<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include/linux/dma-mapping.h, branch v3.17.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm into next</title>
<updated>2014-06-05T22:57:04+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2014-06-05T22:57:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eb3d3ec567e868c8a3bfbfdfc9465ffd52983d11'/>
<id>eb3d3ec567e868c8a3bfbfdfc9465ffd52983d11</id>
<content type='text'>
Pull ARM updates from Russell King:

 - Major clean-up of the L2 cache support code.  The existing mess was
   becoming rather unmaintainable through all the additions that others
   have done over time.  This turns it into a much nicer structure, and
   implements a few performance improvements as well.

 - Clean up some of the CP15 control register tweaks for alignment
   support, moving some code and data into alignment.c

 - DMA properties for ARM, from Santosh and reviewed by DT people.  This
   adds DT properties to specify bus translations we can't discover
   automatically, and to indicate whether devices are coherent.

 - Hibernation support for ARM

 - Make ftrace work with read-only text in modules

 - add suspend support for PJ4B CPUs

 - rework interrupt masking for undefined instruction handling, which
   allows us to enable interrupts earlier in the handling of these
   exceptions.

 - support for big endian page tables

 - fix stacktrace support to exclude stacktrace functions from the
   trace, and add save_stack_trace_regs() implementation so that kprobes
   can record stack traces.

 - Add support for the Cortex-A17 CPU.

 - Remove last vestiges of ARM710 support.

 - Removal of ARM "meminfo" structure, finally converting us solely to
   memblock to handle the early memory initialisation.

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (142 commits)
  ARM: ensure C page table setup code follows assembly code (part II)
  ARM: ensure C page table setup code follows assembly code
  ARM: consolidate last remaining open-coded alignment trap enable
  ARM: remove global cr_no_alignment
  ARM: remove CPU_CP15 conditional from alignment.c
  ARM: remove unused adjust_cr() function
  ARM: move "noalign" command line option to alignment.c
  ARM: provide common method to clear bits in CPU control register
  ARM: 8025/1: Get rid of meminfo
  ARM: 8060/1: mm: allow sub-architectures to override PCI I/O memory type
  ARM: 8066/1: correction for ARM patch 8031/2
  ARM: 8049/1: ftrace/add save_stack_trace_regs() implementation
  ARM: 8065/1: remove last use of CONFIG_CPU_ARM710
  ARM: 8062/1: Modify ldrt fixup handler to re-execute the userspace instruction
  ARM: 8047/1: rwsem: use asm-generic rwsem implementation
  ARM: l2c: trial at enabling some Cortex-A9 optimisations
  ARM: l2c: add warnings for stuff modifying aux_ctrl register values
  ARM: l2c: print a warning with L2C-310 caches if the cache size is modified
  ARM: l2c: remove old .set_debug method
  ARM: l2c: kill L2X0_AUX_CTRL_MASK before anyone else makes use of this
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull ARM updates from Russell King:

 - Major clean-up of the L2 cache support code.  The existing mess was
   becoming rather unmaintainable through all the additions that others
   have done over time.  This turns it into a much nicer structure, and
   implements a few performance improvements as well.

 - Clean up some of the CP15 control register tweaks for alignment
   support, moving some code and data into alignment.c

 - DMA properties for ARM, from Santosh and reviewed by DT people.  This
   adds DT properties to specify bus translations we can't discover
   automatically, and to indicate whether devices are coherent.

 - Hibernation support for ARM

 - Make ftrace work with read-only text in modules

 - add suspend support for PJ4B CPUs

 - rework interrupt masking for undefined instruction handling, which
   allows us to enable interrupts earlier in the handling of these
   exceptions.

 - support for big endian page tables

 - fix stacktrace support to exclude stacktrace functions from the
   trace, and add save_stack_trace_regs() implementation so that kprobes
   can record stack traces.

 - Add support for the Cortex-A17 CPU.

 - Remove last vestiges of ARM710 support.

 - Removal of ARM "meminfo" structure, finally converting us solely to
   memblock to handle the early memory initialisation.

