Commit 249e2a38 authored by Ganesan Ramalingam's avatar Ganesan Ramalingam Committed by Ralf Baechle
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MIPS: Netlogic: MSI enable fix for XLS 



MSI interrupts do not work on XLS after commit a776c491
( "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: default avatarGanesan Ramalingam <ganesanr@broadcom.com>
Signed-off-by: default avatarJayachandran C <jayachandranc@netlogicmicro.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3753/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent ea8e867d

arch/mips/pci/pci-xlr.c

+50 −9
Original line number Diff line number Diff line
@@ -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>
@@ -156,8 +157,27 @@ struct pci_controller nlm_pci_controller = { 
	.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 */
@@ -165,26 +185,27 @@ static int get_irq_vector(const struct pci_dev *dev) 
	 * 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 @@ void arch_teardown_msi_irq(unsigned int irq) 
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)

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