Commit Graph

29 Commits

Author SHA1 Message Date
Christoph Hellwig
9eb9e96e97 Documentation/DMA-API-HOWTO: update dma_mask sections
We don't require drivers to guess a DMA mask that might actually
match the system capabilities any more, so fix up the documentation
to clear this up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-02-20 07:29:47 -07:00
Mauro Carvalho Chehab
266921bdb5 DMA-API-HOWTO.txt: standardize document format
Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Mark titles;
- Mark literal blocks;
- Mark some literals that would otherwise produce warnings;
- Mark authorship.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-07-14 13:51:32 -06:00
Christoph Hellwig
f51f288e23 dma-mapping: remove DMA_ERROR_CODE
And update the documentation - dma_mapping_error has been supported
everywhere for a long time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2017-06-28 06:54:37 -07:00
Andrey Smirnov
be6c30956f Documentation: DMA-API-HOWTO: Fix a typo
Fix a type in example variable name.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-09-20 17:58:46 -06:00
Christoph Hellwig
e92ae527e7 DMA-API-HOWTO: <asm/generic/scatterlist.h> is no more
So don't mention it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-09-16 10:00:25 -06:00
Christoph Hellwig
e1c7e32453 dma-mapping: always provide the dma_map_ops based implementation
Move the generic implementation to <linux/dma-mapping.h> now that all
architectures support it and remove the HAVE_DMA_ATTR Kconfig symbol now
that everyone supports them.

[valentinrothberg@gmail.com: remove leftovers in Kconfig]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Helge Deller <deller@gmx.de>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 17:09:18 -08:00
Sakari Ailus
7bc590b2fc Documentation: DMA API: Be more explicit that nents is always the same
The nents argument to the DMA API functions operating on scatterlists is
always the same. The documentation used different argument names and the
matter was not mentioned in Documentation/DMA-API-HOWTO.txt at all. Fix
these.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-09-24 15:50:06 -06:00
Linus Torvalds
1e467e68e5 Documentation updates for 4.2
The main thing here is Ingo's big subdirectory documenting feature support
 for each architecture.  Beyond that, it's the usual pile of fixes, tweaks,
 and small additions.
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Merge tag 'docs-for-linus' of git://git.lwn.net/linux-2.6

Pull documentation updates from Jonathan Corbet:
 "The main thing here is Ingo's big subdirectory documenting feature
  support for each architecture.  Beyond that, it's the usual pile of
  fixes, tweaks, and small additions"

* tag 'docs-for-linus' of git://git.lwn.net/linux-2.6: (79 commits)
  doc:md: fix typo in md.txt.
  Documentation/mic/mpssd: don't build x86 userspace when cross compiling
  Documentation/prctl: don't build tsc tests when cross compiling
  Documentation/vDSO: don't build tests when cross compiling
  Doc:ABI/testing: Fix typo in sysfs-bus-fcoe
  Doc: Docbook: Change wikipedia's URL from http to https in scsi.tmpl
  Doc: Change wikipedia's URL from http to https
  Documentation/kernel-parameters: add missing pciserial to the earlyprintk
  Doc:pps: Fix typo in pps.txt
  kbuild : Fix documentation of INSTALL_HDR_PATH
  Documentation: filesystems: updated struct file_operations documentation in vfs.txt
  kbuild: edit explanation of clean-files variable
  Doc: ja_JP: Fix typo in HOWTO
  Move freefall program from Documentation/ to tools/
  Documentation: ARM: EXYNOS: Describe boot loaders interface
  Doc:nfc: Fix typo in nfc-hci.txt
  vfs: Minor documentation fix
  Doc: networking: txtimestamp: fix printf format warning
  Documentation, intel_pstate: Improve legacy mode internal governors description
  Documentation: extend use case for EXPORT_SYMBOL_GPL()
  ...
2015-06-24 20:01:36 -07:00
Yinghai Lu
3a9ad0b4fd PCI: Add pci_bus_addr_t
David Ahern reported that d63e2e1f3d ("sparc/PCI: Clip bridge windows
to fit in upstream windows") fails to boot on sparc/T5-8:

  pci 0000:06:00.0: reg 0x184: can't handle BAR above 4GB (bus address 0x110204000)

The problem is that sparc64 assumed that dma_addr_t only needed to hold DMA
addresses, i.e., bus addresses returned via the DMA API (dma_map_single(),
etc.), while the PCI core assumed dma_addr_t could hold *any* bus address,
including raw BAR values.  On sparc64, all DMA addresses fit in 32 bits, so
dma_addr_t is a 32-bit type.  However, BAR values can be 64 bits wide, so
they don't fit in a dma_addr_t.  d63e2e1f3d added new checking that
tripped over this mismatch.

Add pci_bus_addr_t, which is wide enough to hold any PCI bus address,
including both raw BAR values and DMA addresses.  This will be 64 bits
on 64-bit platforms and on platforms with a 64-bit dma_addr_t.  Then
dma_addr_t only needs to be wide enough to hold addresses from the DMA API.

[bhelgaas: changelog, bugzilla, Kconfig to ensure pci_bus_addr_t is at
least as wide as dma_addr_t, documentation]
Fixes: d63e2e1f3d ("sparc/PCI: Clip bridge windows to fit in upstream windows")
Fixes: 23b13bc76f ("PCI: Fail safely if we can't handle BARs larger than 4GB")
Link: http://lkml.kernel.org/r/CAE9FiQU1gJY1LYrxs+ma5LCTEEe4xmtjRG0aXJ9K_Tsu+m9Wuw@mail.gmail.com
Link: http://lkml.kernel.org/r/1427857069-6789-1-git-send-email-yinghai@kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=96231
Reported-by: David Ahern <david.ahern@oracle.com>
Tested-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
CC: stable@vger.kernel.org	# v3.19+
2015-05-29 17:21:45 -05:00
Geert Uytterhoeven
11e285d8ff DMA-API: Spelling s/This/Think/
Also remove spaces before TABs while we're at it.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-05-22 09:30:47 -06:00
Liu Hua
b2dd83b377 Documentation: correct parameter error for dma_mapping_error
dma_mapping_error takes two parameters, but some of examples
in Documentation/DMA-API-HOWTO.txt just takes one. So correct
it.

