drivers/eisa/pci_eisa.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Minimalist driver for a generic PCI-to-EISA bridge.
   4  *
   5  * (C) 2003 Marc Zyngier <maz@wild-wind.fr.eu.org>
   6  *
   7  * Ivan Kokshaysky <ink@jurassic.park.msu.ru> :
   8  * Generalisation from i82375 to PCI_CLASS_BRIDGE_EISA.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/device.h>
  13 #include <linux/eisa.h>
  14 #include <linux/pci.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17
  18 /* There is only *one* pci_eisa device per machine, right ? */
  19 static struct eisa_root_device pci_eisa_root;
  20
  21 static int __init pci_eisa_init(struct pci_dev *pdev)
  22 {
  23         int rc, i;
  24         struct resource *res, *bus_res = NULL;
  25
  26         if ((rc = pci_enable_device (pdev))) {
  27                 dev_err(&pdev->dev, "Could not enable device\n");
  28                 return rc;
  29         }
  30
  31         /*
  32          * The Intel 82375 PCI-EISA bridge is a subtractive-decode PCI
  33          * device, so the resources available on EISA are the same as those
  34          * available on the 82375 bus.  This works the same as a PCI-PCI
  35          * bridge in subtractive-decode mode (see pci_read_bridge_bases()).
  36          * We assume other PCI-EISA bridges are similar.
  37          *
  38          * eisa_root_register() can only deal with a single io port resource,
  39         *  so we use the first valid io port resource.
  40          */
  41         pci_bus_for_each_resource(pdev->bus, res, i)
  42                 if (res && (res->flags & IORESOURCE_IO)) {
  43                         bus_res = res;
  44                         break;
  45                 }
  46
  47         if (!bus_res) {
  48                 dev_err(&pdev->dev, "No resources available\n");
  49                 return -1;
  50         }
  51
  52         pci_eisa_root.dev               = &pdev->dev;
  53         pci_eisa_root.res               = bus_res;
  54         pci_eisa_root.bus_base_addr     = bus_res->start;
  55         pci_eisa_root.slots             = EISA_MAX_SLOTS;
  56         pci_eisa_root.dma_mask          = pdev->dma_mask;
  57         dev_set_drvdata(pci_eisa_root.dev, &pci_eisa_root);
  58
  59         if (eisa_root_register (&pci_eisa_root)) {
  60                 dev_err(&pdev->dev, "Could not register EISA root\n");
  61                 return -1;
  62         }
  63
  64         return 0;
  65 }
  66
  67 /*
  68  * We have to call pci_eisa_init_early() before pnpacpi_init()/isapnp_init().
  69  *   Otherwise pnp resource will get enabled early and could prevent eisa
  70  *   to be initialized.
  71  * Also need to make sure pci_eisa_init_early() is called after
  72  * x86/pci_subsys_init().
  73  * So need to use subsys_initcall_sync with it.
  74  */
  75 static int __init pci_eisa_init_early(void)
  76 {
  77         struct pci_dev *dev = NULL;
  78         int ret;
  79
  80         for_each_pci_dev(dev)
  81                 if ((dev->class >> 8) == PCI_CLASS_BRIDGE_EISA) {
  82                         ret = pci_eisa_init(dev);
  83                         if (ret)
  84                                 return ret;
  85                 }
  86
  87         return 0;
  88 }
  89 subsys_initcall_sync(pci_eisa_init_early);