* [U-Boot] in/out_le32, etc.
@ 2011-02-12 11:23 Aaron Williams
2011-02-13 14:41 ` Shinya Kuribayashi
0 siblings, 1 reply; 2+ messages in thread
From: Aaron Williams @ 2011-02-12 11:23 UTC (permalink / raw
To: u-boot
One thing that is getting confusing to me is that there seems to be many
different methods for doing I/O.
There's in_xxx/out_xxx, __raw_readx/__raw_writex and readx/writex. What
exactly is the difference between all of these? It looks like the in/out was
added recently and is not present in the mips io.h file.
In a related case, I run into problems with a number of drivers because they
assume that readl/writel can be used to access the PCI BAR address space or
that a pointer is a physical address. This is not always the case.
For example, on our platform the PCI BAR address space is mapped to different
64-bit address spaces depending on the bus number. It would be very helpful if
different macros were used for different I/O devices. For example, one set of
macros for accessing PCI BAR address space.
-Aaron
^ permalink raw reply [flat|nested] 2+ messages in thread
* [U-Boot] in/out_le32, etc.
2011-02-12 11:23 [U-Boot] in/out_le32, etc Aaron Williams
@ 2011-02-13 14:41 ` Shinya Kuribayashi
0 siblings, 0 replies; 2+ messages in thread
From: Shinya Kuribayashi @ 2011-02-13 14:41 UTC (permalink / raw
To: u-boot
On 02/12/2011 08:23 PM, Aaron Williams wrote:
> There's in_xxx/out_xxx, __raw_readx/__raw_writex and readx/writex. What
> exactly is the difference between all of these? It looks like the in/out was
> added recently and is not present in the mips io.h file.
In the MIPS code, 'mips_io_port_base' makes in_xxx/out_xxx distinct
from readx/writex. And raw operations are never swapped in software.
Check <asm/io.h> for more details.
> For example, on our platform the PCI BAR address space is mapped to different
> 64-bit address spaces depending on the bus number. It would be very helpful if
> different macros were used for different I/O devices. For example, one set of
> macros for accessing PCI BAR address space.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2011-02-12 11:23 [U-Boot] in/out_le32, etc Aaron Williams
2011-02-13 14:41 ` Shinya Kuribayashi
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