ALSA: ctxfi - Remove useless initializations and cast
[linux-2.6.git] / sound / pci / ctxfi / ctvmem.c
1 /**
2  * Copyright (C) 2008, Creative Technology Ltd. All Rights Reserved.
3  *
4  * This source file is released under GPL v2 license (no other versions).
5  * See the COPYING file included in the main directory of this source
6  * distribution for the license terms and conditions.
7  *
8  * @File    ctvmem.c
9  *
10  * @Brief
11  * This file contains the implementation of virtual memory management object
12  * for card device.
13  *
14  * @Author Liu Chun
15  * @Date Apr 1 2008
16  */
17
18 #include "ctvmem.h"
19 #include <linux/slab.h>
20 #include <linux/mm.h>
21 #include <linux/io.h>
22 #include <sound/pcm.h>
23
24 #define CT_PTES_PER_PAGE (CT_PAGE_SIZE / sizeof(void *))
25 #define CT_ADDRS_PER_PAGE (CT_PTES_PER_PAGE * CT_PAGE_SIZE)
26
27 /* *
28  * Find or create vm block based on requested @size.
29  * @size must be page aligned.
30  * */
31 static struct ct_vm_block *
32 get_vm_block(struct ct_vm *vm, unsigned int size)
33 {
34         struct ct_vm_block *block = NULL, *entry;
35         struct list_head *pos;
36
37         size = CT_PAGE_ALIGN(size);
38         if (size > vm->size) {
39                 printk(KERN_ERR "ctxfi: Fail! No sufficient device virtural "
40                                   "memory space available!\n");
41                 return NULL;
42         }
43
44         mutex_lock(&vm->lock);
45         list_for_each(pos, &vm->unused) {
46                 entry = list_entry(pos, struct ct_vm_block, list);
47                 if (entry->size >= size)
48                         break; /* found a block that is big enough */
49         }
50         if (pos == &vm->unused)
51                 goto out;
52
53         if (entry->size == size) {
54                 /* Move the vm node from unused list to used list directly */
55                 list_del(&entry->list);
56                 list_add(&entry->list, &vm->used);
57                 vm->size -= size;
58                 block = entry;
59                 goto out;
60         }
61
62         block = kzalloc(sizeof(*block), GFP_KERNEL);
63         if (NULL == block)
64                 goto out;
65
66         block->addr = entry->addr;
67         block->size = size;
68         list_add(&block->list, &vm->used);
69         entry->addr += size;
70         entry->size -= size;
71         vm->size -= size;
72
73  out:
74         mutex_unlock(&vm->lock);
75         return block;
76 }
77
78 static void put_vm_block(struct ct_vm *vm, struct ct_vm_block *block)
79 {
80         struct ct_vm_block *entry, *pre_ent;
81         struct list_head *pos, *pre;
82
83         block->size = CT_PAGE_ALIGN(block->size);
84
85         mutex_lock(&vm->lock);
86         list_del(&block->list);
87         vm->size += block->size;
88
89         list_for_each(pos, &vm->unused) {
90                 entry = list_entry(pos, struct ct_vm_block, list);
91                 if (entry->addr >= (block->addr + block->size))
92                         break; /* found a position */
93         }
94         if (pos == &vm->unused) {
95                 list_add_tail(&block->list, &vm->unused);
96                 entry = block;
97         } else {
98                 if ((block->addr + block->size) == entry->addr) {
99                         entry->addr = block->addr;
100                         entry->size += block->size;
101                         kfree(block);
102                 } else {
103                         __list_add(&block->list, pos->prev, pos);
104                         entry = block;
105                 }
106         }
107
108         pos = &entry->list;
109         pre = pos->prev;
110         while (pre != &vm->unused) {
111                 entry = list_entry(pos, struct ct_vm_block, list);
112                 pre_ent = list_entry(pre, struct ct_vm_block, list);
113                 if ((pre_ent->addr + pre_ent->size) > entry->addr)
114                         break;
115
116                 pre_ent->size += entry->size;
117                 list_del(pos);
118                 kfree(entry);