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (142 commits)
  ARM: ensure C page table setup code follows assembly code (part II)
  ARM: ensure C page table setup code follows assembly code
  ARM: consolidate last remaining open-coded alignment trap enable
  ARM: remove global cr_no_alignment
  ARM: remove CPU_CP15 conditional from alignment.c
  ARM: remove unused adjust_cr() function
  ARM: move "noalign" command line option to alignment.c
  ARM: provide common method to clear bits in CPU control register
  ARM: 8025/1: Get rid of meminfo
  ARM: 8060/1: mm: allow sub-architectures to override PCI I/O memory type
  ARM: 8066/1: correction for ARM patch 8031/2
  ARM: 8049/1: ftrace/add save_stack_trace_regs() implementation
  ARM: 8065/1: remove last use of CONFIG_CPU_ARM710
  ARM: 8062/1: Modify ldrt fixup handler to re-execute the userspace instruction
  ARM: 8047/1: rwsem: use asm-generic rwsem implementation
  ARM: l2c: trial at enabling some Cortex-A9 optimisations
  ARM: l2c: add warnings for stuff modifying aux_ctrl register values
  ARM: l2c: print a warning with L2C-310 caches if the cache size is modified
  ARM: l2c: remove old .set_debug method
  ARM: l2c: kill L2X0_AUX_CTRL_MASK before anyone else makes use of this
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>DMA-API: Change dma_declare_coherent_memory() CPU address to phys_addr_t</title>
<updated>2014-05-20T22:55:23+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2014-05-20T22:54:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=88a984ba0795f14a3847edbd7fabe652289ea89b'/>
<id>88a984ba0795f14a3847edbd7fabe652289ea89b</id>
<content type='text'>
dma_declare_coherent_memory() takes two addresses for a region of memory: a
"bus_addr" and a "device_addr".  I think the intent is that "bus_addr" is
the physical address a *CPU* would use to access the region, and
"device_addr" is the bus address the *device* would use to address the
region.

Rename "bus_addr" to "phys_addr" and change its type to phys_addr_t.
Most callers already supply a phys_addr_t for this argument.  The others
supply a 32-bit integer (a constant, unsigned int, or __u32) and need no
change.

Use "unsigned long", not phys_addr_t, to hold PFNs.

No functional change (this could theoretically fix a truncation in a config
with 32-bit dma_addr_t and 64-bit phys_addr_t, but I don't think there are
any such cases involving this code).

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: James Bottomley &lt;jbottomley@Parallels.com&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
dma_declare_coherent_memory() takes two addresses for a region of memory: a
"bus_addr" and a "device_addr".  I think the intent is that "bus_addr" is
the physical address a *CPU* would use to access the region, and
"device_addr" is the bus address the *device* would use to address the
region.

Rename "bus_addr" to "phys_addr" and change its type to phys_addr_t.
Most callers already supply a phys_addr_t for this argument.  The others
supply a 32-bit integer (a constant, unsigned int, or __u32) and need no
change.

Use "unsigned long", not phys_addr_t, to hold PFNs.

No functional change (this could theoretically fix a truncation in a config
with 32-bit dma_addr_t and 64-bit phys_addr_t, but I don't think there are
any such cases involving this code).

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: James Bottomley &lt;jbottomley@Parallels.com&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>DMA-API: Clarify physical/bus address distinction</title>
<updated>2014-05-20T22:54:21+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2014-04-30T17:20:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=77f2ea2f8d0833f9e976368481fb9a0775acf9e7'/>
<id>77f2ea2f8d0833f9e976368481fb9a0775acf9e7</id>
<content type='text'>
The DMA-API documentation sometimes refers to "physical addresses" when it
really means "bus addresses."  Sometimes these are identical, but they may
be different if the bridge leading to the bus performs address translation.
Update the documentation to use "bus address" when appropriate.

Also, consistently capitalize "DMA", use parens with function names, use
dev_printk() in examples, and reword a few sections for clarity.

