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 ... */
29static size_t pool_max[HCD_BUFFER_POOLS] = {
30 32, 128, 512, 2048,
31};
32
33void __init usb_init_pool_max(void)
34{
35 /*
36 * The pool_max values must never be smaller than
37 * ARCH_DMA_MINALIGN.
38 */
39 if (ARCH_DMA_MINALIGN <= 32)
40 ; /* Original value is okay */
41 else if (ARCH_DMA_MINALIGN <= 64)
42 pool_max[0] = 64;
43 else if (ARCH_DMA_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 */
65int 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(buf: name, size: sizeof(name), fmt: "buffer-%d", size);
78 hcd->pool[i] = dma_pool_create(name, dev: hcd->self.sysdev,
79 size, align: size, boundary: 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 */
97void 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(pool: 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
115void *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(pool: 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(pool: hcd->pool[i], mem_flags, handle: dma);
140 }
141 return dma_alloc_coherent(dev: hcd->self.sysdev, size, dma_handle: dma, gfp: mem_flags);
142}
143
144void 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(pool: hcd->localmem_pool, addr: (unsigned long)addr, size);
159 return;
160 }
161
162 if (!hcd_uses_dma(hcd)) {
163 kfree(objp: addr);
164 return;
165 }
166
167 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
168 if (size <= pool_max[i]) {
169 dma_pool_free(pool: hcd->pool[i], vaddr: addr, addr: dma);
170 return;
171 }
172 }
173 dma_free_coherent(dev: hcd->self.sysdev, size, cpu_addr: addr, dma_handle: dma);
174}
175
176void *hcd_buffer_alloc_pages(struct usb_hcd *hcd,
177 size_t size, gfp_t mem_flags, dma_addr_t *dma)
178{
179 if (size == 0)
180 return NULL;
181
182 if (hcd->localmem_pool)
183 return gen_pool_dma_alloc_align(pool: hcd->localmem_pool,
184 size, dma, PAGE_SIZE);
185
186 /* some USB hosts just use PIO */
187 if (!hcd_uses_dma(hcd)) {
188 *dma = DMA_MAPPING_ERROR;
189 return (void *)__get_free_pages(mem_flags,
190 get_order(size));
191 }
192
193 return dma_alloc_coherent(dev: hcd->self.sysdev,
194 size, dma_handle: dma, gfp: mem_flags);
195}
196
197void hcd_buffer_free_pages(struct usb_hcd *hcd,
198 size_t size, void *addr, dma_addr_t dma)
199{
200 if (!addr)
201 return;
202
203 if (hcd->localmem_pool) {
204 gen_pool_free(pool: hcd->localmem_pool,
205 addr: (unsigned long)addr, size);
206 return;
207 }
208
209 if (!hcd_uses_dma(hcd)) {
210 free_pages(addr: (unsigned long)addr, order: get_order(size));
211 return;
212 }
213
214 dma_free_coherent(dev: hcd->self.sysdev, size, cpu_addr: addr, dma_handle: dma);
215}
216

source code of linux/drivers/usb/core/buffer.c