arch/x86_64/kernel/tce.c

   1 /*
   2  * This file manages the translation entries for the IBM Calgary IOMMU.
   3  *
   4  * Derived from arch/powerpc/platforms/pseries/iommu.c
   5  *
   6  * Copyright (C) IBM Corporation, 2006
   7  *
   8  * Author: Jon Mason <jdmason@us.ibm.com>
   9  * Author: Muli Ben-Yehuda <muli@il.ibm.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  24  */
  25
  26 #include <linux/types.h>
  27 #include <linux/slab.h>
  28 #include <linux/mm.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/string.h>
  31 #include <linux/pci.h>
  32 #include <linux/dma-mapping.h>
  33 #include <linux/bootmem.h>
  34 #include <asm/tce.h>
  35 #include <asm/calgary.h>
  36 #include <asm/proto.h>
  37
  38 /* flush a tce at 'tceaddr' to main memory */
  39 static inline void flush_tce(void* tceaddr)
  40 {
  41         /* a single tce can't cross a cache line */
  42         if (cpu_has_clflush)
  43                 asm volatile("clflush (%0)" :: "r" (tceaddr));
  44         else
  45                 asm volatile("wbinvd":::"memory");
  46 }
  47
  48 void tce_build(struct iommu_table *tbl, unsigned long index,
  49         unsigned int npages, unsigned long uaddr, int direction)
  50 {
  51         u64* tp;
  52         u64 t;
  53         u64 rpn;
  54
  55         t = (1 << TCE_READ_SHIFT);
  56         if (direction != DMA_TO_DEVICE)
  57                 t |= (1 << TCE_WRITE_SHIFT);
  58
  59         tp = ((u64*)tbl->it_base) + index;
  60
  61         while (npages--) {
  62                 rpn = (virt_to_bus((void*)uaddr)) >> PAGE_SHIFT;
  63                 t &= ~TCE_RPN_MASK;
  64                 t |= (rpn << TCE_RPN_SHIFT);
  65
  66                 *tp = cpu_to_be64(t);
  67                 flush_tce(tp);
  68
  69                 uaddr += PAGE_SIZE;
  70                 tp++;
  71         }
  72 }
  73
  74 void tce_free(struct iommu_table *tbl, long index, unsigned int npages)
  75 {
  76         u64* tp;
  77
  78         tp  = ((u64*)tbl->it_base) + index;
  79
  80         while (npages--) {
  81                 *tp = cpu_to_be64(0);
  82                 flush_tce(tp);
  83                 tp++;
  84         }
  85 }
  86
  87 static inline unsigned int table_size_to_number_of_entries(unsigned char size)
  88 {
  89         /*
  90          * size is the order of the table, 0-7
  91          * smallest table is 8K entries, so shift result by 13 to
  92          * multiply by 8K
  93          */
  94         return (1 << size) << 13;
  95 }
  96
  97 static int tce_table_setparms(struct pci_dev *dev, struct iommu_table *tbl)
  98 {
  99         unsigned int bitmapsz;
 100         unsigned long bmppages;
 101         int ret;
 102
 103         tbl->it_busno = dev->bus->number;
 104
 105         /* set the tce table size - measured in entries */
 106         tbl->it_size = table_size_to_number_of_entries(specified_table_size);
 107
 108         /*
 109          * number of bytes needed for the bitmap size in number of
 110          * entries; we need one bit per entry
 111          */
 112         bitmapsz = tbl->it_size / BITS_PER_BYTE;
 113         bmppages = __get_free_pages(GFP_KERNEL, get_order(bitmapsz));
 114         if (!bmppages) {
 115                 printk(KERN_ERR "Calgary: cannot allocate bitmap\n");
 116                 ret = -ENOMEM;
 117                 goto done;
 118         }
 119
 120         tbl->it_map = (unsigned long*)bmppages;
 121
 122         memset(tbl->it_map, 0, bitmapsz);
 123
 124         tbl->it_hint = 0;
 125
 126         spin_lock_init(&tbl->it_lock);
 127
 128         return 0;
 129
 130 done:
 131         return ret;
 132 }
 133
 134 int __init build_tce_table(struct pci_dev *dev, void __iomem *bbar)
 135 {
 136         struct iommu_table *tbl;
 137         int ret;
 138
 139         if (pci_iommu(dev->bus)) {
 140                 printk(KERN_ERR "Calgary: dev %p has sysdata->iommu %p\n",
 141                        dev, pci_iommu(dev->bus));
 142                 BUG();
 143         }
 144
 145         tbl = kzalloc(sizeof(struct iommu_table), GFP_KERNEL);
 146         if (!tbl) {
 147                 printk(KERN_ERR "Calgary: error allocating iommu_table\n");
 148                 ret = -ENOMEM;
 149                 goto done;
 150         }
 151
 152         ret = tce_table_setparms(dev, tbl);
 153         if (ret)
 154                 goto free_tbl;
 155
 156         tbl->bbar = bbar;
 157
 158         set_pci_iommu(dev->bus, tbl);
 159
 160         return 0;
 161
 162 free_tbl:
 163         kfree(tbl);
 164 done:
 165         return ret;
 166 }
 167
 168 void * __init alloc_tce_table(void)
 169 {
 170         unsigned int size;
 171
 172         size = table_size_to_number_of_entries(specified_table_size);
 173         size *= TCE_ENTRY_SIZE;
 174
 175         return __alloc_bootmem_low(size, size, 0);
 176 }
 177
 178 void __init free_tce_table(void *tbl)
 179 {
 180         unsigned int size;
 181
 182         if (!tbl)
 183                 return;
 184
 185         size = table_size_to_number_of_entries(specified_table_size);
 186         size *= TCE_ENTRY_SIZE;
 187
 188         free_bootmem(__pa(tbl), size);
 189 }