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(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 */
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 (!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
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(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
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(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(hcd->self.sysdev,
194			size, dma, 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(hcd->localmem_pool,
205				(unsigned long)addr, size);
206		return;
207	}
208
209	if (!hcd_uses_dma(hcd)) {
210		free_pages((unsigned long)addr, get_order(size));
211		return;
212	}
213
214	dma_free_coherent(hcd->self.sysdev, size, addr, dma);
215}
216