1 /*
2 * DMA memory management for framework level HCD code (hc_driver)
3 *
4 * This implementation plugs in through generic "usb_bus" level methods,
5 * and should work with all USB controllers, regardles of bus type.
6 */
7
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/slab.h>
11 #include <linux/device.h>
12 #include <linux/mm.h>
13 #include <linux/io.h>
14 #include <linux/dma-mapping.h>
15 #include <linux/dmapool.h>
16 #include <linux/usb.h>
17 #include <linux/usb/hcd.h>
18
19
20 /*
21 * DMA-Coherent Buffers
22 */
23
24 /* FIXME tune these based on pool statistics ... */
25 static const size_t pool_max[HCD_BUFFER_POOLS] = {
26 /* platforms without dma-friendly caches might need to
27 * prevent cacheline sharing...
28 */
29 32,
30 128,
31 512,
32 PAGE_SIZE / 2
33 /* bigger --> allocate pages */
34 };
35
36
37 /* SETUP primitives */
38
39 /**
40 * hcd_buffer_create - initialize buffer pools
41 * @hcd: the bus whose buffer pools are to be initialized
42 * Context: !in_interrupt()
43 *
44 * Call this as part of initializing a host controller that uses the dma
45 * memory allocators. It initializes some pools of dma-coherent memory that
46 * will be shared by all drivers using that controller, or returns a negative
47 * errno value on error.
48 *
49 * Call hcd_buffer_destroy() to clean up after using those pools.
50 */
hcd_buffer_create(struct usb_hcd * hcd)51 int hcd_buffer_create(struct usb_hcd *hcd)
52 {
53 char name[16];
54 int i, size;
55
56 if (!hcd->self.controller->dma_mask &&
57 !(hcd->driver->flags & HCD_LOCAL_MEM))
58 return 0;
59
60 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
61 size = pool_max[i];
62 if (!size)
63 continue;
64 snprintf(name, sizeof name, "buffer-%d", size);
65 hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
66 size, size, 0);
67 if (!hcd->pool[i]) {
68 hcd_buffer_destroy(hcd);
69 return -ENOMEM;
70 }
71 }
72 return 0;
73 }
74
75
76 /**
77 * hcd_buffer_destroy - deallocate buffer pools
78 * @hcd: the bus whose buffer pools are to be destroyed
79 * Context: !in_interrupt()
80 *
81 * This frees the buffer pools created by hcd_buffer_create().
82 */
hcd_buffer_destroy(struct usb_hcd * hcd)83 void hcd_buffer_destroy(struct usb_hcd *hcd)
84 {
85 int i;
86
87 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
88 struct dma_pool *pool = hcd->pool[i];
89 if (pool) {
90 dma_pool_destroy(pool);
91 hcd->pool[i] = NULL;
92 }
93 }
94 }
95
96
97 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
98 * better sharing and to leverage mm/slab.c intelligence.
99 */
100
hcd_buffer_alloc(struct usb_bus * bus,size_t size,gfp_t mem_flags,dma_addr_t * dma)101 void *hcd_buffer_alloc(
102 struct usb_bus *bus,
103 size_t size,
104 gfp_t mem_flags,
105 dma_addr_t *dma
106 )
107 {
108 struct usb_hcd *hcd = bus_to_hcd(bus);
109 int i;
110
111 /* some USB hosts just use PIO */
112 if (!bus->controller->dma_mask &&
113 !(hcd->driver->flags & HCD_LOCAL_MEM)) {
114 *dma = ~(dma_addr_t) 0;
115 return kmalloc(size, mem_flags);
116 }
117
118 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
119 if (size <= pool_max[i])
120 return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
121 }
122 return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
123 }
124
hcd_buffer_free(struct usb_bus * bus,size_t size,void * addr,dma_addr_t dma)125 void hcd_buffer_free(
126 struct usb_bus *bus,
127 size_t size,
128 void *addr,
129 dma_addr_t dma
130 )
131 {
132 struct usb_hcd *hcd = bus_to_hcd(bus);
133 int i;
134
135 if (!addr)
136 return;
137
138 if (!bus->controller->dma_mask &&
139 !(hcd->driver->flags & HCD_LOCAL_MEM)) {
140 kfree(addr);
141 return;
142 }
143
144 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
145 if (size <= pool_max[i]) {
146 dma_pool_free(hcd->pool[i], addr, dma);
147 return;
148 }
149 }
150 dma_free_coherent(hcd->self.controller, size, addr, dma);
151 }
152