iommu/amd: Add call-back routine for HPET MSI

Add a routine to setup a HPET MSI interrupt for remapping.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

drivers/iommu/amd_iommu.c

@@ -4200,4 +4200,30 @@ static int msi_setup_irq(struct pci_dev *pdev, unsigned int irq,
 	return 0;
 }
 
+static int setup_hpet_msi(unsigned int irq, unsigned int id)
+{
+	struct irq_2_iommu *irte_info;
+	struct irq_cfg *cfg;
+	int index, devid;
+
+	cfg = irq_get_chip_data(irq);
+	if (!cfg)
+		return -EINVAL;
+
+	irte_info = &cfg->irq_2_iommu;
+	devid     = get_hpet_devid(id);
+	if (devid < 0)
+		return devid;
+
+	index = alloc_irq_index(cfg, devid, 1);
+	if (index < 0)
+		return index;
+
+	irte_info->sub_handle = devid;
+	irte_info->irte_index = index;
+	irte_info->iommu      = (void *)cfg;
+
+	return 0;
+}
+
 #endif