drivers/pci/msi/pcidev_msi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MSI[X} related functions which are available unconditionally.
   4  */
   5 #include "../pci.h"
   6
   7 /*
   8  * Disable the MSI[X] hardware to avoid screaming interrupts during boot.
   9  * This is the power on reset default so usually this should be a noop.
  10  */
  11
  12 void pci_msi_init(struct pci_dev *dev)
  13 {
  14         u16 ctrl;
  15
  16         dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
  17         if (!dev->msi_cap)
  18                 return;
  19
  20         pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &ctrl);
  21         if (ctrl & PCI_MSI_FLAGS_ENABLE) {
  22                 pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS,
  23                                       ctrl & ~PCI_MSI_FLAGS_ENABLE);
  24         }
  25
  26         if (!(ctrl & PCI_MSI_FLAGS_64BIT))
  27                 dev->no_64bit_msi = 1;
  28 }
  29
  30 void pci_msix_init(struct pci_dev *dev)
  31 {
  32         u16 ctrl;
  33
  34         dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
  35         if (!dev->msix_cap)
  36                 return;
  37
  38         pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
  39         if (ctrl & PCI_MSIX_FLAGS_ENABLE) {
  40                 pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS,
  41                                       ctrl & ~PCI_MSIX_FLAGS_ENABLE);
  42         }
  43 }