Linux kernel mirror (for testing)
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linux
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_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 */
64int hcd_buffer_create(struct usb_hcd *hcd)
65{
66 char name[16];
67 int i, size;
68
69 if (!IS_ENABLED(CONFIG_HAS_DMA) ||
70 (!is_device_dma_capable(hcd->self.sysdev) &&
71 !hcd->localmem_pool))
72 return 0;
73
74 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
75 size = pool_max[i];
76 if (!size)
77 continue;
78 snprintf(name, sizeof(name), "buffer-%d", size);
79 hcd->pool[i] = dma_pool_create(name, hcd->self.sysdev,
80 size, size, 0);
81 if (!hcd->pool[i]) {
82 hcd_buffer_destroy(hcd);
83 return -ENOMEM;
84 }
85 }
86 return 0;
87}
88
89
90/**
91 * hcd_buffer_destroy - deallocate buffer pools
92 * @hcd: the bus whose buffer pools are to be destroyed
93 * Context: !in_interrupt()
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(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(hcd->localmem_pool, size, dma);
130
131 /* some USB hosts just use PIO */
132 if (!IS_ENABLED(CONFIG_HAS_DMA) ||
133 !is_device_dma_capable(bus->sysdev)) {
134 *dma = ~(dma_addr_t) 0;
135 return kmalloc(size, mem_flags);
136 }
137
138 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
139 if (size <= pool_max[i])
140 return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
141 }
142 return dma_alloc_coherent(hcd->self.sysdev, size, dma, mem_flags);
143}
144
145void hcd_buffer_free(
146 struct usb_bus *bus,
147 size_t size,
148 void *addr,
149 dma_addr_t dma
150)
151{
152 struct usb_hcd *hcd = bus_to_hcd(bus);
153 int i;
154
155 if (!addr)
156 return;
157
158 if (hcd->localmem_pool) {
159 gen_pool_free(hcd->localmem_pool, (unsigned long)addr, size);
160 return;
161 }
162
163 if (!IS_ENABLED(CONFIG_HAS_DMA) ||
164 !is_device_dma_capable(bus->sysdev)) {
165 kfree(addr);
166 return;
167 }
168
169 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
170 if (size <= pool_max[i]) {
171 dma_pool_free(hcd->pool[i], addr, dma);
172 return;
173 }
174 }
175 dma_free_coherent(hcd->self.sysdev, size, addr, dma);
176}