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Date:   Wed, 16 Oct 2019 16:57:56 -0700 (PDT)
Subject:     Re: [PATCH v2] PCI/MSI: Enable PCI_MSI_IRQ_DOMAIN support for Microblaze
In-Reply-To: <fe37e872-09c7-7b60-cd3e-33228c740afc@xilinx.com>
CC:     helgaas@kernel.org, Christoph Hellwig <hch@infradead.org>,
        michal.simek@xilinx.com, linux-kernel@vger.kernel.org,
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        Greg KH <gregkh@linuxfoundation.org>,
        linux-pci@vger.kernel.org, yamada.masahiro@socionext.com,
        firoz.khan@linaro.org, Paul Walmsley <paul.walmsley@sifive.com>,
        linux-riscv@lists.infradead.org, will@kernel.org
From:   Palmer Dabbelt <palmer@sifive.com>
To:     Christoph Hellwig <hch@infradead.org>, michal.simek@xilinx.com
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On Mon, 14 Oct 2019 22:59:07 PDT (-0700), michal.simek@xilinx.com wrote:
> Hi Bjorn,
>
> On 15. 10. 19 1:23, Bjorn Helgaas wrote:
>> On Tue, Oct 08, 2019 at 08:46:52AM -0700, Christoph Hellwig wrote:
>>>> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
>>>> index a304f5ea11b9..9d259372fbfd 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 || RISCV
>>>> +	def_bool ARC || ARM || ARM64 || X86 || RISCV || MICROBLAZE
>>>
>>> Can you find out what the actual dependency is so that we can
>>> automatically enabled this instead of the weird arch list?
>>
>> Hi Michal, I'll wait for your response on whether it's feasible to do
>> something smarter than listing every arch here.  Please ping here or
>> post a v3; since I marked this patch "Changed Requested" in patchwork,
>> it's fallen off my to-do list.
>
> I was waiting more for you to comment this. I was expecting that the
> same question came last time when RISCV was added.
> I am happy to investigate more about it but definitely some your input
> would help.

Sorry: we usually try to do things the right way but it looks like this got 
lost in the shuffle.  It really doesn't look like there's any 
architecture-specific code implementation on our end:

    commit 251a44888183003b0380df184835a2c00bfa39d7
    Author: Wesley Terpstra <wesley@sifive.com>
    Date:   Mon May 20 10:29:26 2019 -0700
    
        riscv: include generic support for MSI irqdomains
    
        Some RISC-V systems include PCIe host controllers that support PCIe
        message-signaled interrupts.  For this to work on Linux, we need to
        enable PCI_MSI_IRQ_DOMAIN and define struct msi_alloc_info.  Support
        for the latter is enabled by including the architecture-generic msi.h
        include.
    
        Signed-off-by: Wesley Terpstra <wesley@sifive.com>
        [paul.walmsley@sifive.com: split initial patch into one arch/riscv
         patch and one drivers/pci patch]
        Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
    
    diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
    index 1efaeddf1e4b..16970f246860 100644
    --- a/arch/riscv/include/asm/Kbuild
    +++ b/arch/riscv/include/asm/Kbuild
    @@ -22,6 +22,7 @@ generic-y += kvm_para.h
     generic-y += local.h
     generic-y += local64.h
     generic-y += mm-arch-hooks.h
    +generic-y += msi.h
     generic-y += percpu.h
     generic-y += preempt.h
     generic-y += sections.h

I bet that dropping the architectures and adding msi.h everywhere it's not 
listed will at least get this building.  I'll give

    diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
    index a304f5ea11b9..77c1428cd945 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 || RISCV
    +       def_bool y
            depends on PCI_MSI
            select GENERIC_MSI_IRQ_DOMAIN
    
a build everywhere to see what falls out.