sys/dev/drm/linux_iomapping.c

   1 /*
   2  * Copyright (c) 2014-2016 François Tigeot
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <machine/pmap.h>
  28 #include <vm/pmap.h>
  29 #include <vm/vm.h>
  30
  31 #include <linux/kernel.h>
  32 #include <linux/slab.h>
  33 #include <linux/bug.h>
  34 #include <asm/page.h>
  35 #include <asm/io.h>
  36
  37 SLIST_HEAD(iomap_list_head, iomap) iomap_list = SLIST_HEAD_INITIALIZER(iomap_list);
  38
  39 void __iomem *
  40 __ioremap_common(unsigned long phys_addr, unsigned long size, int cache_mode)
  41 {
  42         struct iomap *imp;
  43
  44         /* Ensure mappings are page-aligned */
  45         BUG_ON(phys_addr & PAGE_MASK);
  46         BUG_ON(size & PAGE_MASK);
  47
  48         imp = kmalloc(sizeof(struct iomap), M_DRM, M_WAITOK);
  49         imp->paddr = phys_addr;
  50         imp->npages = size / PAGE_SIZE;
  51         imp->pmap_addr = pmap_mapdev_attr(phys_addr, size, cache_mode);
  52         SLIST_INSERT_HEAD(&iomap_list, imp, im_iomaps);
  53
  54         return imp->pmap_addr;
  55 }
  56
  57 void iounmap(void __iomem *ptr)
  58 {
  59         struct iomap *imp, *tmp_imp;
  60         int found = 0;
  61         int indx;
  62         vm_paddr_t paddr_end;
  63
  64         SLIST_FOREACH_MUTABLE(imp, &iomap_list, im_iomaps, tmp_imp) {
  65                 if (imp->pmap_addr == ptr) {
  66                         found = 1;
  67                         break;
  68                 }
  69         }
  70
  71         if (!found) {
  72                 kprintf("iounmap: invalid address %p\n", ptr);
  73                 return;
  74         }
  75
  76         paddr_end = imp->paddr + (imp->npages * PAGE_SIZE) - 1;
  77         /* Is this address space range backed by regular memory ? */
  78         for (indx = 0; phys_avail[indx].phys_end != 0; ++indx) {
  79                 vm_paddr_t range_start = phys_avail[indx].phys_beg;
  80                 vm_paddr_t size = phys_avail[indx].phys_end -
  81                                   phys_avail[indx].phys_beg;
  82                 vm_paddr_t range_end = range_start + size - 1;
  83
  84                 if ((imp->paddr >= range_start) && (paddr_end <= range_end)) {
  85                         /* Yes, change page caching attributes */
  86                         pmap_change_attr(imp->paddr, imp->npages, PAT_WRITE_BACK);
  87                         break;
  88                 }
  89
  90         }
  91
  92         pmap_unmapdev((vm_offset_t)imp->pmap_addr, imp->npages * PAGE_SIZE);
  93
  94         SLIST_REMOVE(&iomap_list, imp, iomap, im_iomaps);
  95         kfree(imp);
  96 }