arch/x86/pci/xen.c

   1 /*
   2  * Xen PCI Frontend Stub - puts some "dummy" functions in to the Linux
   3  *                         x86 PCI core to support the Xen PCI Frontend
   4  *
   5  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
   6  */
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/pci.h>
  10 #include <linux/acpi.h>
  11
  12 #include <linux/io.h>
  13 #include <asm/pci_x86.h>
  14
  15 #include <asm/xen/hypervisor.h>
  16
  17 #include <xen/events.h>
  18 #include <asm/xen/pci.h>
  19
  20 #if defined(CONFIG_PCI_MSI)
  21 #include <linux/msi.h>
  22
  23 struct xen_pci_frontend_ops *xen_pci_frontend;
  24 EXPORT_SYMBOL_GPL(xen_pci_frontend);
  25
  26 /*
  27  * For MSI interrupts we have to use drivers/xen/event.s functions to
  28  * allocate an irq_desc and setup the right */
  29
  30
  31 static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  32 {
  33         int irq, ret, i;
  34         struct msi_desc *msidesc;
  35         int *v;
  36
  37         v = kzalloc(sizeof(int) * max(1, nvec), GFP_KERNEL);
  38         if (!v)
  39                 return -ENOMEM;
  40
  41         if (!xen_initial_domain()) {
  42                 if (type == PCI_CAP_ID_MSIX)
  43                         ret = xen_pci_frontend_enable_msix(dev, &v, nvec);
  44                 else
  45                         ret = xen_pci_frontend_enable_msi(dev, &v);
  46                 if (ret)
  47                         goto error;
  48         }
  49         i = 0;
  50         list_for_each_entry(msidesc, &dev->msi_list, list) {
  51                 irq = xen_allocate_pirq(v[i], 0, /* not sharable */
  52                         (type == PCI_CAP_ID_MSIX) ?
  53                         "pcifront-msi-x" : "pcifront-msi");
  54                 if (irq < 0)
  55                         return -1;
  56
  57                 ret = set_irq_msi(irq, msidesc);
  58                 if (ret)
  59                         goto error_while;
  60                 i++;
  61         }
  62         kfree(v);
  63         return 0;
  64
  65 error_while:
  66         unbind_from_irqhandler(irq, NULL);
  67 error:
  68         if (ret == -ENODEV)
  69                 dev_err(&dev->dev, "Xen PCI frontend has not registered" \
  70                         " MSI/MSI-X support!\n");
  71
  72         kfree(v);
  73         return ret;
  74 }
  75
  76 static void xen_teardown_msi_irqs(struct pci_dev *dev)
  77 {
  78         /* Only do this when were are in non-privileged mode.*/
  79         if (!xen_initial_domain()) {
  80                 struct msi_desc *msidesc;
  81
  82                 msidesc = list_entry(dev->msi_list.next, struct msi_desc, list);
  83                 if (msidesc->msi_attrib.is_msix)
  84                         xen_pci_frontend_disable_msix(dev);
  85                 else
  86                         xen_pci_frontend_disable_msi(dev);
  87         }
  88
  89 }
  90
  91 static void xen_teardown_msi_irq(unsigned int irq)
  92 {
  93         xen_destroy_irq(irq);
  94 }
  95 #endif
  96
  97 static int xen_pcifront_enable_irq(struct pci_dev *dev)
  98 {
  99         int rc;
 100         int share = 1;
 101
 102         dev_info(&dev->dev, "Xen PCI enabling IRQ: %d\n", dev->irq);
 103
 104         if (dev->irq < 0)
 105                 return -EINVAL;
 106
 107         if (dev->irq < NR_IRQS_LEGACY)
 108                 share = 0;
 109
 110         rc = xen_allocate_pirq(dev->irq, share, "pcifront");
 111         if (rc < 0) {
 112                 dev_warn(&dev->dev, "Xen PCI IRQ: %d, failed to register:%d\n",
 113                          dev->irq, rc);
 114                 return rc;
 115         }
 116         return 0;
 117 }
 118
 119 int __init pci_xen_init(void)
 120 {
 121         if (!xen_pv_domain() || xen_initial_domain())
 122                 return -ENODEV;
 123
 124         printk(KERN_INFO "PCI: setting up Xen PCI frontend stub\n");
 125
 126         pcibios_set_cache_line_size();
 127
 128         pcibios_enable_irq = xen_pcifront_enable_irq;
 129         pcibios_disable_irq = NULL;
 130
 131 #ifdef CONFIG_ACPI
 132         /* Keep ACPI out of the picture */
 133         acpi_noirq = 1;
 134 #endif
 135
 136 #ifdef CONFIG_ISAPNP
 137         /* Stop isapnp from probing */
 138         isapnp_disable = 1;
 139 #endif
 140
 141 #ifdef CONFIG_PCI_MSI
 142         x86_msi.setup_msi_irqs = xen_setup_msi_irqs;
 143         x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
 144         x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
 145 #endif
 146         return 0;
 147 }