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 }