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genirq/msi: Provide interface to retrieve Linux interrupt number

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This allows drivers to retrieve the Linux interrupt number instead of
fiddling with MSI descriptors.

msi_get_virq() returns the Linux interrupt number or 0 in case that there
is no entry for the given MSI index.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221814.780824745@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-12-10 23:19:23 +01:00
parent 651b39c488
commit cf15f43aca
2 changed files with 38 additions and 0 deletions
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2
include/linux/msi.h
View File

@ -153,6 +153,8 @@ struct msi_device_data {
int msi_setup_device_data(struct device *dev);
unsigned int msi_get_virq(struct device *dev, unsigned int index);
/* 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)

36
kernel/irq/msi.c
View File

@ -105,6 +105,42 @@ int msi_setup_device_data(struct device *dev)
return 0;
}
/**
* msi_get_virq - Return Linux interrupt number of a MSI interrupt
* @dev: Device to operate on
* @index: MSI interrupt index to look for (0-based)
*
* Return: The Linux interrupt number on success (> 0), 0 if not found
*/
unsigned int msi_get_virq(struct device *dev, unsigned int index)
{
struct msi_desc *desc;
bool pcimsi;
if (!dev->msi.data)
return 0;
pcimsi = dev_is_pci(dev) ? to_pci_dev(dev)->msi_enabled : false;
for_each_msi_entry(desc, dev) {
/* PCI-MSI has only one descriptor for multiple interrupts. */
if (pcimsi) {
if (desc->irq && index < desc->nvec_used)
return desc->irq + index;
break;
}
/*
* PCI-MSIX and platform MSI use a descriptor per
* interrupt.
*/
if (desc->msi_index == index)
return desc->irq;
}
return 0;
}
EXPORT_SYMBOL_GPL(msi_get_virq);
#ifdef CONFIG_SYSFS
static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
char *buf)