1menu "Generic Driver Options" 2 3config UEVENT_HELPER_PATH 4 string "path to uevent helper" 5 depends on HOTPLUG 6 default "" 7 help 8 Path to uevent helper program forked by the kernel for 9 every uevent. 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. 18 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 22 later at runtime. 23 24config DEVTMPFS 25 bool "Maintain a devtmpfs filesystem to mount at /dev" 26 depends on HOTPLUG 27 help 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 36 symlinks. 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. 40 41 Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs 42 file system will be used instead. 43 44config DEVTMPFS_MOUNT 45 bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs" 46 depends on DEVTMPFS 47 help 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. 58 59config STANDALONE 60 bool "Select only drivers that don't need compile-time external firmware" 61 default y 62 help 63 Select this option if you don't have magic firmware for drivers that 64 need it. 65 66 If unsure, say Y. 67 68config PREVENT_FIRMWARE_BUILD 69 bool "Prevent firmware from being built" 70 default y 71 help 72 Say yes to avoid building firmware. Firmware is usually shipped 73 with the driver and only when updating the firmware should a 74 rebuild be made. 75 If unsure, say Y here. 76 77config FW_LOADER 78 tristate "Userspace firmware loading support" if EXPERT 79 default y 80 ---help--- 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 83 out-of-tree does. 84 85config FIRMWARE_IN_KERNEL 86 bool "Include in-kernel firmware blobs in kernel binary" 87 depends on FW_LOADER 88 default y 89 help 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. 96 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. 102 103 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. 107 108 Say 'N' and let firmware be loaded from userspace. 109 110config EXTRA_FIRMWARE 111 string "External firmware blobs to build into the kernel binary" 112 depends on FW_LOADER 113 help 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 118 use an initrd). 119 120 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. 125 126 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. 130 131 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. 136 137config EXTRA_FIRMWARE_DIR 138 string "Firmware blobs root directory" 139 depends on EXTRA_FIRMWARE != "" 140 default "firmware" 141 help 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. 147 148config DEBUG_DRIVER 149 bool "Driver Core verbose debug messages" 150 depends on DEBUG_KERNEL 151 help 152 Say Y here if you want the Driver core to produce a bunch of 153 debug messages to the system log. Select this if you are having a 154 problem with the driver core and want to see more of what is 155 going on. 156 157 If you are unsure about this, say N here. 158 159config DEBUG_DEVRES 160 bool "Managed device resources verbose debug messages" 161 depends on DEBUG_KERNEL 162 help 163 This option enables kernel parameter devres.log. If set to 164 non-zero, devres debug messages are printed. Select this if 165 you are having a problem with devres or want to debug 166 resource management for a managed device. devres.log can be 167 switched on and off from sysfs node. 168 169 If you are unsure about this, Say N here. 170 171config SYS_HYPERVISOR 172 bool 173 default n 174 175config GENERIC_CPU_DEVICES 176 bool 177 default n 178 179config SOC_BUS 180 bool 181 182source "drivers/base/regmap/Kconfig" 183 184config DMA_SHARED_BUFFER 185 bool 186 default n 187 select ANON_INODES 188 help 189 This option enables the framework for buffer-sharing between 190 multiple drivers. A buffer is associated with a file using driver 191 APIs extension; the file's descriptor can then be passed on to other 192 driver. 193 194config CMA 195 bool "Contiguous Memory Allocator" 196 depends on HAVE_DMA_CONTIGUOUS && HAVE_MEMBLOCK 197 select MIGRATION 198 select MEMORY_ISOLATION 199 help 200 This enables the Contiguous Memory Allocator which allows drivers 201 to allocate big physically-contiguous blocks of memory for use with 202 hardware components that do not support I/O map nor scatter-gather. 203 204 For more information see <include/linux/dma-contiguous.h>. 205 If unsure, say "n". 206 207if CMA 208 209config CMA_DEBUG 210 bool "CMA debug messages (DEVELOPMENT)" 211 depends on DEBUG_KERNEL 212 help 213 Turns on debug messages in CMA. This produces KERN_DEBUG 214 messages for every CMA call as well as various messages while 215 processing calls such as dma_alloc_from_contiguous(). 216 This option does not affect warning and error messages. 217 218comment "Default contiguous memory area size:" 219 220config CMA_SIZE_MBYTES 221 int "Size in Mega Bytes" 222 depends on !CMA_SIZE_SEL_PERCENTAGE 223 default 16 224 help 225 Defines the size (in MiB) of the default memory area for Contiguous 226 Memory Allocator. 227 228config CMA_SIZE_PERCENTAGE 229 int "Percentage of total memory" 230 depends on !CMA_SIZE_SEL_MBYTES 231 default 10 232 help 233 Defines the size of the default memory area for Contiguous Memory 234 Allocator as a percentage of the total memory in the system. 235 236choice 237 prompt "Selected region size" 238 default CMA_SIZE_SEL_MBYTES 239 240config CMA_SIZE_SEL_MBYTES 241 bool "Use mega bytes value only" 242 243config CMA_SIZE_SEL_PERCENTAGE 244 bool "Use percentage value only" 245 246config CMA_SIZE_SEL_MIN 247 bool "Use lower value (minimum)" 248 249config CMA_SIZE_SEL_MAX 250 bool "Use higher value (maximum)" 251 252endchoice 253 254config CMA_ALIGNMENT 255 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 256 range 4 9 257 default 8 258 help 259 DMA mapping framework by default aligns all buffers to the smallest 260 PAGE_SIZE order which is greater than or equal to the requested buffer 261 size. This works well for buffers up to a few hundreds kilobytes, but 262 for larger buffers it just a memory waste. With this parameter you can 263 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 264 buffers will be aligned only to this specified order. The order is 265 expressed as a power of two multiplied by the PAGE_SIZE. 266 267 For example, if your system defaults to 4KiB pages, the order value 268 of 8 means that the buffers will be aligned up to 1MiB only. 269 270 If unsure, leave the default value "8". 271 272config CMA_AREAS 273 int "Maximum count of the CMA device-private areas" 274 default 7 275 help 276 CMA allows to create CMA areas for particular devices. This parameter 277 sets the maximum number of such device private CMA areas in the 278 system. 279 280 If unsure, leave the default value "7". 281 282endif 283 284endmenu 285