powerpc/powernv: Patch MSI EOI handler on P8

The EOI handler of MSI/MSI-X interrupts for P8 (PHB3) need additional
steps to handle the P/Q bits in IVE before EOIing the corresponding
interrupt. The patch changes the EOI handler to cover that. we have
individual IRQ chip in each PHB instance. During the MSI IRQ setup
time, the IRQ chip is copied over from the original one for that IRQ,
and the EOI handler is patched with the one that will handle the P/Q
bits (As Ben suggested).

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 3d4e958..3f88c51 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -31,6 +31,7 @@
 #include <asm/opal.h>
 #include <asm/iommu.h>
 #include <asm/tce.h>
+#include <asm/xics.h>
 
 #include "powernv.h"
 #include "pci.h"
@@ -589,11 +590,27 @@
 }
 
 #ifdef CONFIG_PCI_MSI
+static void pnv_ioda2_msi_eoi(struct irq_data *d)
+{
+	unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct pnv_phb *phb = container_of(chip, struct pnv_phb,
+					   ioda.irq_chip);
+	int64_t rc;
+
+	rc = opal_pci_msi_eoi(phb->opal_id, hw_irq);
+	WARN_ON_ONCE(rc);
+
+	icp_native_eoi(d);
+}
+
 static int pnv_pci_ioda_msi_setup(struct pnv_phb *phb, struct pci_dev *dev,
-				  unsigned int hwirq, unsigned int is_64,
-				  struct msi_msg *msg)
+				  unsigned int hwirq, unsigned int virq,
+				  unsigned int is_64, struct msi_msg *msg)
 {
 	struct pnv_ioda_pe *pe = pnv_ioda_get_pe(dev);
+	struct irq_data *idata;
+	struct irq_chip *ichip;
 	unsigned int xive_num = hwirq - phb->msi_base;
 	uint64_t addr64;
 	uint32_t addr32, data;
@@ -638,6 +655,23 @@
 	}
 	msg->data = data;
 
+	/*
+	 * Change the IRQ chip for the MSI interrupts on PHB3.
+	 * The corresponding IRQ chip should be populated for
+	 * the first time.
+	 */
+	if (phb->type == PNV_PHB_IODA2) {
+		if (!phb->ioda.irq_chip_init) {
+			idata = irq_get_irq_data(virq);
+			ichip = irq_data_get_irq_chip(idata);
+			phb->ioda.irq_chip_init = 1;
+			phb->ioda.irq_chip = *ichip;
+			phb->ioda.irq_chip.irq_eoi = pnv_ioda2_msi_eoi;
+		}
+
+		irq_set_chip(virq, &phb->ioda.irq_chip);
+	}
+
 	pr_devel("%s: %s-bit MSI on hwirq %x (xive #%d),"
 		 " address=%x_%08x data=%x PE# %d\n",
 		 pci_name(dev), is_64 ? "64" : "32", hwirq, xive_num,