Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 8 Aug 2019 14:55:46 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Paul Walmsley <paul.walmsley@sifive.com>
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-riscv@lists.infradead.org,
        Wesley Terpstra <wesley@sifive.com>
Subject: Re: [PATCH v2] pci: Kconfig: select PCI_MSI_IRQ_DOMAIN by default on
 RISC-V
Message-ID: <20190808195546.GA7302@google.com>
References: <alpine.DEB.2.21.9999.1907251426450.32766@viisi.sifive.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.21.9999.1907251426450.32766@viisi.sifive.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Paul, Wesley,

On Thu, Jul 25, 2019 at 02:28:07PM -0700, Paul Walmsley wrote:
> From: Wesley Terpstra <wesley@sifive.com>
> 
> This is part of adding support for RISC-V systems with PCIe host 
> controllers that support message-signaled interrupts.
> 
> Signed-off-by: Wesley Terpstra <wesley@sifive.com>
> [paul.walmsley@sifive.com: wrote patch description; split this
>  patch from the arch/riscv patch]
> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> ---
>  drivers/pci/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index 2ab92409210a..beb3408a0272 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -52,7 +52,7 @@ config PCI_MSI
>  	   If you don't know what to do here, say Y.
>  
>  config PCI_MSI_IRQ_DOMAIN
> -	def_bool ARC || ARM || ARM64 || X86
> +	def_bool ARC || ARM || ARM64 || X86 || RISCV

The other arches listed here either supply their own include/asm/msi.h
or generate it:

  $ ls arch/*/include/asm/msi.h
  arch/x86/include/asm/msi.h

  $ grep msi.h arch/*/include/asm/Kbuild
  arch/arc/include/asm/Kbuild:generic-y += msi.h
  arch/arm64/include/asm/Kbuild:generic-y += msi.h
  arch/arm/include/asm/Kbuild:generic-y += msi.h
  arch/mips/include/asm/Kbuild:generic-y += msi.h
  arch/powerpc/include/asm/Kbuild:generic-y += msi.h
  arch/sparc/include/asm/Kbuild:generic-y += msi.h

For example, see

  f8430eae9f1b ("PCI/MSI: Enable PCI_MSI_IRQ_DOMAIN support for ARC")
  be091d468a0a ("arm64: PCI/MSI: Use asm-generic/msi.h")
  0ab089c2548c ("ARM: Add msi.h to Kbuild")

I didn't look into the details of msi.h generation, but I assume
RISC-V needs to do something similar?  If so, I think that should be
part of this patch to avoid issues.

If CONFIG_GENERIC_MSI_IRQ_DOMAIN is defined, include/linux/msi.h
#includes <asm/msi.h> and I don't see where that would come from.

>  	depends on PCI_MSI
>  	select GENERIC_MSI_IRQ_DOMAIN

Bjorn