rfc about an uncommented string

rfc about an uncommented string

[Carlo Perassi]

Hi.
As suggested (*) by Arthur Othieno on the kernel-janitors mailing list,
I bounce here this email for collecting comments.
The old email refers to 2.6.13-rc6 but the code is still the same on
2.6.14-rc3.
Thank you.

Hi.

I'd like to collect some comments about the following code
segment I found in
linux-2.6.13-rc6/arch/mips/ite-boards/generic/it8172_setup.c
(the "^^^" sequence is not mine, it's in the code)

#ifdef CONFIG_SERIO_I8042
/*
 * According to the ITE Special BIOS Note for waking up the
 * keyboard controller...
 */
static int init_8712_keyboard(void)
{
	unsigned int cmd_port = 0x14000064;
	unsigned int data_port = 0x14000060;
	                         ^^^^^^^^^^^
	Somebody here doesn't grok the concept of io ports.

(*)
http://lists.osdl.org/pipermail/kernel-janitors/2005-August/004704.html
http://lists.osdl.org/pipermail/kernel-janitors/2005-August/004705.html
http://lists.osdl.org/pipermail/kernel-janitors/2005-August/004707.html
http://lists.osdl.org/pipermail/kernel-janitors/2005-October/004955.html

-- 
Carlo Perassi - http://www.linux.it/~carlo/

Re: rfc about an uncommented string

[Ralf Baechle]

On Sun, Oct 09, 2005 at 03:41:06PM +0200, Carlo Perassi wrote:

> Hi.
> As suggested (*) by Arthur Othieno on the kernel-janitors mailing list,
> I bounce here this email for collecting comments.
> The old email refers to 2.6.13-rc6 but the code is still the same on
> 2.6.14-rc3.
> Thank you.
> 
> Hi.
> 
> I'd like to collect some comments about the following code
> segment I found in
> linux-2.6.13-rc6/arch/mips/ite-boards/generic/it8172_setup.c
> (the "^^^" sequence is not mine, it's in the code)

I know, I put it there.  The code was obviously broken, so I place this
hard to miss not right into the middle of it.  It's there since ages and
nobody did complain.  So unless somebody complains - and that complaint
better include some patches - I will delete support for the IT8172 and
it's eval board.

  Ralf

Re: rfc about an uncommented string

[Fuxin Zhang]

We are using 8172 for 2.4 kernels presently,although may drop it
sometime later.

I don't read the 2.6 code,but it seems it remains the same as the copy
in 2.4(except that #ifdef changes).I can't see why the code is broken?
In case you mean the ioport address,mips_io_port_base for that board is
0xa0000000, inb(0x14000060) is reading from 0xb4000060, which is correct
for it.

Ralf Baechle wrote:
> On Sun, Oct 09, 2005 at 03:41:06PM +0200, Carlo Perassi wrote:
> 
> 
>>Hi.
>>As suggested (*) by Arthur Othieno on the kernel-janitors mailing list,
>>I bounce here this email for collecting comments.
>>The old email refers to 2.6.13-rc6 but the code is still the same on
>>2.6.14-rc3.
>>Thank you.
>>
>>Hi.
>>
>>I'd like to collect some comments about the following code
>>segment I found in
>>linux-2.6.13-rc6/arch/mips/ite-boards/generic/it8172_setup.c
>>(the "^^^" sequence is not mine, it's in the code)
> 
> 
> I know, I put it there.  The code was obviously broken, so I place this
> hard to miss not right into the middle of it.  It's there since ages and
> nobody did complain.  So unless somebody complains - and that complaint
> better include some patches - I will delete support for the IT8172 and
> it's eval board.
> 
>   Ralf
> 
> 
> 

Re: rfc about an uncommented string

[Geert Uytterhoeven]

On Mon, 10 Oct 2005, Fuxin Zhang wrote:
> We are using 8172 for 2.4 kernels presently,although may drop it
> sometime later.
> 
> I don't read the 2.6 code,but it seems it remains the same as the copy
> in 2.4(except that #ifdef changes).I can't see why the code is broken?
> In case you mean the ioport address,mips_io_port_base for that board is
> 0xa0000000, inb(0x14000060) is reading from 0xb4000060, which is correct
> for it.

Shouldn't mips_io_port_base be 0xb4000000 for your board, so inb(0x60) looks
more like a PC-style keyboard controller access?

> Ralf Baechle wrote:
> > On Sun, Oct 09, 2005 at 03:41:06PM +0200, Carlo Perassi wrote:
> >>As suggested (*) by Arthur Othieno on the kernel-janitors mailing list,
> >>I bounce here this email for collecting comments.
> >>The old email refers to 2.6.13-rc6 but the code is still the same on
> >>2.6.14-rc3.
> >>Thank you.
> >>
> >>Hi.
> >>
> >>I'd like to collect some comments about the following code
> >>segment I found in
> >>linux-2.6.13-rc6/arch/mips/ite-boards/generic/it8172_setup.c
> >>(the "^^^" sequence is not mine, it's in the code)
> > 
> > 
> > I know, I put it there.  The code was obviously broken, so I place this
> > hard to miss not right into the middle of it.  It's there since ages and
> > nobody did complain.  So unless somebody complains - and that complaint
> > better include some patches - I will delete support for the IT8172 and
> > it's eval board.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: rfc about an uncommented string

[Fuxin Zhang]

