[PATCHv3 1/3] ARM: mm: allow sub-architectures to override PCI I/O memory type

[Thomas Petazzoni]

Dear Arnd Bergmann,

On Thu, 15 May 2014 15:21:25 +0200, Arnd Bergmann wrote:
> On Thursday 15 May 2014 11:18:37 Thomas Petazzoni wrote:
> > @@ -445,7 +452,7 @@ int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
> >         return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
> >                                   PCI_IO_VIRT_BASE + offset + SZ_64K,
> >                                   phys_addr,
> > -                                 __pgprot(get_mem_type(MT_DEVICE)->prot_pte));
> > +                                 __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
> >  }
> >  EXPORT_SYMBOL_GPL(pci_ioremap_io);
> > 
> 
> As discussed on IRC, I think we'd be better off making this a strong-ordered
> mapping for all platforms unconditionally. The PCI I/O space semantics
> require non-posted writes, which is the main difference between device
> and SO mappings, so the same fix is required both for mvebu as a workaround
> for the deadlock as well as for everyone else as a fix for an incorrect
> PCI behavior.

Ok, I'll take that into account when posting a v4.

Thanks for the reminder,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com