fix to enet.c to enable networking when booting from flash

fix to enet.c to enable networking when booting from flash

[Robert P. J. Day]

   with our current 2.4.22-pre8 kernel, we found that, on our 850DE
board (ethernet on SCC3), ethernet would work fine when we downloaded
the bootable image, but not if we booted from the image that was
burned into flash.

   eventually, one of the guys here tracked the problem to
arch/ppc/8xx_io/enet.c, and made the following change (around line 915
in enet.c in both this version of the kernel and in the latest bk pull
of linuxppc-2.5):

#if defined(CONFIG_RPXLITE) || defined(CONFIG_RPXCLASSIC) ||
defined(CONFIG_EP8xx) || defined(CONFIG_EP852)
         /* And while we are here, set the configuration to enable
ethernet.
         */
         *((volatile uint *)RPX_CSR_ADDR) &= ~BCSR0_ETHLPBK;
         *((volatile uint *)RPX_CSR_ADDR) |=
              (BCSR0_ETHEN | BCSR0_COLTESTDIS | BCSR0_FULLDPLXDIS);
>        *((volatile uint *)RPX_CSR_ADDR) |=0x00100000;  <-- add this
//1:ethernet,0:SPI
#endif


   i don't know enough about the hardware to know what this is for.  if
anyone does, is it still an issue?  is there a better way to handle
this?  as much as possible, i'm trying to get everything running on
this board without messing with the kernel source.  thanks.  given
that the author of that line is not around at the moment, i'm just
going to poke around the source and see if i can deduce what it's for.

rday


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Re: fix to enet.c to enable networking when booting from flash

[Dan Malek]

On Jul 13, 2004, at 1:34 PM, Robert P. J. Day wrote:

> #if defined(CONFIG_RPXLITE) || defined(CONFIG_RPXCLASSIC) ||
> defined(CONFIG_EP8xx) || defined(CONFIG_EP852)
>         /* And while we are here, set the configuration to enable
> ethernet.
>         */
>         *((volatile uint *)RPX_CSR_ADDR) &= ~BCSR0_ETHLPBK;
>         *((volatile uint *)RPX_CSR_ADDR) |=
>              (BCSR0_ETHEN | BCSR0_COLTESTDIS | BCSR0_FULLDPLXDIS);
>>        *((volatile uint *)RPX_CSR_ADDR) |=0x00100000;  <-- add this
> //1:ethernet,0:SPI
> #endif

In newer drivers, this would be done in a board specific file.  As you
can tell, this code enables the Ethernet PHY.  I don't understand
why that extra 'add this' is necessary.  That does some PCMCIA signal
routing to IP_B5, which should not have any effect on the Ethernet.

What revision of board is this?  I have RPXLite's that I boot from
flash all of the time without trouble.


	-- Dan


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Re: fix to enet.c to enable networking when booting from flash

[Robert P. J. Day]

On Tue, 13 Jul 2004, Dan Malek wrote:

>
> On Jul 13, 2004, at 1:34 PM, Robert P. J. Day wrote:
>
>> #if defined(CONFIG_RPXLITE) || defined(CONFIG_RPXCLASSIC) ||
>> defined(CONFIG_EP8xx) || defined(CONFIG_EP852)
>>         /* And while we are here, set the configuration to enable
>> ethernet.
>>         */
>>         *((volatile uint *)RPX_CSR_ADDR) &= ~BCSR0_ETHLPBK;
>>         *((volatile uint *)RPX_CSR_ADDR) |=
>>              (BCSR0_ETHEN | BCSR0_COLTESTDIS | BCSR0_FULLDPLXDIS);
>>>        *((volatile uint *)RPX_CSR_ADDR) |=0x00100000;  <-- add this
>> //1:ethernet,0:SPI
>> #endif
>
> In newer drivers, this would be done in a board specific file.  As you
> can tell, this code enables the Ethernet PHY.  I don't understand
> why that extra 'add this' is necessary.  That does some PCMCIA signal
> routing to IP_B5, which should not have any effect on the Ethernet.
>
> What revision of board is this?  I have RPXLite's that I boot from
> flash all of the time without trouble.

i *just* *now* talked to the author.  it's board-specific, has to do
with a register in the CPLD on our board, that's the reader's digest
condensed version.  this is a custom board, so i definitely don't
expect it to behave like a regular rpxlite.  so ignore all this,
unless this explanation makes no sense at all. :-)

rday

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