xref: /openbmc/linux/drivers/crypto/omap-crypto.c (revision ffe3ee8b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * OMAP Crypto driver common support routines.
4  *
5  * Copyright (c) 2017 Texas Instruments Incorporated
6  *   Tero Kristo <t-kristo@ti.com>
7  */
8 
9 #include <linux/module.h>
10 #include <linux/kernel.h>
11 #include <linux/scatterlist.h>
12 #include <crypto/scatterwalk.h>
13 
14 #include "omap-crypto.h"
15 
omap_crypto_copy_sg_lists(int total,int bs,struct scatterlist ** sg,struct scatterlist * new_sg,u16 flags)16 static int omap_crypto_copy_sg_lists(int total, int bs,
17 				     struct scatterlist **sg,
18 				     struct scatterlist *new_sg, u16 flags)
19 {
20 	int n = sg_nents(*sg);
21 	struct scatterlist *tmp;
22 
23 	if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY)) {
24 		new_sg = kmalloc_array(n, sizeof(*sg), GFP_KERNEL);
25 		if (!new_sg)
26 			return -ENOMEM;
27 
28 		sg_init_table(new_sg, n);
29 	}
30 
31 	tmp = new_sg;
32 
33 	while (*sg && total) {
34 		int len = (*sg)->length;
35 
36 		if (total < len)
37 			len = total;
38 
39 		if (len > 0) {
40 			total -= len;
41 			sg_set_page(tmp, sg_page(*sg), len, (*sg)->offset);
42 			if (total <= 0)
43 				sg_mark_end(tmp);
44 			tmp = sg_next(tmp);
45 		}
46 
47 		*sg = sg_next(*sg);
48 	}
49 
50 	*sg = new_sg;
51 
52 	return 0;
53 }
54 
omap_crypto_copy_sgs(int total,int bs,struct scatterlist ** sg,struct scatterlist * new_sg,u16 flags)55 static int omap_crypto_copy_sgs(int total, int bs, struct scatterlist **sg,
56 				struct scatterlist *new_sg, u16 flags)
57 {
58 	void *buf;
59 	int pages;
60 	int new_len;
61 
62 	new_len = ALIGN(total, bs);
63 	pages = get_order(new_len);
64 
65 	buf = (void *)__get_free_pages(GFP_ATOMIC, pages);
66 	if (!buf) {
67 		pr_err("%s: Couldn't allocate pages for unaligned cases.\n",
68 		       __func__);
69 		return -ENOMEM;
70 	}
71 
72 	if (flags & OMAP_CRYPTO_COPY_DATA) {
73 		scatterwalk_map_and_copy(buf, *sg, 0, total, 0);
74 		if (flags & OMAP_CRYPTO_ZERO_BUF)
75 			memset(buf + total, 0, new_len - total);
76 	}
77 
78 	if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
79 		sg_init_table(new_sg, 1);
80 
81 	sg_set_buf(new_sg, buf, new_len);
82 
83 	*sg = new_sg;
84 
85 	return 0;
86 }
87 
omap_crypto_check_sg(struct scatterlist * sg,int total,int bs,u16 flags)88 static int omap_crypto_check_sg(struct scatterlist *sg, int total, int bs,
89 				u16 flags)
90 {
91 	int len = 0;
92 	int num_sg = 0;
93 
94 	if (!IS_ALIGNED(total, bs))
95 		return OMAP_CRYPTO_NOT_ALIGNED;
96 
97 	while (sg) {
98 		num_sg++;
99 
100 		if (!IS_ALIGNED(sg->offset, 4))
101 			return OMAP_CRYPTO_NOT_ALIGNED;
102 		if (!IS_ALIGNED(sg->length, bs))
103 			return OMAP_CRYPTO_NOT_ALIGNED;
104 #ifdef CONFIG_ZONE_DMA
105 		if (page_zonenum(sg_page(sg)) != ZONE_DMA)
106 			return OMAP_CRYPTO_NOT_ALIGNED;
107 #endif
108 
109 		len += sg->length;
110 		sg = sg_next(sg);
111 
112 		if (len >= total)
113 			break;
114 	}
115 
116 	if ((flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) && num_sg > 1)
117 		return OMAP_CRYPTO_NOT_ALIGNED;
118 
119 	if (len != total)
120 		return OMAP_CRYPTO_BAD_DATA_LENGTH;
121 
122 	return 0;
123 }
