2005-04-17 06:20:36 +08:00
|
|
|
menu "Generic Driver Options"
|
|
|
|
|
|
2007-08-15 21:38:28 +08:00
|
|
|
config UEVENT_HELPER_PATH
|
|
|
|
|
string "path to uevent helper"
|
2010-01-15 05:49:39 +08:00
|
|
|
default ""
|
2007-08-15 21:38:28 +08:00
|
|
|
help
|
|
|
|
|
Path to uevent helper program forked by the kernel for
|
|
|
|
|
every uevent.
|
2010-01-15 05:49:39 +08:00
|
|
|
Before the switch to the netlink-based uevent source, this was
|
|
|
|
|
used to hook hotplug scripts into kernel device events. It
|
|
|
|
|
usually pointed to a shell script at /sbin/hotplug.
|
|
|
|
|
This should not be used today, because usual systems create
|
|
|
|
|
many events at bootup or device discovery in a very short time
|
|
|
|
|
frame. One forked process per event can create so many processes
|
|
|
|
|
that it creates a high system load, or on smaller systems
|
|
|
|
|
it is known to create out-of-memory situations during bootup.
|
2007-08-15 21:38:28 +08:00
|
|
|
|
2011-06-20 04:30:16 +08:00
|
|
|
To disable user space helper program execution at early boot
|
|
|
|
|
time specify an empty string here. This setting can be altered
|
|
|
|
|
via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper
|
|
|
|
|
later at runtime.
|
|
|
|
|
|
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 21:23:42 +08:00
|
|
|
config DEVTMPFS
|
2010-01-15 05:47:57 +08:00
|
|
|
bool "Maintain a devtmpfs filesystem to mount at /dev"
|
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 21:23:42 +08:00
|
|
|
help
|
2010-03-17 04:55:21 +08:00
|
|
|
This creates a tmpfs/ramfs filesystem instance early at bootup.
|
2010-01-15 05:47:57 +08:00
|
|
|
In this filesystem, the kernel driver core maintains device
|
|
|
|
|
nodes with their default names and permissions for all
|
|
|
|
|
registered devices with an assigned major/minor number.
|
|
|
|
|
Userspace can modify the filesystem content as needed, add
|
|
|
|
|
symlinks, and apply needed permissions.
|
|
|
|
|
It provides a fully functional /dev directory, where usually
|
|
|
|
|
udev runs on top, managing permissions and adding meaningful
|
|
|
|
|
symlinks.
|
|
|
|
|
In very limited environments, it may provide a sufficient
|
|
|
|
|
functional /dev without any further help. It also allows simple
|
|
|
|
|
rescue systems, and reliably handles dynamic major/minor numbers.
|
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 21:23:42 +08:00
|
|
|
|
2010-03-17 04:55:21 +08:00
|
|
|
Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs
|
|
|
|
|
file system will be used instead.
|
|
|
|
|
|
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 21:23:42 +08:00
|
|
|
config DEVTMPFS_MOUNT
|
2010-01-15 05:47:57 +08:00
|
|
|
bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
|
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 21:23:42 +08:00
|
|
|
depends on DEVTMPFS
|
|
|
|
|
help
|
2010-01-15 05:47:57 +08:00
|
|
|
This will instruct the kernel to automatically mount the
|
|
|
|
|
devtmpfs filesystem at /dev, directly after the kernel has
|
|
|
|
|
mounted the root filesystem. The behavior can be overridden
|
|
|
|
|
with the commandline parameter: devtmpfs.mount=0|1.
|
|
|
|
|
This option does not affect initramfs based booting, here
|
|
|
|
|
the devtmpfs filesystem always needs to be mounted manually
|
2013-12-02 21:59:39 +08:00
|
|
|
after the rootfs is mounted.
|
2010-01-15 05:47:57 +08:00
|
|
|
With this option enabled, it allows to bring up a system in
|
|
|
|
|
rescue mode with init=/bin/sh, even when the /dev directory
|
|
|
|
|
on the rootfs is completely empty.
