Re: [RFC PATCH v2 1/3] PCI: hisi: re-architect Hip05/Hip06 controllers driver to preapare for ACPI

[Arnd Bergmann <arnd@arndb.de>]

On Monday 08 February 2016 16:06:54 Gabriele Paoloni wrote:
> > 
> > On Monday 08 February 2016 12:41:02 Gabriele Paoloni wrote:
> > > +
> > > +/* HipXX PCIe host only supports 32-bit config access */
> > > +int hisi_pcie_common_cfg_read(void __iomem *reg_base, int where, int
> > size,
> > > +                         u32 *val)
> > > +{
> > > +   u32 reg;
> > > +   u32 reg_val;
> > > +   void *walker = &reg_val;
> > > +
> > > +   walker += (where & 0x3);
> > > +   reg = where & ~0x3;
> > > +   reg_val = readl(reg_base + reg);
> > > +
> > > +   if (size == 1)
> > > +           *val = *(u8 __force *) walker;
> > > +   else if (size == 2)
> > > +           *val = *(u16 __force *) walker;
> > > +   else if (size == 4)
> > > +           *val = reg_val;
> > > +   else
> > > +           return PCIBIOS_BAD_REGISTER_NUMBER;
> > > +
> > > +   return PCIBIOS_SUCCESSFUL;
> > > +}
> > 
> > Isn't this the same hack that Qualcomm are using?
> 
> As far as I can see Qualcomm defines its own config access
> mechanism only for RC config read and also it seems they're
> having problems with reporting the device class...
> 
> https://github.com/torvalds/linux/blob/master/drivers/pci/host/pcie-qcom.c#L474
> 
> Our problem is that our HW can only perform 32b rd/wr accesses
> So we can't use readw/readb/writew/writeb...
> 
> 

Sorry, my mistake, I meant Cavium not Qualcomm.
See https://lkml.org/lkml/2016/2/5/689 for the patches.

	Arnd