AM335X UART3操作不正常，为什么我ttyO1到O5只有O3属于tty，而其他的都属于dialout？

请问是哪个版本的Linux？

额，改过了，和用户组没关系

在ti-processor-sdk-linux-am335x-evm-03.02.00.05上开发的

Hi,Jian Zhou,
     为什么在系统启动的时候会调用ttyO3这个串口？不停的往里面写入数据，我在tty_io.c的tty_write函数里增加了打印信息，发现在系统启动过程中不停的调用tty_write，再有Started Serial Getty on ttyO3这是启动什么服务？打印如下：
[ 1.180094] [drm] Initialized drm 1.1.0 20060810
[ 1.194723] loop: module loaded
[ 1.203025] libphy: Fixed MDIO Bus: probed
[ 1.269063] davinci_mdio 4a101000.mdio: davinci mdio revision 1.6
[ 1.275507] davinci_mdio 4a101000.mdio: detected phy mask fffffff5
[ 1.283714] libphy: 4a101000.mdio: probed
[ 1.287959] davinci_mdio 4a101000.mdio: phy[1]: device 4a101000.mdio:01, driv
er unknown
[ 1.296517] davinci_mdio 4a101000.mdio: phy[3]: device 4a101000.mdio:03, driv
er unknown
[ 1.305916] cpsw 4a100000.ethernet: Detected MACID = 84:eb:18:bd:a8:9c
[ 1.313178] cpsw 4a100000.ethernet: cpts: overflow check period 850
[ 1.320895] cpsw 4a100000.ethernet: cpsw: Detected MACID = 84:eb:18:bd:a8:9e
[ 1.330283] mousedev: PS/2 mouse device common for all mice
[ 1.336959] i2c /dev entries driver
[ 1.342082] cpuidle: enable-method property 'ti,am3352' found operations
[ 1.350323] omap_hsmmc 48060000.mmc: Got CD GPIO
[ 1.392690] ledtrig-cpu: registered to indicate activity on CPUs
[ 1.408458] NET: Registered protocol family 10
[ 1.415253] sit: IPv6 over IPv4 tunneling driver
[ 1.421301] NET: Registered protocol family 17
[ 1.426374] Key type dns_resolver registered
[ 1.431398] omap_voltage_late_init: Voltage driver support not added
[ 1.443078] omap-gpmc 50000000.gpmc: GPMC revision 6.0
[ 1.448674] gpmc_mem_init: disabling cs 0 mapped at 0x0-0x1000000
[ 1.455260] mmc0: host does not support reading read-only switch, assuming wr
ite-enable
[ 1.465497] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xda
[ 1.472393] nand: Micron MT29F2G08ABAEAWP
[ 1.476762] mmc0: new high speed SDHC card at address 59b4
[ 1.482585] nand: 256 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB siz
e: 64
[ 1.491431] mmcblk0: mmc0:59b4 00000 14.9 GiB
[ 1.496687] nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme
[ 1.502910] 10 ofpart partitions found on MTD device 8000000.nand
[ 1.509524] mmcblk0: p1 p2
[ 1.512812] Creating 10 MTD partitions on "8000000.nand":
[ 1.518513] 0x000000000000-0x000000020000 : "NAND.SPL"
[ 1.526476] 0x000000020000-0x000000040000 : "NAND.SPL.backup1"
[ 1.534168] 0x000000040000-0x000000060000 : "NAND.SPL.backup2"
[ 1.541841] 0x000000060000-0x000000080000 : "NAND.SPL.backup3"
[ 1.549519] 0x000000080000-0x0000000c0000 : "NAND.u-boot-spl-os"
[ 1.557353] 0x0000000c0000-0x0000001c0000 : "NAND.u-boot"
[ 1.564890] 0x0000001c0000-0x0000001e0000 : "NAND.u-boot-env"
[ 1.572502] 0x0000001e0000-0x000000200000 : "NAND.u-boot-env.backup1"
[ 1.580880] 0x000000200000-0x000000a00000 : "NAND.kernel"
[ 1.590852] 0x000000a00000-0x000010000000 : "NAND.file-system"
[ 1.707967] tps65217 0-0024: TPS65217 ID 0x6 version 1.2
[ 1.716450] rtc-ds3232 0-0068: rtc core: registered ds3232 as rtc0
[ 1.723060] omap_i2c 44e0b000.i2c: bus 0 rev0.11 at 400 kHz
[ 1.731133] ubi0: attaching mtd9
[ 2.713573] ubi0: scanning is finished
[ 2.727635] ubi0: attached mtd9 (name "NAND.file-system", size 246 MiB)
