genirq: Introduce callback irq_chip.irq_write_msi_msg

Introduce callback irq_chip.irq_write_msi_msg, so we can share common
code among MSI alike interrupt controllers, such as HPET and DMAR.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/irq.h

@@ -322,6 +322,7 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
  * @irq_release_resources:	optional to release resources acquired with
  *				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
  * @flags:		chip specific flags
  */
 struct irq_chip {
@@ -359,6 +360,7 @@ struct irq_chip {
 	void		(*irq_release_resources)(struct irq_data *data);
 
 	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);
 
 	unsigned long	flags;
 };
@@ -459,6 +461,12 @@ extern int irq_chip_set_affinity_parent(struct irq_data *data,
 					bool force);
 #endif
 
+static inline void irq_chip_write_msi_msg(struct irq_data *data,
+					  struct msi_msg *msg)
+{
+	data->chip->irq_write_msi_msg(data, msg);
+}
+
 /* Handling of unhandled and spurious interrupts: */
 extern void note_interrupt(unsigned int irq, struct irq_desc *desc,
 			   irqreturn_t action_ret);