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b2441318 | 1 | # SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | menu "Generic Driver Options" |
3 | ||
86d56134 MM |
4 | config UEVENT_HELPER |
5 | bool "Support for uevent helper" | |
6 | default y | |
6a8d8abb | 7 | help |
86d56134 | 8 | The uevent helper program is forked by the kernel for |
6a8d8abb | 9 | every uevent. |
7934779a KS |
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. | |
6a8d8abb | 18 | |
86d56134 MM |
19 | config UEVENT_HELPER_PATH |
20 | string "path to uevent helper" | |
21 | depends on UEVENT_HELPER | |
22 | default "" | |
23 | help | |
24 | To disable user space helper program execution at by default | |
25 | specify an empty string here. This setting can still be altered | |
573c9774 MN |
26 | via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper |
27 | later at runtime. | |
28 | ||
2b2af54a | 29 | config DEVTMPFS |
4237e5fd | 30 | bool "Maintain a devtmpfs filesystem to mount at /dev" |
2b2af54a | 31 | help |
da5e4ef7 | 32 | This creates a tmpfs/ramfs filesystem instance early at bootup. |
4237e5fd KS |
33 | In this filesystem, the kernel driver core maintains device |
34 | nodes with their default names and permissions for all | |
35 | registered devices with an assigned major/minor number. | |
36 | Userspace can modify the filesystem content as needed, add | |
37 | symlinks, and apply needed permissions. | |
38 | It provides a fully functional /dev directory, where usually | |
39 | udev runs on top, managing permissions and adding meaningful | |
40 | symlinks. | |
41 | In very limited environments, it may provide a sufficient | |
42 | functional /dev without any further help. It also allows simple | |
43 | rescue systems, and reliably handles dynamic major/minor numbers. | |
2b2af54a | 44 | |
da5e4ef7 PK |
45 | Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs |
46 | file system will be used instead. | |
47 | ||
2b2af54a | 48 | config DEVTMPFS_MOUNT |
4237e5fd | 49 | bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs" |
2b2af54a KS |
50 | depends on DEVTMPFS |
51 | help | |
4237e5fd KS |
52 | This will instruct the kernel to automatically mount the |
53 | devtmpfs filesystem at /dev, directly after the kernel has | |
54 | mounted the root filesystem. The behavior can be overridden | |
55 | with the commandline parameter: devtmpfs.mount=0|1. | |
56 | This option does not affect initramfs based booting, here | |
57 | the devtmpfs filesystem always needs to be mounted manually | |
0feb03af | 58 | after the rootfs is mounted. |
4237e5fd KS |
59 | With this option enabled, it allows to bring up a system in |
60 | rescue mode with init=/bin/sh, even when the /dev directory | |
61 | on the rootfs is completely empty. | |
2b2af54a | 62 | |
1da177e4 | 63 | config STANDALONE |
967857df | 64 | bool "Select only drivers that don't need compile-time external firmware" |
1da177e4 LT |
65 | default y |
66 | help | |
67 | Select this option if you don't have magic firmware for drivers that | |
68 | need it. | |
69 | ||
70 | If unsure, say Y. | |
71 | ||
72 | config PREVENT_FIRMWARE_BUILD | |
73 | bool "Prevent firmware from being built" | |
74 | default y | |
75 | help | |
76 | Say yes to avoid building firmware. Firmware is usually shipped | |
113647a2 | 77 | with the driver and only when updating the firmware should a |
78 | rebuild be made. | |
79 | If unsure, say Y here. | |
1da177e4 LT |
80 | |
81 | config FW_LOADER | |
6a108a14 | 82 | tristate "Userspace firmware loading support" if EXPERT |
d9b19199 | 83 | default y |
1da177e4 | 84 | ---help--- |
113647a2 | 85 | This option is provided for the case where none of the in-tree modules |
86 | require userspace firmware loading support, but a module built | |
87 | out-of-tree does. | |
1da177e4 | 88 | |
d172e7f5 DW |
89 | config FIRMWARE_IN_KERNEL |
