On 6/6/2021 5:30 AM, Sandor Bodo-Merle wrote:
> The interrupt affinity scheme used by this driver is incompatible with
> multi-MSI as it implies moving the doorbell address to that of another MSI
> group. This isn't possible for multi-MSI, as all the MSIs must have the
> same doorbell address. As such it is restricted to systems with a single
> CPU.
>
> Fixes: fc54bae28818 ("PCI: iproc: Allow allocation of multiple MSIs")
> Reported-by: Marc Zyngier <maz@xxxxxxxxxx>
> Signed-off-by: Sandor Bodo-Merle <sbodomerle@xxxxxxxxx>
> ---
> drivers/pci/controller/pcie-iproc-msi.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/pcie-iproc-msi.c b/drivers/pci/controller/pcie-iproc-msi.c
> index 557d93dcb3bc..81b4effeb130 100644
> --- a/drivers/pci/controller/pcie-iproc-msi.c
> +++ b/drivers/pci/controller/pcie-iproc-msi.c
> @@ -171,7 +171,7 @@ static struct irq_chip iproc_msi_irq_chip = {
>
> static struct msi_domain_info iproc_msi_domain_info = {
> .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
> - MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX,
> + MSI_FLAG_PCI_MSIX,
> .chip = &iproc_msi_irq_chip,
> };
>
> @@ -250,6 +250,9 @@ static int iproc_msi_irq_domain_alloc(struct irq_domain *domain,
> struct iproc_msi *msi = domain->host_data;
> int hwirq, i;
>
> + if (msi->nr_cpus > 1 && nr_irqs > 1)
> + return -EINVAL;
> +
This should never happen since the framework would have guarded against
this. But I guess it does not hurt to have the check here.
> mutex_lock(&msi->bitmap_lock);
>
> /*
> @@ -540,6 +543,9 @@ int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node)
> mutex_init(&msi->bitmap_lock);
> msi->nr_cpus = num_possible_cpus();
>
> + if (msi->nr_cpus == 1)
> + iproc_msi_domain_info.flags |= MSI_FLAG_MULTI_PCI_MSI;
> +
> msi->nr_irqs = of_irq_count(node);
> if (!msi->nr_irqs) {
> dev_err(pcie->dev, "found no MSI GIC interrupt\n");
>
Looks fine to me. Thanks.
Acked-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
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