arch/x86/kernel/tce_64.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * This file manages the translation entries for the IBM Calgary IOMMU.
   4  *
   5  * Derived from arch/powerpc/platforms/pseries/iommu.c
   6  *
   7  * Copyright (C) IBM Corporation, 2006
   8  *
   9  * Author: Jon Mason <jdmason@us.ibm.com>
  10  * Author: Muli Ben-Yehuda <muli@il.ibm.com>
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/slab.h>
  15 #include <linux/mm.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/string.h>
  18 #include <linux/pci.h>
  19 #include <linux/dma-mapping.h>
  20 #include <linux/memblock.h>
  21 #include <asm/tce.h>
  22 #include <asm/calgary.h>
  23 #include <asm/proto.h>
  24 #include <asm/cacheflush.h>
  25
  26 /* flush a tce at 'tceaddr' to main memory */
  27 static inline void flush_tce(void* tceaddr)
  28 {
  29         /* a single tce can't cross a cache line */
  30         if (boot_cpu_has(X86_FEATURE_CLFLUSH))
  31                 clflush(tceaddr);
  32         else
  33                 wbinvd();
  34 }
  35
  36 void tce_build(struct iommu_table *tbl, unsigned long index,
  37         unsigned int npages, unsigned long uaddr, int direction)
  38 {
  39         u64* tp;
  40         u64 t;
  41         u64 rpn;
  42
  43         t = (1 << TCE_READ_SHIFT);
  44         if (direction != DMA_TO_DEVICE)
  45                 t |= (1 << TCE_WRITE_SHIFT);
  46
  47         tp = ((u64*)tbl->it_base) + index;
  48
  49         while (npages--) {
  50                 rpn = (virt_to_bus((void*)uaddr)) >> PAGE_SHIFT;
  51                 t &= ~TCE_RPN_MASK;
  52                 t |= (rpn << TCE_RPN_SHIFT);
  53
  54                 *tp = cpu_to_be64(t);
  55                 flush_tce(tp);
  56
  57                 uaddr += PAGE_SIZE;
  58                 tp++;
  59         }
  60 }
  61
  62 void tce_free(struct iommu_table *tbl, long index, unsigned int npages)
  63 {
  64         u64* tp;
  65
  66         tp  = ((u64*)tbl->it_base) + index;
  67
  68         while (npages--) {
  69                 *tp = cpu_to_be64(0);
  70                 flush_tce(tp);
  71                 tp++;
  72         }
  73 }
  74
  75 static inline unsigned int table_size_to_number_of_entries(unsigned char size)
  76 {
  77         /*
  78          * size is the order of the table, 0-7
  79          * smallest table is 8K entries, so shift result by 13 to
  80          * multiply by 8K
  81          */
  82         return (1 << size) << 13;
  83 }
  84
  85 static int tce_table_setparms(struct pci_dev *dev, struct iommu_table *tbl)
  86 {
  87         unsigned int bitmapsz;
  88         unsigned long bmppages;
  89         int ret;
  90
  91         tbl->it_busno = dev->bus->number;
  92
  93         /* set the tce table size - measured in entries */
  94         tbl->it_size = table_size_to_number_of_entries(specified_table_size);
  95
  96         /*
  97          * number of bytes needed for the bitmap size in number of
  98          * entries; we need one bit per entry
  99          */
 100         bitmapsz = tbl->it_size / BITS_PER_BYTE;
 101         bmppages = __get_free_pages(GFP_KERNEL, get_order(bitmapsz));
 102         if (!bmppages) {
 103                 printk(KERN_ERR "Calgary: cannot allocate bitmap\n");
 104                 ret = -ENOMEM;
 105                 goto done;
 106         }
 107
 108         tbl->it_map = (unsigned long*)bmppages;
 109
 110         memset(tbl->it_map, 0, bitmapsz);
 111
 112         tbl->it_hint = 0;
 113
 114         spin_lock_init(&tbl->it_lock);
 115
 116         return 0;
 117
 118 done:
 119         return ret;
 120 }
 121
 122 int __init build_tce_table(struct pci_dev *dev, void __iomem *bbar)
 123 {
 124         struct iommu_table *tbl;
 125         int ret;
 126
 127         if (pci_iommu(dev->bus)) {
 128                 printk(KERN_ERR "Calgary: dev %p has sysdata->iommu %p\n",
 129                        dev, pci_iommu(dev->bus));
 130                 BUG();
 131         }
 132
 133         tbl = kzalloc(sizeof(struct iommu_table), GFP_KERNEL);
 134         if (!tbl) {
 135                 printk(KERN_ERR "Calgary: error allocating iommu_table\n");
 136                 ret = -ENOMEM;
 137                 goto done;
 138         }
 139
 140         ret = tce_table_setparms(dev, tbl);
 141         if (ret)
 142                 goto free_tbl;
 143
 144         tbl->bbar = bbar;
 145
 146         set_pci_iommu(dev->bus, tbl);
 147
 148         return 0;
 149
 150 free_tbl:
 151         kfree(tbl);
 152 done:
 153         return ret;
 154 }
 155
 156 void * __init alloc_tce_table(void)
 157 {
 158         unsigned int size;
 159
 160         size = table_size_to_number_of_entries(specified_table_size);
 161         size *= TCE_ENTRY_SIZE;
 162
 163         return memblock_alloc_low(size, size);
 164 }
 165
 166 void __init free_tce_table(void *tbl)
 167 {
 168         unsigned int size;
 169
 170         if (!tbl)
 171                 return;
 172
 173         size = table_size_to_number_of_entries(specified_table_size);
 174         size *= TCE_ENTRY_SIZE;
 175
 176         memblock_free(__pa(tbl), size);
 177 }