90 | bool "Include in-kernel firmware blobs in kernel binary" | |
91 | depends on FW_LOADER | |
92 | default y | |
93 | help | |
94 | The kernel source tree includes a number of firmware 'blobs' | |
113647a2 | 95 | that are used by various drivers. The recommended way to |
156faf90 | 96 | use these is to run "make firmware_install", which, after |
97 | converting ihex files to binary, copies all of the needed | |
98 | binary files in firmware/ to /lib/firmware/ on your system so | |
d172e7f5 DW |
99 | that they can be loaded by userspace helpers on request. |
100 | ||
101 | Enabling this option will build each required firmware blob | |
102 | into the kernel directly, where request_firmware() will find | |
103 | them without having to call out to userspace. This may be | |
113647a2 | 104 | useful if your root file system requires a device that uses |
105 | such firmware and do not wish to use an initrd. | |
d172e7f5 DW |
106 | |
107 | This single option controls the inclusion of firmware for | |
113647a2 | 108 | every driver that uses request_firmware() and ships its |
109 | firmware in the kernel source tree, which avoids a | |
110 | proliferation of 'Include firmware for xxx device' options. | |
d172e7f5 DW |
111 | |
112 | Say 'N' and let firmware be loaded from userspace. | |
113 | ||
4d2acfbf DW |
114 | config EXTRA_FIRMWARE |
115 | string "External firmware blobs to build into the kernel binary" | |
116 | depends on FW_LOADER | |
117 | help | |
113647a2 | 118 | This option allows firmware to be built into the kernel for the case |
119 | where the user either cannot or doesn't want to provide it from | |
4d2acfbf DW |
120 | userspace at runtime (for example, when the firmware in question is |
121 | required for accessing the boot device, and the user doesn't want to | |
122 | use an initrd). | |
123 | ||
113647a2 | 124 | This option is a string and takes the (space-separated) names of the |
125 | firmware files -- the same names that appear in MODULE_FIRMWARE() | |
4d2acfbf DW |
126 | and request_firmware() in the source. These files should exist under |
127 | the directory specified by the EXTRA_FIRMWARE_DIR option, which is | |
113647a2 | 128 | by default the firmware subdirectory of the kernel source tree. |
4d2acfbf | 129 | |
113647a2 | 130 | For example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin", copy |
131 | the usb8388.bin file into the firmware directory, and build the kernel. | |
132 | Then any request_firmware("usb8388.bin") will be satisfied internally | |
133 | without needing to call out to userspace. | |
4d2acfbf DW |
134 | |
135 | WARNING: If you include additional firmware files into your binary | |
113647a2 | 136 | kernel image that are not available under the terms of the GPL, |
4d2acfbf | 137 | then it may be a violation of the GPL to distribute the resulting |
113647a2 | 138 | image since it combines both GPL and non-GPL work. You should |
4d2acfbf DW |
139 | consult a lawyer of your own before distributing such an image. |
140 | ||
141 | config EXTRA_FIRMWARE_DIR | |
142 | string "Firmware blobs root directory" | |
143 | depends on EXTRA_FIRMWARE != "" | |
df85b2d7 | 144 | default "/lib/firmware" |
4d2acfbf DW |
145 | help |
146 | This option controls the directory in which the kernel build system | |
147 | looks for the firmware files listed in the EXTRA_FIRMWARE option. | |
4d2acfbf | 148 | |
7b1269f7 | 149 | config FW_LOADER_USER_HELPER |
5a1379e8 TI |
150 | bool |
151 | ||
152 | config FW_LOADER_USER_HELPER_FALLBACK | |
7b1269f7 TI |
153 | bool "Fallback user-helper invocation for firmware loading" |
154 | depends on FW_LOADER | |
5a1379e8 | 155 | select FW_LOADER_USER_HELPER |
7b1269f7 TI |
156 | help |
157 | This option enables / disables the invocation of user-helper | |
158 | (e.g. udev) for loading firmware files as a fallback after the | |
159 | direct file loading in kernel fails. The user-mode helper is | |
