xen/x86/PCI: Add support for the Xen PCI subsystem
The frontend stub lives in arch/x86/pci/xen.c, alongside other
sub-arch PCI init code (e.g. olpc.c).
It provides a mechanism for Xen PCI frontend to setup/destroy
legacy interrupts, MSI/MSI-X, and PCI configuration operations.
[ Impact: add core of Xen PCI support ]
[ v2: Removed the IOMMU code and only focusing on PCI.]
[ v3: removed usage of pci_scan_all_fns as that does not exist]
[ v4: introduced pci_xen value to fix compile warnings]
[ v5: squished fixes+features in one patch, changed Reviewed-by to Ccs]
[ v7: added Acked-by]
Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Qing He <qing.he@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
new file mode 100644
index 0000000..b19c873
--- /dev/null
+++ b/arch/x86/pci/xen.c
@@ -0,0 +1,147 @@
+/*
+ * Xen PCI Frontend Stub - puts some "dummy" functions in to the Linux
+ * x86 PCI core to support the Xen PCI Frontend
+ *
+ * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/acpi.h>
+
+#include <linux/io.h>
+#include <asm/pci_x86.h>
+
+#include <asm/xen/hypervisor.h>
+
+#include <xen/events.h>
+#include <asm/xen/pci.h>
+
+#if defined(CONFIG_PCI_MSI)
+#include <linux/msi.h>
+
+struct xen_pci_frontend_ops *xen_pci_frontend;
+EXPORT_SYMBOL_GPL(xen_pci_frontend);
+
+/*
+ * For MSI interrupts we have to use drivers/xen/event.s functions to
+ * allocate an irq_desc and setup the right */
+
+
+static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+ int irq, ret, i;
+ struct msi_desc *msidesc;
+ int *v;
+
+ v = kzalloc(sizeof(int) * max(1, nvec), GFP_KERNEL);
+ if (!v)
+ return -ENOMEM;
+
+ if (!xen_initial_domain()) {
+ if (type == PCI_CAP_ID_MSIX)
+ ret = xen_pci_frontend_enable_msix(dev, &v, nvec);
+ else
+ ret = xen_pci_frontend_enable_msi(dev, &v);
+ if (ret)
+ goto error;
+ }
+ i = 0;
+ list_for_each_entry(msidesc, &dev->msi_list, list) {
+ irq = xen_allocate_pirq(v[i], 0, /* not sharable */
+ (type == PCI_CAP_ID_MSIX) ?
+ "pcifront-msi-x" : "pcifront-msi");
+ if (irq < 0)
+ return -1;
+
+ ret = set_irq_msi(irq, msidesc);
+ if (ret)
+ goto error_while;
+ i++;
+ }
+ kfree(v);
+ return 0;
+
+error_while:
+ unbind_from_irqhandler(irq, NULL);
+error:
+ if (ret == -ENODEV)
+ dev_err(&dev->dev, "Xen PCI frontend has not registered" \
+ " MSI/MSI-X support!\n");
+
+ kfree(v);
+ return ret;
+}
+
+static void xen_teardown_msi_irqs(struct pci_dev *dev)
+{
+ /* Only do this when were are in non-privileged mode.*/
+ if (!xen_initial_domain()) {
+ struct msi_desc *msidesc;
+
+ msidesc = list_entry(dev->msi_list.next, struct msi_desc, list);
+ if (msidesc->msi_attrib.is_msix)
+ xen_pci_frontend_disable_msix(dev);
+ else
+ xen_pci_frontend_disable_msi(dev);
+ }
+
+}
+
+static void xen_teardown_msi_irq(unsigned int irq)
+{
+ xen_destroy_irq(irq);
+}
+#endif
+
+static int xen_pcifront_enable_irq(struct pci_dev *dev)
+{
+ int rc;
+ int share = 1;
+
+ dev_info(&dev->dev, "Xen PCI enabling IRQ: %d\n", dev->irq);
+
+ if (dev->irq < 0)
+ return -EINVAL;
+
+ if (dev->irq < NR_IRQS_LEGACY)
+ share = 0;
+
+ rc = xen_allocate_pirq(dev->irq, share, "pcifront");
+ if (rc < 0) {
+ dev_warn(&dev->dev, "Xen PCI IRQ: %d, failed to register:%d\n",
+ dev->irq, rc);
+ return rc;
+ }
+ return 0;
+}
+
+int __init pci_xen_init(void)
+{
+ if (!xen_pv_domain() || xen_initial_domain())
+ return -ENODEV;
+
+ printk(KERN_INFO "PCI: setting up Xen PCI frontend stub\n");
+
+ pcibios_set_cache_line_size();
+
+ pcibios_enable_irq = xen_pcifront_enable_irq;
+ pcibios_disable_irq = NULL;
+
+#ifdef CONFIG_ACPI
+ /* Keep ACPI out of the picture */
+ acpi_noirq = 1;
+#endif
+
+#ifdef CONFIG_ISAPNP
+ /* Stop isapnp from probing */
+ isapnp_disable = 1;
+#endif
+
+#ifdef CONFIG_PCI_MSI
+ x86_msi.setup_msi_irqs = xen_setup_msi_irqs;
+ x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
+ x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
+#endif
+ return 0;
+}