1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4 * Martin Schwidefsky <schwidefsky@de.ibm.com>
5 * Bugreports.to..: <Linux390@de.ibm.com>
6 * Copyright IBM Corp. 2000
7 *
8 * History of changes
9 * 07/24/00 new file
10 * 05/04/02 code restructuring.
11 */
12
13 #ifndef _S390_IDALS_H
14 #define _S390_IDALS_H
15
16 #include <linux/errno.h>
17 #include <linux/err.h>
18 #include <linux/types.h>
19 #include <linux/slab.h>
20 #include <linux/uaccess.h>
21 #include <asm/dma-types.h>
22 #include <asm/cio.h>
23
24 #define IDA_SIZE_SHIFT 12
25 #define IDA_BLOCK_SIZE (1UL << IDA_SIZE_SHIFT)
26
27 #define IDA_2K_SIZE_SHIFT 11
28 #define IDA_2K_BLOCK_SIZE (1UL << IDA_2K_SIZE_SHIFT)
29
30 /*
31 * Test if an address/length pair needs an idal list.
32 */
33 static inline bool idal_is_needed(void *vaddr, unsigned int length)
34 {
35 dma64_t paddr = virt_to_dma64(vaddr);
36
37 return (((__force unsigned long)(paddr) + length - 1) >> 31) != 0;
38 }
39
40 /*
41 * Return the number of idal words needed for an address/length pair.
42 */
43 static inline unsigned int idal_nr_words(void *vaddr, unsigned int length)
44 {
45 unsigned int cidaw;
46
47 cidaw = (unsigned long)vaddr & (IDA_BLOCK_SIZE - 1);
48 cidaw += length + IDA_BLOCK_SIZE - 1;
49 cidaw >>= IDA_SIZE_SHIFT;
50 return cidaw;
51 }
52
53 /*
54 * Return the number of 2K IDA words needed for an address/length pair.
55 */
56 static inline unsigned int idal_2k_nr_words(void *vaddr, unsigned int length)
57 {
58 unsigned int cidaw;
59
60 cidaw = (unsigned long)vaddr & (IDA_2K_BLOCK_SIZE - 1);
61 cidaw += length + IDA_2K_BLOCK_SIZE - 1;
62 cidaw >>= IDA_2K_SIZE_SHIFT;
63 return cidaw;
64 }
65
66 /*
67 * Create the list of idal words for an address/length pair.
68 */
69 static inline dma64_t *idal_create_words(dma64_t *idaws, void *vaddr, unsigned int length)
70 {
71 dma64_t paddr = virt_to_dma64(vaddr);
72 unsigned int cidaw;
73
74 *idaws++ = paddr;
75 cidaw = idal_nr_words(vaddr, length);
76 paddr = dma64_and(paddr, -IDA_BLOCK_SIZE);
77 while (--cidaw > 0) {
78 paddr = dma64_add(paddr, IDA_BLOCK_SIZE);
79 *idaws++ = paddr;
80 }
81 return idaws;
82 }
83
84 /*
85 * Sets the address of the data in CCW.
86 * If necessary it allocates an IDAL and sets the appropriate flags.
87 */
88 static inline int set_normalized_cda(struct ccw1 *ccw, void *vaddr)
89 {
90 unsigned int nridaws;
91 dma64_t *idal;
92
93 if (ccw->flags & CCW_FLAG_IDA)
94 return -EINVAL;
95 nridaws = idal_nr_words(vaddr, ccw->count);
96 if (nridaws > 0) {
97 idal = kcalloc(nridaws, sizeof(*idal), GFP_ATOMIC | GFP_DMA);
98 if (!idal)
99 return -ENOMEM;
100 idal_create_words(idal, vaddr, ccw->count);
101 ccw->flags |= CCW_FLAG_IDA;
102 vaddr = idal;
103 }
104 ccw->cda = virt_to_dma32(vaddr);
105 return 0;
106 }
107
108 /*
109 * Releases any allocated IDAL related to the CCW.
