公司新做的板子需要将原来的uart0调试串口改为uart4作为调试串口，参考如下帖子，uboot下已经可以正常输出，但是和下面帖子的现象相同，在low level debug时会出现乱码，进到文件系统后调试串口就又正常了，想问一下是不是因为uart4的时钟问题,启动信息如下
Starting kernel ...
Uncompressing Linux... done, booting the kernel.
PID hash table entries: 1024 (order: 0, 4096 bytes)
Dentry cache hash table entries: 32768 (order: 5, 131072 bytes)
Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)
Memory: 134MB 1MB = 135MB total
Memory: 121020k/121020k available, 22340k reserved, 0K highmem
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
DMA : 0xffc00000 - 0xffe00000 ( 2 MB)
vmalloc : 0xc9000000 - 0xf8000000 ( 752 MB)
lowmem : 0xc0000000 - 0xc8c00000 ( 140 MB)
pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
.init : 0xc0008000 - 0xc003f000 ( 220 kB)
.text : 0xc003f000 - 0xc04f7000 (4832 kB)
.data : 0xc04f8000 - 0xc053e800 ( 282 kB)
SLUB: Genslabs=11, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
NR_IRQS:375
Current clocking rate (MPU/DSP/IVA/ISS): 1000/20/450/400 MHz
IRQ: Found an INTC at 0xfa200000 (revision 5.0) with 128 interrupts
Total of 128 interrupts on 1 active controller
GPMC revision 6.0
Trying to install interrupt handler for IRQ368
Trying to install interrupt handler for IRQ369
Trying to install interrupt handler for IRQ370
Trying to install interrupt handler for IRQ371
Trying to install interrupt handler for IRQ372
Trying to install interrupt handler for IRQ373
Trying to install interrupt handler for IRQ374
Trying to install type control for IRQ375
Trying to set irq flags for IRQ375
OMAP clockevent source: GPTIMER1 at 20000000 Hz
Console: colour dummy device 80x30
Calibrating delay loop... 999.42 BogoMIPS (lpj=4997120)
pid_max: default: 32768 minimum: 301
Security Framework initialized
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
devtmpfs: initialized
TI81XX: Map 0x88b00000 to 0xfe500000 for dram barrier
TI81XX: Map 0x40300000 to 0xfe600000 for sram barrier
omap_voltage_early_init: voltage driver support not added
regulator: core version 0.5
regulator: dummy:
NET: Registered protocol family 16
omap_voltage_domain_lookup: Voltage driver init not yet happened.Faulting!
omap_voltage_add_dev: VDD specified does not exist!
OMAP GPIO hardware version 0.1
OMAP GPIO hardware version 0.1
OMAP GPIO hardware version 0.1
OMAP GPIO hardware version 0.1
omap_mux_init: Add partition: #1: core, flags: 4
_omap_mux_get_by_name: Could not find signal i2c2_scl.i2c2_scl
_omap_mux_get_by_name: Could not find signal i2c2_sda.i2c2_sda
_omap_mux_init_gpio: Could not set gpio79
_omap_mux_init_gpio: Could not set gpio80
get_phy_id PHY found at address 4
get_phy_id PHY found at address 5
get_phy_id phy_num 2
=>phy index[2:0] addr[0:4],cpsw_slaves.phy_id 0:04
=>phy index[2:1] addr[0:5],cpsw_slaves.phy_id 0:05
Cannot clk_get ck_32
Debugfs: Only enabling/disabling deep sleep and wakeup timer is supported now
registered ti81xx_vpss device
registered ti81xx_vidout device
registered ti81xx on-chip HDMI device
registered ti81xx_fb device
PWM0 init success.