[ 2.734724] ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 126976 bytes
[ 2.741989] ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 512
[ 2.749066] ubi0: VID header offset: 2048 (aligned 2048), data offset: 4096
[ 2.756401] ubi0: good PEBs: 1968, bad PEBs: 0, corrupted PEBs: 0
[ 2.762834] ubi0: user volume: 1, internal volumes: 1, max. volumes count: 12
8
[ 2.770461] ubi0: max/mean erase counter: 2/0, WL threshold: 4096, image sequ
ence number: 350408399
[ 2.780006] ubi0: available PEBs: 0, total reserved PEBs: 1968, PEBs reserved
for bad PEB handling: 40
[ 2.789838] ubi0: background thread "ubi_bgt0d" started, PID 62
[ 2.796948] rtc-ds3232 0-0068: setting system clock to 2018-04-24 13:51:20 UT
C (1524577880)
[ 2.810488] ALSA device list:
[ 2.813644] No soundcards found.
[ 2.829059] UBIFS (ubi0:0): background thread "ubifs_bgt0_0" started, PID 63
[ 2.856602] UBIFS (ubi0:0): recovery needed
[ 2.929433] UBIFS (ubi0:0): recovery completed
[ 2.934260] UBIFS (ubi0:0): UBIFS: mounted UBI device 0, volume 0, name "root
fs"
[ 2.942097] UBIFS (ubi0:0): LEB size: 126976 bytes (124 KiB), min./max. I/O u
nit sizes: 2048 bytes/2048 bytes
[ 2.952565] UBIFS (ubi0:0): FS size: 242905088 bytes (231 MiB, 1913 LEBs), jo
urnal size 9023488 bytes (8 MiB, 72 LEBs)
[ 2.963862] UBIFS (ubi0:0): reserved for root: 0 bytes (0 KiB)
[ 2.970032] UBIFS (ubi0:0): media format: w4/r0 (latest is w4/r0), UUID CCEA4
194-22A7-4F64-88E2-BE0C3D297256, small LPT model
[ 2.983524] VFS: Mounted root (ubifs filesystem) on device 0:14.
[ 2.991205] devtmpfs: mounted
[ 2.994775] Freeing unused kernel memory: 260K (c08b9000 - c08fa000)
[ 3.001510] This architecture does not have kernel memory protection.
[ 3.276066] random: systemd: uninitialized urandom read (16 bytes read, 7 bit
s of entropy available)
[ 3.309169] random: systemd: uninitialized urandom read (16 bytes read, 8 bit
s of entropy available)
[ 3.332729] systemd[1]: systemd 229 running in system mode. (+PAM -AUDIT -SEL
INUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP -LIBCRYPTSETUP -GCRYPT +GNUTLS +ACL +
XZ -LZ4 -SECCOMP +BLKID -ELFUTILS +KMOD -IDN)
[ 3.353407] systemd[1]: Detected architecture arm.
Welcome to 1mArago 2016.100m!
[ 3.381458] systemd[1]: Set hostname to .
[ 3.576765] random: systemd-sysv-ge: uninitialized urandom read (16 bytes rea
d, 8 bits of entropy available)
[ 3.611523] random: systemd-sysv-ge: uninitialized urandom read (16 bytes rea
d, 8 bits of entropy available)
[ 3.677418] random: systemd: uninitialized urandom read (16 bytes read, 8 bit
s of entropy available)
[ 3.738376] random: systemd: uninitialized urandom read (16 bytes read, 8 bit
s of entropy available)
[ 3.748800] random: systemd: uninitialized urandom read (16 bytes read, 8 bit
s of entropy available)
[ 3.759907] random: systemd: uninitialized urandom read (16 bytes read, 8 bit
s of entropy available)
[ 3.825145] random: systemd: uninitialized urandom read (16 bytes read, 8 bit
s of entropy available)
[ 3.861553] random: systemd: uninitialized urandom read (16 bytes read, 8 bit
s of entropy available)
[ 4.147355] systemd[1]: Listening on /dev/initctl Compatibility Named Pipe.
