linux/drivers/eisa/pci_eisa.c
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   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 ? */
  19static struct eisa_root_device pci_eisa_root;
  20
  21static 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 */
  75static 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}
  89subsys_initcall_sync(pci_eisa_init_early);
  90