Hi,
On 02/08/2016 19:23, Eric Auger wrote:
> This new flags member is meant to store additional information about
> the msi descriptor, starting with allocation status information.
>
> MSI_DESC_FLAG_ALLOCATED bit tells the associated base IRQ is allocated.
> This information is currently used at deallocation time. We also
> introduce MSI_DESC_FLAG_FUNCTIONAL telling the MSIs are functional.
>
> For the time being ALLOCATED and FUNCTIONAL are set at the same time
> but this is going to change in subsequent patch. Indeed in some situations
> some additional tasks need to be carried out for the MSI to be functional.
> For instance the MSI doorbell may need to be mapped in an IOMMU.
>
> FUNCTIONAL value already gets used when enumerating the usable MSIs in
> msix_capability_init.
>
> Signed-off-by: Eric Auger <eric.au...@redhat.com>
>
> ---
>
> v12: new
> ---
> drivers/pci/msi.c | 2 +-
> include/linux/msi.h | 14 ++++++++++++++
> kernel/irq/msi.c | 7 ++++++-
> 3 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index a080f44..d7733ea 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -793,7 +793,7 @@ out_avail:
> int avail = 0;
>
> for_each_pci_msi_entry(entry, dev) {
> - if (entry->irq != 0)
> + if (entry->flags & MSI_DESC_FLAG_FUNCTIONAL)
> avail++;
> }
> if (avail != 0)
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 8b425c6..18f894f 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -47,6 +47,7 @@ struct fsl_mc_msi_desc {
> * @nvec_used: The number of vectors used
> * @dev: Pointer to the device which uses this descriptor
> * @msg: The last set MSI message cached for reuse
> + * @flags: flags to describe the MSI descriptor status or features
> *
> * @masked: [PCI MSI/X] Mask bits
> * @is_msix: [PCI MSI/X] True if MSI-X
> @@ -67,6 +68,7 @@ struct msi_desc {
> unsigned int nvec_used;
> struct device *dev;
> struct msi_msg msg;
> + u32 flags;
I will fix this bad alignment on next version
>
> union {
> /* PCI MSI/X specific data */
> @@ -99,6 +101,18 @@ struct msi_desc {
> };
> };
>
> +/* Flags for msi_desc */
> +enum {
> + /* the base IRQ is allocated */
> + MSI_DESC_FLAG_ALLOCATED = (1 << 0),
> + /**
> + * the MSI is functional; in some cases the fact the base IRQ is
> + * allocated is not sufficient for the MSIs to be functional: for
> + * example the MSI doorbell(s) may need to be IOMMU mapped.
> + */
> + MSI_DESC_FLAG_FUNCTIONAL = (1 << 1),
> +};
> +
> /* Helpers to hide struct msi_desc implementation details */
> #define msi_desc_to_dev(desc) ((desc)->dev)
> #define dev_to_msi_list(dev) (&(dev)->msi_list)
> diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
> index 72bf4d6..9b93766 100644
> --- a/kernel/irq/msi.c
> +++ b/kernel/irq/msi.c
> @@ -361,6 +361,9 @@ int msi_domain_alloc_irqs(struct irq_domain *domain,
> struct device *dev,
> return ret;
> }
>
> + desc->flags |= MSI_DESC_FLAG_ALLOCATED;
> + desc->flags |= MSI_DESC_FLAG_FUNCTIONAL;
> +
> for (i = 0; i < desc->nvec_used; i++)
> irq_set_msi_desc_off(virq, i, desc);
> }
> @@ -395,9 +398,11 @@ void msi_domain_free_irqs(struct irq_domain *domain,
> struct device *dev)
> * enough that there is no IRQ associated to this
> * entry. If that's the case, don't do anything.
> */
> - if (desc->irq) {
> + if (desc->flags & MSI_DESC_FLAG_ALLOCATED) {
> irq_domain_free_irqs(desc->irq, desc->nvec_used);
> desc->irq = 0;
> + desc->flags &= ~MSI_DESC_FLAG_ALLOCATED;
> + desc->flags &= ~MSI_DESC_FLAG_FUNCTIONAL;
Also I will combine those settings
Thanks
Eric
> }
> }
> }
>
