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

From: [email-masked] (Zhou Wang)
Date: Thu, 28 May 2015 19:34:52 +0800

On 2015/5/27 23:43, 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
> 
> 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;
> +#endif
>  
>  			list_add(&sys->node, head);
>  		} else {
> 

Hi Arnd,

I think it does not work in above way(with adaptation as Fabrice mentioned).
As the msi controller is passed to secondary bus one by one during the process of enumeration.
Here we just set msi controller for root bus.

Best Regards,
Zhou

> .