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Ingo Molnar committed Jun 4, 2011
2 parents 74c355f + b273fa9 commit 710054b
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3 changes: 1 addition & 2 deletions Documentation/DocBook/mtdnand.tmpl
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Expand Up @@ -189,8 +189,7 @@ static void __iomem *baseaddr;
<title>Partition defines</title>
<para>
If you want to divide your device into partitions, then
enable the configuration switch CONFIG_MTD_PARTITIONS and define
a partitioning scheme suitable to your board.
define a partitioning scheme suitable to your board.
</para>
<programlisting>
#define NUM_PARTITIONS 2
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17 changes: 5 additions & 12 deletions Documentation/RCU/trace.txt
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Expand Up @@ -99,18 +99,11 @@ o "qp" indicates that RCU still expects a quiescent state from

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.
scheduler or by irq. This number is even if the CPU is in
dyntick idle mode and odd otherwise. The number after the first
"/" is the interrupt nesting depth when in dyntick-idle state,
or one greater than the interrupt-nesting depth otherwise.
The number after the second "/" is the NMI nesting depth.

This field is displayed only for CONFIG_NO_HZ kernels.

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5 changes: 5 additions & 0 deletions Documentation/acpi/method-customizing.txt
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Expand Up @@ -66,3 +66,8 @@ Note: We can use a kernel with multiple custom ACPI method running,
But each individual write to debugfs can implement a SINGLE
method override. i.e. if we want to insert/override multiple
ACPI methods, we need to redo step c) ~ g) for multiple times.

Note: Be aware that root can mis-use this driver to modify arbitrary
memory and gain additional rights, if root's privileges got
restricted (for example if root is not allowed to load additional
modules after boot).
33 changes: 29 additions & 4 deletions Documentation/arm/Booting
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Expand Up @@ -65,13 +65,19 @@ looks at the connected hardware is beyond the scope of this document.
The boot loader must ultimately be able to provide a MACH_TYPE_xxx
value to the kernel. (see linux/arch/arm/tools/mach-types).


4. Setup the kernel tagged list
-------------------------------
4. Setup boot data
------------------

Existing boot loaders: OPTIONAL, HIGHLY RECOMMENDED
New boot loaders: MANDATORY

The boot loader must provide either a tagged list or a dtb image for
passing configuration data to the kernel. The physical address of the
boot data is passed to the kernel in register r2.

4a. Setup the kernel tagged list
--------------------------------

The boot loader must create and initialise the kernel tagged list.
A valid tagged list starts with ATAG_CORE and ends with ATAG_NONE.
The ATAG_CORE tag may or may not be empty. An empty ATAG_CORE tag
Expand Down Expand Up @@ -101,6 +107,24 @@ The tagged list must be placed in a region of memory where neither
the kernel decompressor nor initrd 'bootp' program will overwrite
it. The recommended placement is in the first 16KiB of RAM.

4b. Setup the device tree
-------------------------

The boot loader must load a device tree image (dtb) into system ram
at a 64bit aligned address and initialize it with the boot data. The
dtb format is documented in Documentation/devicetree/booting-without-of.txt.
The kernel will look for the dtb magic value of 0xd00dfeed at the dtb
physical address to determine if a dtb has been passed instead of a
tagged list.

The boot loader must pass at a minimum the size and location of the
system memory, and the root filesystem location. The dtb must be
placed in a region of memory where the kernel decompressor will not
overwrite it. The recommended placement is in the first 16KiB of RAM
with the caveat that it may not be located at physical address 0 since
the kernel interprets a value of 0 in r2 to mean neither a tagged list
nor a dtb were passed.

5. Calling the kernel image
---------------------------

Expand All @@ -125,7 +149,8 @@ In either case, the following conditions must be met:
- CPU register settings
r0 = 0,
r1 = machine type number discovered in (3) above.
r2 = physical address of tagged list in system RAM.
r2 = physical address of tagged list in system RAM, or
physical address of device tree block (dtb) in system RAM

- CPU mode
All forms of interrupts must be disabled (IRQs and FIQs)
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2 changes: 0 additions & 2 deletions Documentation/arm/Samsung/Overview.txt
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Expand Up @@ -14,7 +14,6 @@ Introduction
- S3C24XX: See Documentation/arm/Samsung-S3C24XX/Overview.txt for full list
- S3C64XX: S3C6400 and S3C6410
- S5P6440
- S5P6442
- S5PC100
- S5PC110 / S5PV210

Expand All @@ -36,7 +35,6 @@ Configuration
unifying all the SoCs into one kernel.

s5p6440_defconfig - S5P6440 specific default configuration
s5p6442_defconfig - S5P6442 specific default configuration
s5pc100_defconfig - S5PC100 specific default configuration
s5pc110_defconfig - S5PC110 specific default configuration
s5pv210_defconfig - S5PV210 specific default configuration
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48 changes: 44 additions & 4 deletions Documentation/devicetree/booting-without-of.txt
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Expand Up @@ -12,8 +12,9 @@ Table of Contents
=================

I - Introduction
1) Entry point for arch/powerpc
2) Entry point for arch/x86
1) Entry point for arch/arm
2) Entry point for arch/powerpc
3) Entry point for arch/x86

II - The DT block format
1) Header
Expand Down Expand Up @@ -148,7 +149,46 @@ upgrades without significantly impacting the kernel code or cluttering
it with special cases.