160 | no longer required unless you have a special firmware file that | |
5a1379e8 TI |
161 | resides in a non-standard path. Moreover, the udev support has |
162 | been deprecated upstream. | |
163 | ||
164 | If you are unsure about this, say N here. | |
7b1269f7 | 165 | |
833c9545 JB |
166 | config WANT_DEV_COREDUMP |
167 | bool | |
168 | help | |
169 | Drivers should "select" this option if they desire to use the | |
170 | device coredump mechanism. | |
171 | ||
cd3d9ea1 JB |
172 | config ALLOW_DEV_COREDUMP |
173 | bool "Allow device coredump" if EXPERT | |
9c602699 | 174 | default y |
833c9545 | 175 | help |
9c602699 AR |
176 | This option controls if the device coredump mechanism is available or |
177 | not; if disabled, the mechanism will be omitted even if drivers that | |
178 | can use it are enabled. | |
179 | Say 'N' for more sensitive systems or systems that don't want | |
180 | to ever access the information to not have the code, nor keep any | |
181 | data. | |
833c9545 | 182 | |
9c602699 | 183 | If unsure, say Y. |
833c9545 JB |
184 | |
185 | config DEV_COREDUMP | |
186 | bool | |
187 | default y if WANT_DEV_COREDUMP | |
cd3d9ea1 | 188 | depends on ALLOW_DEV_COREDUMP |
833c9545 | 189 | |
1da177e4 LT |
190 | config DEBUG_DRIVER |
191 | bool "Driver Core verbose debug messages" | |
192 | depends on DEBUG_KERNEL | |
193 | help | |
194 | Say Y here if you want the Driver core to produce a bunch of | |
195 | debug messages to the system log. Select this if you are having a | |
196 | problem with the driver core and want to see more of what is | |
197 | going on. | |
198 | ||
199 | If you are unsure about this, say N here. | |
200 | ||
9ac7849e TH |
201 | config DEBUG_DEVRES |
202 | bool "Managed device resources verbose debug messages" | |
203 | depends on DEBUG_KERNEL | |
204 | help | |
205 | This option enables kernel parameter devres.log. If set to | |
206 | non-zero, devres debug messages are printed. Select this if | |
207 | you are having a problem with devres or want to debug | |
208 | resource management for a managed device. devres.log can be | |
209 | switched on and off from sysfs node. | |
210 | ||
211 | If you are unsure about this, Say N here. | |
212 | ||
bea5b158 | 213 | config DEBUG_TEST_DRIVER_REMOVE |
248ff021 | 214 | bool "Test driver remove calls during probe (UNSTABLE)" |
bea5b158 RH |
215 | depends on DEBUG_KERNEL |
216 | help | |
217 | Say Y here if you want the Driver core to test driver remove functions | |
218 | by calling probe, remove, probe. This tests the remove path without | |
219 | having to unbind the driver or unload the driver module. | |
220 | ||
248ff021 LA |
221 | This option is expected to find errors and may render your system |
222 | unusable. You should say N here unless you are explicitly looking to | |
223 | test this functionality. | |
bea5b158 | 224 | |
79543cf2 DT |
225 | source "drivers/base/test/Kconfig" |
226 | ||
4039483f MH |
227 | config SYS_HYPERVISOR |
228 | bool | |
229 | default n | |
eba6cd67 | 230 | |
9f13a1fd BH |
231 | config GENERIC_CPU_DEVICES |
232 | bool | |
233 | default n | |
234 | ||
67bad2fd AB |
235 | config GENERIC_CPU_AUTOPROBE |
236 | bool | |
67bad2fd | 237 | |
74d1d82c LJ |
238 | config SOC_BUS |
239 | bool | |
c97db7cc | 240 | select GLOB |
74d1d82c | 241 | |
b83a313b MB |
242 | source "drivers/base/regmap/Kconfig" |
243 | ||
d15bd7ee | 244 | config DMA_SHARED_BUFFER |
3b32a592 | 245 | bool |
d15bd7ee SS |
246 | default n |
247 | select ANON_INODES | |
248 | help | |
249 | This option enables the framework for buffer-sharing between | |
250 | multiple drivers. A buffer is associated with a file using driver | |
251 | APIs extension; the file's descriptor can then be passed on to other | |
252 | driver. | |
253 | ||
f54d1867 CW |
254 | config DMA_FENCE_TRACE |
255 | bool "Enable verbose DMA_FENCE_TRACE messages" | |
e941759c ML |
