MIPS: Netlogic: MSI enable fix for XLS
MSI interrupts do not work on XLS after commit a776c49
( "PCI: msi: Disable msi interrupts when we initialize a pci device" )
because the change disables MSI interrupts on the XLS PCIe bridges
during the PCI enumeration.
Fix this by enabling MSI interrupts on the bridge in the
arch_setup_msi_irq() function. A new function xls_get_pcie_link()
has been introduced to get the PCI device corresponding to the
top level PCIe bridge on which MSI has to be enabled.
Also, update get_irq_vector() to use the new xls_get_pcie_link()
function and PCI_SLOT() macro for determining the IRQ of PCI devices.
Signed-off-by: Ganesan Ramalingam <ganesanr@broadcom.com>
Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3753/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/pci/pci-xlr.c b/arch/mips/pci/pci-xlr.c
index 50ff4dc..172af1c 100644
--- a/arch/mips/pci/pci-xlr.c
+++ b/arch/mips/pci/pci-xlr.c
@@ -41,6 +41,7 @@
#include <linux/irq.h>
#include <linux/irqdesc.h>
#include <linux/console.h>
+#include <linux/pci_regs.h>
#include <asm/io.h>
@@ -156,35 +157,55 @@
.io_offset = 0x00000000UL,
};
+/*
+ * The top level PCIe links on the XLS PCIe controller appear as
+ * bridges. Given a device, this function finds which link it is
+ * on.
+ */
+static struct pci_dev *xls_get_pcie_link(const struct pci_dev *dev)
+{
+ struct pci_bus *bus, *p;
+
+ /* Find the bridge on bus 0 */
+ bus = dev->bus;
+ for (p = bus->parent; p && p->number != 0; p = p->parent)
+ bus = p;
+
+ return p ? bus->self : NULL;
+}
+
static int get_irq_vector(const struct pci_dev *dev)
{
+ struct pci_dev *lnk;
+
if (!nlm_chip_is_xls())
- return PIC_PCIX_IRQ; /* for XLR just one IRQ*/
+ return PIC_PCIX_IRQ; /* for XLR just one IRQ */
/*
* For XLS PCIe, there is an IRQ per Link, find out which
* link the device is on to assign interrupts
- */
- if (dev->bus->self == NULL)
+ */
+ lnk = xls_get_pcie_link(dev);
+ if (lnk == NULL)
return 0;
- switch (dev->bus->self->devfn) {
- case 0x0:
+ switch (PCI_SLOT(lnk->devfn)) {
+ case 0:
return PIC_PCIE_LINK0_IRQ;
- case 0x8:
+ case 1:
return PIC_PCIE_LINK1_IRQ;
- case 0x10:
+ case 2:
if (nlm_chip_is_xls_b())
return PIC_PCIE_XLSB0_LINK2_IRQ;
else
return PIC_PCIE_LINK2_IRQ;
- case 0x18:
+ case 3:
if (nlm_chip_is_xls_b())
return PIC_PCIE_XLSB0_LINK3_IRQ;
else
return PIC_PCIE_LINK3_IRQ;
}
- WARN(1, "Unexpected devfn %d\n", dev->bus->self->devfn);
+ WARN(1, "Unexpected devfn %d\n", lnk->devfn);
return 0;
}
@@ -202,7 +223,27 @@
int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
{
struct msi_msg msg;
+ struct pci_dev *lnk;
int irq, ret;
+ u16 val;
+
+ /* MSI not supported on XLR */
+ if (!nlm_chip_is_xls())
+ return 1;
+
+ /*
+ * Enable MSI on the XLS PCIe controller bridge which was disabled
+ * at enumeration, the bridge MSI capability is at 0x50
+ */
+ lnk = xls_get_pcie_link(dev);
+ if (lnk == NULL)
+ return 1;
+
+ pci_read_config_word(lnk, 0x50 + PCI_MSI_FLAGS, &val);
+ if ((val & PCI_MSI_FLAGS_ENABLE) == 0) {
+ val |= PCI_MSI_FLAGS_ENABLE;
+ pci_write_config_word(lnk, 0x50 + PCI_MSI_FLAGS, val);
+ }
irq = get_irq_vector(dev);
if (irq <= 0)