[PATCH 3/3] powerpc/pci: Enable pSeries multiple MSI feature

Mike Qiu
2013-01-15T07:39:16Z

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 <qiudayu@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