[0;32m OK 0m] Listening on /dev/initctl Compatibility Named Pipe.
[ 4.180845] systemd[1]: Listening on Network Service Netlink Socket.
[0;32m OK 0m] Listening on Network Service Netlink Socket.
[ 4.209775] systemd[1]: Listening on udev Control Socket.
[0;32m OK 0m] Listening on udev Control Socket.
[ 4.229764] systemd[1]: Started Forward Password Requests to Wall Directory W
atch.
[0;32m OK 0m] Started Forward Password Requests to Wall Directory Watch.
[ 4.290656] systemd[1]: Created slice User and Session Slice.
[0;32m OK 0m] Created slice User and Session Slice.
[ 4.319988] systemd[1]: Listening on Journal Socket.
[0;32m OK 0m] Listening on Journal Socket.
[ 4.341023] systemd[1]: Created slice System Slice.
[0;32m OK 0m] Created slice System Slice.
[ 4.361071] systemd[1]: Created slice system-serialx2dgetty.slice.
[0;32m OK 0m] Created slice system-serialx2dgetty.slice.
[ 4.396272] systemd[1]: Mounting Temporary Directory...
Mounting Temporary Directory...
[ 4.435470] systemd[1]: Mounting Debug File System...
Mounting Debug File System...
[ 4.516958] systemd[1]: Starting Setup Virtual Console...
Starting Setup Virtual Console...
[ 4.589619] systemd[1]: Reached target Slices.
[0;32m OK 0m] Reached target Slices.
[ 4.609480] systemd[1]: Reached target Remote File Systems.
[0;32m OK 0m] Reached target Remote File Systems.
[ 4.629644] systemd[1]: Listening on Syslog Socket.
[0;32m OK 0m] Listening on Syslog Socket.
[ 4.651153] systemd[1]: Created slice system-getty.slice.
[0;32m OK 0m] Created slice system-getty.slice.
[ 4.689995] systemd[1]: Starting Apply Kernel Variables...
Starting Apply Kernel Variables...
[ 4.729879] systemd[1]: Listening on Journal Socket (/dev/log).
[0;32m OK 0m] Listening on Journal Socket (/dev/log).
[ 4.765045] systemd[1]: Starting Journal Service...
Starting Journal Service...
[ 4.814379] systemd[1]: Starting Create list of required static device nodes
for the current kernel...
Starting Create list of required st... nodes for the current kernel...
[ 4.890027] systemd[1]: Started Dispatch Password Requests to Console Directo
ry Watch.
[0;32m OK 0m] Started Dispatch Password Requests to Console Directory Watch.
[ 4.929594] systemd[1]: Reached target Paths.
[0;32m OK 0m] Reached target Paths.
[ 4.959563] systemd[1]: Reached target Swap.
[0;32m OK 0m] Reached target Swap.
[ 4.995166] systemd[1]: Starting Remount Root and Kernel File Systems...
Starting Remount Root and Kernel File Systems...
[ 5.060762] systemd[1]: Listening on udev Kernel Socket.
[0;32m OK 0m] Listening on udev Kernel Socket.
[ 5.144969] systemd[1]: Mounting POSIX Message Queue File System...
Mounting POSIX Message Queue File System...
[ 5.228769] systemd[1]: Mounted Debug File System.
[0;32m OK 0m] Mounted Debug File System.
[ 5.249688] systemd[1]: Mounted POSIX Message Queue File System.
[0;32m OK 0m] Mounted POSIX Message Queue File System.
[ 5.269549] systemd[1]: Mounted Temporary Directory.
[0;32m OK 0m] Mounted Temporary Directory.
[ 5.290312] systemd[1]: Started Journal Service.
