered : the ordered mode the driver/device supports
@prepare_flush_fn : this function should prepare @rq such that it
flushes cache to physical medium when executed
@gfp_mask : gfp_mask used when allocating data structures
for ordered processing

For example, SCSI disk driver's prepare_flush_fn looks like the
following.

static void sd_prepare_flush(request_queue_t *q, struct request *rq)
{
memset(rq->cmd, 0, sizeof(rq->cmd));
rq->flags |= REQ_BLOCK_PC;
rq->cmd_type = REQ_TYPE_BLOCK_PC;
rq->timeout = SD_TIMEOUT;
rq->cmd[0] = SYNCHRONIZE_CACHE;
rq->cmd_len = 10;
}

The following seven ordered modes are supported. The following table
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