1/*
2 * File...........: linux/include/asm-s390x/idals.h
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 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 2000a
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 <asm/uaccess.h>
22
23#ifdef __s390x__
24#define IDA_SIZE_LOG 12 /* 11 for 2k , 12 for 4k */
25#else
26#define IDA_SIZE_LOG 11 /* 11 for 2k , 12 for 4k */
27#endif
28#define IDA_BLOCK_SIZE (1L<<IDA_SIZE_LOG)
29
30/*
31 * Test if an address/length pair needs an idal list.
32 */
33static inline int
34idal_is_needed(void *vaddr, unsigned int length)
35{
36#ifdef __s390x__
37	return ((__pa(vaddr) + length - 1) >> 31) != 0;
38#else
39	return 0;
40#endif
41}
42
43
44/*
45 * Return the number of idal words needed for an address/length pair.
46 */
47static inline unsigned int
48idal_nr_words(void *vaddr, unsigned int length)
49{
50#ifdef __s390x__
51	if (idal_is_needed(vaddr, length))
52		return ((__pa(vaddr) & (IDA_BLOCK_SIZE-1)) + length +
53			(IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
54#endif
55	return 0;
56}
57
58/*
59 * Create the list of idal words for an address/length pair.
60 */
61static inline unsigned long *
62idal_create_words(unsigned long *idaws, void *vaddr, unsigned int length)
63{
64#ifdef __s390x__
65	unsigned long paddr;
66	unsigned int cidaw;
67
68	paddr = __pa(vaddr);
69	cidaw = ((paddr & (IDA_BLOCK_SIZE-1)) + length +
70		 (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
71	*idaws++ = paddr;
72	paddr &= -IDA_BLOCK_SIZE;
73	while (--cidaw > 0) {
74		paddr += IDA_BLOCK_SIZE;
75		*idaws++ = paddr;
76	}
77#endif
78	return idaws;
79}
80
81/*
82 * Sets the address of the data in CCW.
83 * If necessary it allocates an IDAL and sets the appropriate flags.
84 */
85static inline int
86set_normalized_cda(struct ccw1 * ccw, void *vaddr)
87{
88#ifdef __s390x__
89	unsigned int nridaws;
90	unsigned long *idal;
91
92	if (ccw->flags & CCW_FLAG_IDA)
93		return -EINVAL;
94	nridaws = idal_nr_words(vaddr, ccw->count);
95	if (nridaws > 0) {
96		idal = kmalloc(nridaws * sizeof(unsigned long),
97			       GFP_ATOMIC | GFP_DMA );
98		if (idal == NULL)
99			return -ENOMEM;
100		idal_create_words(idal, vaddr, ccw->count);
101		ccw->flags |= CCW_FLAG_IDA;
102		vaddr = idal;
103	}
104#endif
105	ccw->cda = (__u32)(unsigned long) vaddr;
106	return 0;
107}
108
109/*
110 * Releases any allocated IDAL related to the CCW.
