drivers/eisa/virtual_root.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Virtual EISA root driver.
   4  * Acts as a placeholder if we don't have a proper EISA bridge.
   5  *
   6  * (C) 2003 Marc Zyngier <maz@wild-wind.fr.eu.org>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/eisa.h>
  12 #include <linux/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/init.h>
  15
  16 #if defined(CONFIG_ALPHA_JENSEN) || defined(CONFIG_EISA_VLB_PRIMING)
  17 #define EISA_FORCE_PROBE_DEFAULT 1
  18 #else
  19 #define EISA_FORCE_PROBE_DEFAULT 0
  20 #endif
  21
  22 static int force_probe = EISA_FORCE_PROBE_DEFAULT;
  23 static void virtual_eisa_release (struct device *);
  24
  25 /* The default EISA device parent (virtual root device).
  26  * Now use a platform device, since that's the obvious choice. */
  27
  28 static struct platform_device eisa_root_dev = {
  29         .name = "eisa",
  30         .id   = 0,
  31         .dev  = {
  32                 .release = virtual_eisa_release,
  33         },
  34 };
  35
  36 static struct eisa_root_device eisa_bus_root = {
  37         .dev            = &eisa_root_dev.dev,
  38         .bus_base_addr  = 0,
  39         .res            = &ioport_resource,
  40         .slots          = EISA_MAX_SLOTS,
  41         .dma_mask       = 0xffffffff,
  42 };
  43
  44 static void virtual_eisa_release (struct device *dev)
  45 {
  46         /* nothing really to do here */
  47 }
  48
  49 static int __init virtual_eisa_root_init (void)
  50 {
  51         int r;
  52
  53         if ((r = platform_device_register (&eisa_root_dev)))
  54                 return r;
  55
  56         eisa_bus_root.force_probe = force_probe;
  57
  58         dev_set_drvdata(&eisa_root_dev.dev, &eisa_bus_root);
  59
  60         if (eisa_root_register (&eisa_bus_root)) {
  61                 /* A real bridge may have been registered before
  62                  * us. So quietly unregister. */
  63                 platform_device_unregister (&eisa_root_dev);
  64                 return -1;
  65         }
  66
  67         return 0;
  68 }
  69
  70 module_param (force_probe, int, 0444);
  71
  72 device_initcall (virtual_eisa_root_init);