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1 menu "Generic Driver Options"
2
3 config UEVENT_HELPER
4 bool "Support for uevent helper"
5 default y
6 help
7 The uevent helper program is forked by the kernel for
8 every uevent.
9 Before the switch to the netlink-based uevent source, this was
10 used to hook hotplug scripts into kernel device events. It
11 usually pointed to a shell script at /sbin/hotplug.
12 This should not be used today, because usual systems create
13 many events at bootup or device discovery in a very short time
14 frame. One forked process per event can create so many processes
15 that it creates a high system load, or on smaller systems
16 it is known to create out-of-memory situations during bootup.
17
18 config UEVENT_HELPER_PATH
19 string "path to uevent helper"
20 depends on UEVENT_HELPER
21 default ""
22 help
23 To disable user space helper program execution at by default
24 specify an empty string here. This setting can still be altered
25 via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper
26 later at runtime.
27
28 config DEVTMPFS
29 bool "Maintain a devtmpfs filesystem to mount at /dev"
30 help
31 This creates a tmpfs/ramfs filesystem instance early at bootup.
32 In this filesystem, the kernel driver core maintains device
33 nodes with their default names and permissions for all
34 registered devices with an assigned major/minor number.
35 Userspace can modify the filesystem content as needed, add
36 symlinks, and apply needed permissions.
37 It provides a fully functional /dev directory, where usually
38 udev runs on top, managing permissions and adding meaningful
39 symlinks.
40 In very limited environments, it may provide a sufficient
41 functional /dev without any further help. It also allows simple
42 rescue systems, and reliably handles dynamic major/minor numbers.
43
44 Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs
45 file system will be used instead.
46
47 config DEVTMPFS_MOUNT
48 bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
49 depends on DEVTMPFS
50 help
51 This will instruct the kernel to automatically mount the
52 devtmpfs filesystem at /dev, directly after the kernel has
53 mounted the root filesystem. The behavior can be overridden
54 with the commandline parameter: devtmpfs.mount=0|1.
55 This option does not affect initramfs based booting, here
56 the devtmpfs filesystem always needs to be mounted manually
57 after the rootfs is mounted.
58 With this option enabled, it allows to bring up a system in
59 rescue mode with init=/bin/sh, even when the /dev directory
60 on the rootfs is completely empty.
61
62 config STANDALONE
63 bool "Select only drivers that don't need compile-time external firmware"
64 default y
65 help
66 Select this option if you don't have magic firmware for drivers that
67 need it.
68
69 If unsure, say Y.
70
71 config PREVENT_FIRMWARE_BUILD
72 bool "Prevent firmware from being built"
73 default y
74 help
75 Say yes to avoid building firmware. Firmware is usually shipped
76 with the driver and only when updating the firmware should a
77 rebuild be made.
78 If unsure, say Y here.
79
80 config FW_LOADER
81 tristate "Userspace firmware loading support" if EXPERT
82 default y
83 ---help---
84 This option is provided for the case where none of the in-tree modules
85 require userspace firmware loading support, but a module built
86 out-of-tree does.
87
88 config FIRMWARE_IN_KERNEL
89 bool "Include in-kernel firmware blobs in kernel binary"
90 depends on FW_LOADER
91 default y
92 help
93 The kernel source tree includes a number of firmware 'blobs'
94 that are used by various drivers. The recommended way to
95 use these is to run "make firmware_install", which, after
96 converting ihex files to binary, copies all of the needed
97 binary files in firmware/ to /lib/firmware/ on your system so
98 that they can be loaded by userspace helpers on request.
99
100 Enabling this option will build each required firmware blob
101 into the kernel directly, where request_firmware() will find
102 them without having to call out to userspace. This may be
103 useful if your root file system requires a device that uses
104 such firmware and do not wish to use an initrd.
105
106 This single option controls the inclusion of firmware for
107 every driver that uses request_firmware() and ships its
108 firmware in the kernel source tree, which avoids a
109 proliferation of 'Include firmware for xxx device' options.