|
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 21:23:42 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
config STANDALONE
|
2012-10-24 04:01:50 +08:00
|
|
|
bool "Select only drivers that don't need compile-time external firmware"
|
2005-04-17 06:20:36 +08:00
|
|
|
default y
|
|
|
|
|
help
|
|
|
|
|
Select this option if you don't have magic firmware for drivers that
|
|
|
|
|
need it.
|
|
|
|
|
|
|
|
|
|
If unsure, say Y.
|
|
|
|
|
|
|
|
|
|
config PREVENT_FIRMWARE_BUILD
|
|
|
|
|
bool "Prevent firmware from being built"
|
|
|
|
|
default y
|
|
|
|
|
help
|
|
|
|
|
Say yes to avoid building firmware. Firmware is usually shipped
|
2011-06-13 02:17:30 +08:00
|
|
|
with the driver and only when updating the firmware should a
|
|
|
|
|
rebuild be made.
|
|
|
|
|
If unsure, say Y here.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
|
config FW_LOADER
|
2011-01-21 06:44:16 +08:00
|
|
|
tristate "Userspace firmware loading support" if EXPERT
|
2008-06-11 00:04:08 +08:00
|
|
|
default y
|
2005-04-17 06:20:36 +08:00
|
|
|
---help---
|
2011-06-13 02:17:30 +08:00
|
|
|
This option is provided for the case where none of the in-tree modules
|
|
|
|
|
require userspace firmware loading support, but a module built
|
|
|
|
|
out-of-tree does.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-06-25 20:56:07 +08:00
|
|
|
config FIRMWARE_IN_KERNEL
|
|
|
|
|
bool "Include in-kernel firmware blobs in kernel binary"
|
|
|
|
|
depends on FW_LOADER
|
|
|
|
|
default y
|
|
|
|
|
help
|
|
|
|
|
The kernel source tree includes a number of firmware 'blobs'
|
2011-06-13 02:17:30 +08:00
|
|
|
that are used by various drivers. The recommended way to
|
2011-06-13 02:17:31 +08:00
|
|
|
use these is to run "make firmware_install", which, after
|
|
|
|
|
converting ihex files to binary, copies all of the needed
|
|
|
|
|
binary files in firmware/ to /lib/firmware/ on your system so
|
2008-06-25 20:56:07 +08:00
|
|
|
that they can be loaded by userspace helpers on request.
|
|
|
|
|
|
|
|
|
|
Enabling this option will build each required firmware blob
|
|
|
|
|
into the kernel directly, where request_firmware() will find
|
|
|
|
|
them without having to call out to userspace. This may be
|
2011-06-13 02:17:30 +08:00
|
|
|
useful if your root file system requires a device that uses
|
|
|
|
|
such firmware and do not wish to use an initrd.
|
2008-06-25 20:56:07 +08:00
|
|
|
|
|
|
|
|
This single option controls the inclusion of firmware for
|
2011-06-13 02:17:30 +08:00
|
|
|
every driver that uses request_firmware() and ships its
|
|
|
|
|
firmware in the kernel source tree, which avoids a
|
|
|
|
|
proliferation of 'Include firmware for xxx device' options.
|
2008-06-25 20:56:07 +08:00
|
|
|
|
|
|
|
|
Say 'N' and let firmware be loaded from userspace.
|
|
|
|
|
|
2008-05-23 20:58:12 +08:00
|
|
|
config EXTRA_FIRMWARE
|
|
|
|
|
string "External firmware blobs to build into the kernel binary"
|
|
|
|
|
depends on FW_LOADER
|
|
|
|
|
help
|
2011-06-13 02:17:30 +08:00
|
|
|
This option allows firmware to be built into the kernel for the case
|
|
|
|
|
where the user either cannot or doesn't want to provide it from
|
2008-05-23 20:58:12 +08:00
|
|
|
userspace at runtime (for example, when the firmware in question is
|
|
|
|
|
required for accessing the boot device, and the user doesn't want to
|
|
|
|
|
use an initrd).
