PCI devices support MSI, MSIX as well as multiple MSI.
But pSeries does not support multiple MSI yet.

This patch enable multiple MSI feature in pSeries.

Signed-off-by: Mike Qiu <qiud...@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/msi.c            |    4 --
 arch/powerpc/platforms/pseries/msi.c |   62 ++++++++++++++++++++++++++++++++-
 2 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/msi.c b/arch/powerpc/kernel/msi.c
index 8bbc12d..46b1470 100644
--- a/arch/powerpc/kernel/msi.c
+++ b/arch/powerpc/kernel/msi.c
@@ -20,10 +20,6 @@ int arch_msi_check_device(struct pci_dev* dev, int nvec, int 
type)
                return -ENOSYS;
        }
 
-       /* PowerPC doesn't support multiple MSI yet */
-       if (type == PCI_CAP_ID_MSI && nvec > 1)
-               return 1;
-
        if (ppc_md.msi_check_device) {
                pr_debug("msi: Using platform check routine.\n");
                return ppc_md.msi_check_device(dev, nvec, type);
diff --git a/arch/powerpc/platforms/pseries/msi.c 
b/arch/powerpc/platforms/pseries/msi.c
index e5b0847..6633b18 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -132,13 +132,17 @@ static int rtas_query_irq_number(struct pci_dn *pdn, int 
offset)
 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
 {
        struct msi_desc *entry;
+       int nvec, i;
 
        list_for_each_entry(entry, &pdev->msi_list, list) {
                if (entry->irq == NO_IRQ)
                        continue;
 
                irq_set_msi_desc(entry->irq, NULL);
-               irq_dispose_mapping(entry->irq);
+               nvec = entry->msi_attrib.is_msix ? 1 : 1 <<
+                                       entry->msi_attrib.multiple;
+               for (i = 0; i < nvec; i++)
+                       irq_dispose_mapping(entry->irq + i);
        }
 
        rtas_disable_msi(pdev);
@@ -392,6 +396,55 @@ static int check_msix_entries(struct pci_dev *pdev)
        return 0;
 }
 
+static int setup_multiple_msi_irqs(struct pci_dev *pdev, int nvec)
+{
+       struct pci_dn *pdn;
+       int hwirq, virq_base, i, hwirq_base = 0;
+       struct msi_desc *entry;
+       struct msi_msg msg;
+
+       pdn = get_pdn(pdev);
+       entry = list_entry(pdev->msi_list.next, typeof(*entry), list);
+
+       /*
+        * Get the hardware IRQ base and ensure the retrieved
+        * hardware IRQs are continuous
+        */
+       for (i = 0; i < nvec; i++) {
+               hwirq = rtas_query_irq_number(pdn, i);
+               if (i == 0)
+                       hwirq_base = hwirq;
+
+               if (hwirq < 0 || hwirq != (hwirq_base + i)) {
+                       pr_debug("rtas_msi: Failure to get %d IRQs on"
+                               "PCI device %04x:%02x:%02x.%01x\n", nvec,
+                               pci_domain_nr(pdev->bus), pdev->bus->number,
+                               PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+                       return hwirq;
+               }
+       }
+
+       virq_base = irq_create_mapping_many(NULL, hwirq_base, nvec);
+       if (virq_base <= 0) {
+               pr_debug("rtas_msi: Failure to map IRQs (%d, %d) "
+                       "for PCI device %04x:%02x:%02x.%01x\n",
+                       hwirq_base, nvec, pci_domain_nr(pdev->bus),
+                       pdev->bus->number, PCI_SLOT(pdev->devfn),
+                       PCI_FUNC(pdev->devfn));
+               return -ENOSPC;
+       }
+
+       entry->msi_attrib.multiple = ilog2(nvec & 0x3f);
+       irq_set_multiple_msi_desc(virq_base, nvec, entry);
+       for (i = 0; i < nvec; i++) {
+               /* Read config space back so we can restore after reset */
+               read_msi_msg(virq_base + i, &msg);
+               entry->msg = msg;
+       }
+
+       return 0;
+}
+
 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
 {
        struct pci_dn *pdn;
@@ -444,11 +497,16 @@ again:
                return rc;
        }
 
+       if (type == PCI_CAP_ID_MSI && nvec > 1) {
+               rc = setup_multiple_msi_irqs(pdev, nvec);
+               return rc;
+       }
+
        i = 0;
        list_for_each_entry(entry, &pdev->msi_list, list) {
                hwirq = rtas_query_irq_number(pdn, i++);
                if (hwirq < 0) {
-                       pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
+                       pr_debug("rtas_msi: error (%d) getting hwirq\n", nvec);
                        return hwirq;
                }
 
-- 
1.7.7.6

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