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Date:   Thu, 27 Apr 2023 14:57:57 +0530
From:   Sunil V L <sunilvl@ventanamicro.com>
To:     =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
Cc:     linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-riscv@lists.infradead.org, linux-acpi@vger.kernel.org,
        linux-crypto@vger.kernel.org, platform-driver-x86@vger.kernel.org,
        llvm@lists.linux.dev, Jonathan Corbet <corbet@lwn.net>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
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        Zhou Wang <wangzhou1@hisilicon.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Marc Zyngier <maz@kernel.org>,
        Maximilian Luz <luzmaximilian@gmail.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Mark Gross <markgross@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH V4 05/23] ACPI: OSL: Make should_use_kmap() 0 for RISC-V
Message-ID: <ZEpAHfccImGsJGjk@sunil-laptop>
References: <20230404182037.863533-1-sunilvl@ventanamicro.com>
 <20230404182037.863533-6-sunilvl@ventanamicro.com>
 <87a5yua8vb.fsf@all.your.base.are.belong.to.us>
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Hi Bjorn,

On Wed, Apr 26, 2023 at 06:47:20PM +0200, Björn Töpel wrote:
> Sunil V L <sunilvl@ventanamicro.com> writes:
> 
> > Without this, if the tables are larger than 4K,
> > acpi_map() will fail.
> >
> > Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> >  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