Signed-off-by: Liu Hua <sdu.liu@huawei.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-26 11:22:29 +02:00
Gioh Kim
2af9da8638 DMA-API: Update dma_pool_create ()and dma_pool_alloc() descriptions
Use "boundary" to be more descriptive than "alloc" in the dma_pool_create()
documentation.

Replace "SLAB_KERNEL" and "SLAB_ATOMIC" with the correct "GFP_KERNEL" and
"GFP_ATOMIC."

[bhelgaas: changelog]
Signed-off-by: Gioh Kim <gioh.kim@lge.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-05-26 17:28:28 -06:00
Emilio López
34c815fbdc DMA-API: Fix duplicated word in DMA-API-HOWTO.txt
"coherent" is written twice when it should be just once.

Signed-off-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-05-26 17:28:27 -06:00
Bjorn Helgaas
f311a724a7 DMA-API: Capitalize "CPU" consistently
Sometimes we used "cpu," other times "CPU."  Use "CPU" consistently.

Suggested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-05-26 17:28:27 -06:00
Bjorn Helgaas
77f2ea2f8d DMA-API: Clarify physical/bus address distinction
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 <bhelgaas@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: James Bottomley <jbottomley@Parallels.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
2014-05-20 16:54:21 -06:00
Russell King
4aa806b771 DMA-API: provide a helper to set both DMA and coherent DMA masks
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 <rmk+kernel@arm.linux.org.uk>
2013-09-17 15:32:37 +01:00
Andrew Morton
11cd3db01b Documentation/DMA-API-HOWTO.txt: fix typo
Noted by Jesper

Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Shuah Khan <shuah.khan@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:23 -08:00
Shuah Khan
be62bc4100 Documentation/DMA-API-HOWTO.txt: minor grammar corrections
Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:11 -08:00
Shuah Khan
8d7f62e6a7 Documentation DMA-API-HOWTO.txt Add dma mapping error check usage examples
Enhance the document to discuss the importance of dma
mapping error checks after dma_map_single() and
dma_map_page() calls. Also added usage examples that include
unmap examples in error paths when dma mapping error is
returned.  Includes correct and incorrect usages to high
light some common mistakes in error paths especially when
dma mapping fails when more than one dma mapping call is
made.

Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2012-10-24 17:07:43 +02:00
Michal Miroslaw
3f0fb4e85b Documentation/DMA-API-HOWTO.txt: fix misleading example
See: DMA-API.txt, part Id, DMA_FROM_DEVICE description.

Signed-off-by: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26 16:49:45 -07:00
FUJITA Tomonori
ce00f7feb0 Documentation: DMA-API-HOWTO.txt: rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN
ARCH_KMALLOC_MINALIGN was renamed to ARCH_DMA_MINALIGN (the commit
a6eb9fe105).

ARCH_DMA_MINALIGN must be defined instead of ARCH_KMALLOC_MINALIGN to
ensure that kmalloc'ed buffer is DMA-safe.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-14 11:56:46 -07:00
FUJITA Tomonori
c31e74c4c3 Documentation: DMA-API-HOWTO.txt: add multiple types of IOMMUs support
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:21 -07:00
FUJITA Tomonori
2fd74e25df Documentation/DMA-API-HOWTO: add ARCH_KMALLOC_MINALIGN description
Add ARCH_KMALLOC_MINALIGN description in "Platform Issues" section.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:53 -07:00
FUJITA Tomonori
4ae9ca825e Documentation: move the error handling to the better place in DMA-API-HOWTO
Handing DMA mapping errors is essential.  Let's put it in the more
appropriate place rather than the end of the doc.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:53 -07:00
FUJITA Tomonori
b02de87161 Documentation: update scatterlist struct description in DMA-API-HOWTO
Now we have <asm-generic/scatterlist.h>.  Architectures should use it
instead of inventing the own scatterlist struct.  Let's update the
description.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:53 -07:00
FUJITA Tomonori
7cdcc8e476 Documentation: add SCSI drivers' mapping error handling to DMA-API-HOWTO
Add the concrete DMA mapping error handling for SCSI drivers on the
queuecommand path.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:53 -07:00
FUJITA Tomonori
f671be04dc Documentation: add networking driver's mapping error handling to DMA-API-HOWTO
Adds the concrete DMA mapping error handling for Networking drivers on the
transmit path.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:52 -07:00
Francis Galiegue
a33f32244d Documentation/: it's -> its where appropriate
Fix obvious cases of "it's" being used when "its" was meant.

Signed-off-by: Francis Galiegue <fgaliegue@gmail.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-04-23 02:09:52 +02:00
FUJITA Tomonori
5e07c2c730 Documentation: rename PCI/PCI-DMA-mapping.txt to DMA-API-HOWTO.txt
This patch renames PCI/PCI-DMA-mapping.txt to DMA-API-HOWTO.txt.

The commit 51e7364ef2 "Documentation: rename
PCI-DMA-mapping.txt to DMA-API-HOWTO.txt" was supposed to do this but it
didn't.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:20 -07:00