Merge branch 'master' of /home/shaggy/git/linus-clean/

N: David Woodhouse

E: dwmw2@infradead.org

D: ARCnet stuff, Applicom board driver, SO_BINDTODEVICE,

D: some Alpha platform porting from 2.0, Memory Technology Devices,

D: Acquire watchdog timer, PC speaker driver maintenance,

D: JFFS2 file system, Memory Technology Device subsystem,

D: various other stuff that annoyed me by not working.

S: c/o Red Hat Engineering

S: Rustat House

S: 60 Clifton Road

S: Cambridge. CB1 7EG

S: c/o Intel Corporation

S: Pipers Way

S: Swindon. SN3 1RJ

S: England

N: Chris Wright

o  binutils               2.12                    # ld -v

o  util-linux             2.10o                   # fdformat --version

o  module-init-tools      0.9.10                  # depmod -V

o  e2fsprogs              1.29                    # tune2fs

o  e2fsprogs              1.41.4                  # e2fsck -V

o  jfsutils               1.1.3                   # fsck.jfs -V

o  reiserfsprogs          3.6.3                   # reiserfsck -V 2>&1|grep reiserfsprogs

o  xfsprogs               2.6.0                   # xfs_db -V

o  squashfs-tools         4.0                     # mksquashfs -version

o  btrfs-progs            0.18                    # btrfsck

o  pcmciautils            004                     # pccardctl -V

o  quota-tools            3.09                    # quota -V

o  PPP                    2.4.0                   # pppd --version

    (* (max steps 1)

       c-basic-offset)))

(add-hook 'c-mode-common-hook

          (lambda ()

            ;; Add kernel style

            (c-add-style

             "linux-tabs-only"

             '("linux" (c-offsets-alist

                        (arglist-cont-nonempty

                         c-lineup-gcc-asm-reg

                         c-lineup-arglist-tabs-only))))))

(add-hook 'c-mode-hook

          (lambda ()

            (let ((filename (buffer-file-name)))

              ;; Enable kernel mode for the appropriate files

              (when (and filename

                         (string-match "~/src/linux-trees" filename))

                         (string-match (expand-file-name "~/src/linux-trees")

                                       filename))

                (setq indent-tabs-mode t)

                (c-set-style "linux")

                (c-set-offset 'arglist-cont-nonempty

                              '(c-lineup-gcc-asm-reg

                                c-lineup-arglist-tabs-only))))))

                (c-set-style "linux-tabs-only")))))

This will make emacs go better with the kernel coding style for C

files below ~/src/linux-trees.

This document describes the DMA API.  For a more gentle introduction

phrased in terms of the pci_ equivalents (and actual examples) see

DMA-mapping.txt

Documentation/PCI/PCI-DMA-mapping.txt.

This API is split into two pieces.  Part I describes the API and the

corresponding pci_ API.  Part II describes the extensions to the API

u64

dma_get_required_mask(struct device *dev)

After setting the mask with dma_set_mask(), this API returns the

actual mask (within that already set) that the platform actually

requires to operate efficiently.  Usually this means the returned mask

This API returns the mask that the platform requires to

operate efficiently.  Usually this means the returned mask

is the minimum required to cover all of memory.  Examining the

required mask gives drivers with variable descriptor sizes the

opportunity to use smaller descriptors as necessary.

Requesting the required mask does not alter the current mask.  If you

wish to take advantage of it, you should issue another dma_set_mask()

call to lower the mask again.

wish to take advantage of it, you should issue a dma_set_mask()

call to set the mask to the value returned.

Part Id - Streaming DMA mappings

</abstract>

<revhistory>

	<revision>

	<revnumber>0.7</revnumber>

	<date>2008-12-23</date>

	<authorinitials>hjk</authorinitials>

	<revremark>Added generic platform drivers and offset attribute.</revremark>

	</revision>

	<revision>

	<revnumber>0.6</revnumber>

	<date>2008-12-05</date>

	pointed to by addr.

	</para>

</listitem>

<listitem>

	<para>

	<filename>offset</filename>: The offset, in bytes, that has to be

	added to the pointer returned by <function>mmap()</function> to get

	to the actual device memory. This is important if the device's memory

	is not page aligned. Remember that pointers returned by

	<function>mmap()</function> are always page aligned, so it is good

	style to always add this offset.

	</para>

</listitem>

</itemizedlist>

<para>

	</para>

</sect1>

<sect1 id="using_uio_pdrv">

<title>Using uio_pdrv for platform devices</title>

	<para>

	In many cases, UIO drivers for platform devices can be handled in a

	generic way. In the same place where you define your

	<varname>struct platform_device</varname>, you simply also implement

	your interrupt handler and fill your

	<varname>struct uio_info</varname>. A pointer to this

	<varname>struct uio_info</varname> is then used as

	<varname>platform_data</varname> for your platform device.

	</para>

	<para>

	You also need to set up an array of <varname>struct resource</varname>

	containing addresses and sizes of your memory mappings. This

	information is passed to the driver using the

	<varname>.resource</varname> and <varname>.num_resources</varname>

	elements of <varname>struct platform_device</varname>.

	</para>

	<para>

	You now have to set the <varname>.name</varname> element of

	<varname>struct platform_device</varname> to

	<varname>"uio_pdrv"</varname> to use the generic UIO platform device

	driver. This driver will fill the <varname>mem[]</varname> array

	according to the resources given, and register the device.

	</para>

	<para>

	The advantage of this approach is that you only have to edit a file

	you need to edit anyway. You do not have to create an extra driver.

	</para>

</sect1>

<sect1 id="using_uio_pdrv_genirq">

<title>Using uio_pdrv_genirq for platform devices</title>

	<para>

	Especially in embedded devices, you frequently find chips where the

	irq pin is tied to its own dedicated interrupt line. In such cases,

	where you can be really sure the interrupt is not shared, we can take

	the concept of <varname>uio_pdrv</varname> one step further and use a

	generic interrupt handler. That's what

	<varname>uio_pdrv_genirq</varname> does.

	</para>

	<para>

	The setup for this driver is the same as described above for

	<varname>uio_pdrv</varname>, except that you do not implement an

	interrupt handler. The <varname>.handler</varname> element of

	<varname>struct uio_info</varname> must remain

	<varname>NULL</varname>. The  <varname>.irq_flags</varname> element

	must not contain <varname>IRQF_SHARED</varname>.

	</para>

	<para>

	You will set the <varname>.name</varname> element of

	<varname>struct platform_device</varname> to

	<varname>"uio_pdrv_genirq"</varname> to use this driver.

	</para>

	<para>

	The generic interrupt handler of <varname>uio_pdrv_genirq</varname>

	will simply disable the interrupt line using

	<function>disable_irq_nosync()</function>. After doing its work,

	userspace can reenable the interrupt by writing 0x00000001 to the UIO

	device file. The driver already implements an

	<function>irq_control()</function> to make this possible, you must not

	implement your own.

	</para>

	<para>

	Using <varname>uio_pdrv_genirq</varname> not only saves a few lines of

	interrupt handler code. You also do not need to know anything about

	the chip's internal registers to create the kernel part of the driver.

	All you need to know is the irq number of the pin the chip is

	connected to.

	</para>

</sect1>

</chapter>

<chapter id="userspace_driver" xreflabel="Writing a driver in user space">