110
111 Say 'N' and let firmware be loaded from userspace.
112
113 config EXTRA_FIRMWARE
114 string "External firmware blobs to build into the kernel binary"
115 depends on FW_LOADER
116 help
117 This option allows firmware to be built into the kernel for the case
118 where the user either cannot or doesn't want to provide it from
119 userspace at runtime (for example, when the firmware in question is
120 required for accessing the boot device, and the user doesn't want to
121 use an initrd).
122
123 This option is a string and takes the (space-separated) names of the
124 firmware files -- the same names that appear in MODULE_FIRMWARE()
125 and request_firmware() in the source. These files should exist under
126 the directory specified by the EXTRA_FIRMWARE_DIR option, which is
127 by default the firmware subdirectory of the kernel source tree.
128
129 For example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin", copy
130 the usb8388.bin file into the firmware directory, and build the kernel.
131 Then any request_firmware("usb8388.bin") will be satisfied internally
132 without needing to call out to userspace.
133
134 WARNING: If you include additional firmware files into your binary
135 kernel image that are not available under the terms of the GPL,
136 then it may be a violation of the GPL to distribute the resulting
137 image since it combines both GPL and non-GPL work. You should
138 consult a lawyer of your own before distributing such an image.
139
140 config EXTRA_FIRMWARE_DIR
141 string "Firmware blobs root directory"
142 depends on EXTRA_FIRMWARE != ""
143 default "firmware"
144 help
145 This option controls the directory in which the kernel build system
146 looks for the firmware files listed in the EXTRA_FIRMWARE option.
147 The default is firmware/ in the kernel source tree, but by changing
148 this option you can point it elsewhere, such as /lib/firmware/ or
149 some other directory containing the firmware files.
150
151 config FW_LOADER_USER_HELPER
152 bool
153
154 config FW_LOADER_USER_HELPER_FALLBACK
155 bool "Fallback user-helper invocation for firmware loading"
156 depends on FW_LOADER
157 select FW_LOADER_USER_HELPER
158 help
159 This option enables / disables the invocation of user-helper
160 (e.g. udev) for loading firmware files as a fallback after the
161 direct file loading in kernel fails. The user-mode helper is
162 no longer required unless you have a special firmware file that
163 resides in a non-standard path. Moreover, the udev support has
164 been deprecated upstream.
165
166 If you are unsure about this, say N here.
167
168 config WANT_DEV_COREDUMP
169 bool
170 help
171 Drivers should "select" this option if they desire to use the
172 device coredump mechanism.
173
174 config ALLOW_DEV_COREDUMP
175 bool "Allow device coredump" if EXPERT
176 default y
177 help
178 This option controls if the device coredump mechanism is available or
179 not; if disabled, the mechanism will be omitted even if drivers that
180 can use it are enabled.
181 Say 'N' for more sensitive systems or systems that don't want
182 to ever access the information to not have the code, nor keep any
183 data.
184
185 If unsure, say Y.
186
187 config DEV_COREDUMP
188 bool
189 default y if WANT_DEV_COREDUMP
190 depends on ALLOW_DEV_COREDUMP
191
192 config DEBUG_DRIVER
193 bool "Driver Core verbose debug messages"
194 depends on DEBUG_KERNEL
195 help
196 Say Y here if you want the Driver core to produce a bunch of
197 debug messages to the system log. Select this if you are having a
198 problem with the driver core and want to see more of what is
199 going on.
200
201 If you are unsure about this, say N here.
202
203 config DEBUG_DEVRES
204 bool "Managed device resources verbose debug messages"
205 depends on DEBUG_KERNEL
206 help
207 This option enables kernel parameter devres.log. If set to
208 non-zero, devres debug messages are printed. Select this if
209 you are having a problem with devres or want to debug
210 resource management for a managed device. devres.log can be
211 switched on and off from sysfs node.
212
213 If you are unsure about this, Say N here.
214
215 config DEBUG_TEST_DRIVER_REMOVE
216 bool "Test driver remove calls during probe (UNSTABLE)"
217 depends on DEBUG_KERNEL
218 help
219 Say Y here if you want the Driver core to test driver remove functions
220 by calling probe, remove, probe. This tests the remove path without
221 having to unbind the driver or unload the driver module.
