drivers/pnp/system.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * system.c - a driver for reserving pnp system resources
0004  *
0005  * Some code is based on pnpbios_core.c
0006  * Copyright 2002 Adam Belay <ambx1@neo.rr.com>
0007  * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
0008  *  Bjorn Helgaas <bjorn.helgaas@hp.com>
0009  */
0010
0011 #include <linux/pnp.h>
0012 #include <linux/device.h>
0013 #include <linux/init.h>
0014 #include <linux/slab.h>
0015 #include <linux/kernel.h>
0016 #include <linux/ioport.h>
0017
0018 static const struct pnp_device_id pnp_dev_table[] = {
0019     /* General ID for reserving resources */
0020     {"PNP0c02", 0},
0021     /* memory controller */
0022     {"PNP0c01", 0},
0023     {"", 0}
0024 };
0025
0026 static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
0027 {
0028     char *regionid;
0029     const char *pnpid = dev_name(&dev->dev);
0030     resource_size_t start = r->start, end = r->end;
0031     struct resource *res;
0032
0033     regionid = kmalloc(16, GFP_KERNEL);
0034     if (!regionid)
0035         return;
0036
0037     snprintf(regionid, 16, "pnp %s", pnpid);
0038     if (port)
0039         res = request_region(start, end - start + 1, regionid);
0040     else
0041         res = request_mem_region(start, end - start + 1, regionid);
0042     if (res)
0043         res->flags &= ~IORESOURCE_BUSY;
0044     else
0045         kfree(regionid);
0046
0047     /*
0048      * Failures at this point are usually harmless. pci quirks for
0049      * example do reserve stuff they know about too, so we may well
0050      * have double reservations.
0051      */
0052     dev_info(&dev->dev, "%pR %s reserved\n", r,
0053          res ? "has been" : "could not be");
0054 }
0055
0056 static void reserve_resources_of_dev(struct pnp_dev *dev)
0057 {
0058     struct resource *res;
0059     int i;
0060
0061     for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_IO, i)); i++) {
0062         if (res->flags & IORESOURCE_DISABLED)
0063             continue;
0064         if (res->start == 0)
0065             continue;   /* disabled */
0066         if (res->start < 0x100)
0067             /*
0068              * Below 0x100 is only standard PC hardware
0069              * (pics, kbd, timer, dma, ...)
0070              * We should not get resource conflicts there,
0071              * and the kernel reserves these anyway
0072              * (see arch/i386/kernel/setup.c).
0073              * So, do nothing
0074              */
0075             continue;
0076         if (res->end < res->start)
0077             continue;   /* invalid */
0078
0079         reserve_range(dev, res, 1);
0080     }
0081
0082     for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_MEM, i)); i++) {
0083         if (res->flags & IORESOURCE_DISABLED)
0084             continue;
0085
0086         reserve_range(dev, res, 0);
0087     }
0088 }
0089
0090 static int system_pnp_probe(struct pnp_dev *dev,
0091                 const struct pnp_device_id *dev_id)
0092 {
0093     reserve_resources_of_dev(dev);
0094     return 0;
0095 }
0096
0097 static struct pnp_driver system_pnp_driver = {
0098     .name     = "system",
0099     .id_table = pnp_dev_table,
0100     .flags    = PNP_DRIVER_RES_DO_NOT_CHANGE,
0101     .probe    = system_pnp_probe,
0102 };
0103
0104 static int __init pnp_system_init(void)
0105 {
0106     return pnp_register_driver(&system_pnp_driver);
0107 }
0108
0109 /*
0110  * Reserve motherboard resources after PCI claim BARs,
0111  * but before PCI assign resources for uninitialized PCI devices
0112  */
0113 fs_initcall(pnp_system_init);