No functional change; documentation changes only.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: James Bottomley &lt;jbottomley@Parallels.com&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The DMA-API documentation sometimes refers to "physical addresses" when it
really means "bus addresses."  Sometimes these are identical, but they may
be different if the bridge leading to the bus performs address translation.
Update the documentation to use "bus address" when appropriate.

Also, consistently capitalize "DMA", use parens with function names, use
dev_printk() in examples, and reword a few sections for clarity.

No functional change; documentation changes only.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: James Bottomley &lt;jbottomley@Parallels.com&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>of: configure the platform device dma parameters</title>
<updated>2014-05-07T13:21:21+00:00</updated>
<author>
<name>Santosh Shilimkar</name>
<email>santosh.shilimkar@ti.com</email>
</author>
<published>2014-04-24T15:30:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=591c1ee465ce5372385dbc41e7d3e36cbb477bd8'/>
<id>591c1ee465ce5372385dbc41e7d3e36cbb477bd8</id>
<content type='text'>
Retrieve DMA configuration from DT and setup platform device's DMA
parameters. The DMA configuration in DT has to be specified using
"dma-ranges" and "dma-coherent" properties if supported.

We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
using "dma-coherent" device tree properties.

The set_arch_dma_coherent_ops macro has to be defined by arch if
it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
declared as nop.

Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Russell King &lt;linux@arm.linux.org.uk&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Olof Johansson &lt;olof@lixom.net&gt;
Cc: Grant Likely &lt;grant.likely@linaro.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Reviewed-by: Rob Herring &lt;robh@kernel.org&gt;
Signed-off-by: Grygorii Strashko &lt;grygorii.strashko@ti.com&gt;
Signed-off-by: Santosh Shilimkar &lt;santosh.shilimkar@ti.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Retrieve DMA configuration from DT and setup platform device's DMA
parameters. The DMA configuration in DT has to be specified using
"dma-ranges" and "dma-coherent" properties if supported.

We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
using "dma-coherent" device tree properties.

The set_arch_dma_coherent_ops macro has to be defined by arch if
it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
declared as nop.

Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Russell King &lt;linux@arm.linux.org.uk&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Olof Johansson &lt;olof@lixom.net&gt;
Cc: Grant Likely &lt;grant.likely@linaro.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Reviewed-by: Rob Herring &lt;robh@kernel.org&gt;
Signed-off-by: Grygorii Strashko &lt;grygorii.strashko@ti.com&gt;
Signed-off-by: Santosh Shilimkar &lt;santosh.shilimkar@ti.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 7795/1: mm: dma-mapping: Add dma_max_pfn(dev) helper function</title>
<updated>2013-10-31T14:49:24+00:00</updated>
<author>
<name>Santosh Shilimkar</name>
<email>santosh.shilimkar@ti.com</email>
</author>
<published>2013-07-29T13:18:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=00c8f1623658947a97345ecb86b71232ff540d0d'/>
<id>00c8f1623658947a97345ecb86b71232ff540d0d</id>
<content type='text'>
Most of the kernel assumes that PFN0 is the start of the physical
memory (RAM). This assumptions is not true on most of the ARM SOCs
and hence and if one try to update the ARM port to follow the assumptions,
we end of breaking the dma bounce limit for few block layer drivers.
One such example is trying to unify the meaning of max*_pfn on ARM
as the bootmem layer expects, breaks few block layer driver dma
bounce limit.

To fix this problem, we introduce dma_max_pfn(dev) generic helper with
a possibility of override from the architecture code. The helper converts
a DMA bitmask of bits to a block PFN number. In all the generic cases,
it is just  "dev-&gt;dma_mask &gt;&gt; PAGE_SHIFT" and hence default behavior
is maintained as is.

Subsequent patches will make use of the helper. No functional change.

Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Santosh Shilimkar &lt;santosh.shilimkar@ti.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Most of the kernel assumes that PFN0 is the start of the physical
memory (RAM). This assumptions is not true on most of the ARM SOCs
and hence and if one try to update the ARM port to follow the assumptions,
we end of breaking the dma bounce limit for few block layer drivers.
One such example is trying to unify the meaning of max*_pfn on ARM
as the bootmem layer expects, breaks few block layer driver dma
bounce limit.

