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

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Date:	Tue, 15 Jan 2013 15:38:56 +0800
From:	Mike Qiu <qiudayu@...ux.vnet.ibm.com>
To:	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Cc:	benh@...nel.crashing.org, tglx@...utronix.de,
	Mike Qiu <qiudayu@...ux.vnet.ibm.com>
Subject: [PATCH 3/3] powerpc/pci: Enable pSeries multiple MSI feature

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@...ux.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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