1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * DMA memory management for framework level HCD code (hc_driver)
4 *
5 * This implementation plugs in through generic "usb_bus" level methods,
6 * and should work with all USB controllers, regardless of bus type.
7 *
8 * Released under the GPLv2 only.
9 */
10
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/device.h>
15 #include <linux/mm.h>
16 #include <linux/io.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/dmapool.h>
19 #include <linux/genalloc.h>
20 #include <linux/usb.h>
21 #include <linux/usb/hcd.h>
22
23
24 /*
25 * DMA-Coherent Buffers
26 */
27
28 /* FIXME tune these based on pool statistics ... */
29 static size_t pool_max[HCD_BUFFER_POOLS] = {
30 32, 128, 512, 2048,
31 };
32
usb_init_pool_max(void)33 void __init usb_init_pool_max(void)
34 {
35 /*
36 * The pool_max values must never be smaller than
37 * ARCH_KMALLOC_MINALIGN.
38 */
39 if (ARCH_KMALLOC_MINALIGN <= 32)
40 ; /* Original value is okay */
41 else if (ARCH_KMALLOC_MINALIGN <= 64)
42 pool_max[0] = 64;
43 else if (ARCH_KMALLOC_MINALIGN <= 128)
44 pool_max[0] = 0; /* Don't use this pool */
45 else
46 BUILD_BUG(); /* We don't allow this */
47 }
48
49 /* SETUP primitives */
50
51 /**
52 * hcd_buffer_create - initialize buffer pools
53 * @hcd: the bus whose buffer pools are to be initialized
54 *
55 * Context: task context, might sleep
56 *
57 * Call this as part of initializing a host controller that uses the dma
58 * memory allocators. It initializes some pools of dma-coherent memory that
59 * will be shared by all drivers using that controller.
60 *
61 * Call hcd_buffer_destroy() to clean up after using those pools.
62 *
63 * Return: 0 if successful. A negative errno value otherwise.
64 */
hcd_buffer_create(struct usb_hcd * hcd)65 int hcd_buffer_create(struct usb_hcd *hcd)
66 {
67 char name[16];
68 int i, size;
69
70 if (hcd->localmem_pool || !hcd_uses_dma(hcd))
71 return 0;
72
73 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
74 size = pool_max[i];
75 if (!size)
76 continue;
77 snprintf(name, sizeof(name), "buffer-%d", size);
78 hcd->pool[i] = dma_pool_create(name, hcd->self.sysdev,
79 size, size, 0);
80 if (!hcd->pool[i]) {
81 hcd_buffer_destroy(hcd);
82 return -ENOMEM;
83 }
84 }
85 return 0;
86 }
87
88
89 /**
90 * hcd_buffer_destroy - deallocate buffer pools
91 * @hcd: the bus whose buffer pools are to be destroyed
92 *
93 * Context: task context, might sleep
94 *
95 * This frees the buffer pools created by hcd_buffer_create().
96 */
hcd_buffer_destroy(struct usb_hcd * hcd)97 void hcd_buffer_destroy(struct usb_hcd *hcd)
98 {
99 int i;
100
101 if (!IS_ENABLED(CONFIG_HAS_DMA))
102 return;
103
104 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
105 dma_pool_destroy(hcd->pool[i]);
106 hcd->pool[i] = NULL;
107 }
108 }
109
110
111 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
112 * better sharing and to leverage mm/slab.c intelligence.
113 */
114
hcd_buffer_alloc(struct usb_bus * bus,size_t size,gfp_t mem_flags,dma_addr_t * dma)115 void *hcd_buffer_alloc(
116 struct usb_bus *bus,
117 size_t size,
118 gfp_t mem_flags,
119 dma_addr_t *dma
120 )
121 {
122 struct usb_hcd *hcd = bus_to_hcd(bus);
123 int i;
124
125 if (size == 0)
126 return NULL;
127
128 if (hcd->localmem_pool)
129 return gen_pool_dma_alloc(hcd->localmem_pool, size, dma);
130
131 /* some USB hosts just use PIO */
132 if (!hcd_uses_dma(hcd)) {
133 *dma = ~(dma_addr_t) 0;
134 return kmalloc(size, mem_flags);
135 }
136
137 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
138 if (size <= pool_max[i])
139 return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
140 }
141 return dma_alloc_coherent(hcd->self.sysdev, size, dma, mem_flags);
142 }
143
hcd_buffer_free(struct usb_bus * bus,size_t size,void * addr,dma_addr_t dma)144 void hcd_buffer_free(
145 struct usb_bus *bus,
146 size_t size,
147 void *addr,
148 dma_addr_t dma
149 )
150 {
151 struct usb_hcd *hcd = bus_to_hcd(bus);
152 int i;
153
154 if (!addr)
155 return;
156
157 if (hcd->localmem_pool) {
158 gen_pool_free(hcd->localmem_pool, (unsigned long)addr, size);
159 return;
160 }
161
162 if (!hcd_uses_dma(hcd)) {
163 kfree(addr);
164 return;
165 }
166
167 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
168 if (size <= pool_max[i]) {
169 dma_pool_free(hcd->pool[i], addr, dma);
170 return;
171 }
172 }
173 dma_free_coherent(hcd->self.sysdev, size, addr, dma);
174 }
175