[MPC7448] machdep_calls

[MPC7448] machdep_calls

[Sébastien Chrétien]

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Hello,

I am developping a Linux for my PPC Board. I must write a define_machine
structure (marchdep_calls). Where can I find some Information about
functions of this structure ?

Thanx
Sébastien Chrétien

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Re: [MPC7448] machdep_calls

[Benjamin Herrenschmidt]

On Mon, 2008-08-18 at 10:45 +0200, Sébastien Chrétien wrote:
> Hello,
> 
> I am developping a Linux for my PPC Board. I must write a
> define_machine structure (marchdep_calls). Where can I find some
> Information about functions of this structure ?

It isn't well documented unfortunately. Best is to look at what others
do... and then find your way through.

I agree somebody should write dome doco one day ... in the meantime,
feel free to ask questions here.

Cheers,
Ben.

Re: [MPC7448] machdep_calls

[Sébastien Chrétien]

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Ok I am going to copy some examples.

2008/8/18, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>
> On Mon, 2008-08-18 at 10:45 +0200, Sébastien Chrétien wrote:
> > Hello,
> >
> > I am developping a Linux for my PPC Board. I must write a
> > define_machine structure (marchdep_calls). Where can I find some
> > Information about functions of this structure ?
>
>
> It isn't well documented unfortunately. Best is to look at what others
> do... and then find your way through.
>
> I agree somebody should write dome doco one day ... in the meantime,
> feel free to ask questions here.
>
> Cheers,
> Ben.
>
>
>

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Re: [MPC7448] machdep_calls

[Sébastien Chrétien]

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Can somebody explain me the aim of the function  "setup_arch" in the
machine_call structure ?

2008/8/18, Sébastien Chrétien <sebastien.chretien.enseirb@gmail.com>:
>
> Ok I am going to copy some examples.
>
> 2008/8/18, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>>
>> On Mon, 2008-08-18 at 10:45 +0200, Sébastien Chrétien wrote:
>> > Hello,
>> >
>> > I am developping a Linux for my PPC Board. I must write a
>> > define_machine structure (marchdep_calls). Where can I find some
>> > Information about functions of this structure ?
>>
>>
>> It isn't well documented unfortunately. Best is to look at what others
>> do... and then find your way through.
>>
>> I agree somebody should write dome doco one day ... in the meantime,
>> feel free to ask questions here.
>>
>> Cheers,
>> Ben.
>>
>>
>>
>

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Re: [MPC7448] machdep_calls

[Michael Ellerman]

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On Mon, 2008-08-18 at 13:35 +0200, Sébastien Chrétien wrote:
> Can somebody explain me the aim of the function  "setup_arch" in the
> machine_call structure ?

Is this MPC7448 anything like an mpc7448hpc2 ?

If so maybe you should start by looking at the code for it in:

arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c

Even if it's not related, that will give you some idea of what the
callbacks are for.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: [MPC7448] machdep_calls

[Sébastien Chrétien]

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The mpc7448hpc2 uses a tsi108-bridge. My board uses an IP on a FPGA.. I read
the code of mpc7448_hpc2.c.
It uses a ioremap in order to iniatilize the tsi108 registers. But I have
already initialized MMU with my registers in HEAD_32.S. Do I need to use
ioremap in setup_arch() ?




2008/8/18, Michael Ellerman <michael@ellerman.id.au>:
>
> On Mon, 2008-08-18 at 13:35 +0200, Sébastien Chrétien wrote:
> > Can somebody explain me the aim of the function  "setup_arch" in the
> > machine_call structure ?
>
>
> Is this MPC7448 anything like an mpc7448hpc2 ?
>
> If so maybe you should start by looking at the code for it in:
>
> arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
>
> Even if it's not related, that will give you some idea of what the
> callbacks are for.
>
> cheers
>
> --
> Michael Ellerman
> OzLabs, IBM Australia Development Lab
>
> wwweb: http://michael.ellerman.id.au
> phone: +61 2 6212 1183 (tie line 70 21183)
>
> We do not inherit the earth from our ancestors,
> we borrow it from our children. - S.M.A.R.T Person
>
>