222
223 This option is expected to find errors and may render your system
224 unusable. You should say N here unless you are explicitly looking to
225 test this functionality.
226
227 config SYS_HYPERVISOR
228 bool
229 default n
230
231 config GENERIC_CPU_DEVICES
232 bool
233 default n
234
235 config GENERIC_CPU_AUTOPROBE
236 bool
237
238 config SOC_BUS
239 bool
240
241 source "drivers/base/regmap/Kconfig"
242
243 config DMA_SHARED_BUFFER
244 bool
245 default n
246 select ANON_INODES
247 help
248 This option enables the framework for buffer-sharing between
249 multiple drivers. A buffer is associated with a file using driver
250 APIs extension; the file's descriptor can then be passed on to other
251 driver.
252
253 config FENCE_TRACE
254 bool "Enable verbose FENCE_TRACE messages"
255 depends on DMA_SHARED_BUFFER
256 help
257 Enable the FENCE_TRACE printks. This will add extra
258 spam to the console log, but will make it easier to diagnose
259 lockup related problems for dma-buffers shared across multiple
260 devices.
261
262 config DMA_CMA
263 bool "DMA Contiguous Memory Allocator"
264 depends on HAVE_DMA_CONTIGUOUS && CMA
265 help
266 This enables the Contiguous Memory Allocator which allows drivers
267 to allocate big physically-contiguous blocks of memory for use with
268 hardware components that do not support I/O map nor scatter-gather.
269
270 You can disable CMA by specifying "cma=0" on the kernel's command
271 line.
272
273 For more information see <include/linux/dma-contiguous.h>.
274 If unsure, say "n".
275
276 if DMA_CMA
277 comment "Default contiguous memory area size:"
278
279 config CMA_SIZE_MBYTES
280 int "Size in Mega Bytes"
281 depends on !CMA_SIZE_SEL_PERCENTAGE
282 default 0 if X86
283 default 16
284 help
285 Defines the size (in MiB) of the default memory area for Contiguous
286 Memory Allocator. If the size of 0 is selected, CMA is disabled by
287 default, but it can be enabled by passing cma=size[MG] to the kernel.
288
289
290 config CMA_SIZE_PERCENTAGE
291 int "Percentage of total memory"
292 depends on !CMA_SIZE_SEL_MBYTES
293 default 0 if X86
294 default 10
295 help
296 Defines the size of the default memory area for Contiguous Memory
297 Allocator as a percentage of the total memory in the system.
298 If 0 percent is selected, CMA is disabled by default, but it can be
299 enabled by passing cma=size[MG] to the kernel.
300
301 choice
302 prompt "Selected region size"
303 default CMA_SIZE_SEL_MBYTES
304
305 config CMA_SIZE_SEL_MBYTES
306 bool "Use mega bytes value only"
307
308 config CMA_SIZE_SEL_PERCENTAGE
309 bool "Use percentage value only"
310
311 config CMA_SIZE_SEL_MIN
312 bool "Use lower value (minimum)"
313
314 config CMA_SIZE_SEL_MAX
315 bool "Use higher value (maximum)"
316
317 endchoice
318
319 config CMA_ALIGNMENT
320 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
321 range 4 12
322 default 8
323 help
324 DMA mapping framework by default aligns all buffers to the smallest
325 PAGE_SIZE order which is greater than or equal to the requested buffer
326 size. This works well for buffers up to a few hundreds kilobytes, but
327 for larger buffers it just a memory waste. With this parameter you can
328 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
329 buffers will be aligned only to this specified order. The order is
330 expressed as a power of two multiplied by the PAGE_SIZE.
331
332 For example, if your system defaults to 4KiB pages, the order value
333 of 8 means that the buffers will be aligned up to 1MiB only.
334
335 If unsure, leave the default value "8".
336
337 endif
338
339 endmenu