119                 pos = pre;
120                 pre = pos->prev;
121         }
122         mutex_unlock(&vm->lock);
123 }
124
125 /* Map host addr (kmalloced/vmalloced) to device logical addr. */
126 static struct ct_vm_block *
127 ct_vm_map(struct ct_vm *vm, struct snd_pcm_substream *substream, int size)
128 {
129         struct ct_vm_block *block;
130         unsigned int pte_start;
131         unsigned i, pages;
132         unsigned long *ptp;
133
134         block = get_vm_block(vm, size);
135         if (block == NULL) {
136                 printk(KERN_ERR "ctxfi: No virtual memory block that is big "
137                                   "enough to allocate!\n");
138                 return NULL;
139         }
140
141         ptp = vm->ptp[0];
142         pte_start = (block->addr >> CT_PAGE_SHIFT);
143         pages = block->size >> CT_PAGE_SHIFT;
144         for (i = 0; i < pages; i++) {
145                 unsigned long addr;
146                 addr = snd_pcm_sgbuf_get_addr(substream, i << CT_PAGE_SHIFT);
147                 ptp[pte_start + i] = addr;
148         }
149
150         block->size = size;
151         return block;
152 }
153
154 static void ct_vm_unmap(struct ct_vm *vm, struct ct_vm_block *block)
155 {
156         /* do unmapping */
157         put_vm_block(vm, block);
158 }
159
160 /* *
161  * return the host (kmalloced) addr of the @index-th device
162  * page talbe page on success, or NULL on failure.
163  * The first returned NULL indicates the termination.
164  * */
165 static void *
166 ct_get_ptp_virt(struct ct_vm *vm, int index)
167 {
168         void *addr;
169
170         addr = (index >= CT_PTP_NUM) ? NULL : vm->ptp[index];
171
172         return addr;
173 }
174
175 int ct_vm_create(struct ct_vm **rvm)
176 {
177         struct ct_vm *vm;
178         struct ct_vm_block *block;
179         int i;
180
181         *rvm = NULL;
182
183         vm = kzalloc(sizeof(*vm), GFP_KERNEL);
184         if (NULL == vm)
185                 return -ENOMEM;
186
187         mutex_init(&vm->lock);
188
189         /* Allocate page table pages */
190         for (i = 0; i < CT_PTP_NUM; i++) {
191                 vm->ptp[i] = kmalloc(PAGE_SIZE, GFP_KERNEL);
192                 if (NULL == vm->ptp[i])
193                         break;
194         }
195         if (!i) {
196                 /* no page table pages are allocated */
197                 kfree(vm);
198                 return -ENOMEM;
199         }
200         vm->size = CT_ADDRS_PER_PAGE * i;
201         /* Initialise remaining ptps */
202         for (; i < CT_PTP_NUM; i++)
203                 vm->ptp[i] = NULL;
204
205         vm->map = ct_vm_map;
206         vm->unmap = ct_vm_unmap;
207         vm->get_ptp_virt = ct_get_ptp_virt;
208         INIT_LIST_HEAD(&vm->unused);
209         INIT_LIST_HEAD(&vm->used);
210         block = kzalloc(sizeof(*block), GFP_KERNEL);
211         if (NULL != block) {
212                 block->addr = 0;
213                 block->size = vm->size;
214                 list_add(&block->list, &vm->unused);
215         }
216
217         *rvm = vm;
218         return 0;
219 }
220
221 /* The caller must ensure no mapping pages are being used
222  * by hardware before calling this function */
223 void ct_vm_destroy(struct ct_vm *vm)
224 {
225         int i;
226         struct list_head *pos;
227         struct ct_vm_block *entry;
228
229         /* free used and unused list nodes */
230         while (!list_empty(&vm->used)) {
231                 pos = vm->used.next;
232                 list_del(pos);
233                 entry = list_entry(pos, struct ct_vm_block, list);
234                 kfree(entry);
235         }
236         while (!list_empty(&vm->unused)) {
237                 pos = vm->unused.next;
238                 list_del(pos);
239                 entry = list_entry(pos, struct ct_vm_block, list);
240                 kfree(entry);
241         }
242
243         /* free allocated page table pages */
244         for (i = 0; i < CT_PTP_NUM; i++)
245                 kfree(vm->ptp[i]);
246
247         vm->size = 0;
248
249         kfree(vm);
250 }