124 
omap_crypto_align_sg(struct scatterlist ** sg,int total,int bs,struct scatterlist * new_sg,u16 flags,u8 flags_shift,unsigned long * dd_flags)125 int omap_crypto_align_sg(struct scatterlist **sg, int total, int bs,
126 			 struct scatterlist *new_sg, u16 flags,
127 			 u8 flags_shift, unsigned long *dd_flags)
128 {
129 	int ret;
130 
131 	*dd_flags &= ~(OMAP_CRYPTO_COPY_MASK << flags_shift);
132 
133 	if (flags & OMAP_CRYPTO_FORCE_COPY)
134 		ret = OMAP_CRYPTO_NOT_ALIGNED;
135 	else
136 		ret = omap_crypto_check_sg(*sg, total, bs, flags);
137 
138 	if (ret == OMAP_CRYPTO_NOT_ALIGNED) {
139 		ret = omap_crypto_copy_sgs(total, bs, sg, new_sg, flags);
140 		if (ret)
141 			return ret;
142 		*dd_flags |= OMAP_CRYPTO_DATA_COPIED << flags_shift;
143 	} else if (ret == OMAP_CRYPTO_BAD_DATA_LENGTH) {
144 		ret = omap_crypto_copy_sg_lists(total, bs, sg, new_sg, flags);
145 		if (ret)
146 			return ret;
147 		if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
148 			*dd_flags |= OMAP_CRYPTO_SG_COPIED << flags_shift;
149 	} else if (flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) {
150 		sg_set_buf(new_sg, sg_virt(*sg), (*sg)->length);
151 	}
152 
153 	return 0;
154 }
155 EXPORT_SYMBOL_GPL(omap_crypto_align_sg);
156 
omap_crypto_copy_data(struct scatterlist * src,struct scatterlist * dst,int offset,int len)157 static void omap_crypto_copy_data(struct scatterlist *src,
158 				  struct scatterlist *dst,
159 				  int offset, int len)
160 {
161 	int amt;
162 	void *srcb, *dstb;
163 	int srco = 0, dsto = offset;
164 
165 	while (src && dst && len) {
166 		if (srco >= src->length) {
167 			srco -= src->length;
168 			src = sg_next(src);
169 			continue;
170 		}
171 
172 		if (dsto >= dst->length) {
173 			dsto -= dst->length;
174 			dst = sg_next(dst);
175 			continue;
176 		}
177 
178 		amt = min(src->length - srco, dst->length - dsto);
179 		amt = min(len, amt);
180 
181 		srcb = kmap_atomic(sg_page(src)) + srco + src->offset;
182 		dstb = kmap_atomic(sg_page(dst)) + dsto + dst->offset;
183 
184 		memcpy(dstb, srcb, amt);
185 
186 		flush_dcache_page(sg_page(dst));
187 
188 		kunmap_atomic(srcb);
189 		kunmap_atomic(dstb);
190 
191 		srco += amt;
192 		dsto += amt;
193 		len -= amt;
194 	}
195 }
196 
omap_crypto_cleanup(struct scatterlist * sg,struct scatterlist * orig,int offset,int len,u8 flags_shift,unsigned long flags)197 void omap_crypto_cleanup(struct scatterlist *sg, struct scatterlist *orig,
198 			 int offset, int len, u8 flags_shift,
199 			 unsigned long flags)
200 {
201 	void *buf;
202 	int pages;
203 
204 	flags >>= flags_shift;
205 	flags &= OMAP_CRYPTO_COPY_MASK;
206 
207 	if (!flags)
208 		return;
209 
210 	buf = sg_virt(sg);
211 	pages = get_order(len);
212 
213 	if (orig && (flags & OMAP_CRYPTO_DATA_COPIED))
214 		omap_crypto_copy_data(sg, orig, offset, len);
215 
216 	if (flags & OMAP_CRYPTO_DATA_COPIED)
217 		free_pages((unsigned long)buf, pages);
218 	else if (flags & OMAP_CRYPTO_SG_COPIED)
219 		kfree(sg);
220 }
221 EXPORT_SYMBOL_GPL(omap_crypto_cleanup);
222 
223 MODULE_DESCRIPTION("OMAP crypto support library.");
224 MODULE_LICENSE("GPL v2");
225 MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
226