To fix this problem, we introduce dma_max_pfn(dev) generic helper with
a possibility of override from the architecture code. The helper converts
a DMA bitmask of bits to a block PFN number. In all the generic cases,
it is just  "dev-&gt;dma_mask &gt;&gt; PAGE_SHIFT" and hence default behavior
is maintained as is.

Subsequent patches will make use of the helper. No functional change.

Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Santosh Shilimkar &lt;santosh.shilimkar@ti.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>DMA-API: provide a helper to setup DMA masks</title>
<updated>2013-10-31T14:48:46+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk+kernel@arm.linux.org.uk</email>
</author>
<published>2013-06-27T11:21:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fa6a8d6d65b19ab44e5244ea499bcd553cc72343'/>
<id>fa6a8d6d65b19ab44e5244ea499bcd553cc72343</id>
<content type='text'>
Many drivers contain code such as:

	dev-&gt;dma_mask = &amp;dev-&gt;coherent_dma_mask;
	dev-&gt;coherent_dma_mask = MASK;

Let's move this pattern out of drivers and have the DMA API provide a
helper for it.  This helper uses dma_set_mask_and_coherent() to allow
platform issues to be properly dealt with via dma_set_mask()/
dma_is_supported().

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Many drivers contain code such as:

	dev-&gt;dma_mask = &amp;dev-&gt;coherent_dma_mask;
	dev-&gt;coherent_dma_mask = MASK;

Let's move this pattern out of drivers and have the DMA API provide a
helper for it.  This helper uses dma_set_mask_and_coherent() to allow
platform issues to be properly dealt with via dma_set_mask()/
dma_is_supported().

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>DMA-API: provide a helper to set both DMA and coherent DMA masks</title>
<updated>2013-09-17T14:32:37+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk+kernel@arm.linux.org.uk</email>
</author>
<published>2013-06-26T12:49:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4aa806b771d16b810771d86ce23c4c3160888db3'/>
<id>4aa806b771d16b810771d86ce23c4c3160888db3</id>
<content type='text'>
Provide a helper to set both the DMA and coherent DMA masks to the
same value - this avoids duplicated code in a number of drivers,
sometimes with buggy error handling, and also allows us identify
which drivers do things differently.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Provide a helper to set both the DMA and coherent DMA masks to the
same value - this avoids duplicated code in a number of drivers,
sometimes with buggy error handling, and also allows us identify
which drivers do things differently.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drivers:net: Convert dma_alloc_coherent(...__GFP_ZERO) to dma_zalloc_coherent</title>
<updated>2013-08-30T01:55:23+00:00</updated>
<author>
<name>Joe Perches</name>
<email>joe@perches.com</email>
</author>
<published>2013-08-27T05:45:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ede23fa8161c1a04aa1b3bf5447812ca14b3fef1'/>
<id>ede23fa8161c1a04aa1b3bf5447812ca14b3fef1</id>
<content type='text'>
__GFP_ZERO is an uncommon flag and perhaps is better
not used.  static inline dma_zalloc_coherent exists
so convert the uses of dma_alloc_coherent with __GFP_ZERO
to the more common kernel style with zalloc.

Remove memset from the static inline dma_zalloc_coherent
and add just one use of __GFP_ZERO instead.

Trivially reduces the size of the existing uses of
dma_zalloc_coherent.

Realign arguments as appropriate.

Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Acked-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
Acked-by: Jesse Brandeburg &lt;jesse.brandeburg@intel.com&gt;
Acked-by: Jeff Kirsher &lt;jeffrey.t.kirsher@intel.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
__GFP_ZERO is an uncommon flag and perhaps is better
not used.  static inline dma_zalloc_coherent exists
so convert the uses of dma_alloc_coherent with __GFP_ZERO
to the more common kernel style with zalloc.

Remove memset from the static inline dma_zalloc_coherent
and add just one use of __GFP_ZERO instead.

Trivially reduces the size of the existing uses of
dma_zalloc_coherent.