110 */
111 static inline void clear_normalized_cda(struct ccw1 *ccw)
112 {
113 if (ccw->flags & CCW_FLAG_IDA) {
114 kfree(dma32_to_virt(ccw->cda));
115 ccw->flags &= ~CCW_FLAG_IDA;
116 }
117 ccw->cda = 0;
118 }
119
120 /*
121 * Idal buffer extension
122 */
123 struct idal_buffer {
124 size_t size;
125 size_t page_order;
126 dma64_t data[];
127 };
128
129 /*
130 * Allocate an idal buffer
131 */
132 static inline struct idal_buffer *idal_buffer_alloc(size_t size, int page_order)
133 {
134 int nr_chunks, nr_ptrs, i;
135 struct idal_buffer *ib;
136 void *vaddr;
137
138 nr_ptrs = (size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_SHIFT;
139 nr_chunks = (PAGE_SIZE << page_order) >> IDA_SIZE_SHIFT;
140 ib = kmalloc(struct_size(ib, data, nr_ptrs), GFP_DMA | GFP_KERNEL);
141 if (!ib)
142 return ERR_PTR(-ENOMEM);
143 ib->size = size;
144 ib->page_order = page_order;
145 for (i = 0; i < nr_ptrs; i++) {
146 if (i & (nr_chunks - 1)) {
147 ib->data[i] = dma64_add(ib->data[i - 1], IDA_BLOCK_SIZE);
148 continue;
149 }
150 vaddr = (void *)__get_free_pages(GFP_KERNEL, page_order);
151 if (!vaddr)
152 goto error;
153 ib->data[i] = virt_to_dma64(vaddr);
154 }
155 return ib;
156 error:
157 while (i >= nr_chunks) {
158 i -= nr_chunks;
159 vaddr = dma64_to_virt(ib->data[i]);
160 free_pages((unsigned long)vaddr, ib->page_order);
161 }
162 kfree(ib);
163 return ERR_PTR(-ENOMEM);
164 }
165
166 /*
167 * Free an idal buffer.
168 */
169 static inline void idal_buffer_free(struct idal_buffer *ib)
170 {
171 int nr_chunks, nr_ptrs, i;
172 void *vaddr;
173
174 nr_ptrs = (ib->size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_SHIFT;
175 nr_chunks = (PAGE_SIZE << ib->page_order) >> IDA_SIZE_SHIFT;
176 for (i = 0; i < nr_ptrs; i += nr_chunks) {
177 vaddr = dma64_to_virt(ib->data[i]);
178 free_pages((unsigned long)vaddr, ib->page_order);
179 }
180 kfree(ib);
181 }
182
183 /*
184 * Test if a idal list is really needed.
185 */
186 static inline bool __idal_buffer_is_needed(struct idal_buffer *ib)
187 {
188 if (ib->size > (PAGE_SIZE << ib->page_order))
189 return true;
190 return idal_is_needed(dma64_to_virt(ib->data[0]), ib->size);
191 }
192
193 /*
194 * Set channel data address to idal buffer.
195 */
196 static inline void idal_buffer_set_cda(struct idal_buffer *ib, struct ccw1 *ccw)
197 {
198 void *vaddr;
199
200 if (__idal_buffer_is_needed(ib)) {
201 /* Setup idals */
202 ccw->cda = virt_to_dma32(ib->data);
203 ccw->flags |= CCW_FLAG_IDA;
204 } else {
205 /*
206 * No idals needed - use direct addressing. Convert from
207 * dma64_t to virt and then to dma32_t only because of type
208 * checking. The physical address is known to be below 2GB.
209 */
210 vaddr = dma64_to_virt(ib->data[0]);
211 ccw->cda = virt_to_dma32(vaddr);
212 }
213 ccw->count = ib->size;
214 }
215
216 /*
217 * Copy count bytes from an idal buffer to user memory
218 */
219 static inline size_t idal_buffer_to_user(struct idal_buffer *ib, void __user *to, size_t count)
220 {
221 size_t left;
222 void *vaddr;
223 int i;
224
225 BUG_ON(count > ib->size);
226 for (i = 0; count > IDA_BLOCK_SIZE; i++) {
227 vaddr = dma64_to_virt(ib->data[i]);
228 left = copy_to_user(to, vaddr, IDA_BLOCK_SIZE);
229 if (left)
230 return left + count - IDA_BLOCK_SIZE;
231 to = (void __user *)to + IDA_BLOCK_SIZE;
232 count -= IDA_BLOCK_SIZE;
233 }
234 vaddr = dma64_to_virt(ib->data[i]);
235 return copy_to_user(to, vaddr, count);
236 }
237
238 /*
239 * Copy count bytes from user memory to an idal buffer
240 */
241 static inline size_t idal_buffer_from_user(struct idal_buffer *ib, const void __user *from, size_t count)
242 {
243 size_t left;
244 void *vaddr;
245 int i;
246
247 BUG_ON(count > ib->size);
248 for (i = 0; count > IDA_BLOCK_SIZE; i++) {
249 vaddr = dma64_to_virt(ib->data[i]);
250 left = copy_from_user(vaddr, from, IDA_BLOCK_SIZE);
251 if (left)
252 return left + count - IDA_BLOCK_SIZE;
253 from = (void __user *)from + IDA_BLOCK_SIZE;
254 count -= IDA_BLOCK_SIZE;
255 }
256 vaddr = dma64_to_virt(ib->data[i]);
257 return copy_from_user(vaddr, from, count);
258 }
259
260 #endif
261
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