256 | depends on DMA_SHARED_BUFFER |
257 | help | |
f54d1867 | 258 | Enable the DMA_FENCE_TRACE printks. This will add extra |
e941759c ML |
259 | spam to the console log, but will make it easier to diagnose |
260 | lockup related problems for dma-buffers shared across multiple | |
261 | devices. | |
262 | ||
f825c736 AK |
263 | config DMA_CMA |
264 | bool "DMA Contiguous Memory Allocator" | |
265 | depends on HAVE_DMA_CONTIGUOUS && CMA | |
c64be2bb MS |
266 | help |
267 | This enables the Contiguous Memory Allocator which allows drivers | |
268 | to allocate big physically-contiguous blocks of memory for use with | |
269 | hardware components that do not support I/O map nor scatter-gather. | |
270 | ||
f0d6d1f6 JD |
271 | You can disable CMA by specifying "cma=0" on the kernel's command |
272 | line. | |
273 | ||
c64be2bb MS |
274 | For more information see <include/linux/dma-contiguous.h>. |
275 | If unsure, say "n". | |
276 | ||
f825c736 | 277 | if DMA_CMA |
c64be2bb MS |
278 | comment "Default contiguous memory area size:" |
279 | ||
280 | config CMA_SIZE_MBYTES | |
281 | int "Size in Mega Bytes" | |
282 | depends on !CMA_SIZE_SEL_PERCENTAGE | |
d7be003a | 283 | default 0 if X86 |
c64be2bb MS |
284 | default 16 |
285 | help | |
286 | Defines the size (in MiB) of the default memory area for Contiguous | |
d7be003a AM |
287 | Memory Allocator. If the size of 0 is selected, CMA is disabled by |
288 | default, but it can be enabled by passing cma=size[MG] to the kernel. | |
289 | ||
c64be2bb MS |
290 | |
291 | config CMA_SIZE_PERCENTAGE | |
292 | int "Percentage of total memory" | |
293 | depends on !CMA_SIZE_SEL_MBYTES | |
d7be003a | 294 | default 0 if X86 |
c64be2bb MS |
295 | default 10 |
296 | help | |
297 | Defines the size of the default memory area for Contiguous Memory | |
298 | Allocator as a percentage of the total memory in the system. | |
d7be003a AM |
299 | If 0 percent is selected, CMA is disabled by default, but it can be |
300 | enabled by passing cma=size[MG] to the kernel. | |
c64be2bb MS |
301 | |
302 | choice | |
303 | prompt "Selected region size" | |
5e97f3f9 | 304 | default CMA_SIZE_SEL_MBYTES |
c64be2bb MS |
305 | |
306 | config CMA_SIZE_SEL_MBYTES | |
307 | bool "Use mega bytes value only" | |
308 | ||
309 | config CMA_SIZE_SEL_PERCENTAGE | |
310 | bool "Use percentage value only" | |
311 | ||
312 | config CMA_SIZE_SEL_MIN | |
313 | bool "Use lower value (minimum)" | |
314 | ||
315 | config CMA_SIZE_SEL_MAX | |
316 | bool "Use higher value (maximum)" | |
317 | ||
318 | endchoice | |
319 | ||
320 | config CMA_ALIGNMENT | |
321 | int "Maximum PAGE_SIZE order of alignment for contiguous buffers" | |
fe54b1fd | 322 | range 4 12 |
c64be2bb MS |
323 | default 8 |
324 | help | |
325 | DMA mapping framework by default aligns all buffers to the smallest | |
326 | PAGE_SIZE order which is greater than or equal to the requested buffer | |
327 | size. This works well for buffers up to a few hundreds kilobytes, but | |
328 | for larger buffers it just a memory waste. With this parameter you can | |
329 | specify the maximum PAGE_SIZE order for contiguous buffers. Larger | |
330 | buffers will be aligned only to this specified order. The order is | |
331 | expressed as a power of two multiplied by the PAGE_SIZE. | |
332 | ||
333 | For example, if your system defaults to 4KiB pages, the order value | |
334 | of 8 means that the buffers will be aligned up to 1MiB only. | |
335 | ||
336 | If unsure, leave the default value "8". | |
337 | ||
c64be2bb MS |
338 | endif |
339 | ||
2ef7a295 JL |
340 | config GENERIC_ARCH_TOPOLOGY |
341 | bool | |
342 | help | |
343 | Enable support for architectures common topology code: e.g., parsing | |
344 | CPU capacity information from DT, usage of such information for | |
345 | appropriate scaling, sysfs interface for changing capacity values at | |
346 | runtime. | |
347 | ||
eba6cd67 | 348 | endmenu |