Realign arguments as appropriate.

Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Acked-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
Acked-by: Jesse Brandeburg &lt;jesse.brandeburg@intel.com&gt;
Acked-by: Jeff Kirsher &lt;jeffrey.t.kirsher@intel.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>common: dma-mapping: introduce dma_get_sgtable() function</title>
<updated>2012-07-30T10:25:46+00:00</updated>
<author>
<name>Marek Szyprowski</name>
<email>m.szyprowski@samsung.com</email>
</author>
<published>2012-06-13T08:05:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d2b7428eb0caa7c66e34b6ac869a43915b294123'/>
<id>d2b7428eb0caa7c66e34b6ac869a43915b294123</id>
<content type='text'>
This patch adds dma_get_sgtable() function which is required to let
drivers to share the buffers allocated by DMA-mapping subsystem. Right
now the driver gets a dma address of the allocated buffer and the kernel
virtual mapping for it. If it wants to share it with other device (= map
into its dma address space) it usually hacks around kernel virtual
addresses to get pointers to pages or assumes that both devices share
the DMA address space. Both solutions are just hacks for the special
cases, which should be avoided in the final version of buffer sharing.

To solve this issue in a generic way, a new call to DMA mapping has been
introduced - dma_get_sgtable(). It allocates a scatter-list which
describes the allocated buffer and lets the driver(s) to use it with
other device(s) by calling dma_map_sg() on it.

This patch provides a generic implementation based on virt_to_page()
call. Architectures which require more sophisticated translation might
provide their own get_sgtable() methods.

Signed-off-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reviewed-by: Kyungmin Park &lt;kyungmin.park@samsung.com&gt;
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds dma_get_sgtable() function which is required to let
drivers to share the buffers allocated by DMA-mapping subsystem. Right
now the driver gets a dma address of the allocated buffer and the kernel
virtual mapping for it. If it wants to share it with other device (= map
into its dma address space) it usually hacks around kernel virtual
addresses to get pointers to pages or assumes that both devices share
the DMA address space. Both solutions are just hacks for the special
cases, which should be avoided in the final version of buffer sharing.

To solve this issue in a generic way, a new call to DMA mapping has been
introduced - dma_get_sgtable(). It allocates a scatter-list which
describes the allocated buffer and lets the driver(s) to use it with
other device(s) by calling dma_map_sg() on it.

This patch provides a generic implementation based on virt_to_page()
call. Architectures which require more sophisticated translation might
provide their own get_sgtable() methods.

Signed-off-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reviewed-by: Kyungmin Park &lt;kyungmin.park@samsung.com&gt;
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping</title>
<updated>2012-04-05T00:13:43+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2012-04-05T00:13:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=58bca4a8fa90fcf9069379653b396b2cec642f7f'/>
<id>58bca4a8fa90fcf9069379653b396b2cec642f7f</id>
<content type='text'>
Pull DMA mapping branch from Marek Szyprowski:
 "Short summary for the whole series:

  A few limitations have been identified in the current dma-mapping
  design and its implementations for various architectures.  There exist
  more than one function for allocating and freeing the buffers:
  currently these 3 are used dma_{alloc, free}_coherent,
  dma_{alloc,free}_writecombine, dma_{alloc,free}_noncoherent.

  For most of the systems these calls are almost equivalent and can be
  interchanged.  For others, especially the truly non-coherent ones
  (like ARM), the difference can be easily noticed in overall driver
  performance.  Sadly not all architectures provide implementations for
  all of them, so the drivers might need to be adapted and cannot be
  easily shared between different architectures.  The provided patches
  unify all these functions and hide the differences under the already
  existing dma attributes concept.  The thread with more references is
  available here:

    http://www.spinics.net/lists/linux-sh/msg09777.html

  These patches are also a prerequisite for unifying DMA-mapping
  implementation on ARM architecture with the common one provided by
  dma_map_ops structure and extending it with IOMMU support.  More
  information is available in the following thread:

    http://thread.gmane.org/gmane.linux.kernel.cross-arch/12819

  More works on dma-mapping framework are planned, especially in the
  area of buffer sharing and managing the shared mappings (together with
  the recently introduced dma_buf interface: commit d15bd7ee445d
  "dma-buf: Introduce dma buffer sharing mechanism").