|
|
|
|
|
|
2011-06-13 02:17:30 +08:00
|
|
|
This option is a string and takes the (space-separated) names of the
|
|
|
|
|
firmware files -- the same names that appear in MODULE_FIRMWARE()
|
2008-05-23 20:58:12 +08:00
|
|
|
and request_firmware() in the source. These files should exist under
|
|
|
|
|
the directory specified by the EXTRA_FIRMWARE_DIR option, which is
|
2011-06-13 02:17:30 +08:00
|
|
|
by default the firmware subdirectory of the kernel source tree.
|
2008-05-23 20:58:12 +08:00
|
|
|
|
2011-06-13 02:17:30 +08:00
|
|
|
For example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin", copy
|
|
|
|
|
the usb8388.bin file into the firmware directory, and build the kernel.
|
|
|
|
|
Then any request_firmware("usb8388.bin") will be satisfied internally
|
|
|
|
|
without needing to call out to userspace.
|
2008-05-23 20:58:12 +08:00
|
|
|
|
|
|
|
|
WARNING: If you include additional firmware files into your binary
|
2011-06-13 02:17:30 +08:00
|
|
|
kernel image that are not available under the terms of the GPL,
|
2008-05-23 20:58:12 +08:00
|
|
|
then it may be a violation of the GPL to distribute the resulting
|
2011-06-13 02:17:30 +08:00
|
|
|
image since it combines both GPL and non-GPL work. You should
|
2008-05-23 20:58:12 +08:00
|
|
|
consult a lawyer of your own before distributing such an image.
|
|
|
|
|
|
|
|
|
|
config EXTRA_FIRMWARE_DIR
|
|
|
|
|
string "Firmware blobs root directory"
|
|
|
|
|
depends on EXTRA_FIRMWARE != ""
|
|
|
|
|
default "firmware"
|
|
|
|
|
help
|
|
|
|
|
This option controls the directory in which the kernel build system
|
|
|
|
|
looks for the firmware files listed in the EXTRA_FIRMWARE option.
|
2011-06-13 02:17:30 +08:00
|
|
|
The default is firmware/ in the kernel source tree, but by changing
|
|
|
|
|
this option you can point it elsewhere, such as /lib/firmware/ or
|
|
|
|
|
some other directory containing the firmware files.
|
2008-05-23 20:58:12 +08:00
|
|
|
|
2013-01-31 18:13:55 +08:00
|
|
|
config FW_LOADER_USER_HELPER
|
|
|
|
|
bool "Fallback user-helper invocation for firmware loading"
|
|
|
|
|
depends on FW_LOADER
|
|
|
|
|
default y
|
|
|
|
|
help
|
|
|
|
|
This option enables / disables the invocation of user-helper
|
|
|
|
|
(e.g. udev) for loading firmware files as a fallback after the
|
|
|
|
|
direct file loading in kernel fails. The user-mode helper is
|
|
|
|
|
no longer required unless you have a special firmware file that
|
|
|
|
|
resides in a non-standard path.
|
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
config DEBUG_DRIVER
|
|
|
|
|
bool "Driver Core verbose debug messages"
|
|
|
|
|
depends on DEBUG_KERNEL
|
|
|
|
|
help
|
|
|
|
|
Say Y here if you want the Driver core to produce a bunch of
|
|
|
|
|
debug messages to the system log. Select this if you are having a
|
|
|
|
|
problem with the driver core and want to see more of what is
|
|
|
|
|
going on.
|
|
|
|
|
|
|
|
|
|
If you are unsure about this, say N here.
|
|
|
|
|
|
devres: device resource management
Implement device resource management, in short, devres. A device
driver can allocate arbirary size of devres data which is associated
with a release function. On driver detach, release function is
invoked on the devres data, then, devres data is freed.
devreses are typed by associated release functions. Some devreses are
better represented by single instance of the type while others need
multiple instances sharing the same release function. Both usages are
supported.
devreses can be grouped using devres group such that a device driver
can easily release acquired resources halfway through initialization
or selectively release resources (e.g. resources for port 1 out of 4
ports).
This patch adds devres core including documentation and the following
managed interfaces.
