Subject: [PATCH 1/2] irqchip/gicv3-its: Support share device ID

From: [email-masked] (Marc Zyngier)
Date: Wed, 15 Apr 2015 17:36:54 +0100

On Wed, 15 Apr 2015 17:49:23 +0800
Minghuan Lian <[email-masked]> wrote:

> SMMU of some platforms can only isolate limited device ID.
> This may require that all PCI devices share the same ITS
> device with the fixed device ID. The patch adds function
> arch_msi_share_devid_update used for these platforms to update
> the fixed device ID and maximum MSI interrupts number.
> 
> Signed-off-by: Minghuan Lian <[email-masked]>
> ---
>  drivers/irqchip/irq-gic-v3-its.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index d0374a6..be78d0a 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -1169,6 +1169,15 @@ static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
>  	return 0;
>  }
>  
> +void __weak
> +arch_msi_share_devid_update(struct pci_dev *pdev, u32 *dev_id, u32 *nvesc)
> +{
> +	/*
> +	 * use PCI_DEVID NOT share device ID as default
> +	 * so nothing need to do
> +	 */
> +}
> +

NAK. On top of being ugly as sin, this breaks any form of multiplatform
support. No way anything like this is going in. Guys, you really should
know better.

>  static int its_msi_prepare(struct irq_domain *domain, struct device *dev,
>  			   int nvec, msi_alloc_info_t *info)
>  {
> @@ -1185,6 +1194,8 @@ static int its_msi_prepare(struct irq_domain *domain, struct device *dev,
>  	dev_alias.count = nvec;
>  
>  	pci_for_each_dma_alias(pdev, its_get_pci_alias, &dev_alias);
> +	arch_msi_share_devid_update(pdev, &dev_alias.dev_id, &dev_alias.count);
> +

See the function above? That's where the aliasing should be taken care
of.

>  	its = domain->parent->host_data;
>  
>  	its_dev = its_find_device(its, dev_alias.dev_id);

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny.