64G-128G的tf卡文件系统格式为exfat，而hi3518e默认只支持fat32格式的tf卡。为了挂载64G以上的tf卡，只能将sd卡先格式化成FAT32。鉴于exfat性能比FAT32强，因此考虑移植exfat驱动到海思3518e平台,这样就不用强制格式化tf卡。
拷贝驱动源码到内核
# cp /home/dyx/exfat /home/dyx/sdk_hi3518e/Hi3518_SDK_V1.0.A.0/osdrv/kernel/linux-3.0.y/fs/exfat -frv
切换路径至内核编译顶层路径
# cd /home/dyx/sdk_hi3518e/Hi3518_SDK_V1.0.A.0/osdrv/kernel/linux-3.0.y
修改fs/Kconfig
# vi ./fs/Kconfig
if BLOCK
menu "DOS/FAT/NT Filesystems"
source "fs/fat/Kconfig"
source "fs/exfat/Kconfig"
source "fs/ntfs/Kconfig"
修改fs/Makefile
# vi ./fs/Makefile
obj-$(CONFIG_MINIX_FS)+= minix/
obj-$(CONFIG_FAT_FS) += fat/
obj-$(CONFIG_EXFAT_FS) += exfat/
exfat层makefile示例
- <span style="font-size:14px;">#
- # Makefile for the Linux fat filesystem support.
- #
- obj-$(CONFIG_EXFAT_FS) += exfat.o
- exfat-y := exfat_core.o exfat_super.o exfat_api.o exfat_blkdev.o exfat_cache.o
- exfat_data.o exfat_bitmap.o exfat_nls.o exfat_oal.o exfat_upcase.o</span></span></span>
menuconfig配置
# make ARCH=arm CROSS_COMPILE=arm-hisiv100nptl-linux- menuconfig
进入图形化配置界面
File systems --->
DOS/FAT/NT Filesystems --->
<*> exFAT fs support
[*] enable discard support
[*] enable delayed sync
[ ] enable kernel debug features via ioctl
[ ] print debug messages
(437) Default codepage for exFAT
(utf8) Default iocharset for exFAT
保存退出
内核编译
# make ARCH=arm CROSS_COMPILE=arm-hisiv100nptl-linux- uImage
挂载
mount -t exfat /dev/mmcblk0p1 /media/
或者可以不指定挂载的文件系统类型，让系统自动识别
mount /dev/mmcblk0p1 /media/
[EXFAT] trying to mount...
[EXFAT] mounted successfully
# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 12.0M 4.6M 7.4M 38% /
tmpfs 16.1M 4.0K 16.1M 0% /dev
/dev/mmcblk0p1 117.0G 512.0K 117.0G 0% /mnt