drivers/pci/msi/legacy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * PCI Message Signaled Interrupt (MSI).
   4  *
   5  * Legacy architecture specific setup and teardown mechanism.
   6  */
   7 #include "msi.h"
   8
   9 /* Arch hooks */
  10 int __weak arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
  11 {
  12         return -EINVAL;
  13 }
  14
  15 void __weak arch_teardown_msi_irq(unsigned int irq)
  16 {
  17 }
  18
  19 int __weak arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  20 {
  21         struct msi_desc *desc;
  22         int ret;
  23
  24         /*
  25          * If an architecture wants to support multiple MSI, it needs to
  26          * override arch_setup_msi_irqs()
  27          */
  28         if (type == PCI_CAP_ID_MSI && nvec > 1)
  29                 return 1;
  30
  31         msi_for_each_desc(desc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
  32                 ret = arch_setup_msi_irq(dev, desc);
  33                 if (ret)
  34                         return ret < 0 ? ret : -ENOSPC;
  35         }
  36
  37         return 0;
  38 }
  39
  40 void __weak arch_teardown_msi_irqs(struct pci_dev *dev)
  41 {
  42         struct msi_desc *desc;
  43         int i;
  44
  45         msi_for_each_desc(desc, &dev->dev, MSI_DESC_ASSOCIATED) {
  46                 for (i = 0; i < desc->nvec_used; i++)
  47                         arch_teardown_msi_irq(desc->irq + i);
  48         }
  49 }
  50
  51 static int pci_msi_setup_check_result(struct pci_dev *dev, int type, int ret)
  52 {
  53         struct msi_desc *desc;
  54         int avail = 0;
  55
  56         if (type != PCI_CAP_ID_MSIX || ret >= 0)
  57                 return ret;
  58
  59         /* Scan the MSI descriptors for successfully allocated ones. */
  60         msi_for_each_desc(desc, &dev->dev, MSI_DESC_ASSOCIATED)
  61                 avail++;
  62
  63         return avail ? avail : ret;
  64 }
  65
  66 int pci_msi_legacy_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  67 {
  68         int ret = arch_setup_msi_irqs(dev, nvec, type);
  69
  70         ret = pci_msi_setup_check_result(dev, type, ret);
  71         if (!ret)
  72                 ret = msi_device_populate_sysfs(&dev->dev);
  73         return ret;
  74 }
  75
  76 void pci_msi_legacy_teardown_msi_irqs(struct pci_dev *dev)
  77 {
  78         msi_device_destroy_sysfs(&dev->dev);
  79         arch_teardown_msi_irqs(dev);
  80 }