[0;32m OK 0m] Started Journal Service.
[0;32m OK 0m] Started Setup Virtual Console.
[0;32m OK 0m] Started Apply Kernel Variables.
[0;32m OK 0m] Started Create list of required sta...ce nodes for the current k
ernel.
[0;32m OK 0m] Started Remount Root and Kernel File Systems.
Starting udev Coldplug all Devices...
Starting Create Static Device Nodes in /dev...
Starting Flush Journal to Persistent Storage...
[0;32m OK 0m] Started Create Static Device Nodes in /dev.
[ 6.956940] systemd-journald[93]: Received request to flush runtime journal f
rom PID 1
[0;32m OK 0m] Started Flush Journal to Persistent Storage.
[0;32m OK 0m] Reached target Local File Systems (Pre).
Mounting /media/ram...
Mounting /var/volatile...
Starting udev Kernel Device Manager...
[0;32m OK 0m] Mounted /var/volatile.
[0;32m OK 0m] Mounted /media/ram.
[0;32m OK 0m] Started udev Kernel Device Manager.
Starting Load/Save Random Seed...
[0;32m OK 0m] Reached target Local File Systems.
Starting Create Volatile Files and Directories...
[0;32m OK 0m] Started Load/Save Random Seed.
[0;32m OK 0m] Started Create Volatile Files and Directories.
[ 9.402985] omap_wdt: OMAP Watchdog Timer Rev 0x01: initial timeout 60 sec
[ 9.472106] 47401300.u***-phy supply vcc not found, using dummy regulator
[ 9.621925] 47401b00.u***-phy supply vcc not found, using dummy regulator
[0;32m OK 0m] Started udev Coldplug all Devices.
[ 10.138227] spidev spi1.1: buggy DT: spidev listed directly in DT
[0;32m OK 0m] Found device /dev/ttyO0.
[ 10.175510] omap_rng 48310000.rng: OMAP Random Number Generator ver. 20
[ 10.235961] ------------[ cut here ]------------
[ 10.295512] WARNING: CPU: 0 PID: 169 at drivers/spi/spidev.c:719 spidev_probe
+0x1a8/0x1c4 [spidev]()
[ 10.410793] Modules linked in: omap_rng rng_core spidev(+) mu***_am335x omap_w
dt sch_fq_codel
[ 10.442564] CPU: 0 PID: 169 Comm: systemd-udevd Not tainted 4.4.32-gadde2ca9f
8 #71
[ 10.512782] Hardware name: Generic AM33XX (Flattened Device Tree)
[ 10.570717] Backtrace:
[ 10.573386] [] (dump_backtrace) from [] (show_stack+0x18/
0x1c)
[ 10.728813] r7:bf00e360 r6:000002cf r5:00000009 r4:00000000
[ 10.772889] [] (show_stack) from [] (dump_stack+0x24/0x28
)
[ 10.848796] omap_hwmod: pruss: _wait_target_ready failed: -16
[ 10.870385] [] (dump_stack) from [] (warn_slowpath_common
+0x88/0xb4)
[ 10.878947] [] (warn_slowpath_common) from [] (warn_slowp
ath_null+0x24/0x2c)
[ 10.926904] ti-pruss 4a300000.pruss: couldn't enable pruss
[ 10.985765] ti-pruss: probe of 4a300000.pruss failed with error -16
[ 11.006706] r8:0000000f[0;32m OK 0m] Found device /dev/ttyO3.
r7:bf00f4a4 r6:bf00f494 r5:cf3f6400 r4:cf3f6400
[ 11.074527] [] (warn_slowpath_null) from [] (spidev_probe
+0x1a8/0x1c4 [spidev])
[ 11.111780] omap-sham 53100000.sham: hw accel on OMAP rev 4.3
[ 11.228701] [] (spidev_probe [spidev]) from [] (spi_drv_p
robe+0x84/0xb0)
[ 11.291737] r8:0000000f r7:bf00f4a4 r6:bf00f494 r5:00000000 r4:cf3f6400
[ 11.298898] [] (spi_drv_probe) from [] (driver_probe_devi
ce+0x204/0x2f8)
[ 11.475716] r7:bf00f4a4 r6:00000000 r5:cf3f6400 r4:c097c088
[ 11.497754] [] (driver_probe_device) from [] (__driver_at
tach+0x94/0x98)
Starting Network Time Synchronization...
