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PCI: iproc: Support multi-MSI only on uniprocessor kernel

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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.

Link: https://lore.kernel.org/r/20210622152630.40842-2-sbodomerle@gmail.com
Fixes: fc54bae288 ("PCI: iproc: Allow allocation of multiple MSIs")
Reported-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Sandor Bodo-Merle <sbodomerle@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Ray Jui <ray.jui@broadcom.com>
This commit is contained in:
Sandor Bodo-Merle 2021-06-22 17:26:30 +02:00 committed by Lorenzo Pieralisi
parent e673d697b9
commit 2dc0a201d0
1 changed files with 7 additions and 1 deletions
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8
drivers/pci/controller/pcie-iproc-msi.c
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@ -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;
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");