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Re: [MPC7448] machdep_calls

[Benjamin Herrenschmidt]

On Mon, 2008-08-18 at 16:17 +0200, Sébastien Chrétien wrote:
> The mpc7448hpc2 uses a tsi108-bridge. My board uses an IP on a FPGA..
> I read the code of mpc7448_hpc2.c.
> It uses a ioremap in order to iniatilize the tsi108 registers. But I
> have already initialized MMU with my registers in HEAD_32.S. Do I need
> to use ioremap in setup_arch() ?

Why did you hack head_32.S ? You shouldn't do that... This is common
code, not platform code.

Ben.
> 
> 
> 
> 2008/8/18, Michael Ellerman <michael@ellerman.id.au>:
>         On Mon, 2008-08-18 at 13:35 +0200, Sébastien Chrétien wrote:
>         > Can somebody explain me the aim of the
>         function  "setup_arch" in the
>         > machine_call structure ?
>         
>         
>         Is this MPC7448 anything like an mpc7448hpc2 ?
>         
>         If so maybe you should start by looking at the code for it in:
>         
>         arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
>         
>         Even if it's not related, that will give you some idea of what
>         the
>         callbacks are for.
>         
>         cheers
>         
>         --
>         Michael Ellerman
>         OzLabs, IBM Australia Development Lab
>         
>         wwweb: http://michael.ellerman.id.au
>         phone: +61 2 6212 1183 (tie line 70 21183)
>         
>         We do not inherit the earth from our ancestors,
>         we borrow it from our children. - S.M.A.R.T Person
>         
> 

Re: [MPC7448] machdep_calls

[Sébastien Chrétien]

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I have no screen that's why I have to use UART. I followed the CPM model in
head_32.S :
#ifdef CONFIG_PPC_EARLY_DEBUG_CPM
setup_cpm_bat:
    lis    r8, 0xf000
    ori    r8, r8,    0x002a
    mtspr    SPRN_DBAT1L, r8

    lis    r11, 0xf000
    ori    r11, r11, (BL_1M << 2) | 2
    mtspr    SPRN_DBAT1U, r11

    blr
#endif

With this code  I can use udbg.

According to you, what is the best way ?

2008/8/18, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>
> On Mon, 2008-08-18 at 16:17 +0200, Sébastien Chrétien wrote:
> > The mpc7448hpc2 uses a tsi108-bridge. My board uses an IP on a FPGA..
> > I read the code of mpc7448_hpc2.c.
> > It uses a ioremap in order to iniatilize the tsi108 registers. But I
> > have already initialized MMU with my registers in HEAD_32.S. Do I need
> > to use ioremap in setup_arch() ?
>
>
> Why did you hack head_32.S ? You shouldn't do that... This is common
> code, not platform code.
>
> Ben.
>
> >
> >
> >
> > 2008/8/18, Michael Ellerman <michael@ellerman.id.au>:
> >         On Mon, 2008-08-18 at 13:35 +0200, Sébastien Chrétien wrote:
> >         > Can somebody explain me the aim of the
> >         function  "setup_arch" in the
> >         > machine_call structure ?
> >
> >
> >         Is this MPC7448 anything like an mpc7448hpc2 ?
> >
> >         If so maybe you should start by looking at the code for it in:
> >
> >         arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
> >
> >         Even if it's not related, that will give you some idea of what
> >         the
> >         callbacks are for.
> >
> >         cheers
> >
> >         --
> >         Michael Ellerman
> >         OzLabs, IBM Australia Development Lab
> >
> >         wwweb: http://michael.ellerman.id.au
> >         phone: +61 2 6212 1183 (tie line 70 21183)
> >
> >         We do not inherit the earth from our ancestors,
> >         we borrow it from our children. - S.M.A.R.T Person
> >
> >
>
>

