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

[Varun Sethi]

Hi Minghuan,
Not clear what this patch intends to do. Can you please explain the point about SMMU isolating limited device ID.

Regards
Varun

> -----Original Message-----
> From: linux-arm-kernel [mailto:linux-arm-kernel-
> bounces at lists.infradead.org] On Behalf Of Minghuan Lian
> Sent: Wednesday, April 15, 2015 3:19 PM
> To: linux-pci at vger.kernel.org
> Cc: Arnd Bergmann; Lian Minghuan-B31939; Hu Mingkai-B21284; Zang Roy-
> R61911; Yoder Stuart-B08248; Bjorn Helgaas; Wood Scott-B07421; linux-arm-
> kernel at lists.infradead.org
> Subject: [PATCH 1/2] irqchip/gicv3-its: Support share device ID
> 
> 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 <Minghuan.Lian at freescale.com>
> ---
>  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
> +	 */
> +}
> +
>  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);
> +
>  	its = domain->parent->host_data;
> 
>  	its_dev = its_find_device(its, dev_alias.dev_id);
> --
> 1.9.1
> 
> 
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