Re: [patch V2 43/46] genirq/msi: Provide and use msi_domain_set_default_info_flags()
From: Marc Zyngier <maz@kernel.org>
Date: 2020-08-27 08:17:37
Also in:
linux-iommu, linux-pci, lkml, xen-devel
On 2020-08-26 12:17, Thomas Gleixner wrote:
quoted hunk ↗ jump to hunk
MSI interrupts have some common flags which should be set not only for PCI/MSI interrupts. Move the PCI/MSI flag setting into a common function so it can be reused. Signed-off-by: Thomas Gleixner <redacted> --- V2: New patch --- drivers/pci/msi.c | 7 +------ include/linux/msi.h | 1 + kernel/irq/msi.c | 24 ++++++++++++++++++++++++ 3 files changed, 26 insertions(+), 6 deletions(-)--- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c@@ -1469,12 +1469,7 @@ struct irq_domain *pci_msi_create_irq_do if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS) pci_msi_domain_update_chip_ops(info); - info->flags |= MSI_FLAG_ACTIVATE_EARLY; - if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE)) - info->flags |= MSI_FLAG_MUST_REACTIVATE; - - /* PCI-MSI is oneshot-safe */ - info->chip->flags |= IRQCHIP_ONESHOT_SAFE; + msi_domain_set_default_info_flags(info); domain = msi_create_irq_domain(fwnode, info, parent); if (!domain) --- a/include/linux/msi.h +++ b/include/linux/msi.h@@ -410,6 +410,7 @@ int platform_msi_domain_alloc(struct irq void platform_msi_domain_free(struct irq_domain *domain, unsigned intvirq, unsigned int nvec); void *platform_msi_get_host_data(struct irq_domain *domain); +void msi_domain_set_default_info_flags(struct msi_domain_info *info); #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */ #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN--- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c@@ -70,6 +70,30 @@ void get_cached_msi_msg(unsigned int irq EXPORT_SYMBOL_GPL(get_cached_msi_msg); #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN +void msi_domain_set_default_info_flags(struct msi_domain_info *info) +{ + /* Required so that a device latches a valid MSI message on startup*/ + info->flags |= MSI_FLAG_ACTIVATE_EARLY;
As far as I remember the story behind this flag (it's been a while),
it was working around a PCI-specific issue, hence being located in
the PCI code.
Now, the "program the MSI before enabling it" concept makes sense no
matter
what bus this is on, and I wonder why we are even keeping this flag
around.
Can't we just drop it together with the check in
msi_domain_alloc_irqs()?
Thanks,
M.
--
Jazz is not dead. It just smells funny...