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Re: [MPC7448] machdep_calls

[Benjamin Herrenschmidt]

On Tue, 2008-08-19 at 09:00 +0200, Sébastien Chrétien wrote:
> I have no screen that's why I have to use UART. I followed the CPM
> model in head_32.S : 
> #ifdef CONFIG_PPC_EARLY_DEBUG_CPM
> setup_cpm_bat:
>     lis    r8, 0xf000
>     ori    r8, r8,    0x002a
>     mtspr    SPRN_DBAT1L, r8
> 
>     lis    r11, 0xf000
>     ori    r11, r11, (BL_1M << 2) | 2
>     mtspr    SPRN_DBAT1U, r11
> 
>     blr
> #endif

The "EARLY DEBUG" stuff is a pile of hacks to help with bringup,
it's definitely not a long term solution to your problems.

You may also want to look at Grant Likely's work on doing proper
early ioremap using BATs.

> With this code  I can use udbg.
> 
> According to you, what is the best way ?

The above is fine for early debug console. But that's definitely
not the only kind of thing you may want to put in your setup_arch()...
Look at what others do. 

Ben.

> 2008/8/18, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>         On Mon, 2008-08-18 at 16:17 +0200, Sébastien Chrétien wrote:
>         > The mpc7448hpc2 uses a tsi108-bridge. My board uses an IP on
>         a FPGA..
>         > I read the code of mpc7448_hpc2.c.
>         > It uses a ioremap in order to iniatilize the tsi108
>         registers. But I
>         > have already initialized MMU with my registers in HEAD_32.S.
>         Do I need
>         > to use ioremap in setup_arch() ?
>         
>         
>         Why did you hack head_32.S ? You shouldn't do that... This is
>         common
>         code, not platform code.
>         
>         Ben.
>         
>         >
>         >
>         >
>         > 2008/8/18, Michael Ellerman <michael@ellerman.id.au>:
>         >         On Mon, 2008-08-18 at 13:35 +0200, Sébastien
>         Chrétien wrote:
>         >         > Can somebody explain me the aim of the
>         >         function  "setup_arch" in the
>         >         > machine_call structure ?
>         >
>         >
>         >         Is this MPC7448 anything like an mpc7448hpc2 ?
>         >
>         >         If so maybe you should start by looking at the code
>         for it in:
>         >
>         >         arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
>         >
>         >         Even if it's not related, that will give you some
>         idea of what
>         >         the
>         >         callbacks are for.
>         >
>         >         cheers
>         >
>         >         --
>         >         Michael Ellerman
>         >         OzLabs, IBM Australia Development Lab
>         >
>         >         wwweb: http://michael.ellerman.id.au
>         >         phone: +61 2 6212 1183 (tie line 70 21183)
>         >
>         >         We do not inherit the earth from our ancestors,
>         >         we borrow it from our children. - S.M.A.R.T Person
>         >
>         >
>         
> 

Re: [MPC7448] machdep_calls

[Sébastien Chrétien]

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So I will write .setup_arch of machine_call  structure.
When is ppc_md.setup_arch() called ?

