1 menu "Generic Driver Options"
3 config UEVENT_HELPER_PATH
4 string "path to uevent helper"
8 Path to uevent helper program forked by the kernel for
10 Before the switch to the netlink-based uevent source, this was
11 used to hook hotplug scripts into kernel device events. It
12 usually pointed to a shell script at /sbin/hotplug.
13 This should not be used today, because usual systems create
14 many events at bootup or device discovery in a very short time
15 frame. One forked process per event can create so many processes
16 that it creates a high system load, or on smaller systems
17 it is known to create out-of-memory situations during bootup.
19 To disable user space helper program execution at early boot
20 time specify an empty string here. This setting can be altered
21 via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper
25 bool "Maintain a devtmpfs filesystem to mount at /dev"
28 This creates a tmpfs/ramfs filesystem instance early at bootup.
29 In this filesystem, the kernel driver core maintains device
30 nodes with their default names and permissions for all
31 registered devices with an assigned major/minor number.
32 Userspace can modify the filesystem content as needed, add
33 symlinks, and apply needed permissions.
34 It provides a fully functional /dev directory, where usually
35 udev runs on top, managing permissions and adding meaningful
37 In very limited environments, it may provide a sufficient
38 functional /dev without any further help. It also allows simple
39 rescue systems, and reliably handles dynamic major/minor numbers.
41 Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs
42 file system will be used instead.
45 bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
48 This will instruct the kernel to automatically mount the
49 devtmpfs filesystem at /dev, directly after the kernel has
50 mounted the root filesystem. The behavior can be overridden
51 with the commandline parameter: devtmpfs.mount=0|1.
52 This option does not affect initramfs based booting, here
53 the devtmpfs filesystem always needs to be mounted manually
54 after the roots is mounted.
55 With this option enabled, it allows to bring up a system in
56 rescue mode with init=/bin/sh, even when the /dev directory
57 on the rootfs is completely empty.
60 bool "Select only drivers that don't need compile-time external firmware"
63 Select this option if you don't have magic firmware for drivers that
68 config PREVENT_FIRMWARE_BUILD
69 bool "Prevent firmware from being built"
72 Say yes to avoid building firmware. Firmware is usually shipped
73 with the driver and only when updating the firmware should a
75 If unsure, say Y here.
78 tristate "Userspace firmware loading support" if EXPERT
81 This option is provided for the case where none of the in-tree modules
82 require userspace firmware loading support, but a module built
85 config FIRMWARE_IN_KERNEL
86 bool "Include in-kernel firmware blobs in kernel binary"
90 The kernel source tree includes a number of firmware 'blobs'
91 that are used by various drivers. The recommended way to
92 use these is to run "make firmware_install", which, after
93 converting ihex files to binary, copies all of the needed
94 binary files in firmware/ to /lib/firmware/ on your system so
95 that they can be loaded by userspace helpers on request.
97 Enabling this option will build each required firmware blob
98 into the kernel directly, where request_firmware() will find
99 them without having to call out to userspace. This may be
100 useful if your root file system requires a device that uses
101 such firmware and do not wish to use an initrd.
103 This single option controls the inclusion of firmware for
104 every driver that uses request_firmware() and ships its
105 firmware in the kernel source tree, which avoids a
106 proliferation of 'Include firmware for xxx device' options.
108 Say 'N' and let firmware be loaded from userspace.
110 config EXTRA_FIRMWARE
111 string "External firmware blobs to build into the kernel binary"
114 This option allows firmware to be built into the kernel for the case
115 where the user either cannot or doesn't want to provide it from
116 userspace at runtime (for example, when the firmware in question is
117 required for accessing the boot device, and the user doesn't want to
120 This option is a string and takes the (space-separated) names of the
121 firmware files -- the same names that appear in MODULE_FIRMWARE()
122 and request_firmware() in the source. These files should exist under
123 the directory specified by the EXTRA_FIRMWARE_DIR option, which is
124 by default the firmware subdirectory of the kernel source tree.
126 For example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin", copy
127 the usb8388.bin file into the firmware directory, and build the kernel.
128 Then any request_firmware("usb8388.bin") will be satisfied internally
129 without needing to call out to userspace.
131 WARNING: If you include additional firmware files into your binary
132 kernel image that are not available under the terms of the GPL,
133 then it may be a violation of the GPL to distribute the resulting
134 image since it combines both GPL and non-GPL work. You should
135 consult a lawyer of your own before distributing such an image.