Starting Update UTMP about System Boot/Shutdown...
[ 11.679188] r9:308d409c r8:cf72bf88 r7:00000000 r6:cf3f6434 r5:bf00f4a4 r4:c
f3f6400
[ 11.687446] [] (__driver_attach) from [] (bus_for_each_de
v+0x70/0xa4)
[ 11.889161] r7:00000000 r6:c03db8f0 r5:bf00f4a4 r4:00000000
[ 11.895215] [] (bus_for_each_dev) from [] (driver_attach+
0x24/0x28)
[ 12.026280] r6:c0931ec8 r5:cf771380 r4:bf00f4a4
[ 12.144550] [] (driver_attach) from [] (bus_add_driver+0x
1a8/0x220)
[ 12.244188] [] (bus_add_driver) from [] (driver_register+
0x80/0x100)
[ 12.368045] omap-aes 53500000.aes: OMAP AES hw accel rev: 3.2
[ 12.377974] r7:cf72b380 r6:bf00f47c r5:bf00f6c0 r4:bf00f4a4
[ 12.450510] [] (driver_register) from [] (__spi_register_
driver+0x60/0x64)
[ 12.596548] r5:bf00f6c0 r4:c08feca0
[ 12.650648] [] (__spi_register_driver) from [] (spidev_in
it+0x98/0xd0 [spidev])
[0;32m OK 0m] Started Network Time Synchronization.
[ 12.784675] [] (spidev_init [spidev]) from [] (do_one_ini
tcall+0x98/0x1e4)
[ 12.942376] r6:c08feca0 r5:bf011000 r4:c08feca0
[ 12.947335] [] (do_one_initcall) from [] (do_init_module+
0x68/0x390)
[ 13.120552] remoteproc0: wkup_m3 is available
[ 13.125264] remoteproc0: Note: remoteproc is still under development and con
sidered experimental.
[ 13.150894] r10:bf00f500 r9:308d409c r8:cf72bf88 r7:00000001 r6:cf72bf40 r5:
00000001
[ 13.264172] r4:bf00f500
[ 13.266933] [] (do_init_module) from [] (load_module+0x1d
38/0x1f88)
[ 13.355253] remoteproc0: THE BINARY FORMAT IS NOT YET FINALIZED, and backwar
d compatibility isn't yet guaranteed.
[ 13.408893] wkup_m3_ipc 44e11324.wkup_m3_ipc: could not get rproc handle
[ 13.439166] r6:cf72bf80 r5:00000001 r4:cf7cdf44
[ 13.444120] [] (load_module) from [] (SyS_finit_module+0x
88/0x98)
[ 13.575480] PM: Cannot get wkup_m3_ipc handle
[ 13.605518] remoteproc0: powering up wkup_m3
[ 13.628345] r10:00000000
[ 13.662580] remoteproc0: Booting fw image am335x-pm-firmware.elf, size 21728
0
[ 13.681772] r9:cf7cc000 r8:c000fbc4 r7:0000017b r6:b6e30d90 r5:00000007
[ 13.688890] r4:00000000
[ 13.726766] PM: bootloader does not support rtc-only!
[ 13.812292] remoteproc0: remote processor wkup_m3 is now up
[ 13.812329] wkup_m3_ipc 44e11324.wkup_m3_ipc: CM3 Firmware Version = 0x192
[ 13.839170]
[ 13.840833] [] (SyS_finit_module) from [] (ret_fast_sysca
ll+0x0/0x3c)
[ 13.930956] r6:00000000 r5:7f5df928 r4:00000000
[ 13.935879] ---[ end trace f3fc4c1dd27b4946 ]---
[0;32m OK 0m] Started Update UTMP about System Boot/Shutdown.
[ 14.970619] FAT-fs (mmcblk0p1): Volume was not properly unmounted. Some data
may be corrupt. Please run fsck.
[0;32m OK 0m] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch.