2008/8/19, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>
> On Tue, 2008-08-19 at 09:00 +0200, Sébastien Chrétien wrote:
> > I have no screen that's why I have to use UART. I followed the CPM
> > model in head_32.S :
> > #ifdef CONFIG_PPC_EARLY_DEBUG_CPM
> > setup_cpm_bat:
> >     lis    r8, 0xf000
> >     ori    r8, r8,    0x002a
> >     mtspr    SPRN_DBAT1L, r8
> >
> >     lis    r11, 0xf000
> >     ori    r11, r11, (BL_1M << 2) | 2
> >     mtspr    SPRN_DBAT1U, r11
> >
> >     blr
> > #endif
>
>
> The "EARLY DEBUG" stuff is a pile of hacks to help with bringup,
> it's definitely not a long term solution to your problems.
>
> You may also want to look at Grant Likely's work on doing proper
> early ioremap using BATs.
>
>
> > With this code  I can use udbg.
> >
> > According to you, what is the best way ?
>
>
> The above is fine for early debug console. But that's definitely
> not the only kind of thing you may want to put in your setup_arch()...
> Look at what others do.
>
> Ben.
>
>
> > 2008/8/18, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
> >         On Mon, 2008-08-18 at 16:17 +0200, Sébastien Chrétien wrote:
> >         > The mpc7448hpc2 uses a tsi108-bridge. My board uses an IP on
> >         a FPGA..
> >         > I read the code of mpc7448_hpc2.c.
> >         > It uses a ioremap in order to iniatilize the tsi108
> >         registers. But I
> >         > have already initialized MMU with my registers in HEAD_32.S.
> >         Do I need
> >         > to use ioremap in setup_arch() ?
> >
> >
> >         Why did you hack head_32.S ? You shouldn't do that... This is
> >         common
> >         code, not platform code.
> >
> >         Ben.
> >
> >         >
> >         >
> >         >
> >         > 2008/8/18, Michael Ellerman <michael@ellerman.id.au>:
> >         >         On Mon, 2008-08-18 at 13:35 +0200, Sébastien
> >         Chrétien wrote:
> >         >         > Can somebody explain me the aim of the
> >         >         function  "setup_arch" in the
> >         >         > machine_call structure ?
> >         >
> >         >
> >         >         Is this MPC7448 anything like an mpc7448hpc2 ?
> >         >
> >         >         If so maybe you should start by looking at the code
> >         for it in:
> >         >
> >         >         arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
> >         >
> >         >         Even if it's not related, that will give you some
> >         idea of what
> >         >         the
> >         >         callbacks are for.
> >         >
> >         >         cheers
> >         >
> >         >         --
> >         >         Michael Ellerman
> >         >         OzLabs, IBM Australia Development Lab
> >         >
> >         >         wwweb: http://michael.ellerman.id.au
> >         >         phone: +61 2 6212 1183 (tie line 70 21183)
> >         >
> >         >         We do not inherit the earth from our ancestors,
> >         >         we borrow it from our children. - S.M.A.R.T Person
> >         >
> >         >
> >
> >
>
>

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Re: [MPC7448] machdep_calls

[Benjamin Herrenschmidt]

On Mon, 2008-08-18 at 13:35 +0200, Sébastien Chrétien wrote:
> Can somebody explain me the aim of the function  "setup_arch" in the
> machine_call structure ?

This is where most of your arch code gets a chance to initialize before
most of the core is.

The generic core linux code calls the architecture setup_arch() very
early during boot, before most other initializations. The powerpc
architecture code performs various early initialisations there, on
32-bit that includes unflattening the device-tree, looking for legacy
serial ports, etc... and initializing bootmem.

It then calls ppc_md.setup_arch to give the platform a chance to perform
other platform specific early initializations before the rest of the
kernel starts initializing.

This is very early, ie, for memory allocation you can only use bootmem
for example. Interrupts haven't been initialized or switched on yet,
etc...

This is typically the place where your arch code will setup it's SMP ops
if any, will discover the fixed PCI host bridges, and initialize low
level HW components that need early initialization.

Ben.

> 2008/8/18, Sébastien Chrétien <sebastien.chretien.enseirb@gmail.com>:
>         Ok I am going to copy some examples.
>         
>         2008/8/18, Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>                 On Mon, 2008-08-18 at 10:45 +0200, Sébastien Chrétien
>                 wrote:
>                 > Hello,
>                 >
>                 > I am developping a Linux for my PPC Board. I must
>                 write a
>                 > define_machine structure (marchdep_calls). Where can
>                 I find some
>                 > Information about functions of this structure ?
>                 
>                 
>                 It isn't well documented unfortunately. Best is to
>                 look at what others
>                 do... and then find your way through.
>                 
>                 I agree somebody should write dome doco one day ... in
>                 the meantime,
>                 feel free to ask questions here.
>                 
>                 Cheers,
>                 Ben.
>                 
>                 
>         
>