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Date: Wed, 27 May 2015 18:19:57 +0200
From: Fabrice Gasnier <fabrice.gasnier@st.com>
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To: Arnd Bergmann <arnd@arndb.de>,
	<linux-arm-kernel@lists.infradead.org>
CC: Zhou Wang <wangzhou1@hisilicon.com>, <zhudacai@hisilicon.com>,
	<devicetree@vger.kernel.org>,
	"'Zhang Jukuo'" <zhangjukuo@huawei.com>,
	"'Gabriele Paoloni'" <gabriele.paoloni@huawei.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	"'Pratyush Anand'" <pratyush.anand@gmail.com>,
	"'Richard Zhu'" <Richard.Zhu@freescale.com>,
	"'Zhichang Yuan'" <yuanzhichang@hisilicon.com>,
	"'Kishon Vijay Abraham I'" <kishon@ti.com>,
	<qiuzhenfa@hisilicon.com>, <linux-pci@vger.kernel.org>,
	"'Bjorn Helgaas'" <bhelgaas@google.com>,
	"'Liviu Dudau'" <liviu.dudau@arm.com>,
	"'Liguozhu'" <liguozhu@hisilicon.com>,
	"'Lucas Stach'" <l.stach@pengutronix.de>
Subject: Re: [RFC PATCH v1 1/3] PCI: designware: Add ARM64 support
References: <000001d096a9$27bf43f0$773dcbd0$@com> <5565CD0B.6020206@hisilicon.com> <2378629.Ocol8HRDqD@wuerfel> <2095085.CuXXeGT0Wg@wuerfel>
In-Reply-To: <2095085.CuXXeGT0Wg@wuerfel>
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List-ID: <linux-pci.vger.kernel.org>

On 05/27/2015 05:43 PM, Arnd Bergmann wrote:
> On Wednesday 27 May 2015 17:31:46 Arnd Bergmann wrote:
>> Yes, that works. However there are two problems with the approach:
>>
>> - we have to change all PCI host drivers on ARM to do this in order to remove
>>    the ARM-specific pcibios_msi_controller() function
>> - it's possible that there are dw_pcie implementations that do not include
>>    an MSI controller, so that pointer would be NULL, which leads to the
>>    core code to still call the ARM-specific pcibios_msi_controller() function
>>    unless we remove it.
> I wonder if this simple patch would be sufficient to kill off
> pcibios_msi_controller().
>
> Can one of you try it?
>
> 	Arnd

Hi Arnd,
I tested it quickly on my platform, with and without CONFIG_PCI_MSI.
In both case it seems to run fine with dw pcie.

>
> diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
> index fcbbbb1b9e95..7afb6d253162 100644
> --- a/arch/arm/kernel/bios32.c
> +++ b/arch/arm/kernel/bios32.c
> @@ -18,15 +18,6 @@
>   
>   static int debug_pci;
>   
> -#ifdef CONFIG_PCI_MSI
> -struct msi_controller *pcibios_msi_controller(struct pci_dev *dev)
> -{
> -	struct pci_sys_data *sysdata = dev->bus->sysdata;
> -
> -	return sysdata->msi_ctrl;
> -}
> -#endif
> -
>   /*
>    * We can't use pci_get_device() here since we are
>    * called from interrupt context.
> @@ -462,9 +453,6 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
>   		if (!sys)
>   			panic("PCI: unable to allocate sys data!");
>   
> -#ifdef CONFIG_PCI_MSI
> -		sys->msi_ctrl = hw->msi_ctrl;
> -#endif
>   		sys->busnr   = busnr;
>   		sys->swizzle = hw->swizzle;
>   		sys->map_irq = hw->map_irq;
> @@ -493,6 +481,9 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
>   				panic("PCI: unable to scan bus!");
>   
>   			busnr = sys->bus->busn_res.end + 1;
> +#ifdef CONFIG_PCI_MSI
> +			bus->msi = hw->msi_ctrl;

(with small adaptation here: s/bus->msi/sys->bus->msi)

BR,
Fabrice
> +#endif
>   
>   			list_add(&sys->node, head);
>   		} else {
>