[0;32m OK 0m] Reached target System Time Synchronized.
Starting Synchronize System and HW clocks...
[0;32m OK 0m] Started Synchronize System and HW clocks.
[0;32m OK 0m] Reached target System Initialization.
[0;32m OK 0m] Listening on D-Bus System Message Bus Socket.
[0;32m OK 0m] Started Daily Cleanup of Temporary Directories.
[0;32m OK 0m] Reached target Timers.
[0;32m OK 0m] Listening on RPCbind Server Activation Socket.
[0;32m OK 0m] Reached target Sockets.
[0;32m OK 0m] Reached target Basic System.
Starting Permit User Sessions...
[0;32m OK 0m] Started D-Bus System Message Bus.
Starting Network Service...
Starting sshd.service...
[0;32m OK 0m] Started System Logging Service.
[0;32m OK 0m] Started Kernel Logging Service.
Starting Login Service...
Starting Print notice about GPLv3 packages...
[0;32m OK 0m] Started Permit User Sessions.
[ 18.650483] u***core: registered new interface driver u***fs
[ 18.656391] u***core: registered new interface driver hub
[ 18.797655] u***core: registered new device driver u***
[ 19.184041] mu***-hdrc mu***-hdrc.0.auto: MUSB HDRC host driver
[ 19.254022] mu***-hdrc mu***-hdrc.0.auto: new USB bus registered, assigned bus
number 1
[ 19.312984] hub 1-0:1.0: USB hub found
[ 19.324279] hub 1-0:1.0: 1 port detected
[ 19.408259] mu***-hdrc mu***-hdrc.1.auto: MUSB HDRC host driver
[0;32m OK 0m] Started Network Service.
[ 19.499218] mu***-hdrc mu***-hdrc.1.auto: new USB bus registered, assigned bus
number 2
[ 19.546994] hub 2-0:1.0: USB hub found
[ 19.563321] hub 2-0:1.0: 1 port detected
[ 19.606017] net eth1: initializing cpsw version 1.12 (0)
[ 19.634600] net eth0: initialized cpsw ale version 1.4
[ 19.659252] net eth0: ALE Table size 1024
[ 19.789517] net eth1: phy found : id is : 0x20005ce1
[ 19.822497] IPv6: ADDRCONF(NETDEV_UP): eth1: link is not ready
[ 19.909637] net eth0: initializing cpsw version 1.12 (0)
[ 20.029497] net eth0: phy found : id is : 0x20005ce1
[ 20.093054] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[0;32m OK 0m] Started sshd.service.
***************************************************************
***************************************************************
NOTICE: This file system contains the following GPLv3 packages:
binutils
dosfstools
m4
If you do not wish to distribute GPLv3 components please remove
the above packages prior to distribution. This can be done using
the opkg remove command. i.e.:
opkg remove
Where is the name printed in the list above
NOTE: If the package is a dependency of another package you
will be notified of the dependent packages. You should
use the --force-removal-of-dependent-packages option to
also remove the dependent packages as well
***************************************************************
***************************************************************
[ 23.040268] cpsw 4a100000.ethernet eth0: Link is Up - 100Mbps/Full - flow con
trol rx/tx
[[ 23.069381] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
0;32m OK 0m] Started Print notice about GPLv3 packages.
[0;32m OK 0m] Started Login Service.
Starting rng-tools.service...
[0;32m OK 0m] Reached target Network.
Starting Network Name Resolution...
[0;32m OK 0m] Started Getty on tty1.
[0;32m OK 0m] Started Serial Getty on ttyO0.
[0;32m OK 0m] Started Serial Getty on ttyO3.
[ 23.532279] random: nonblocking pool is initialized
[0;32m OK 0m] Started rng-tools.service.
[0;32m OK 0m] Started Network Name Resolution.
Starting userconfig.service...
Starting thermal-zone-init.service...
[0;32m OK 0m] Started thermal-zone-init.service.
[0;32m OK 0m] Started userconfig.service.
Starting appstart.service...
[0;32m OK 0m] Started appstart.service.