  The patches in the current set introduce a new alloc/free methods
  (with support for memory attributes) in dma_map_ops structure, which
  will later replace dma_alloc_coherent and dma_alloc_writecombine
  functions."

People finally started piping up with support for merging this, so I'm
merging it as the last of the pending stuff from the merge window.
Looks like pohmelfs is going to wait for 3.5 and more external support
for merging.

* 'for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  common: DMA-mapping: add NON-CONSISTENT attribute
  common: DMA-mapping: add WRITE_COMBINE attribute
  common: dma-mapping: introduce mmap method
  common: dma-mapping: remove old alloc_coherent and free_coherent methods
  Hexagon: adapt for dma_map_ops changes
  Unicore32: adapt for dma_map_ops changes
  Microblaze: adapt for dma_map_ops changes
  SH: adapt for dma_map_ops changes
  Alpha: adapt for dma_map_ops changes
  SPARC: adapt for dma_map_ops changes
  PowerPC: adapt for dma_map_ops changes
  MIPS: adapt for dma_map_ops changes
  X86 &amp; IA64: adapt for dma_map_ops changes
  common: dma-mapping: introduce generic alloc() and free() methods
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull DMA mapping branch from Marek Szyprowski:
 "Short summary for the whole series:

  A few limitations have been identified in the current dma-mapping
  design and its implementations for various architectures.  There exist
  more than one function for allocating and freeing the buffers:
  currently these 3 are used dma_{alloc, free}_coherent,
  dma_{alloc,free}_writecombine, dma_{alloc,free}_noncoherent.

  For most of the systems these calls are almost equivalent and can be
  interchanged.  For others, especially the truly non-coherent ones
  (like ARM), the difference can be easily noticed in overall driver
  performance.  Sadly not all architectures provide implementations for
  all of them, so the drivers might need to be adapted and cannot be
  easily shared between different architectures.  The provided patches
  unify all these functions and hide the differences under the already
  existing dma attributes concept.  The thread with more references is
  available here:

    http://www.spinics.net/lists/linux-sh/msg09777.html

  These patches are also a prerequisite for unifying DMA-mapping
  implementation on ARM architecture with the common one provided by
  dma_map_ops structure and extending it with IOMMU support.  More
  information is available in the following thread:

    http://thread.gmane.org/gmane.linux.kernel.cross-arch/12819

  More works on dma-mapping framework are planned, especially in the
  area of buffer sharing and managing the shared mappings (together with
  the recently introduced dma_buf interface: commit d15bd7ee445d
  "dma-buf: Introduce dma buffer sharing mechanism").

  The patches in the current set introduce a new alloc/free methods
  (with support for memory attributes) in dma_map_ops structure, which
  will later replace dma_alloc_coherent and dma_alloc_writecombine
  functions."

People finally started piping up with support for merging this, so I'm
merging it as the last of the pending stuff from the merge window.
Looks like pohmelfs is going to wait for 3.5 and more external support
for merging.

* 'for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  common: DMA-mapping: add NON-CONSISTENT attribute
  common: DMA-mapping: add WRITE_COMBINE attribute
  common: dma-mapping: introduce mmap method
  common: dma-mapping: remove old alloc_coherent and free_coherent methods
  Hexagon: adapt for dma_map_ops changes
  Unicore32: adapt for dma_map_ops changes
  Microblaze: adapt for dma_map_ops changes
  SH: adapt for dma_map_ops changes
  Alpha: adapt for dma_map_ops changes
  SPARC: adapt for dma_map_ops changes
  PowerPC: adapt for dma_map_ops changes
  MIPS: adapt for dma_map_ops changes
  X86 &amp; IA64: adapt for dma_map_ops changes
  common: dma-mapping: introduce generic alloc() and free() methods
</pre>
</div>
</content>
</entry>
</feed>
