Subject: [RFC PATCH v1 1/3] PCI: designware: Add ARM64 support

From: [email-masked] (Fabrice Gasnier)
Date: Wed, 27 May 2015 18:19:57 +0200

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 {
>