[ 29.573718] kernel:tty(3) write data len is 2
_____ _____ _ [ 29.588409] kernel:tty(3) write
data len is 1
_
| _ |___ ___ ___ ___ | _ |___ ___ |_|___ ___| |_
| | _| .'| . | . | [ 29.606425] kernel:tty(3) write data len is 1
| __| _| . | | | -_| _| _|
|__|__|_| |__,|_ |___| |__| |_| |___|_| |___|___|_| [ 29.623517] kernel:tty
(3) write data len is 1
|___| |___|
Arago Project http:[ 29.640162] kernel:tty(3) write data len is 1
//arago-project.org am335x-evm ttyO0
Arago 2016.10 am335x-evm ttyO0
[ 29.653870] kernel:tty(3) write data len is 1
[ 29.663606] kernel:tty(3) write data len is 1
[ 29.668585] kernel:tty(3) write data len is 1
am335x-evm login: [ 29.679477] kernel:tty(3) write data len is 1
[ 29.687859] kernel:tty(3) write data len is 1
[ 29.699707] kernel:tty(3) write data len is 1
[ 29.705055] kernel:tty(3) write data len is 1
[ 29.716529] kernel:tty(3) write data len is 1
[ 29.725623] kernel:tty(3) write data len is 1
[ 29.734750] kernel:tty(3) write data len is 1
[ 29.743731] kernel:tty(3) write data len is 1
[ 29.748485] kernel:tty(3) write data len is 1

顶一下！
有没有大神能给点指导啊？急！
其余五个串口都正常，就uart3不正常，开始能有几帧数据发送正常，然后再写就return -1了，跟踪了一下驱动代码，返回-1时根本没有进到tty_write函数，有时应用层没有调用write但是驱动层一直在tty_write不停的循环，着到底是哪的问题？
现在可以确定的是硬件肯定没问题，有内核可以在上面正常运行！！！

又测了一下，如果我在dts文件里把uart3_rxd配置成为其他脚（原来是spi0_cs1  0x160）后，发送就正常了，一直往外发数据，PC机也能正常接收，是我这个rxd脚用得不对么？原来配置如下：
uart3_pins: pinmux_uart3_pins [
pinctrl-single,pins = <
0x160 ( PIN_INPUT_PULLUP | MUX_MODE1 ) /* (C15) spi0_cs1.uart3_rxd */
0x164 ( PIN_OUTPUT_PULLDOWN | MUX_MODE1 ) /* (C18) eCAP0_in_PWM0_out.uart3_txd */
>;
];

uart3_pins_sleep: pinmux_uart3_pins_sleep [
pinctrl-single,pins = <
0x160 ( PIN_INPUT_PULLDOWN | MUX_MODE7 ) /* (C15) spi0_cs1.uart3_rxd */
0x164 ( PIN_INPUT_PULLDOWN | MUX_MODE7 ) /* (C18) eCAP0_in_PWM0_out.uart3_txd */
>;
];

发现问题了，为什么会同时在ttyO0和ttyO3输出console信息？
_____ _____ _ _
| _ |___ ___ ___ ___ | _ |___ ___ |_|___ ___| |_
| | _| .'| . | . | | __| _| . | | | -_| _| _|
|__|__|_| |__,|_ |___| |__| |_| |___|_| |___|___|_|
|___| |___|
Arago Project http://arago-project.org am335x-evm ttyO3
Arago 2016.10 am335x-evm ttyO3
am335x-evm login:

_____ _____ _ _
| _ |___ ___ ___ ___ | _ |___ ___ |_|___ ___| |_
| | _| .'| . | . | | __| _| . | | | -_| _| _|
|__|__|_| |__,|_ |___| |__| |_| |___|_| |___|___|_|
|___| |___|
Arago Project http://arago-project.org am335x-evm ttyO0
Arago 2016.10 am335x-evm ttyO0
am335x-evm login:
两个串口同时有！！！

解决了，关闭rootfs的console功能！这个问题真有点坑，不知道TI SDK包里的文件系统为什么要搞个这玩意，害我查了一个星期！
即将/etc/systemd/system/getty.target.wants/serial-getty@ttyO3.service文件删除或者重命名！