1) Entry point for arch/powerpc
1) Entry point for arch/arm
---------------------------

There is one single entry point to the kernel, at the start
of the kernel image. That entry point supports two calling
conventions. A summary of the interface is described here. A full
description of the boot requirements is documented in
Documentation/arm/Booting

a) ATAGS interface. Minimal information is passed from firmware
to the kernel with a tagged list of predefined parameters.

r0 : 0

r1 : Machine type number

r2 : Physical address of tagged list in system RAM

b) Entry with a flattened device-tree block. Firmware loads the
physical address of the flattened device tree block (dtb) into r2,
r1 is not used, but it is considered good practise to use a valid
machine number as described in Documentation/arm/Booting.

r0 : 0

r1 : Valid machine type number. When using a device tree,
a single machine type number will often be assigned to
represent a class or family of SoCs.

r2 : physical pointer to the device-tree block
(defined in chapter II) in RAM. Device tree can be located
anywhere in system RAM, but it should be aligned on a 64 bit
boundary.

The kernel will differentiate between ATAGS and device tree booting by
reading the memory pointed to by r2 and looking for either the flattened
device tree block magic value (0xd00dfeed) or the ATAG_CORE value at
offset 0x4 from r2 (0x54410001).

2) Entry point for arch/powerpc
-------------------------------

There is one single entry point to the kernel, at the start
Expand Down Expand Up @@ -226,7 +266,7 @@ it with special cases.
cannot support both configurations with Book E and configurations
with classic Powerpc architectures.

2) Entry point for arch/x86
3) Entry point for arch/x86
-------------------------------

There is one single 32bit entry point to the kernel at code32_start,
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97 changes: 96 additions & 1 deletion Documentation/dmaengine.txt
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@@ -1 +1,96 @@
See Documentation/crypto/async-tx-api.txt
DMA Engine API Guide
====================

Vinod Koul <vinod dot koul at intel.com>

NOTE: For DMA Engine usage in async_tx please see:
Documentation/crypto/async-tx-api.txt


Below is a guide to device driver writers on how to use the Slave-DMA API of the
DMA Engine. This is applicable only for slave DMA usage only.

The slave DMA usage consists of following steps
1. Allocate a DMA slave channel
2. Set slave and controller specific parameters
3. Get a descriptor for transaction
4. Submit the transaction and wait for callback notification

1. Allocate a DMA slave channel
Channel allocation is slightly different in the slave DMA context, client
drivers typically need a channel from a particular DMA controller only and even
in some cases a specific channel is desired. To request a channel
dma_request_channel() API is used.

Interface:
struct dma_chan *dma_request_channel(dma_cap_mask_t mask,
dma_filter_fn filter_fn,
void *filter_param);
where dma_filter_fn is defined as:
typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param);

When the optional 'filter_fn' parameter is set to NULL dma_request_channel
simply returns the first channel that satisfies the capability mask. Otherwise,
when the mask parameter is insufficient for specifying the necessary channel,
the filter_fn routine can be used to disposition the available channels in the
system. The filter_fn routine is called once for each free channel in the
system. Upon seeing a suitable channel filter_fn returns DMA_ACK which flags
that channel to be the return value from dma_request_channel. A channel
allocated via this interface is exclusive to the caller, until
dma_release_channel() is called.

2. Set slave and controller specific parameters
Next step is always to pass some specific information to the DMA driver. Most of
the generic information which a slave DMA can use is in struct dma_slave_config.
It allows the clients to specify DMA direction, DMA addresses, bus widths, DMA
burst lengths etc. If some DMA controllers have more parameters to be sent then
they should try to embed struct dma_slave_config in their controller specific
structure. That gives flexibility to client to pass more parameters, if
required.

Interface:
int dmaengine_slave_config(struct dma_chan *chan,
struct dma_slave_config *config)

3. Get a descriptor for transaction
For slave usage the various modes of slave transfers supported by the
DMA-engine are:
slave_sg - DMA a list of scatter gather buffers from/to a peripheral
dma_cyclic - Perform a cyclic DMA operation from/to a peripheral till the
operation is explicitly stopped.
The non NULL return of this transfer API represents a "descriptor" for the given
transaction.

