drivers/pnp/system.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * system.c - a driver for reserving pnp system resources
   4  *
   5  * Some code is based on pnpbios_core.c
   6  * Copyright 2002 Adam Belay <ambx1@neo.rr.com>
   7  * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
   8  *      Bjorn Helgaas <bjorn.helgaas@hp.com>
   9  */
  10
  11 #include <linux/pnp.h>
  12 #include <linux/device.h>
  13 #include <linux/init.h>
  14 #include <linux/slab.h>
  15 #include <linux/kernel.h>
  16 #include <linux/ioport.h>
  17
  18 static const struct pnp_device_id pnp_dev_table[] = {
  19         /* General ID for reserving resources */
  20         {"PNP0c02", 0},
  21         /* memory controller */
  22         {"PNP0c01", 0},
  23         {"", 0}
  24 };
  25
  26 static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
  27 {
  28         char *regionid;
  29         const char *pnpid = dev_name(&dev->dev);
  30         resource_size_t start = r->start, end = r->end;
  31         struct resource *res;
  32
  33         regionid = kmalloc(16, GFP_KERNEL);
  34         if (!regionid)
  35                 return;
  36
  37         snprintf(regionid, 16, "pnp %s", pnpid);
  38         if (port)
  39                 res = request_region(start, end - start + 1, regionid);
  40         else
  41                 res = request_mem_region(start, end - start + 1, regionid);
  42         if (res)
  43                 res->flags &= ~IORESOURCE_BUSY;
  44         else
  45                 kfree(regionid);
  46
  47         /*
  48          * Failures at this point are usually harmless. pci quirks for
  49          * example do reserve stuff they know about too, so we may well
  50          * have double reservations.
  51          */
  52         dev_info(&dev->dev, "%pR %s reserved\n", r,
  53                  res ? "has been" : "could not be");
  54 }
  55
  56 static void reserve_resources_of_dev(struct pnp_dev *dev)
  57 {
  58         struct resource *res;
  59         int i;
  60
  61         for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_IO, i)); i++) {
  62                 if (res->flags & IORESOURCE_DISABLED)
  63                         continue;
  64                 if (res->start == 0)
  65                         continue;       /* disabled */
  66                 if (res->start < 0x100)
  67                         /*
  68                          * Below 0x100 is only standard PC hardware
  69                          * (pics, kbd, timer, dma, ...)
  70                          * We should not get resource conflicts there,
  71                          * and the kernel reserves these anyway
  72                          * (see arch/i386/kernel/setup.c).
  73                          * So, do nothing
  74                          */
  75                         continue;
  76                 if (res->end < res->start)
  77                         continue;       /* invalid */
  78
  79                 reserve_range(dev, res, 1);
  80         }
  81
  82         for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_MEM, i)); i++) {
  83                 if (res->flags & IORESOURCE_DISABLED)
  84                         continue;
  85
  86                 reserve_range(dev, res, 0);
  87         }
  88 }
  89
  90 static int system_pnp_probe(struct pnp_dev *dev,
  91                             const struct pnp_device_id *dev_id)
  92 {
  93         reserve_resources_of_dev(dev);
  94         return 0;
  95 }
  96
  97 static struct pnp_driver system_pnp_driver = {
  98         .name     = "system",
  99         .id_table = pnp_dev_table,
 100         .flags    = PNP_DRIVER_RES_DO_NOT_CHANGE,
 101         .probe    = system_pnp_probe,
 102 };
 103
 104 static int __init pnp_system_init(void)
 105 {
 106         return pnp_register_driver(&system_pnp_driver);
 107 }
 108
 109 /*
 110  * Reserve motherboard resources after PCI claim BARs,
 111  * but before PCI assign resources for uninitialized PCI devices
 112  */
 113 fs_initcall(pnp_system_init);