1/*
2 * CMA DebugFS Interface
3 *
4 * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
5 */
6
7
8#include <linux/debugfs.h>
9#include <linux/cma.h>
10#include <linux/list.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/mm_types.h>
14
15#include "cma.h"
16
17struct cma_mem {
18	struct hlist_node node;
19	struct page *p;
20	unsigned long n;
21};
22
23static struct dentry *cma_debugfs_root;
24
25static int cma_debugfs_get(void *data, u64 *val)
26{
27	unsigned long *p = data;
28
29	*val = *p;
30
31	return 0;
32}
33DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
34
35static int cma_used_get(void *data, u64 *val)
36{
37	struct cma *cma = data;
38	unsigned long used;
39
40	mutex_lock(&cma->lock);
41	/* pages counter is smaller than sizeof(int) */
42	used = bitmap_weight(cma->bitmap, (int)cma->count);
43	mutex_unlock(&cma->lock);
44	*val = (u64)used << cma->order_per_bit;
45
46	return 0;
47}
48DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
49
50static int cma_maxchunk_get(void *data, u64 *val)
51{
52	struct cma *cma = data;
53	unsigned long maxchunk = 0;
54	unsigned long start, end = 0;
55
56	mutex_lock(&cma->lock);
57	for (;;) {
58		start = find_next_zero_bit(cma->bitmap, cma->count, end);
59		if (start >= cma->count)
60			break;
61		end = find_next_bit(cma->bitmap, cma->count, start);
62		maxchunk = max(end - start, maxchunk);
63	}
64	mutex_unlock(&cma->lock);
65	*val = (u64)maxchunk << cma->order_per_bit;
66
67	return 0;
68}
69DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
70
71static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
72{
73	spin_lock(&cma->mem_head_lock);
74	hlist_add_head(&mem->node, &cma->mem_head);
75	spin_unlock(&cma->mem_head_lock);
76}
77
78static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
79{
80	struct cma_mem *mem = NULL;
81
82	spin_lock(&cma->mem_head_lock);
83	if (!hlist_empty(&cma->mem_head)) {
84		mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
85		hlist_del_init(&mem->node);
86	}
87	spin_unlock(&cma->mem_head_lock);
88
89	return mem;
90}
91
92static int cma_free_mem(struct cma *cma, int count)
93{
94	struct cma_mem *mem = NULL;
95
96	while (count) {
97		mem = cma_get_entry_from_list(cma);
98		if (mem == NULL)
99			return 0;
100
101		if (mem->n <= count) {
102			cma_release(cma, mem->p, mem->n);
103			count -= mem->n;
104			kfree(mem);
105		} else if (cma->order_per_bit == 0) {
106			cma_release(cma, mem->p, count);
107			mem->p += count;
108			mem->n -= count;
109			count = 0;
110			cma_add_to_cma_mem_list(cma, mem);
111		} else {
112			pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
113			cma_add_to_cma_mem_list(cma, mem);
114			break;
115		}
116	}
117
118	return 0;
119
120}
121
122static int cma_free_write(void *data, u64 val)
123{
124	int pages = val;
125	struct cma *cma = data;
126
127	return cma_free_mem(cma, pages);
128}
129DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
130
131static int cma_alloc_mem(struct cma *cma, int count)
132{
133	struct cma_mem *mem;
134	struct page *p;
135
136	mem = kzalloc(sizeof(*mem), GFP_KERNEL);
137	if (!mem)
138		return -ENOMEM;
139
140	p = cma_alloc(cma, count, 0);
141	if (!p) {
142		kfree(mem);
143		return -ENOMEM;
144	}
145
146	mem->p = p;
147	mem->n = count;
148
149	cma_add_to_cma_mem_list(cma, mem);
150
151	return 0;
152}
153
154static int cma_alloc_write(void *data, u64 val)
155{
156	int pages = val;
157	struct cma *cma = data;
158
159	return cma_alloc_mem(cma, pages);
160}
161DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
162
163static void cma_debugfs_add_one(struct cma *cma, int idx)
164{
165	struct dentry *tmp;
166	char name[16];
167	int u32s;
168
169	sprintf(name, "cma-%d", idx);
170
171	tmp = debugfs_create_dir(name, cma_debugfs_root);
172
173	debugfs_create_file("alloc", S_IWUSR, cma_debugfs_root, cma,
174				&cma_alloc_fops);
175
176	debugfs_create_file("free", S_IWUSR, cma_debugfs_root, cma,
177				&cma_free_fops);
178
179	debugfs_create_file("base_pfn", S_IRUGO, tmp,
180				&cma->base_pfn, &cma_debugfs_fops);
181	debugfs_create_file("count", S_IRUGO, tmp,
182				&cma->count, &cma_debugfs_fops);
183	debugfs_create_file("order_per_bit", S_IRUGO, tmp,
184				&cma->order_per_bit, &cma_debugfs_fops);
185	debugfs_create_file("used", S_IRUGO, tmp, cma, &cma_used_fops);
186	debugfs_create_file("maxchunk", S_IRUGO, tmp, cma, &cma_maxchunk_fops);
187
188	u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
189	debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);
190}
191
192static int __init cma_debugfs_init(void)
193{
194	int i;
195
196	cma_debugfs_root = debugfs_create_dir("cma", NULL);
197	if (!cma_debugfs_root)
198		return -ENOMEM;
199
200	for (i = 0; i < cma_area_count; i++)
201		cma_debugfs_add_one(&cma_areas[i], i);
202
203	return 0;
204}
205late_initcall(cma_debugfs_init);
206