111 */
112static inline void
113clear_normalized_cda(struct ccw1 * ccw)
114{
115#ifdef __s390x__
116	if (ccw->flags & CCW_FLAG_IDA) {
117		kfree((void *)(unsigned long) ccw->cda);
118		ccw->flags &= ~CCW_FLAG_IDA;
119	}
120#endif
121	ccw->cda = 0;
122}
123
124/*
125 * Idal buffer extension
126 */
127struct idal_buffer {
128	size_t size;
129	size_t page_order;
130	void *data[0];
131};
132
133/*
134 * Allocate an idal buffer
135 */
136static inline struct idal_buffer *
137idal_buffer_alloc(size_t size, int page_order)
138{
139	struct idal_buffer *ib;
140	int nr_chunks, nr_ptrs, i;
141
142	nr_ptrs = (size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
143	nr_chunks = (4096 << page_order) >> IDA_SIZE_LOG;
144	ib = kmalloc(sizeof(struct idal_buffer) + nr_ptrs*sizeof(void *),
145		     GFP_DMA | GFP_KERNEL);
146	if (ib == NULL)
147		return ERR_PTR(-ENOMEM);
148	ib->size = size;
149	ib->page_order = page_order;
150	for (i = 0; i < nr_ptrs; i++) {
151		if ((i & (nr_chunks - 1)) != 0) {
152			ib->data[i] = ib->data[i-1] + IDA_BLOCK_SIZE;
153			continue;
154		}
155		ib->data[i] = (void *)
156			__get_free_pages(GFP_KERNEL, page_order);
157		if (ib->data[i] != NULL)
158			continue;
159		// Not enough memory
160		while (i >= nr_chunks) {
161			i -= nr_chunks;
162			free_pages((unsigned long) ib->data[i],
163				   ib->page_order);
164		}
165		kfree(ib);
166		return ERR_PTR(-ENOMEM);
167	}
168	return ib;
169}
170
171/*
172 * Free an idal buffer.
173 */
174static inline void
175idal_buffer_free(struct idal_buffer *ib)
176{
177	int nr_chunks, nr_ptrs, i;
178
179	nr_ptrs = (ib->size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
180	nr_chunks = (4096 << ib->page_order) >> IDA_SIZE_LOG;
181	for (i = 0; i < nr_ptrs; i += nr_chunks)
182		free_pages((unsigned long) ib->data[i], ib->page_order);
183	kfree(ib);
184}
185
186/*
187 * Test if a idal list is really needed.
188 */
189static inline int
190__idal_buffer_is_needed(struct idal_buffer *ib)
191{
192#ifdef __s390x__
193	return ib->size > (4096ul << ib->page_order) ||
194		idal_is_needed(ib->data[0], ib->size);
195#else
196	return ib->size > (4096ul << ib->page_order);
197#endif
198}
199
200/*
201 * Set channel data address to idal buffer.
202 */
203static inline void
204idal_buffer_set_cda(struct idal_buffer *ib, struct ccw1 *ccw)
205{
206	if (__idal_buffer_is_needed(ib)) {
207		// setup idals;
208		ccw->cda = (u32)(addr_t) ib->data;
209		ccw->flags |= CCW_FLAG_IDA;
210	} else
211		// we do not need idals - use direct addressing
212		ccw->cda = (u32)(addr_t) ib->data[0];
213	ccw->count = ib->size;
214}
215
216/*
217 * Copy count bytes from an idal buffer to user memory
218 */
219static inline size_t
220idal_buffer_to_user(struct idal_buffer *ib, void __user *to, size_t count)
221{
222	size_t left;
223	int i;
224
225	BUG_ON(count > ib->size);
226	for (i = 0; count > IDA_BLOCK_SIZE; i++) {
227		left = copy_to_user(to, ib->data[i], IDA_BLOCK_SIZE);
228		if (left)
229			return left + count - IDA_BLOCK_SIZE;
230		to = (void __user *) to + IDA_BLOCK_SIZE;
231		count -= IDA_BLOCK_SIZE;
232	}
233	return copy_to_user(to, ib->data[i], count);
234}
235
236/*
237 * Copy count bytes from user memory to an idal buffer
238 */
239static inline size_t
240idal_buffer_from_user(struct idal_buffer *ib, const void __user *from, size_t count)
241{
242	size_t left;
243	int i;
244
245	BUG_ON(count > ib->size);
246	for (i = 0; count > IDA_BLOCK_SIZE; i++) {
247		left = copy_from_user(ib->data[i], from, IDA_BLOCK_SIZE);
248		if (left)
249			return left + count - IDA_BLOCK_SIZE;
250		from = (void __user *) from + IDA_BLOCK_SIZE;
251		count -= IDA_BLOCK_SIZE;
252	}
253	return copy_from_user(ib->data[i], from, count);
254}
255
256#endif
257