> From: [email protected]
> To: [email protected]
> CC: [email protected]
> Date: Wed, 30 Jun 2010 14:56:24 +0530
> Subject: RE: A PROBLEM of writing register in linux-2.6.34
>
> Hello,
>
> On Wed, Jun 30, 2010 at 14:25:11, [email protected] wrote:
> > hi,
> >
> > i'm using linux kernel v2.6.34 and porting to a omapl137 (da830) board..
> > the kernel seems to be running well and mounts the NFS rootfs well just
> > like the previous one(2.6.18_pro500) i used...
> >
> > BUT when i set a PINMUX register or write a common register of omapl137,
> > for example the USB configuration register CFGCHIP2, it seems to be
> > failed...
> >
> > why i said it failed..becoz i checked the value of the register after
> > writing, it was not the value i had written...and it was the same as the
> > original value...
> >
> > [ 0.260000] MUX: initialized GPIO2_11
> > [ 0.260000] MUX: Setting register GPIO2_11
> > [ 0.260000] PINMUX9 (0x00000024) = 0x00000000 -> 0x00000800
> > [ 0.260000] MUX:now register(0xfec14144) is 0x00000000
> >
> > the log above can obviously show the problem i said...it used the
> > function 'davinci_cfg_reg' in mux.c to set the PI! NMUX9 register
>
> On this device, the SYSCFG registers are protected by what are
> known as KICK registers. They need to be unlocked before this
> memory can be written to.
>
> The MV kernel may be unlocking the kick registers which will
> explain the behavior you describe.
>
> These registers are better unlocked on early in the boot-up and
> kept unlocked for through booted-up time.
>
> Can you please upgrade the DSP/ARM UBL and U-Boot from the release below:
> http://software-dl.ti.com/dsps/dsps_public_sw/psp/LinuxPSP/DaVinci_03_20/03_20_00_12/index_FDS.html
>
> That should make the problem go away.
>
> Thanks,
> Sekhar
>
Thank you Sekhar!!
you just reminded me.i should find the cause by myself.
for a temporary solution, i add a unlocking code in head.S before the kernel
being uncompressed, and it makes the issue gone.
i'll also consider to upgrade the newer u-boot you recommended.
Thank you so much!
Best regards,
Nicole
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