Linux Kernel  3.7.1
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ohci-mem.c
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1 /*
2  * OHCI HCD (Host Controller Driver) for USB.
3  *
4  * (C) Copyright 1999 Roman Weissgaerber <[email protected]>
5  * (C) Copyright 2000-2002 David Brownell <[email protected]>
6  *
7  * This file is licenced under the GPL.
8  */
9 
10 /*-------------------------------------------------------------------------*/
11 
12 /*
13  * OHCI deals with three types of memory:
14  * - data used only by the HCD ... kmalloc is fine
15  * - async and periodic schedules, shared by HC and HCD ... these
16  * need to use dma_pool or dma_alloc_coherent
17  * - driver buffers, read/written by HC ... the hcd glue or the
18  * device driver provides us with dma addresses
19  *
20  * There's also "register" data, which is memory mapped.
21  * No memory seen by this driver (or any HCD) may be paged out.
22  */
23 
24 /*-------------------------------------------------------------------------*/
25 
26 static void ohci_hcd_init (struct ohci_hcd *ohci)
27 {
28  ohci->next_statechange = jiffies;
29  spin_lock_init (&ohci->lock);
30  INIT_LIST_HEAD (&ohci->pending);
31 }
32 
33 /*-------------------------------------------------------------------------*/
34 
35 static int ohci_mem_init (struct ohci_hcd *ohci)
36 {
37  ohci->td_cache = dma_pool_create ("ohci_td",
38  ohci_to_hcd(ohci)->self.controller,
39  sizeof (struct td),
40  32 /* byte alignment */,
41  0 /* no page-crossing issues */);
42  if (!ohci->td_cache)
43  return -ENOMEM;
44  ohci->ed_cache = dma_pool_create ("ohci_ed",
45  ohci_to_hcd(ohci)->self.controller,
46  sizeof (struct ed),
47  16 /* byte alignment */,
48  0 /* no page-crossing issues */);
49  if (!ohci->ed_cache) {
50  dma_pool_destroy (ohci->td_cache);
51  return -ENOMEM;
52  }
53  return 0;
54 }
55 
56 static void ohci_mem_cleanup (struct ohci_hcd *ohci)
57 {
58  if (ohci->td_cache) {
59  dma_pool_destroy (ohci->td_cache);
60  ohci->td_cache = NULL;
61  }
62  if (ohci->ed_cache) {
63  dma_pool_destroy (ohci->ed_cache);
64  ohci->ed_cache = NULL;
65  }
66 }
67 
68 /*-------------------------------------------------------------------------*/
69 
70 /* ohci "done list" processing needs this mapping */
71 static inline struct td *
72 dma_to_td (struct ohci_hcd *hc, dma_addr_t td_dma)
73 {
74  struct td *td;
75 
76  td_dma &= TD_MASK;
77  td = hc->td_hash [TD_HASH_FUNC(td_dma)];
78  while (td && td->td_dma != td_dma)
79  td = td->td_hash;
80  return td;
81 }
82 
83 /* TDs ... */
84 static struct td *
85 td_alloc (struct ohci_hcd *hc, gfp_t mem_flags)
86 {
87  dma_addr_t dma;
88  struct td *td;
89 
90  td = dma_pool_alloc (hc->td_cache, mem_flags, &dma);
91  if (td) {
92  /* in case hc fetches it, make it look dead */
93  memset (td, 0, sizeof *td);
94  td->hwNextTD = cpu_to_hc32 (hc, dma);
95  td->td_dma = dma;
96  /* hashed in td_fill */
97  }
98  return td;
99 }
100 
101 static void
102 td_free (struct ohci_hcd *hc, struct td *td)
103 {
104  struct td **prev = &hc->td_hash [TD_HASH_FUNC (td->td_dma)];
105 
106  while (*prev && *prev != td)
107  prev = &(*prev)->td_hash;
108  if (*prev)
109  *prev = td->td_hash;
110  else if ((td->hwINFO & cpu_to_hc32(hc, TD_DONE)) != 0)
111  ohci_dbg (hc, "no hash for td %p\n", td);
112  dma_pool_free (hc->td_cache, td, td->td_dma);
113 }
114 
115 /*-------------------------------------------------------------------------*/
116 
117 /* EDs ... */
118 static struct ed *
119 ed_alloc (struct ohci_hcd *hc, gfp_t mem_flags)
120 {
121  dma_addr_t dma;
122  struct ed *ed;
123 
124  ed = dma_pool_alloc (hc->ed_cache, mem_flags, &dma);
125  if (ed) {
126  memset (ed, 0, sizeof (*ed));
127  INIT_LIST_HEAD (&ed->td_list);
128  ed->dma = dma;
129  }
130  return ed;
131 }
132 
133 static void
134 ed_free (struct ohci_hcd *hc, struct ed *ed)
135 {
136  dma_pool_free (hc->ed_cache, ed, ed->dma);
137 }
138 
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