PWM1 init success.
bio: create slab <bio-0> at 0
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
USBSS revision 4ea2080b
registerd cppi-dma Intr @ IRQ 17
Cppi41 Init Done
omap_i2c omap_i2c.1: bus 1 rev4.0 at 100 kHz
tps65910 1-002d: read from reg 3f failed
tps65910 1-002d: read from reg 1e failed
set_machine_constraints: failed to enable VRTC
tps65910 1-002d: failed to register tps65910-pmic regulator
tps65910-pmic: probe of tps65910-pmic failed with error -121
tps65910 1-002d: No interrupt support, no core IRQ
omap_i2c omap_i2c.2: bus 2 rev4.0 at 100 kHz
Advanced Linux Sound Architecture Driver Version 1.0.23.
Switching to clocksource gp timer
musb-hdrc: version 6.0, host, debug=0
musb-hdrc musb-hdrc.0: dma type: dma-cppi41
MUSB controller-0 revision 4ea20800
usb2phy: computed values rxcalib(15)DACs(30 12 11)
usb2phy: override computed values rxcalib(15)DACs(30 12 11)
usb2phy_config: musb(0) rxcalib done, rxcalib read value 6f6f595e
musb-hdrc musb-hdrc.0: MUSB HDRC host driver
musb-hdrc musb-hdrc.0: new USB bus registered, assigned bus number 1
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 1 port detected
musb-hdrc musb-hdrc.0: USB Host mode controller at c909e000 using DMA, IRQ 18
musb-hdrc musb-hdrc.1: dma type: dma-cppi41
MUSB controller-1 revision 4ea20800
usb2phy: computed values rxcalib(15)DACs(21 12 15)
usb2phy: override computed values rxcalib(15)DACs(21 12 15)
usb2phy_config: musb(1) rxcalib done, rxcalib read value 6f6ad97e
musb-hdrc musb-hdrc.1: MUSB HDRC host driver
musb-hdrc musb-hdrc.1: new USB bus registered, assigned bus number 2
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 1 port detected
musb-hdrc musb-hdrc.1: USB Host mode controller at c90a8800 using DMA, IRQ 19
NET: Registered protocol family 2
IP route cache hash table entries: 2048 (order: 1, 8192 bytes)
TCP established hash table entries: 8192 (order: 4, 65536 bytes)
TCP bind hash table entries: 8192 (order: 3, 32768 bytes)
TCP: Hash tables configured (established 8192 bind 8192)
TCP reno registered
UDP hash table entries: 256 (order: 0, 4096 bytes)
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
NET: Registered protocol family 1
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
Trying to unpack rootfs image as initramfs...
rootfs image is not initramfs (junk in compressed archive); looks like an initrd
Freeing initrd memory: 10240K
NetWinder Floating Point Emulator V0.97 (double precision)
PMU: registered new PMU device of type 0
omap-iommu omap-iommu.0: ducati registered
omap-iommu omap-iommu.1: sys registered
JFFS2 version 2.2. (NAND) ? 2001-2006 Red Hat, Inc.
msgmni has been set to 256
io scheduler noop registered
io scheduler deadline registered
io scheduler cfq registered (default)
CMEMK module: built on Oct 10 2017 at 16:08:16
Reference Linux version 2.6.37
File /mnt/ext_vmdk1/workdir/TI-8127/IPNC_RDK/Source/ti_tools/linuxutils_3_23_00_01/packages/ti/sdo/linuxutils/cmem/src/module/cmemk.c
allocated heap buffer 0xca000000 of size 0x5e00000
cmemk initialized
uc_gpio major#: 252, minor#: 0
uc_gpio_snap major#: 251, minor#: 0
need to add new config.
uc_gpio_red major#: 250, minor#: 0
uc_gpio_exp major#: 249, minor#: 0
uc_gpio_flash major#: 248, minor#: 0
Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
omap_uart.0: ttyO0 at MMIO 0x48020000 (irq = 72) is a OMAP UART0
console [ttyO4] enabled, bootconsole disabled
omap_uart.4: ttyO4 at MMIO 0x481a8000 (irq = 45) is a OMAP UART4
ˉ+?-4?￡1?-+?
4.
!
现在的现象是只要串口驱动初始化了uart4就会出问题
参考帖子:
