* Unable to read/write consistently to a device.
@ 2001-02-27 17:02 gopi krishna
2001-02-27 19:27 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 3+ messages in thread
From: gopi krishna @ 2001-02-27 17:02 UTC (permalink / raw)
To: linuxppc-dev
Hi..
We have custom board based on 860T running
linux2.2.14
We have a device 0xf0040000. This address has been
ioremapped.
(Hence directly using the physical address to access
the memory)
We tried to read the registers using:
in_be32(addr)
*address
in_be32(volatile unsigned *addr)
but, none of them are giving any consistent results.
With BDM, we are able to get correct and consistent
results.
Can there be any cache/coherency/any other issues of
linux which we are overlooking?
thanx in advance
gopi
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Unable to read/write consistently to a device.
@ 2001-02-27 17:10 gopi krishna
0 siblings, 0 replies; 3+ messages in thread
From: gopi krishna @ 2001-02-27 17:10 UTC (permalink / raw)
To: linuxppc-embedded
Hi..
We have custom board based on 860T running
linux2.2.14
We have a device 0xf0040000. This address has been
ioremapped.
(Hence directly using the physical address to access
the memory)
We tried to read the registers using:
in_be32(addr)
*address
in_be32(volatile unsigned *addr)
but, none of them are giving any consistent results.
With BDM, we are able to get correct and consistent
results.
Can there be any cache/coherency/any other issues of
linux which we are overlooking?
thanx in advance
gopi
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Unable to read/write consistently to a device.
2001-02-27 17:02 Unable to read/write consistently to a device gopi krishna
@ 2001-02-27 19:27 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2001-02-27 19:27 UTC (permalink / raw)
To: gopi krishna, linuxppc-dev
> We have a device 0xf0040000. This address has been
>ioremapped.
>(Hence directly using the physical address to access
>the memory)
What do you mean by ioremapped ? You should use the virtual address
returned by ioremap (which is usually _not_ the same as the physical
address, except in some specific cases), not the physical address, to
access the registers.
Ben.
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
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2001-02-27 17:02 Unable to read/write consistently to a device gopi krishna
2001-02-27 19:27 ` Benjamin Herrenschmidt
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2001-02-27 17:10 gopi krishna
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