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 * Context: !in_interrupt()
55 *
56 * Call this as part of initializing a host controller that uses the dma
57 * memory allocators. It initializes some pools of dma-coherent memory that
58 * will be shared by all drivers using that controller.
59 *
60 * Call hcd_buffer_destroy() to clean up after using those pools.
61 *
62 * Return: 0 if successful. A negative errno value otherwise.
63 */
hcd_buffer_create(struct usb_hcd * hcd)64 int hcd_buffer_create(struct usb_hcd *hcd)
65 {
66 char name[16];
67 int i, size;
68
69 if (hcd->localmem_pool || !hcd_uses_dma(hcd))
70 return 0;
71
72 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
73 size = pool_max[i];
74 if (!size)
75 continue;
76 snprintf(name, sizeof(name), "buffer-%d", size);
77 hcd->pool[i] = dma_pool_create(name, hcd->self.sysdev,
78 size, size, 0);
79 if (!hcd->pool[i]) {
80 hcd_buffer_destroy(hcd);
81 return -ENOMEM;
82 }
83 }
84 return 0;
85 }
86
87
88 /**
89 * hcd_buffer_destroy - deallocate buffer pools
90 * @hcd: the bus whose buffer pools are to be destroyed
91 * Context: !in_interrupt()
92 *
93 * This frees the buffer pools created by hcd_buffer_create().
94 */
hcd_buffer_destroy(struct usb_hcd * hcd)95 void hcd_buffer_destroy(struct usb_hcd *hcd)
96 {
97 int i;
98
99 if (!IS_ENABLED(CONFIG_HAS_DMA))
100 return;
101
102 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
103 dma_pool_destroy(hcd->pool[i]);
104 hcd->pool[i] = NULL;
105 }
106 }
107
108
109 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
110 * better sharing and to leverage mm/slab.c intelligence.
111 */
112
hcd_buffer_alloc(struct usb_bus * bus,size_t size,gfp_t mem_flags,dma_addr_t * dma)113 void *hcd_buffer_alloc(
114 struct usb_bus *bus,
115 size_t size,
116 gfp_t mem_flags,
117 dma_addr_t *dma
118 )
119 {
120 struct usb_hcd *hcd = bus_to_hcd(bus);
121 int i;
122
123 if (size == 0)
124 return NULL;
125
126 if (hcd->localmem_pool)
127 return gen_pool_dma_alloc(hcd->localmem_pool, size, dma);
128
129 /* some USB hosts just use PIO */
130 if (!hcd_uses_dma(hcd)) {
131 *dma = ~(dma_addr_t) 0;
132 return kmalloc(size, mem_flags);
133 }
134
135 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
136 if (size <= pool_max[i])
137 return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
138 }
139 return dma_alloc_coherent(hcd->self.sysdev, size, dma, mem_flags);
140 }
141
hcd_buffer_free(struct usb_bus * bus,size_t size,void * addr,dma_addr_t dma)142 void hcd_buffer_free(
143 struct usb_bus *bus,
144 size_t size,
145 void *addr,
146 dma_addr_t dma
147 )
148 {
149 struct usb_hcd *hcd = bus_to_hcd(bus);
150 int i;
151
152 if (!addr)
153 return;
154
155 if (hcd->localmem_pool) {
156 gen_pool_free(hcd->localmem_pool, (unsigned long)addr, size);
157 return;
158 }
159
160 if (!hcd_uses_dma(hcd)) {
161 kfree(addr);
162 return;
163 }
164
165 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
166 if (size <= pool_max[i]) {
167 dma_pool_free(hcd->pool[i], addr, dma);
168 return;
169 }
170 }
171 dma_free_coherent(hcd->self.sysdev, size, addr, dma);
172 }
173
