idals.h

  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 */
 33static 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 */
 43static 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 */
 56static 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 */
 69static 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 */
 88static 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 */
111static 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 */
123struct idal_buffer {
124	size_t size;
125	size_t page_order;
126	dma64_t data[];
127};
128
129/*
130 * Allocate an idal buffer
131 */
132static 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;
156error:
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 */
169static 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 * Allocate an array of IDAL buffers to cover a total data size of @size. The
185 * resulting array is null-terminated.
186 *
187 * The amount of individual IDAL buffers is determined based on @size.
188 * Each IDAL buffer can have a maximum size of @CCW_MAX_BYTE_COUNT.
189 */
190static inline struct idal_buffer **idal_buffer_array_alloc(size_t size, int page_order)
191{
192	struct idal_buffer **ibs;
193	size_t ib_size; /* Size of a single idal buffer */
194	int count; /* Amount of individual idal buffers */
195	int i;
196
197	count = (size + CCW_MAX_BYTE_COUNT - 1) / CCW_MAX_BYTE_COUNT;
198	ibs = kmalloc_array(count + 1, sizeof(*ibs), GFP_KERNEL);
199	for (i = 0; i < count; i++) {
200		/* Determine size for the current idal buffer */
201		ib_size = min(size, CCW_MAX_BYTE_COUNT);
202		size -= ib_size;
203		ibs[i] = idal_buffer_alloc(ib_size, page_order);
204		if (IS_ERR(ibs[i])) {
205			while (i--)
206				idal_buffer_free(ibs[i]);
207			kfree(ibs);
208			ibs = NULL;
209			return ERR_PTR(-ENOMEM);
210		}
211	}
212	ibs[i] = NULL;
213	return ibs;
214}
215
216/*
217 * Free array of IDAL buffers
218 */
219static inline void idal_buffer_array_free(struct idal_buffer ***ibs)
220{
221	struct idal_buffer **p;
222
223	if (!ibs || !*ibs)
224		return;
225	for (p = *ibs; *p; p++)
226		idal_buffer_free(*p);
227	kfree(*ibs);
228	*ibs = NULL;
229}
230
231/*
232 * Determine size of IDAL buffer array
233 */
234static inline int idal_buffer_array_size(struct idal_buffer **ibs)
235{
236	int size = 0;
237
238	while (ibs && *ibs) {
239		size++;
240		ibs++;
241	}
242	return size;
243}
244
245/*
246 * Determine total data size covered by IDAL buffer array
247 */
248static inline size_t idal_buffer_array_datasize(struct idal_buffer **ibs)
249{
250	size_t size = 0;
251
252	while (ibs && *ibs) {
253		size += (*ibs)->size;
254		ibs++;
255	}
256	return size;
257}
258
259/*
260 * Test if a idal list is really needed.
261 */
262static inline bool __idal_buffer_is_needed(struct idal_buffer *ib)
263{
264	if (ib->size > (PAGE_SIZE << ib->page_order))
265		return true;
266	return idal_is_needed(dma64_to_virt(ib->data[0]), ib->size);
267}
268
269/*
270 * Set channel data address to idal buffer.
271 */
272static inline void idal_buffer_set_cda(struct idal_buffer *ib, struct ccw1 *ccw)
273{
274	void *vaddr;
275
276	if (__idal_buffer_is_needed(ib)) {
277		/* Setup idals */
278		ccw->cda = virt_to_dma32(ib->data);
279		ccw->flags |= CCW_FLAG_IDA;
280	} else {
281		/*
282		 * No idals needed - use direct addressing. Convert from
283		 * dma64_t to virt and then to dma32_t only because of type
284		 * checking. The physical address is known to be below 2GB.
285		 */
286		vaddr = dma64_to_virt(ib->data[0]);
287		ccw->cda = virt_to_dma32(vaddr);
288	}
289	ccw->count = ib->size;
290}
291
292/*
293 * Copy count bytes from an idal buffer to user memory
294 */
295static inline size_t idal_buffer_to_user(struct idal_buffer *ib, void __user *to, size_t count)
296{
297	size_t left;
298	void *vaddr;
299	int i;
300
301	BUG_ON(count > ib->size);
302	for (i = 0; count > IDA_BLOCK_SIZE; i++) {
303		vaddr = dma64_to_virt(ib->data[i]);
304		left = copy_to_user(to, vaddr, IDA_BLOCK_SIZE);
305		if (left)
306			return left + count - IDA_BLOCK_SIZE;
307		to = (void __user *)to + IDA_BLOCK_SIZE;
308		count -= IDA_BLOCK_SIZE;
309	}
310	vaddr = dma64_to_virt(ib->data[i]);
311	return copy_to_user(to, vaddr, count);
312}
313
314/*
315 * Copy count bytes from user memory to an idal buffer
316 */
317static inline size_t idal_buffer_from_user(struct idal_buffer *ib, const void __user *from, size_t count)
318{
319	size_t left;
320	void *vaddr;
321	int i;
322
323	BUG_ON(count > ib->size);
324	for (i = 0; count > IDA_BLOCK_SIZE; i++) {
325		vaddr = dma64_to_virt(ib->data[i]);
326		left = copy_from_user(vaddr, from, IDA_BLOCK_SIZE);
327		if (left)
328			return left + count - IDA_BLOCK_SIZE;
329		from = (void __user *)from + IDA_BLOCK_SIZE;
330		count -= IDA_BLOCK_SIZE;
331	}
332	vaddr = dma64_to_virt(ib->data[i]);
333	return copy_from_user(vaddr, from, count);
334}
335
336#endif