* alloc/free : devm_kzalloc(), devm_kzfree()
* IO region : devm_request_region(), devm_release_region()
* IRQ : devm_request_irq(), devm_free_irq()
* DMA : dmam_alloc_coherent(), dmam_free_coherent(),
dmam_declare_coherent_memory(), dmam_pool_create(),
dmam_pool_destroy()
* PCI : pcim_enable_device(), pcim_pin_device(), pci_is_managed()
* iomap : devm_ioport_map(), devm_ioport_unmap(), devm_ioremap(),
devm_ioremap_nocache(), devm_iounmap(), pcim_iomap_table(),
pcim_iomap(), pcim_iounmap()
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-01-20 15:00:26 +08:00
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config DEBUG_DEVRES
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bool "Managed device resources verbose debug messages"
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depends on DEBUG_KERNEL
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help
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This option enables kernel parameter devres.log. If set to
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non-zero, devres debug messages are printed. Select this if
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you are having a problem with devres or want to debug
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resource management for a managed device. devres.log can be
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switched on and off from sysfs node.
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If you are unsure about this, Say N here.
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2006-05-09 18:53:49 +08:00
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config SYS_HYPERVISOR
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bool
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default n
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2006-10-29 01:38:55 +08:00
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2012-01-10 11:04:32 +08:00
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config GENERIC_CPU_DEVICES
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bool
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default n
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2014-02-08 20:34:09 +08:00
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config GENERIC_CPU_AUTOPROBE
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bool
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2012-02-07 03:22:22 +08:00
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config SOC_BUS
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bool
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2011-05-12 01:59:58 +08:00
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source "drivers/base/regmap/Kconfig"
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dma-buf: Introduce dma buffer sharing mechanism
This is the first step in defining a dma buffer sharing mechanism.
A new buffer object dma_buf is added, with operations and API to allow easy
sharing of this buffer object across devices.
The framework allows:
- creation of a buffer object, its association with a file pointer, and
associated allocator-defined operations on that buffer. This operation is
called the 'export' operation.
- different devices to 'attach' themselves to this exported buffer object, to
facilitate backing storage negotiation, using dma_buf_attach() API.
- the exported buffer object to be shared with the other entity by asking for
its 'file-descriptor (fd)', and sharing the fd across.
- a received fd to get the buffer object back, where it can be accessed using
the associated exporter-defined operations.
- the exporter and user to share the scatterlist associated with this buffer
object using map_dma_buf and unmap_dma_buf operations.
Atleast one 'attach()' call is required to be made prior to calling the
map_dma_buf() operation.
Couple of building blocks in map_dma_buf() are added to ease introduction
of sync'ing across exporter and users, and late allocation by the exporter.
For this first version, this framework will work with certain conditions:
- *ONLY* exporter will be allowed to mmap to userspace (outside of this
framework - mmap is not a buffer object operation),
- currently, *ONLY* users that do not need CPU access to the buffer are
allowed.
More details are there in the documentation patch.
This is based on design suggestions from many people at the mini-summits[1],
most notably from Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
Daniel Vetter <daniel@ffwll.ch>.
The implementation is inspired from proof-of-concept patch-set from
Tomasz Stanislawski <t.stanislaws@samsung.com>, who demonstrated buffer sharing
between two v4l2 devices. [2]
[1]: https://wiki.linaro.org/OfficeofCTO/MemoryManagement
[2]: http://lwn.net/Articles/454389
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-and-Tested-by: Rob Clark <rob.clark@linaro.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-12-26 17:23:15 +08:00
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config DMA_SHARED_BUFFER
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2012-01-13 17:05:14 +08:00
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bool
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dma-buf: Introduce dma buffer sharing mechanism
This is the first step in defining a dma buffer sharing mechanism.
A new buffer object dma_buf is added, with operations and API to allow easy
sharing of this buffer object across devices.
The framework allows:
- creation of a buffer object, its association with a file pointer, and
associated allocator-defined operations on that buffer. This operation is
called the 'export' operation.
- different devices to 'attach' themselves to this exported buffer object, to
facilitate backing storage negotiation, using dma_buf_attach() API.
- the exported buffer object to be shared with the other entity by asking for
its 'file-descriptor (fd)', and sharing the fd across.
- a received fd to get the buffer object back, where it can be accessed using
the associated exporter-defined operations.
- the exporter and user to share the scatterlist associated with this buffer
object using map_dma_buf and unmap_dma_buf operations.