137 config EXTRA_FIRMWARE_DIR
138 string "Firmware blobs root directory"
139 depends on EXTRA_FIRMWARE != ""
142 This option controls the directory in which the kernel build system
143 looks for the firmware files listed in the EXTRA_FIRMWARE option.
144 The default is firmware/ in the kernel source tree, but by changing
145 this option you can point it elsewhere, such as /lib/firmware/ or
146 some other directory containing the firmware files.
148 config FW_LOADER_USER_HELPER
149 bool "Fallback user-helper invocation for firmware loading"
153 This option enables / disables the invocation of user-helper
154 (e.g. udev) for loading firmware files as a fallback after the
155 direct file loading in kernel fails. The user-mode helper is
156 no longer required unless you have a special firmware file that
157 resides in a non-standard path.
160 bool "Driver Core verbose debug messages"
161 depends on DEBUG_KERNEL
163 Say Y here if you want the Driver core to produce a bunch of
164 debug messages to the system log. Select this if you are having a
165 problem with the driver core and want to see more of what is
168 If you are unsure about this, say N here.
171 bool "Managed device resources verbose debug messages"
172 depends on DEBUG_KERNEL
174 This option enables kernel parameter devres.log. If set to
175 non-zero, devres debug messages are printed. Select this if
176 you are having a problem with devres or want to debug
177 resource management for a managed device. devres.log can be
178 switched on and off from sysfs node.
180 If you are unsure about this, Say N here.
182 config SYS_HYPERVISOR
186 config GENERIC_CPU_DEVICES
190 config HAVE_CPU_AUTOPROBE
191 def_bool ARCH_HAS_CPU_AUTOPROBE
193 config GENERIC_CPU_AUTOPROBE
195 depends on !ARCH_HAS_CPU_AUTOPROBE
196 select HAVE_CPU_AUTOPROBE
201 source "drivers/base/regmap/Kconfig"
203 config DMA_SHARED_BUFFER
208 This option enables the framework for buffer-sharing between
209 multiple drivers. A buffer is associated with a file using driver
210 APIs extension; the file's descriptor can then be passed on to other
214 bool "DMA Contiguous Memory Allocator"
215 depends on HAVE_DMA_CONTIGUOUS && CMA
217 This enables the Contiguous Memory Allocator which allows drivers
218 to allocate big physically-contiguous blocks of memory for use with
219 hardware components that do not support I/O map nor scatter-gather.
221 For more information see <include/linux/dma-contiguous.h>.
225 comment "Default contiguous memory area size:"
227 config CMA_SIZE_MBYTES
228 int "Size in Mega Bytes"
229 depends on !CMA_SIZE_SEL_PERCENTAGE
232 Defines the size (in MiB) of the default memory area for Contiguous
235 config CMA_SIZE_PERCENTAGE
236 int "Percentage of total memory"
237 depends on !CMA_SIZE_SEL_MBYTES
240 Defines the size of the default memory area for Contiguous Memory
241 Allocator as a percentage of the total memory in the system.
244 prompt "Selected region size"
245 default CMA_SIZE_SEL_MBYTES
247 config CMA_SIZE_SEL_MBYTES
248 bool "Use mega bytes value only"
250 config CMA_SIZE_SEL_PERCENTAGE
251 bool "Use percentage value only"
253 config CMA_SIZE_SEL_MIN
254 bool "Use lower value (minimum)"
256 config CMA_SIZE_SEL_MAX
257 bool "Use higher value (maximum)"
262 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
266 DMA mapping framework by default aligns all buffers to the smallest
267 PAGE_SIZE order which is greater than or equal to the requested buffer
268 size. This works well for buffers up to a few hundreds kilobytes, but
269 for larger buffers it just a memory waste. With this parameter you can
270 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
271 buffers will be aligned only to this specified order. The order is
272 expressed as a power of two multiplied by the PAGE_SIZE.
274 For example, if your system defaults to 4KiB pages, the order value
275 of 8 means that the buffers will be aligned up to 1MiB only.
277 If unsure, leave the default value "8".
280 int "Maximum count of the CMA device-private areas"
283 CMA allows to create CMA areas for particular devices. This parameter
284 sets the maximum number of such device private CMA areas in the
287 If unsure, leave the default value "7".