Interface:
struct dma_async_tx_descriptor *(*chan->device->device_prep_dma_sg)(
struct dma_chan *chan,
struct scatterlist *dst_sg, unsigned int dst_nents,
struct scatterlist *src_sg, unsigned int src_nents,
unsigned long flags);
struct dma_async_tx_descriptor *(*chan->device->device_prep_dma_cyclic)(
struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
size_t period_len, enum dma_data_direction direction);

4. Submit the transaction and wait for callback notification
To schedule the transaction to be scheduled by dma device, the "descriptor"
returned in above (3) needs to be submitted.
To tell the dma driver that a transaction is ready to be serviced, the
descriptor->submit() callback needs to be invoked. This chains the descriptor to
the pending queue.
The transactions in the pending queue can be activated by calling the
issue_pending API. If channel is idle then the first transaction in queue is
started and subsequent ones queued up.
On completion of the DMA operation the next in queue is submitted and a tasklet
triggered. The tasklet would then call the client driver completion callback
routine for notification, if set.
Interface:
void dma_async_issue_pending(struct dma_chan *chan);

==============================================================================

Additional usage notes for dma driver writers
1/ Although DMA engine specifies that completion callback routines cannot submit
any new operations, but typically for slave DMA subsequent transaction may not
be available for submit prior to callback routine being called. This requirement
is not a requirement for DMA-slave devices. But they should take care to drop
the spin-lock they might be holding before calling the callback routine
36 changes: 36 additions & 0 deletions Documentation/feature-removal-schedule.txt
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Expand Up @@ -6,6 +6,42 @@ be removed from this file.

---------------------------

What: x86 floppy disable_hlt
When: 2012
Why: ancient workaround of dubious utility clutters the
code used by everybody else.
Who: Len Brown <len.brown@intel.com>

---------------------------

What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle
When: 2012
Why: This optional sub-feature of APM is of dubious reliability,
and ancient APM laptops are likely better served by calling HLT.
Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting
the pm_idle function pointer to modules.
Who: Len Brown <len.brown@intel.com>

----------------------------

What: x86_32 "no-hlt" cmdline param
When: 2012
Why: remove a branch from idle path, simplify code used by everybody.
This option disabled the use of HLT in idle and machine_halt()
for hardware that was flakey 15-years ago. Today we have
"idle=poll" that removed HLT from idle, and so if such a machine
is still running the upstream kernel, "idle=poll" is likely sufficient.
Who: Len Brown <len.brown@intel.com>

----------------------------

What: x86 "idle=mwait" cmdline param
When: 2012
Why: simplify x86 idle code
Who: Len Brown <len.brown@intel.com>

----------------------------

What: PRISM54
When: 2.6.34

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4 changes: 2 additions & 2 deletions Documentation/filesystems/Locking
Original file line number Diff line number Diff line change
Expand Up @@ -104,7 +104,7 @@ of the locking scheme for directory operations.
prototypes:
struct inode *(*alloc_inode)(struct super_block *sb);
void (*destroy_inode)(struct inode *);
void (*dirty_inode) (struct inode *);
void (*dirty_inode) (struct inode *, int flags);
int (*write_inode) (struct inode *, struct writeback_control *wbc);
int (*drop_inode) (struct inode *);
void (*evict_inode) (struct inode *);
Expand All @@ -126,7 +126,7 @@ locking rules:
s_umount
alloc_inode:
destroy_inode:
dirty_inode: (must not sleep)
dirty_inode:
write_inode:
drop_inode: !!!inode->i_lock!!!
evict_inode:
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2 changes: 1 addition & 1 deletion Documentation/filesystems/vfs.txt
Original file line number Diff line number Diff line change
Expand Up @@ -211,7 +211,7 @@ struct super_operations {
struct inode *(*alloc_inode)(struct super_block *sb);
void (*destroy_inode)(struct inode *);

void (*dirty_inode) (struct inode *);
void (*dirty_inode) (struct inode *, int flags);
int (*write_inode) (struct inode *, int);
void (*drop_inode) (struct inode *);
void (*delete_inode) (struct inode *);
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5 changes: 4 additions & 1 deletion Documentation/kernel-parameters.txt
Original file line number Diff line number Diff line change
Expand Up @@ -999,7 +999,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
With this option on every unmap_single operation will
result in a hardware IOTLB flush operation as opposed
to batching them for performance.

sp_off [Default Off]
By default, super page will be supported if Intel IOMMU
has the capability. With this option, super page will
not be supported.
intremap= [X86-64, Intel-IOMMU]
Format: { on (default) | off | nosid }
on enable Interrupt Remapping (default)
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