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 <asm/cio.h>
21#include <linux/uaccess.h>
22
23#define IDA_SIZE_LOG 12 /* 11 for 2k , 12 for 4k */
24#define IDA_BLOCK_SIZE (1L<<IDA_SIZE_LOG)
25
26#define IDA_2K_SIZE_LOG 11
27#define IDA_2K_BLOCK_SIZE (1L << IDA_2K_SIZE_LOG)
28
29/*
30 * Test if an address/length pair needs an idal list.
31 */
32static inline int
33idal_is_needed(void *vaddr, unsigned int length)
34{
35	return ((__pa(vaddr) + length - 1) >> 31) != 0;
36}
37
38
39/*
40 * Return the number of idal words needed for an address/length pair.
41 */
42static inline unsigned int idal_nr_words(void *vaddr, unsigned int length)
43{
44	return ((__pa(vaddr) & (IDA_BLOCK_SIZE-1)) + length +
45		(IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
46}
47
48/*
49 * Return the number of 2K IDA words needed for an address/length pair.
50 */
51static inline unsigned int idal_2k_nr_words(void *vaddr, unsigned int length)
52{
53	return ((__pa(vaddr) & (IDA_2K_BLOCK_SIZE - 1)) + length +
54		(IDA_2K_BLOCK_SIZE - 1)) >> IDA_2K_SIZE_LOG;
55}
56
57/*
58 * Create the list of idal words for an address/length pair.
59 */
60static inline unsigned long *idal_create_words(unsigned long *idaws,
61					       void *vaddr, unsigned int length)
62{
63	unsigned long paddr;
64	unsigned int cidaw;
65
66	paddr = __pa(vaddr);
67	cidaw = ((paddr & (IDA_BLOCK_SIZE-1)) + length +
68		 (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
69	*idaws++ = paddr;
70	paddr &= -IDA_BLOCK_SIZE;
71	while (--cidaw > 0) {
72		paddr += IDA_BLOCK_SIZE;
73		*idaws++ = paddr;
74	}
75	return idaws;
76}
77
78/*
79 * Sets the address of the data in CCW.
80 * If necessary it allocates an IDAL and sets the appropriate flags.
81 */
82static inline int
83set_normalized_cda(struct ccw1 * ccw, void *vaddr)
84{
85	unsigned int nridaws;
86	unsigned long *idal;
87
88	if (ccw->flags & CCW_FLAG_IDA)
89		return -EINVAL;
90	nridaws = idal_nr_words(vaddr, ccw->count);
91	if (nridaws > 0) {
92		idal = kmalloc(nridaws * sizeof(unsigned long),
93			       GFP_ATOMIC | GFP_DMA );
94		if (idal == NULL)
95			return -ENOMEM;
96		idal_create_words(idal, vaddr, ccw->count);
97		ccw->flags |= CCW_FLAG_IDA;
98		vaddr = idal;
99	}
100	ccw->cda = (__u32)(unsigned long) vaddr;
101	return 0;
102}
103
104/*
105 * Releases any allocated IDAL related to the CCW.
106 */
107static inline void
108clear_normalized_cda(struct ccw1 * ccw)
109{
110	if (ccw->flags & CCW_FLAG_IDA) {
111		kfree((void *)(unsigned long) ccw->cda);
112		ccw->flags &= ~CCW_FLAG_IDA;
113	}
114	ccw->cda = 0;
115}
116
117/*
118 * Idal buffer extension
119 */
120struct idal_buffer {
121	size_t size;
122	size_t page_order;
123	void *data[];
124};
125
126/*
127 * Allocate an idal buffer
128 */
129static inline struct idal_buffer *
130idal_buffer_alloc(size_t size, int page_order)
131{
132	struct idal_buffer *ib;
133	int nr_chunks, nr_ptrs, i;
134
135	nr_ptrs = (size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
136	nr_chunks = (4096 << page_order) >> IDA_SIZE_LOG;
137	ib = kmalloc(struct_size(ib, data, nr_ptrs), GFP_DMA | GFP_KERNEL);
138	if (ib == NULL)
139		return ERR_PTR(-ENOMEM);
140	ib->size = size;
141	ib->page_order = page_order;
142	for (i = 0; i < nr_ptrs; i++) {
143		if ((i & (nr_chunks - 1)) != 0) {
144			ib->data[i] = ib->data[i-1] + IDA_BLOCK_SIZE;
145			continue;
146		}
147		ib->data[i] = (void *)
148			__get_free_pages(GFP_KERNEL, page_order);
149		if (ib->data[i] != NULL)
150			continue;
151		// Not enough memory
152		while (i >= nr_chunks) {
153			i -= nr_chunks;
154			free_pages((unsigned long) ib->data[i],
155				   ib->page_order);
156		}
157		kfree(ib);
158		return ERR_PTR(-ENOMEM);
159	}
160	return ib;
161}
162
163/*
164 * Free an idal buffer.
165 */
166static inline void
167idal_buffer_free(struct idal_buffer *ib)
168{
169	int nr_chunks, nr_ptrs, i;
170
171	nr_ptrs = (ib->size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
172	nr_chunks = (4096 << ib->page_order) >> IDA_SIZE_LOG;
173	for (i = 0; i < nr_ptrs; i += nr_chunks)
174		free_pages((unsigned long) ib->data[i], ib->page_order);
175	kfree(ib);
176}
177
178/*
179 * Test if a idal list is really needed.
180 */
181static inline int
182__idal_buffer_is_needed(struct idal_buffer *ib)
183{
184	return ib->size > (4096ul << ib->page_order) ||
185		idal_is_needed(ib->data[0], ib->size);
186}
187
188/*
189 * Set channel data address to idal buffer.
190 */
191static inline void
192idal_buffer_set_cda(struct idal_buffer *ib, struct ccw1 *ccw)
193{
194	if (__idal_buffer_is_needed(ib)) {
195		// setup idals;
196		ccw->cda = (u32)(addr_t) ib->data;
197		ccw->flags |= CCW_FLAG_IDA;
198	} else
199		// we do not need idals - use direct addressing
200		ccw->cda = (u32)(addr_t) ib->data[0];
201	ccw->count = ib->size;
202}
203
204/*
205 * Copy count bytes from an idal buffer to user memory
206 */
207static inline size_t
208idal_buffer_to_user(struct idal_buffer *ib, void __user *to, size_t count)
209{
210	size_t left;
211	int i;
212
213	BUG_ON(count > ib->size);
214	for (i = 0; count > IDA_BLOCK_SIZE; i++) {
215		left = copy_to_user(to, ib->data[i], IDA_BLOCK_SIZE);
216		if (left)
217			return left + count - IDA_BLOCK_SIZE;
218		to = (void __user *) to + IDA_BLOCK_SIZE;
219		count -= IDA_BLOCK_SIZE;
220	}
221	return copy_to_user(to, ib->data[i], count);
222}
223
224/*
225 * Copy count bytes from user memory to an idal buffer
226 */
227static inline size_t
228idal_buffer_from_user(struct idal_buffer *ib, const void __user *from, size_t count)
229{
230	size_t left;
231	int i;
232
233	BUG_ON(count > ib->size);
234	for (i = 0; count > IDA_BLOCK_SIZE; i++) {
235		left = copy_from_user(ib->data[i], from, IDA_BLOCK_SIZE);
236		if (left)
237			return left + count - IDA_BLOCK_SIZE;
238		from = (void __user *) from + IDA_BLOCK_SIZE;
239		count -= IDA_BLOCK_SIZE;
240	}
241	return copy_from_user(ib->data[i], from, count);
242}
243
244#endif
245