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