/** * pci_enable_msi - configure device's MSI capability structure * @dev: pointer to the pci_dev data structure of MSI device function * * Setup the MSI capability structure of device function with * a single MSI vector upon its software driver call to request for * MSI mode enabled on its hardware device function. A return of zero * indicates the successful setup of an entry zero with the new MSI * vector or non-zero for otherwise. **/ int pci_enable_msi(struct pci_dev* dev) { int pos, temp, status = -EINVAL; u16 control; if (!pci_msi_enable || !dev) return status; if (dev->no_msi) return status; temp = dev->irq; if ((status = msi_init()) < 0) return status; if (!(pos = pci_find_capability(dev, PCI_CAP_ID_MSI))) return -EINVAL; pci_read_config_word(dev, msi_control_reg(pos), &control); if (control & PCI_MSI_FLAGS_ENABLE) return 0; /* Already in MSI mode */ if (!msi_lookup_vector(dev, PCI_CAP_ID_MSI)) { /* Lookup Sucess */ unsigned long flags; spin_lock_irqsave(&msi_lock, flags); if (!vector_irq[dev->irq]) { msi_desc[dev->irq]->msi_attrib.state = 0; vector_irq[dev->irq] = -1; nr_released_vectors--; spin_unlock_irqrestore(&msi_lock, flags); enable_msi_mode(dev, pos, PCI_CAP_ID_MSI); return 0; } spin_unlock_irqrestore(&msi_lock, flags); dev->irq = temp; } /* Check whether driver already requested for MSI-X vectors */ if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)) > 0 && !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) { printk(KERN_INFO "PCI: %s: Can't enable MSI. " "Device already has MSI-X vectors assigned\n", pci_name(dev)); dev->irq = temp; return -EINVAL; } status = msi_capability_init(dev); if (!status) { if (!pos) nr_reserved_vectors--; /* Only MSI capable */ else if (nr_msix_devices > 0) nr_msix_devices--; /* Both MSI and MSI-X capable, but choose enabling MSI */ } return status; }
/** * pci_enable_msi - configure device's MSI capability structure * @dev: pointer to the pci_dev data structure of MSI device function * * Setup the MSI capability structure of device function with * a single MSI vector upon its software driver call to request for * MSI mode enabled on its hardware device function. A return of zero * indicates the successful setup of an entry zero with the new MSI * vector or non-zero for otherwise. **/ int pci_enable_msi(struct pci_dev* dev) { int pos, temp, status; if (pci_msi_supported(dev) < 0) return -EINVAL; temp = dev->irq; status = msi_init(); if (status < 0) return status; pos = pci_find_capability(dev, PCI_CAP_ID_MSI); if (!pos) return -EINVAL; WARN_ON(!msi_lookup_vector(dev, PCI_CAP_ID_MSI)); /* Check whether driver already requested for MSI-X vectors */ pos = pci_find_capability(dev, PCI_CAP_ID_MSIX); if (pos > 0 && !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) { printk(KERN_INFO "PCI: %s: Can't enable MSI. " "Device already has MSI-X vectors assigned\n", pci_name(dev)); dev->irq = temp; return -EINVAL; } status = msi_capability_init(dev); if (!status) { if (!pos) nr_reserved_vectors--; /* Only MSI capable */ } return status; }