Re: [PATCH 1/5] ARM: vexpress: Get rid of MMIO_P2V

[Pawel Moll <pawel.moll@arm.com>]

On Wed, 2011-11-16 at 15:35 +0000, Dave Martin wrote:
> On Fri, Nov 11, 2011 at 06:27:02PM +0000, Pawel Moll wrote:
> > This patch gets rid of the MMIO_P2V and __MMPIO_P2V macros,
> > defining constant virtual base for motherboard and tile
> > peripherals instead.
> > 
> > Additionally, in preparation for the new motherboard memory
> > map, the motherboard peripherals are using base pointers
> > calculated in runtime, instead of compile-time calculated
> > values.
> > 
> > Signed-off-by: Pawel Moll <pawel.moll@arm.com>
> > ---
> >  arch/arm/include/asm/hardware/arm_timer.h         |    5 ++
> >  arch/arm/mach-vexpress/core.h                     |   12 +++-
> >  arch/arm/mach-vexpress/ct-ca9x4.c                 |   52 ++++-------------
> >  arch/arm/mach-vexpress/include/mach/ct-ca9x4.h    |   13 ++---
> >  arch/arm/mach-vexpress/include/mach/motherboard.h |   53 ++++++++---------
> >  arch/arm/mach-vexpress/platsmp.c                  |    4 +-
> >  arch/arm/mach-vexpress/v2m.c                      |   64 ++++++++++++++-------
> >  7 files changed, 100 insertions(+), 103 deletions(-)
> 
> [...]
> 
> > diff --git a/arch/arm/mach-vexpress/ct-ca9x4.c b/arch/arm/mach-vexpress/ct-ca9x4.c
> > index 2b1e836..47c0733 100644
> > --- a/arch/arm/mach-vexpress/ct-ca9x4.c
> > +++ b/arch/arm/mach-vexpress/ct-ca9x4.c
> > @@ -30,57 +30,26 @@
> >  
> >  #include <plat/clcd.h>
> >  
> > -#define V2M_PA_CS7	0x10000000
> > -
> >  static struct map_desc ct_ca9x4_io_desc[] __initdata = {
> >  	{
> > -		.virtual	= __MMIO_P2V(CT_CA9X4_MPIC),
> > -		.pfn		= __phys_to_pfn(CT_CA9X4_MPIC),
> > -		.length		= SZ_16K,
> > -		.type		= MT_DEVICE,
> > +		.virtual        = V2T_PERIPH,
> > +		.pfn            = __phys_to_pfn(CT_CA9X4_MPIC),
> > +		.length         = SZ_8K,
>
> Can you explain the size change?

The SCU's "Private memory region" is 8K big, not 16:

http://infocenter.arm.com/help/topic/com.arm.doc.ddi0407g/CACCJFCJ.html
http://infocenter.arm.com/help/topic/com.arm.doc.dui0448e/CHDCBJCB.html

> > diff --git a/arch/arm/mach-vexpress/v2m.c b/arch/arm/mach-vexpress/v2m.c
> > index 1fafc32..b84fa45 100644
> > --- a/arch/arm/mach-vexpress/v2m.c
> > +++ b/arch/arm/mach-vexpress/v2m.c
> 
> [...]
> 
> > @@ -413,6 +431,10 @@ static void __init v2m_populate_ct_desc(void)
> >  static void __init v2m_map_io(void)
> >  {
> >  	iotable_init(v2m_io_desc, ARRAY_SIZE(v2m_io_desc));
> > +
> > +	/* Will become an ioremap() when possible */
> > +	v2m_sysreg_base = V2M_PERIPH_P2V(V2M_SYSREGS);
> 
> linux/of_fdt.h has functions for manipulating the flattened device tree
> blob.
> 
> Could that solve our problem?  We just need to get the root node compatible
> property out.

What do you exaclty mean? This function is non-DT related. It's not used
by DT platform at all...

> Is there anything else blocking the building of legacy and RS1 memory
> maps into a single kernel?
> (I'm still hazy on how all the remapping stuff works, myself.)

This works now - I have a single binary kernel that works on both A9 and
A5 coretiles. Of course the ATAG-based support works with A9 only.

Paweł



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