1menu "Generic Driver Options" 2 3config 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 18config 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 28config 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 47config 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 62config 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 71config 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 80config 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 88config 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 113config 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 140config 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 151config FW_LOADER_USER_HELPER 152 bool "Fallback user-helper invocation for firmware loading" 153 depends on FW_LOADER 154 default y 155 help 156 This option enables / disables the invocation of user-helper 157 (e.g. udev) for loading firmware files as a fallback after the 158 direct file loading in kernel fails. The user-mode helper is 159 no longer required unless you have a special firmware file that 160 resides in a non-standard path. 161 162config DEBUG_DRIVER 163 bool "Driver Core verbose debug messages" 164 depends on DEBUG_KERNEL 165 help 166 Say Y here if you want the Driver core to produce a bunch of 167 debug messages to the system log. Select this if you are having a 168 problem with the driver core and want to see more of what is 169 going on. 170 171 If you are unsure about this, say N here. 172 173config DEBUG_DEVRES 174 bool "Managed device resources verbose debug messages" 175 depends on DEBUG_KERNEL 176 help 177 This option enables kernel parameter devres.log. If set to 178 non-zero, devres debug messages are printed. Select this if 179 you are having a problem with devres or want to debug 180 resource management for a managed device. devres.log can be 181 switched on and off from sysfs node. 182 183 If you are unsure about this, Say N here. 184 185config SYS_HYPERVISOR 186 bool 187 default n 188 189config GENERIC_CPU_DEVICES 190 bool 191 default n 192 193config GENERIC_CPU_AUTOPROBE 194 bool 195 196config SOC_BUS 197 bool 198 199source "drivers/base/regmap/Kconfig" 200 201config DMA_SHARED_BUFFER 202 bool 203 default n 204 select ANON_INODES 205 help 206 This option enables the framework for buffer-sharing between 207 multiple drivers. A buffer is associated with a file using driver 208 APIs extension; the file's descriptor can then be passed on to other 209 driver. 210 211config DMA_CMA 212 bool "DMA Contiguous Memory Allocator" 213 depends on HAVE_DMA_CONTIGUOUS && CMA 214 help 215 This enables the Contiguous Memory Allocator which allows drivers 216 to allocate big physically-contiguous blocks of memory for use with 217 hardware components that do not support I/O map nor scatter-gather. 218 219 For more information see <include/linux/dma-contiguous.h>. 220 If unsure, say "n". 221 222if DMA_CMA 223comment "Default contiguous memory area size:" 224 225config CMA_SIZE_MBYTES 226 int "Size in Mega Bytes" 227 depends on !CMA_SIZE_SEL_PERCENTAGE 228 default 16 229 help 230 Defines the size (in MiB) of the default memory area for Contiguous 231 Memory Allocator. 232 233config CMA_SIZE_PERCENTAGE 234 int "Percentage of total memory" 235 depends on !CMA_SIZE_SEL_MBYTES 236 default 10 237 help 238 Defines the size of the default memory area for Contiguous Memory 239 Allocator as a percentage of the total memory in the system. 240 241choice 242 prompt "Selected region size" 243 default CMA_SIZE_SEL_MBYTES 244 245config CMA_SIZE_SEL_MBYTES 246 bool "Use mega bytes value only" 247 248config CMA_SIZE_SEL_PERCENTAGE 249 bool "Use percentage value only" 250 251config CMA_SIZE_SEL_MIN 252 bool "Use lower value (minimum)" 253 254config CMA_SIZE_SEL_MAX 255 bool "Use higher value (maximum)" 256 257endchoice 258 259config CMA_ALIGNMENT 260 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 261 range 4 12 262 default 8 263 help 264 DMA mapping framework by default aligns all buffers to the smallest 265 PAGE_SIZE order which is greater than or equal to the requested buffer 266 size. This works well for buffers up to a few hundreds kilobytes, but 267 for larger buffers it just a memory waste. With this parameter you can 268 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 269 buffers will be aligned only to this specified order. The order is 270 expressed as a power of two multiplied by the PAGE_SIZE. 271 272 For example, if your system defaults to 4KiB pages, the order value 273 of 8 means that the buffers will be aligned up to 1MiB only. 274 275 If unsure, leave the default value "8". 276 277config CMA_AREAS 278 int "Maximum count of the CMA device-private areas" 279 default 7 280 help 281 CMA allows to create CMA areas for particular devices. This parameter 282 sets the maximum number of such device private CMA areas in the 283 system. 284 285 If unsure, leave the default value "7". 286 287endif 288 289endmenu 290