* MPC5200, PCI, udelay(10)
@ 2006-01-20 8:31 Roman Kuzmenko
2006-01-20 17:24 ` Andrey Volkov
2006-02-04 10:51 ` Sylvain Munaut
0 siblings, 2 replies; 3+ messages in thread
From: Roman Kuzmenko @ 2006-01-20 8:31 UTC (permalink / raw)
To: Linuxppc-embedded
Hello.
Please, help me to investigate why the delays present in the
"mpc5xxx_read_config_dword" and "mpc5xxx_write_config_dword" functions
in the "arch/ppc/kernel/mpc52xx_pci.c" file.
I.e.
==========================
*(volatile u32 *)MPC5xxx_PCI_CAR = 0;
> udelay(10);
return 0;
==========================
I was neither able to find any reference at the MPC5200 documentation
supplied by FreeScale nor reproduce any error with these lines got
removed.
Thank you.
--
Roman Kuzmenko <roman.kuzmenko@auriga.ru>
Auriga, Inc.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: MPC5200, PCI, udelay(10)
2006-01-20 8:31 MPC5200, PCI, udelay(10) Roman Kuzmenko
@ 2006-01-20 17:24 ` Andrey Volkov
2006-02-04 10:51 ` Sylvain Munaut
1 sibling, 0 replies; 3+ messages in thread
From: Andrey Volkov @ 2006-01-20 17:24 UTC (permalink / raw)
To: roman.kuzmenko; +Cc: Linuxppc-embedded
Roman Kuzmenko wrote:
> Hello.
>
> Please, help me to investigate why the delays present in the
> "mpc5xxx_read_config_dword" and "mpc5xxx_write_config_dword" functions
> in the "arch/ppc/kernel/mpc52xx_pci.c" file.
>
> I.e.
> ==========================
> *(volatile u32 *)MPC5xxx_PCI_CAR = 0;
>> udelay(10);
> return 0;
> ==========================
>
> I was neither able to find any reference at the MPC5200 documentation
> supplied by FreeScale nor reproduce any error with these lines got
> removed.
>
> Thank you.
>
kernel version?
--
Regards
Andrey Volkov
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: MPC5200, PCI, udelay(10)
2006-01-20 8:31 MPC5200, PCI, udelay(10) Roman Kuzmenko
2006-01-20 17:24 ` Andrey Volkov
@ 2006-02-04 10:51 ` Sylvain Munaut
1 sibling, 0 replies; 3+ messages in thread
From: Sylvain Munaut @ 2006-02-04 10:51 UTC (permalink / raw)
To: roman.kuzmenko; +Cc: Linuxppc-embedded
Roman Kuzmenko wrote:
> Hello.
>
> Please, help me to investigate why the delays present in the
> "mpc5xxx_read_config_dword" and "mpc5xxx_write_config_dword" functions
> in the "arch/ppc/kernel/mpc52xx_pci.c" file.
>
> I.e.
> ==========================
> *(volatile u32 *)MPC5xxx_PCI_CAR = 0;
>
>>udelay(10);
>
> return 0;
> ==========================
>
> I was neither able to find any reference at the MPC5200 documentation
> supplied by FreeScale nor reproduce any error with these lines got
> removed.
I wasn't able to reproduce any problem either but people kept reporting
problems. But it seems that it's not a delay that's needed but a mb() to
ensure the write all _completly_ done before the next write. A
udelay(10) almost ensure that also but is a lot less elegant imho.
Sylvain
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2006-02-04 10:51 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2006-01-20 8:31 MPC5200, PCI, udelay(10) Roman Kuzmenko
2006-01-20 17:24 ` Andrey Volkov
2006-02-04 10:51 ` Sylvain Munaut
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