Clock / Timebase / Bus Frequencies Help

Tue Aug 19 23:52:52 EST 2008

Hi Richard,

  Thanks for your response,
i have fixed the problem. The problem was while U-boot is doing boardsetup
it is filling incorrect frequencies which causes the problem.

Regards
Surendra

> Hi,
>
> Is it really hanging?
> Or is it just sending console output somewhere else?
> Try pinging the board after you think its hung. Can you ssh in and dmesg
> to find out what went wrong?
> I've had two problems similar to this recently. The first was that the
> serial clock frequency was wrong in the dts file.
> The second was schoolboy error when the console was handed over to ttyS1
> when I was plugged in to ttyS0.
> If that all fails - put a scope on your serial port and see what its
> really doing.
> Good luck,
>
>
>
>
> Richard.
>
> surendranath.moilla at cmcltd.com wrote:
>> Hi,
>>
>>   I have a similar problem with custom MPC8360 board.
>> I am able to boot Linux with the mpc836x_dts.dtb provided by freescale.
>> but when use dtb customised for my  board i am unable to boot Linux.
>> It is hanging after the console handover to real console from boot
>> console.
>>
>> I am filling all the frequencies properly, can someone help me to fix
>> this
>> Where to set the baud rate in dts file.
>>
>> Here is the log:
>>
>>
>> => tftp $loadaddr /nfk684/vpm_test/uImage
>> Using FSL UEC0 device
>> TFTP from server 192.168.0.2; our IP address is 192.168.0.100
>> Filename '/nfk684/vpm_test/uImage'.
>> Load address: 0x200000
>> Loading:
>> #################################################################
>>          ##########
>> done
>> Bytes transferred = 1095689 (10b809 hex)
>> => tftp $fdtaddr /nfk684/vpm_test/mpc8360_vpm.dtb
>> Using FSL UEC0 device
>> TFTP from server 192.168.0.2; our IP address is 192.168.0.100
>> Filename '/nfk684/vpm_test/mpc8360_vpm.dtb'.
>> Load address: 0x400000
>> Loading: #
>> done
>> Bytes transferred = 12288 (3000 hex)
>> => bootm $loadaddr - $fdtaddr
>> ## Booting image at 00200000 ...
>>    Image Name:   Linux-2.6.22
>>    Image Type:   PowerPC Linux Kernel Image (gzip compressed)
>>    Data Size:    1095625 Bytes =  1 MB
>>    Load Address: 00000000
>>    Entry Point:  00000000
>>    Verifying Checksum ... OK
>>    Uncompressing Kernel Image ... OK
>>    Booting using the fdt at 0x400000
>>  Probing machine type
>> Using MPC8360 VPM machine description
>> Linux version 2.6.22 (nfk684 at ilec4411) (gcc version 4.0.0 (DENX ELDK 4.1
>> 4.0.0))
>>  #17 Fri Aug 15 16:13:41 CDT 2008
>> setup_arch: bootmem
>> mpc8360_vpm_setup_arch()
>> Bad clock source for time stamp 1
>> Bad clock source for time stamp 2
>> arch: exit
>> Zone PFN ranges:
>>   DMA             0 ->    65536
>>   Normal      65536 ->    65536
>> early_node_map[1] active PFN ranges
>>     0:        0 ->    65536
>> Built 1 zonelists.  Total pages: 65024
>> Kernel command line: root=/dev/ram rw console=ttyS1,115200
>> IPIC (128 IRQ sources) at fdefc700
>> QEIC (64 IRQ sources) at fdefb080
>> PID hash table entries: 1024 (order: 10, 4096 bytes)
>> Dentry cache hash table entries: 32768 (order: 5, 131072 bytes)
>> Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)
>> Memory: 257280k/262144k available (2152k kernel code, 4624k reserved,
>> 96k
>> data,
>> 80k bss, 128k init)
>> Mount-cache hash table entries: 512
>> NET: Registered protocol family 16
>>
>> Generic PHY: Registered new driver
>> SCSI subsystem initialized
>> 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
>> JFFS2 version 2.2. (NAND) Â© 2001-2006 Red Hat, Inc.
>> io scheduler noop registered
>> io scheduler anticipatory registered (default)
>> io scheduler deadline registered
>> io scheduler cfq registered
>> Generic RTC Driver v1.07
>> Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing
>> disabled
>> serial8250.0: ttyS0 at MMIO 0xe0004500 (irq = 16) is a 16550A
>> serial8250.0: ttyS1 at MMIO 0xe0004600 (irq = 17) is a 16550A
>> console handover: boot [udbg0] -> real [ttyS1]
>>
>> Regards
>> Surendra
>>
>>
>>
>>> On Mon, Aug 18, 2008 at 07:52:12AM -0400, richw at netcomuk.co.uk wrote:
>>>
>>>> We've got an 8347 based board very similar to the A&M asp8347. Core
>>>> clock
>>>> is 400MHz. Bus clock is 266666666Hz.
>>>> According to the data sheet for the 8347, the decrementer clock runs
>>>> at
>>>> a
>>>> quarter of the rate of the bus clock. I have two questions:
>>>> In arch/powerpc/boot/redboot-83xx.c, the timebase clock is passed to
>>>> dt_fixup_cpu_clocks() as bi_busfreq / 16. If I leave it like this, my
>>>> system clock runs approximately 4 times too fast.
>>>> Can anyone point me in the direction of an explanation for the div by
>>>> 16
>>>> rather than 4?
>>>>
>>> It's a bug, which I pointed out here:
>>> http://ozlabs.org/pipermail/linuxppc-dev/2008-June/058704.html
>>>
>>>
>>>> If I change the call to dt_fixup_cpu_clocks so that bi_busfreq/4 is
>>>> passed
>>>> in, then the clock runs more accurately. However, its still not
>>>> correct.
>>>> This gives a decrementer frequency of 66666666Hz, but if I hard code
>>>> the
>>>> value to 66000000Hz, the clock runs accurately.
>>>> Can anyone shed any light on why the value passed in by the boot
>>>> loader
>>>> (redboot) seems to be inaccurate.
>>>>
>>> Redboot probably has the wrong crystal frequency hardcoded.
>>>
>>> -Scott
>>> _______________________________________________
>>> Linuxppc-dev mailing list
>>> Linuxppc-dev at ozlabs.org
>>> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>>>
>>>
>>
>>
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>>
>
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