VS-RK3399板卡TF卡识别并挂载方法介绍
1、插上tf卡，查看打印信息。
[ 293.194013] mmc1: new high speed SDXC card at address 59b4
[ 293.198185] mmcblk1: mmc1:59b4 00000 59.6 GiB
[ 293.204351] mmcblk1: p1
如果在内核看到这样的打印，说明SD卡已经被正确识别，并且已经有一个可用的分区p1 。
2、挂载分区
mount -t vfat /dev/mmcblk1p1 /mnt
或者
mount -t vfat /dev/mmcblk1 /mnt
然后到mnt目录下看下是否有SD卡里面的文件。
3、出现概率性不识别的情况
打印信息：
mmc1: new high speed SD card at address b368
mmcblk1: mmc1:b368 SMI 486 MiB
[mmc1] Data transmission error !!!! MINTSTS: [0x00002000]
dwmmc_rockchip ff0c0000.rksdmmc: data FIFO error (status=00002000)
mmcblk1: error ‐110 sending status command, retrying
need_retune:0,brq‐>retune_retry_done:0.
降频和增加卡检测延时增强电源稳定性，如果降频OK的话，请检查硬件layout；
&sdmmc {
card‐detect‐delay = <1200>;
｝
4、TF卡已经mount，但不能访问TF卡目录，看起来是卡文件系统问题，但卡在Windows下可以访问。
请尝试使用fsck对TF卡做修复。
5、硬件问题，io电压异常
Workqueue: kmmcd mmc_rescan
[<c0013e24>] (unwind_backtrace+0x0/0xe0) from [<c001172c>] (show_stack+0x10/0x14)
[<c001172c>] (show_stack+0x10/0x14) from [<c04fa444>] (dw_mci_set_ios+0x9c/0x21c)
[<c04fa444>] (dw_mci_set_ios+0x9c/0x21c) from [<c04e7748>] (mmc_set_chip_select+0x18/0x1c)
[<c04e7748>] (mmc_set_chip_select+0x18/0x1c) from [<c04ebd5c>] (mmc_go_idle+0x94/0xc4)
[<c04ebd5c>] (mmc_go_idle+0x94/0xc4) from [<c0748d80>] (mmc_rescan_try_freq+0x54/0xd0)
[<c0748d80>] (mmc_rescan_try_freq+0x54/0xd0) from [<c04e85d0>] (mmc_rescan+0x2c4/0x390)
[<c04e85d0>] (mmc_rescan+0x2c4/0x390) from [<c004d738>] (process_one_work+0x29c/0x458)
[<c004d738>] (process_one_work+0x29c/0x458) from [<c004da88>] (worker_thread+0x194/0x2d4)
[<c004da88>] (worker_thread+0x194/0x2d4) from [<c0052fb4>] (kthread+0xa0/0xac)
[<c0052fb4>] (kthread+0xa0/0xac) from [<c000da98>] (ret_from_fork+0x14/0x3c)
1409..dw_mci_set_ios: wait for unbusy timeout....... STATUS = 0x306 [mmc1]
请检查CMD线与DATA的电压是否在空载状态下为高电平。并且检测IO电压是否过低，以及IO电压与电源域的配置
是否一致。如果是SDIO接口，建议排查VCCIO_WL电压，VBAT_WL和WIFI_REG_ON以及晶振是否正常。另可以尝试排查走线太长导致波形质量很差，降频进行测试
1、插上tf卡，查看打印信息。
[ 293.194013] mmc1: new high speed SDXC card at address 59b4
[ 293.198185] mmcblk1: mmc1:59b4 00000 59.6 GiB
[ 293.204351] mmcblk1: p1
如果在内核看到这样的打印，说明SD卡已经被正确识别，并且已经有一个可用的分区p1 。
2、挂载分区
mount -t vfat /dev/mmcblk1p1 /mnt
或者
mount -t vfat /dev/mmcblk1 /mnt
然后到mnt目录下看下是否有SD卡里面的文件。
3、出现概率性不识别的情况
打印信息：
mmc1: new high speed SD card at address b368
mmcblk1: mmc1:b368 SMI 486 MiB
[mmc1] Data transmission error !!!! MINTSTS: [0x00002000]
dwmmc_rockchip ff0c0000.rksdmmc: data FIFO error (status=00002000)
mmcblk1: error ‐110 sending status command, retrying
need_retune:0,brq‐>retune_retry_done:0.
降频和增加卡检测延时增强电源稳定性，如果降频OK的话，请检查硬件layout；
&sdmmc {
card‐detect‐delay = <1200>;
｝
4、TF卡已经mount，但不能访问TF卡目录，看起来是卡文件系统问题，但卡在Windows下可以访问。
请尝试使用fsck对TF卡做修复。
5、硬件问题，io电压异常
Workqueue: kmmcd mmc_rescan
[<c0013e24>] (unwind_backtrace+0x0/0xe0) from [<c001172c>] (show_stack+0x10/0x14)
[<c001172c>] (show_stack+0x10/0x14) from [<c04fa444>] (dw_mci_set_ios+0x9c/0x21c)
[<c04fa444>] (dw_mci_set_ios+0x9c/0x21c) from [<c04e7748>] (mmc_set_chip_select+0x18/0x1c)
[<c04e7748>] (mmc_set_chip_select+0x18/0x1c) from [<c04ebd5c>] (mmc_go_idle+0x94/0xc4)
[<c04ebd5c>] (mmc_go_idle+0x94/0xc4) from [<c0748d80>] (mmc_rescan_try_freq+0x54/0xd0)
[<c0748d80>] (mmc_rescan_try_freq+0x54/0xd0) from [<c04e85d0>] (mmc_rescan+0x2c4/0x390)
[<c04e85d0>] (mmc_rescan+0x2c4/0x390) from [<c004d738>] (process_one_work+0x29c/0x458)
[<c004d738>] (process_one_work+0x29c/0x458) from [<c004da88>] (worker_thread+0x194/0x2d4)
[<c004da88>] (worker_thread+0x194/0x2d4) from [<c0052fb4>] (kthread+0xa0/0xac)
[<c0052fb4>] (kthread+0xa0/0xac) from [<c000da98>] (ret_from_fork+0x14/0x3c)
1409..dw_mci_set_ios: wait for unbusy timeout....... STATUS = 0x306 [mmc1]
请检查CMD线与DATA的电压是否在空载状态下为高电平。并且检测IO电压是否过低，以及IO电压与电源域的配置
是否一致。如果是SDIO接口，建议排查VCCIO_WL电压，VBAT_WL和WIFI_REG_ON以及晶振是否正常。另可以尝试排查走线太长导致波形质量很差，降频进行测试