Geert Uytterhoeven wrote:
> On Mon, 10 Oct 2005, Fuxin Zhang wrote:
> 
>>We are using 8172 for 2.4 kernels presently,although may drop it
>>sometime later.
>>
>>I don't read the 2.6 code,but it seems it remains the same as the copy
>>in 2.4(except that #ifdef changes).I can't see why the code is broken?
>>In case you mean the ioport address,mips_io_port_base for that board is
>>0xa0000000, inb(0x14000060) is reading from 0xb4000060, which is correct
>>for it.
> 
> 
> Shouldn't mips_io_port_base be 0xb4000000 for your board, so inb(0x60) looks
> more like a PC-style keyboard controller access?
It is not my code. But anyway the board has more than one discontinuous
io ranges(0xb4000000 is in fact for it8712 superio and legacy ios,
it8172's system registers are located around 0xb8000000, while others
begins at 0xb4010000).
> 
> 
>>Ralf Baechle wrote:
>>
>>>On Sun, Oct 09, 2005 at 03:41:06PM +0200, Carlo Perassi wrote:
>>>
>>>>As suggested (*) by Arthur Othieno on the kernel-janitors mailing list,
>>>>I bounce here this email for collecting comments.
>>>>The old email refers to 2.6.13-rc6 but the code is still the same on
>>>>2.6.14-rc3.
>>>>Thank you.
>>>>
>>>>Hi.
>>>>
>>>>I'd like to collect some comments about the following code
>>>>segment I found in
>>>>linux-2.6.13-rc6/arch/mips/ite-boards/generic/it8172_setup.c
>>>>(the "^^^" sequence is not mine, it's in the code)
>>>
>>>
>>>I know, I put it there.  The code was obviously broken, so I place this
>>>hard to miss not right into the middle of it.  It's there since ages and
>>>nobody did complain.  So unless somebody complains - and that complaint
>>>better include some patches - I will delete support for the IT8172 and
>>>it's eval board.
> 
> 
> Gr{oetje,eeting}s,
> 
> 						Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> 							    -- Linus Torvalds
> 
> 
> 

Re: rfc about an uncommented string

[Geert Uytterhoeven]

On Mon, 10 Oct 2005, Fuxin Zhang wrote:
> Geert Uytterhoeven wrote:
> > On Mon, 10 Oct 2005, Fuxin Zhang wrote:
> >>We are using 8172 for 2.4 kernels presently,although may drop it
> >>sometime later.
> >>
> >>I don't read the 2.6 code,but it seems it remains the same as the copy
> >>in 2.4(except that #ifdef changes).I can't see why the code is broken?
> >>In case you mean the ioport address,mips_io_port_base for that board is
> >>0xa0000000, inb(0x14000060) is reading from 0xb4000060, which is correct
> >>for it.
> > 
> > Shouldn't mips_io_port_base be 0xb4000000 for your board, so inb(0x60) looks
> > more like a PC-style keyboard controller access?
> It is not my code. But anyway the board has more than one discontinuous
> io ranges(0xb4000000 is in fact for it8712 superio and legacy ios,

So 0xb4000000 is the base for ISA and PCI I/O port accesses, right? Hence if
mips_io_port_base is 0xb4000000, all drivers for PCI (and ISA) expansion cards
that use inb() and friends will work.

> it8172's system registers are located around 0xb8000000, while others
> begins at 0xb4010000).

So these can use ITE8172-specific access macros.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: rfc about an uncommented string

[Maciej W. Rozycki]

On Mon, 10 Oct 2005, Geert Uytterhoeven wrote:

> > It is not my code. But anyway the board has more than one discontinuous
> > io ranges(0xb4000000 is in fact for it8712 superio and legacy ios,
> 
> So 0xb4000000 is the base for ISA and PCI I/O port accesses, right? Hence if
> mips_io_port_base is 0xb4000000, all drivers for PCI (and ISA) expansion cards
> that use inb() and friends will work.
> 
> > it8172's system registers are located around 0xb8000000, while others
> > begins at 0xb4010000).
> 
> So these can use ITE8172-specific access macros.

 IOW, MIPS has no concept of I/O space in the CPU, so whatever is decoded
as I/O cycles to PCI/EISA/ISA is I/O and everything else is MMIO.  In
particular I/O spaces are private to their respective buses -- if there
are more than one disjoint PCI/EISA/ISA buses in a given system, then each
of them can have its private 4GB or 16MB (or whatever) space reserved for
I/O cycles.  If there is only one PCI/EISA/ISA bus, then mips_io_port_base
should refer to the base address where decoding as I/O cycles for that bus
starts, holding an appropriate virtual mapping, typically obtained with
ioremap().

  Maciej

Re: rfc about an uncommented string

[Ralf Baechle]

On Mon, Oct 10, 2005 at 01:28:43PM +0200, Geert Uytterhoeven wrote:

> > I don't read the 2.6 code,but it seems it remains the same as the copy
> > in 2.4(except that #ifdef changes).I can't see why the code is broken?
> > In case you mean the ioport address,mips_io_port_base for that board is
> > 0xa0000000, inb(0x14000060) is reading from 0xb4000060, which is correct
> > for it.
> 
> Shouldn't mips_io_port_base be 0xb4000000 for your board, so inb(0x60) looks
> more like a PC-style keyboard controller access?

Exactly.

Anyway - what this did actually demonstrate is that at least there's
no 2.6 user of the IT8172.

  Ralf