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/usb.h>
20#include <linux/usb/hcd.h>
21
22
23/*
24 * DMA-Coherent Buffers
25 */
26
27/* FIXME tune these based on pool statistics ... */
28static size_t pool_max[HCD_BUFFER_POOLS] = {
29 32, 128, 512, 2048,
30};
31
32void __init usb_init_pool_max(void)
33{
34 /*
35 * The pool_max values must never be smaller than
36 * ARCH_KMALLOC_MINALIGN.
37 */
38 if (ARCH_KMALLOC_MINALIGN <= 32)
39 ; /* Original value is okay */
40 else if (ARCH_KMALLOC_MINALIGN <= 64)
41 pool_max[0] = 64;
42 else if (ARCH_KMALLOC_MINALIGN <= 128)
43 pool_max[0] = 0; /* Don't use this pool */
44 else
45 BUILD_BUG(); /* We don't allow this */
46}
47
48/* SETUP primitives */
49
50/**
51 * hcd_buffer_create - initialize buffer pools
52 * @hcd: the bus whose buffer pools are to be initialized
53 * Context: !in_interrupt()
54 *
55 * Call this as part of initializing a host controller that uses the dma
56 * memory allocators. It initializes some pools of dma-coherent memory that
57 * will be shared by all drivers using that controller.
58 *
59 * Call hcd_buffer_destroy() to clean up after using those pools.
60 *
61 * Return: 0 if successful. A negative errno value otherwise.
62 */
63int hcd_buffer_create(struct usb_hcd *hcd)
64{
65 char name[16];
66 int i, size;
67
68 if (!IS_ENABLED(CONFIG_HAS_DMA) ||
69 (!is_device_dma_capable(hcd->self.sysdev) &&
70 !(hcd->driver->flags & HCD_LOCAL_MEM)))
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 * Context: !in_interrupt()
93 *
94 * This frees the buffer pools created by hcd_buffer_create().
95 */
96void hcd_buffer_destroy(struct usb_hcd *hcd)
97{
98 int i;
99
100 if (!IS_ENABLED(CONFIG_HAS_DMA))
101 return;
102
103 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
104 dma_pool_destroy(hcd->pool[i]);
105 hcd->pool[i] = NULL;
106 }
107}
108
109
110/* sometimes alloc/free could use kmalloc with GFP_DMA, for
111 * better sharing and to leverage mm/slab.c intelligence.
112 */
113
114void *hcd_buffer_alloc(
115 struct usb_bus *bus,
116 size_t size,
117 gfp_t mem_flags,
118 dma_addr_t *dma
119)
120{
121 struct usb_hcd *hcd = bus_to_hcd(bus);
122 int i;
123
124 if (size == 0)
125 return NULL;
126
127 /* some USB hosts just use PIO */
128 if (!IS_ENABLED(CONFIG_HAS_DMA) ||
129 (!is_device_dma_capable(bus->sysdev) &&
130 !(hcd->driver->flags & HCD_LOCAL_MEM))) {
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
142void 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 (!IS_ENABLED(CONFIG_HAS_DMA) ||
156 (!is_device_dma_capable(bus->sysdev) &&
157 !(hcd->driver->flags & HCD_LOCAL_MEM))) {
158 kfree(addr);
159 return;
160 }
161
162 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
163 if (size <= pool_max[i]) {
164 dma_pool_free(hcd->pool[i], addr, dma);
165 return;
166 }
167 }
168 dma_free_coherent(hcd->self.sysdev, size, addr, dma);
169}