Atleast one 'attach()' call is required to be made prior to calling the
map_dma_buf() operation.
Couple of building blocks in map_dma_buf() are added to ease introduction
of sync'ing across exporter and users, and late allocation by the exporter.
For this first version, this framework will work with certain conditions:
- *ONLY* exporter will be allowed to mmap to userspace (outside of this
framework - mmap is not a buffer object operation),
- currently, *ONLY* users that do not need CPU access to the buffer are
allowed.
More details are there in the documentation patch.
This is based on design suggestions from many people at the mini-summits[1],
most notably from Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
Daniel Vetter <daniel@ffwll.ch>.
The implementation is inspired from proof-of-concept patch-set from
Tomasz Stanislawski <t.stanislaws@samsung.com>, who demonstrated buffer sharing
between two v4l2 devices. [2]
[1]: https://wiki.linaro.org/OfficeofCTO/MemoryManagement
[2]: http://lwn.net/Articles/454389
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-and-Tested-by: Rob Clark <rob.clark@linaro.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-12-26 17:23:15 +08:00
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default n
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select ANON_INODES
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help
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This option enables the framework for buffer-sharing between
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multiple drivers. A buffer is associated with a file using driver
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APIs extension; the file's descriptor can then be passed on to other
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driver.
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2013-07-02 13:45:15 +08:00
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config DMA_CMA
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bool "DMA Contiguous Memory Allocator"
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depends on HAVE_DMA_CONTIGUOUS && CMA
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2011-12-29 20:09:51 +08:00
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help
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This enables the Contiguous Memory Allocator which allows drivers
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to allocate big physically-contiguous blocks of memory for use with
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hardware components that do not support I/O map nor scatter-gather.
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For more information see <include/linux/dma-contiguous.h>.
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If unsure, say "n".
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2013-07-02 13:45:15 +08:00
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if DMA_CMA
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2011-12-29 20:09:51 +08:00
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comment "Default contiguous memory area size:"
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config CMA_SIZE_MBYTES
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int "Size in Mega Bytes"
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depends on !CMA_SIZE_SEL_PERCENTAGE
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default 16
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help
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Defines the size (in MiB) of the default memory area for Contiguous
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Memory Allocator.
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config CMA_SIZE_PERCENTAGE
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int "Percentage of total memory"
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depends on !CMA_SIZE_SEL_MBYTES
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default 10
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help
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Defines the size of the default memory area for Contiguous Memory
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Allocator as a percentage of the total memory in the system.
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choice
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prompt "Selected region size"
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2012-10-18 15:29:44 +08:00
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default CMA_SIZE_SEL_MBYTES
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2011-12-29 20:09:51 +08:00
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config CMA_SIZE_SEL_MBYTES
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bool "Use mega bytes value only"
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config CMA_SIZE_SEL_PERCENTAGE
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bool "Use percentage value only"
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config CMA_SIZE_SEL_MIN
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bool "Use lower value (minimum)"
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config CMA_SIZE_SEL_MAX
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bool "Use higher value (maximum)"
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endchoice
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config CMA_ALIGNMENT
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int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
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range 4 9
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default 8
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help
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DMA mapping framework by default aligns all buffers to the smallest
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PAGE_SIZE order which is greater than or equal to the requested buffer
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size. This works well for buffers up to a few hundreds kilobytes, but
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for larger buffers it just a memory waste. With this parameter you can
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specify the maximum PAGE_SIZE order for contiguous buffers. Larger
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buffers will be aligned only to this specified order. The order is
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expressed as a power of two multiplied by the PAGE_SIZE.
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For example, if your system defaults to 4KiB pages, the order value
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of 8 means that the buffers will be aligned up to 1MiB only.
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If unsure, leave the default value "8".
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config CMA_AREAS
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int "Maximum count of the CMA device-private areas"
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default 7
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help
|
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CMA allows to create CMA areas for particular devices. This parameter
|
|
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sets the maximum number of such device private CMA areas in the
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system.
|
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If unsure, leave the default value "7".
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endif
|
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2006-10-29 01:38:55 +08:00
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endmenu
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