Re: [PATCH V4 05/23] ACPI: OSL: Make should_use_kmap() 0 for RISC-V

[Sunil V L]

Hi Bjorn,

On Wed, Apr 26, 2023 at 06:47:20PM +0200, Björn Töpel wrote:
> Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> writes:
> 
> > Without this, if the tables are larger than 4K,
> > acpi_map() will fail.
> >
> > Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>
> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > ---
> >  drivers/acpi/osl.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> > index 3269a888fb7a..f725813d0cce 100644
> > --- a/drivers/acpi/osl.c
> > +++ b/drivers/acpi/osl.c
> > @@ -276,7 +276,7 @@ acpi_map_lookup_virt(void __iomem *virt, acpi_size size)
> >  	return NULL;
> >  }
> >  
> > -#if defined(CONFIG_IA64) || defined(CONFIG_ARM64)
> > +#if defined(CONFIG_IA64) || defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
> >  /* ioremap will take care of cache attributes */
> >  #define should_use_kmap(pfn)   0
> 
> An observation, which can be addressed later; The acpi_os_ioremap()
> (called when the config above is enabled for RV), does not have an arch
> specific implementation for RISC-V. The generic one calls
> ioremap_cached(), which on RISC-V defaults to ioremap() -- caching
> disabled/_PAGE_IO.
> 
> That is probably not what we want, but rather something similar that
> arm64 does.
> 
Actually, for RISC-V acpi_os_ioremap() is currently a wrapper around
memremap(). Sure, this can be enhanced in future if required.

Thanks,
Sunil