drivers/crypto/omap-crypto.c

   1 /*
   2  * OMAP Crypto driver common support routines.
   3  *
   4  * Copyright (c) 2017 Texas Instruments Incorporated
   5  *   Tero Kristo <t-kristo@ti.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as published
   9  * by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/scatterlist.h>
  15 #include <crypto/scatterwalk.h>
  16
  17 #include "omap-crypto.h"
  18
  19 static int omap_crypto_copy_sg_lists(int total, int bs,
  20                                      struct scatterlist **sg,
  21                                      struct scatterlist *new_sg, u16 flags)
  22 {
  23         int n = sg_nents(*sg);
  24         struct scatterlist *tmp;
  25
  26         if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY)) {
  27                 new_sg = kmalloc_array(n, sizeof(*sg), GFP_KERNEL);
  28                 if (!new_sg)
  29                         return -ENOMEM;
  30
  31                 sg_init_table(new_sg, n);
  32         }
  33
  34         tmp = new_sg;
  35
  36         while (*sg && total) {
  37                 int len = (*sg)->length;
  38
  39                 if (total < len)
  40                         len = total;
  41
  42                 if (len > 0) {
  43                         total -= len;
  44                         sg_set_page(tmp, sg_page(*sg), len, (*sg)->offset);
  45                         if (total <= 0)
  46                                 sg_mark_end(tmp);
  47                         tmp = sg_next(tmp);
  48                 }
  49
  50                 *sg = sg_next(*sg);
  51         }
  52
  53         *sg = new_sg;
  54
  55         return 0;
  56 }
  57
  58 static int omap_crypto_copy_sgs(int total, int bs, struct scatterlist **sg,
  59                                 struct scatterlist *new_sg, u16 flags)
  60 {
  61         void *buf;
  62         int pages;
  63         int new_len;
  64
  65         new_len = ALIGN(total, bs);
  66         pages = get_order(new_len);
  67
  68         buf = (void *)__get_free_pages(GFP_ATOMIC, pages);
  69         if (!buf) {
  70                 pr_err("%s: Couldn't allocate pages for unaligned cases.\n",
  71                        __func__);
  72                 return -ENOMEM;
  73         }
  74
  75         if (flags & OMAP_CRYPTO_COPY_DATA) {
  76                 scatterwalk_map_and_copy(buf, *sg, 0, total, 0);
  77                 if (flags & OMAP_CRYPTO_ZERO_BUF)
  78                         memset(buf + total, 0, new_len - total);
  79         }
  80
  81         if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
  82                 sg_init_table(new_sg, 1);
  83
  84         sg_set_buf(new_sg, buf, new_len);
  85
  86         *sg = new_sg;
  87
  88         return 0;
  89 }
  90
  91 static int omap_crypto_check_sg(struct scatterlist *sg, int total, int bs,
  92                                 u16 flags)
  93 {
  94         int len = 0;
  95         int num_sg = 0;
  96
  97         if (!IS_ALIGNED(total, bs))
  98                 return OMAP_CRYPTO_NOT_ALIGNED;
  99
 100         while (sg) {
 101                 num_sg++;
 102
 103                 if (!IS_ALIGNED(sg->offset, 4))
 104                         return OMAP_CRYPTO_NOT_ALIGNED;
 105                 if (!IS_ALIGNED(sg->length, bs))
 106                         return OMAP_CRYPTO_NOT_ALIGNED;
 107
 108                 len += sg->length;
 109                 sg = sg_next(sg);
 110
 111                 if (len >= total)
 112                         break;
 113         }
 114
 115         if ((flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) && num_sg > 1)
 116                 return OMAP_CRYPTO_NOT_ALIGNED;
 117
 118         if (len != total)
 119                 return OMAP_CRYPTO_BAD_DATA_LENGTH;
 120
 121         return 0;
 122 }
 123
 124 int omap_crypto_align_sg(struct scatterlist **sg, int total, int bs,
 125                          struct scatterlist *new_sg, u16 flags,
 126                          u8 flags_shift, unsigned long *dd_flags)
 127 {
 128         int ret;
 129
 130         *dd_flags &= ~(OMAP_CRYPTO_COPY_MASK << flags_shift);
 131
 132         if (flags & OMAP_CRYPTO_FORCE_COPY)
 133                 ret = OMAP_CRYPTO_NOT_ALIGNED;
 134         else
 135                 ret = omap_crypto_check_sg(*sg, total, bs, flags);
 136
 137         if (ret == OMAP_CRYPTO_NOT_ALIGNED) {
 138                 ret = omap_crypto_copy_sgs(total, bs, sg, new_sg, flags);
 139                 if (ret)
 140                         return ret;
 141                 *dd_flags |= OMAP_CRYPTO_DATA_COPIED << flags_shift;
 142         } else if (ret == OMAP_CRYPTO_BAD_DATA_LENGTH) {
 143                 ret = omap_crypto_copy_sg_lists(total, bs, sg, new_sg, flags);
 144                 if (ret)
 145                         return ret;
 146                 if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
 147                         *dd_flags |= OMAP_CRYPTO_SG_COPIED << flags_shift;
 148         } else if (flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) {
 149                 sg_set_buf(new_sg, sg_virt(*sg), (*sg)->length);
 150         }
 151
 152         return 0;
 153 }
 154 EXPORT_SYMBOL_GPL(omap_crypto_align_sg);
 155
 156 void omap_crypto_cleanup(struct scatterlist *sg, struct scatterlist *orig,
 157                          int offset, int len, u8 flags_shift,
 158                          unsigned long flags)
 159 {
 160         void *buf;
 161         int pages;
 162
 163         flags >>= flags_shift;
 164         flags &= OMAP_CRYPTO_COPY_MASK;
 165
 166         if (!flags)
 167                 return;
 168
 169         buf = sg_virt(sg);
 170         pages = get_order(len);
 171
 172         if (orig && (flags & OMAP_CRYPTO_COPY_MASK))
 173                 scatterwalk_map_and_copy(buf, orig, offset, len, 1);
 174
 175         if (flags & OMAP_CRYPTO_DATA_COPIED)
 176                 free_pages((unsigned long)buf, pages);
 177         else if (flags & OMAP_CRYPTO_SG_COPIED)
 178                 kfree(sg);
 179 }
 180 EXPORT_SYMBOL_GPL(omap_crypto_cleanup);
 181
 182 MODULE_DESCRIPTION("OMAP crypto support library.");
 183 MODULE_LICENSE("GPL v2");
 184 MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");