[PATCH 08/12] genirq: Set auxiliary data for an interrupt

Megha Dey
2021-02-03T21:03:06Z

Introduce a new function pointer in the irq_chip structure(irq_set_auxdata)
which is responsible for updating data which is stored in a shared register
or data storage. For example, the idxd driver uses the auxiliary data API
to enable/set and disable PASID field that is in the IMS entry (introduced
in a later patch) and that data are not typically present in MSI entry.

Reviewed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Megha Dey <megha.dey@intel.com>
---
include/linux/interrupt.h | 2 ++
include/linux/irq.h | 4 ++++
kernel/irq/manage.c | 32 ++++++++++++++++++++++++++++++++
3 files changed, 38 insertions(+)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index bb8ff90..d3f419b 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -496,6 +496,8 @@ extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
bool state);

+int irq_set_auxdata(unsigned int irq, unsigned int which, u64 val);
+
#ifdef CONFIG_IRQ_FORCED_THREADING
# ifdef CONFIG_PREEMPT_RT
# define force_irqthreads (true)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 4aeb1c4..568cdf5 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -491,6 +491,8 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
* irq_request_resources
* @irq_compose_msi_msg: optional to compose message content for MSI
* @irq_write_msi_msg: optional to write message content for MSI
+ * @irq_set_auxdata: Optional function to update auxiliary data e.g. in
+ * shared registers
* @irq_get_irqchip_state: return the internal state of an interrupt
* @irq_set_irqchip_state: set the internal state of a interrupt
* @irq_set_vcpu_affinity: optional to target a vCPU in a virtual machine
@@ -538,6 +540,8 @@ struct irq_chip {
void (*irq_compose_msi_msg)(struct irq_data *data, struct msi_msg *msg);
void (*irq_write_msi_msg)(struct irq_data *data, struct msi_msg *msg);

+ int (*irq_set_auxdata)(struct irq_data *data, unsigned int which, u64 auxval);
+
int (*irq_get_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool *state);
int (*irq_set_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool state);

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 85ede4e..68ff559 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -2860,3 +2860,35 @@ bool irq_check_status_bit(unsigned int irq, unsigned int bitmask)
return res;
}
EXPORT_SYMBOL_GPL(irq_check_status_bit);
+
+/**
+ * irq_set_auxdata - Set auxiliary data
+ * @irq: Interrupt to update
+ * @which: Selector which data to update
+ * @auxval: Auxiliary data value
+ *
+ * Function to update auxiliary data for an interrupt, e.g. to update data
+ * which is stored in a shared register or data storage (e.g. IMS).
+ */
+int irq_set_auxdata(unsigned int irq, unsigned int which, u64 val)
+{
+ struct irq_desc *desc;
+ struct irq_data *data;
+ unsigned long flags;
+ int res = -ENODEV;
+
+ desc = irq_get_desc_buslock(irq, &flags, 0);
+ if (!desc)
+ return -EINVAL;
+
+ for (data = &desc->irq_data; data; data = irqd_get_parent_data(data)) {
+ if (data->chip->irq_set_auxdata) {
+ res = data->chip->irq_set_auxdata(data, which, val);
+ break;
+ }
+ }
+
+ irq_put_desc_busunlock(desc, flags);
+ return res;
+}
+EXPORT_SYMBOL_GPL(irq_set_auxdata);
--
2.7.4