Hi Marc,
On 3/25/2021 10:53 AM, Marc Zyngier wrote:
On Fri, 26 Feb 2021 20:11:17 +0000,
Megha Dey <megha.dey@xxxxxxxxx> wrote:
From: Dave Jiang <dave.jiang@xxxxxxxxx>
Add new helpers to get the Linux IRQ number and device specific index
for given device-relative vector so that the drivers don't need to
allocate their own arrays to keep track of the vectors and hwirq for
the multi vector device MSI case.
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Signed-off-by: Megha Dey <megha.dey@xxxxxxxxx>
---
include/linux/msi.h | 2 ++
kernel/irq/msi.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 24abec0..d60a6ba 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -451,6 +451,8 @@ struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
irq_write_msi_msg_t write_msi_msg);
void platform_msi_domain_free_irqs(struct device *dev);
+int msi_irq_vector(struct device *dev, unsigned int nr);
+int dev_msi_hwirq(struct device *dev, unsigned int nr);
/* When an MSI domain is used as an intermediate domain */
int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 047b59d..f2a8f55 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -581,4 +581,48 @@ struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
return (struct msi_domain_info *)domain->host_data;
}
+/**
+ * msi_irq_vector - Get the Linux IRQ number of a device vector
+ * @dev: device to operate on
+ * @nr: device-relative interrupt vector index (0-based).
+ *
+ * Returns the Linux IRQ number of a device vector.
+ */
+int msi_irq_vector(struct device *dev, unsigned int nr)
+{
+ struct msi_desc *entry;
+ int i = 0;
+
+ for_each_msi_entry(entry, dev) {
+ if (i == nr)
+ return entry->irq;
+ i++;
This obviously doesn't work with Multi-MSI, does it?
This API is only for devices that support device MSI interrupts. They
follow MSI-x format and don't support multi MSI (part of MSI).
Not sure if I am missing something here, can you please let me know?
+ }
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(msi_irq_vector);
+
+/**
+ * dev_msi_hwirq - Get the device MSI hw IRQ number of a device vector
+ * @dev: device to operate on
+ * @nr: device-relative interrupt vector index (0-based).
+ *
+ * Return the dev_msi hw IRQ number of a device vector.
+ */
+int dev_msi_hwirq(struct device *dev, unsigned int nr)
+{
+ struct msi_desc *entry;
+ int i = 0;
+
+ for_each_msi_entry(entry, dev) {
+ if (i == nr)
+ return entry->device_msi.hwirq;
+ i++;
+ }
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(dev_msi_hwirq);
+
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
And what uses these helpers?]
These helpers are to be used by a driver series(Intel's IDXD driver)
which is currently stuck due to VFIO refactoring.
Thanks,
M.
