arch/i386/kernel/quirks-xen.c

   1 /*
   2  * This file contains work-arounds for x86 and x86_64 platform bugs.
   3  */
   4 #include <linux/pci.h>
   5 #include <linux/irq.h>
   6
   7 #if defined(CONFIG_X86_IO_APIC) && (defined(CONFIG_SMP) || defined(CONFIG_XEN)) && defined(CONFIG_PCI)
   8
   9 static void __devinit quirk_intel_irqbalance(struct pci_dev *dev)
  10 {
  11         u8 config, rev;
  12         u32 word;
  13
  14         /* BIOS may enable hardware IRQ balancing for
  15          * E7520/E7320/E7525(revision ID 0x9 and below)
  16          * based platforms.
  17          * Disable SW irqbalance/affinity on those platforms.
  18          */
  19         pci_read_config_byte(dev, PCI_CLASS_REVISION, &rev);
  20         if (rev > 0x9)
  21                 return;
  22
  23         printk(KERN_INFO "Intel E7520/7320/7525 detected.");
  24
  25         /* enable access to config space*/
  26         pci_read_config_byte(dev, 0xf4, &config);
  27         pci_write_config_byte(dev, 0xf4, config|0x2);
  28
  29         /* read xTPR register */
  30         raw_pci_ops->read(0, 0, 0x40, 0x4c, 2, &word);
  31
  32         if (!(word & (1 << 13))) {
  33                 dom0_op_t op;
  34                 printk(KERN_INFO "Disabling irq balancing and affinity\n");
  35                 op.cmd = DOM0_PLATFORM_QUIRK;
  36                 op.u.platform_quirk.quirk_id = QUIRK_NOIRQBALANCING;
  37                 (void)HYPERVISOR_dom0_op(&op);
  38         }
  39
  40         /* put back the original value for config space*/
  41         if (!(config & 0x2))
  42                 pci_write_config_byte(dev, 0xf4, config);
  43 }
  44 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,    PCI_DEVICE_ID_INTEL_E7320_MCH,  quirk_intel_irqbalance);
  45 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,    PCI_DEVICE_ID_INTEL_E7525_MCH,  quirk_intel_irqbalance);
  46 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,    PCI_DEVICE_ID_INTEL_E7520_MCH,  quirk_intel_irqbalance);
  47 #endif