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 153 154config 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 168config DEBUG_DRIVER 169 bool "Driver Core verbose debug messages" 170 depends on DEBUG_KERNEL 171 help 172 Say Y here if you want the Driver core to produce a bunch of 173 debug messages to the system log. Select this if you are having a 174 problem with the driver core and want to see more of what is 175 going on. 176 177 If you are unsure about this, say N here. 178 179config DEBUG_DEVRES 180 bool "Managed device resources verbose debug messages" 181 depends on DEBUG_KERNEL 182 help 183 This option enables kernel parameter devres.log. If set to 184 non-zero, devres debug messages are printed. Select this if 185 you are having a problem with devres or want to debug 186 resource management for a managed device. devres.log can be 187 switched on and off from sysfs node. 188 189 If you are unsure about this, Say N here. 190 191config SYS_HYPERVISOR 192 bool 193 default n 194 195config GENERIC_CPU_DEVICES 196 bool 197 default n 198 199config GENERIC_CPU_AUTOPROBE 200 bool 201 202config SOC_BUS 203 bool 204 205source "drivers/base/regmap/Kconfig" 206 207config DMA_SHARED_BUFFER 208 bool 209 default n 210 select ANON_INODES 211 help 212 This option enables the framework for buffer-sharing between 213 multiple drivers. A buffer is associated with a file using driver 214 APIs extension; the file's descriptor can then be passed on to other 215 driver. 216 217config FENCE_TRACE 218 bool "Enable verbose FENCE_TRACE messages" 219 depends on DMA_SHARED_BUFFER 220 help 221 Enable the FENCE_TRACE printks. This will add extra 222 spam to the console log, but will make it easier to diagnose 223 lockup related problems for dma-buffers shared across multiple 224 devices. 225 226config DMA_CMA 227 bool "DMA Contiguous Memory Allocator" 228 depends on HAVE_DMA_CONTIGUOUS && CMA 229 help 230 This enables the Contiguous Memory Allocator which allows drivers 231 to allocate big physically-contiguous blocks of memory for use with 232 hardware components that do not support I/O map nor scatter-gather. 233 234 For more information see <include/linux/dma-contiguous.h>. 235 If unsure, say "n". 236 237if DMA_CMA 238comment "Default contiguous memory area size:" 239 240config CMA_SIZE_MBYTES 241 int "Size in Mega Bytes" 242 depends on !CMA_SIZE_SEL_PERCENTAGE 243 default 16 244 help 245 Defines the size (in MiB) of the default memory area for Contiguous 246 Memory Allocator. 247 248config CMA_SIZE_PERCENTAGE 249 int "Percentage of total memory" 250 depends on !CMA_SIZE_SEL_MBYTES 251 default 10 252 help 253 Defines the size of the default memory area for Contiguous Memory 254 Allocator as a percentage of the total memory in the system. 255 256choice 257 prompt "Selected region size" 258 default CMA_SIZE_SEL_MBYTES 259 260config CMA_SIZE_SEL_MBYTES 261 bool "Use mega bytes value only" 262 263config CMA_SIZE_SEL_PERCENTAGE 264 bool "Use percentage value only" 265 266config CMA_SIZE_SEL_MIN 267 bool "Use lower value (minimum)" 268 269config CMA_SIZE_SEL_MAX 270 bool "Use higher value (maximum)" 271 272endchoice 273 274config CMA_ALIGNMENT 275 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 276 range 4 12 277 default 8 278 help 279 DMA mapping framework by default aligns all buffers to the smallest 280 PAGE_SIZE order which is greater than or equal to the requested buffer 281 size. This works well for buffers up to a few hundreds kilobytes, but 282 for larger buffers it just a memory waste. With this parameter you can 283 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 284 buffers will be aligned only to this specified order. The order is 285 expressed as a power of two multiplied by the PAGE_SIZE. 286 287 For example, if your system defaults to 4KiB pages, the order value 288 of 8 means that the buffers will be aligned up to 1MiB only. 289 290 If unsure, leave the default value "8". 291 292config CMA_AREAS 293 int "Maximum count of the CMA device-private areas" 294 default 7 295 help 296 CMA allows to create CMA areas for particular devices. This parameter 297 sets the maximum number of such device private CMA areas in the 298 system. 299 300 If unsure, leave the default value "7". 301 302endif 303 304endmenu 305