summaryrefslogtreecommitdiff
path: root/arch/powerpc/sysdev/msi_bitmap.c
blob: 2ff630267e9efaef1eac6cf15634751e6de51b9e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
/*
 * Copyright 2006-2008, Michael Ellerman, IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2 of the
 * License.
 *
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/bitmap.h>
#include <asm/msi_bitmap.h>
#include <asm/setup.h>

int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
{
	unsigned long flags;
	int offset, order = get_count_order(num);

	spin_lock_irqsave(&bmp->lock, flags);
	/*
	 * This is fast, but stricter than we need. We might want to add
	 * a fallback routine which does a linear search with no alignment.
	 */
	offset = bitmap_find_free_region(bmp->bitmap, bmp->irq_count, order);
	spin_unlock_irqrestore(&bmp->lock, flags);

	pr_debug("msi_bitmap: allocated 0x%x (2^%d) at offset 0x%x\n",
		 num, order, offset);

	return offset;
}

void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset,
			    unsigned int num)
{
	unsigned long flags;
	int order = get_count_order(num);

	pr_debug("msi_bitmap: freeing 0x%x (2^%d) at offset 0x%x\n",
		 num, order, offset);

	spin_lock_irqsave(&bmp->lock, flags);
	bitmap_release_region(bmp->bitmap, offset, order);
	spin_unlock_irqrestore(&bmp->lock, flags);
}

void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq)
{
	unsigned long flags;

	pr_debug("msi_bitmap: reserving hwirq 0x%x\n", hwirq);

	spin_lock_irqsave(&bmp->lock, flags);
	bitmap_allocate_region(bmp->bitmap, hwirq, 0);
	spin_unlock_irqrestore(&bmp->lock, flags);
}

/**
 * msi_bitmap_reserve_dt_hwirqs - Reserve irqs specified in the device tree.
 * @bmp: pointer to the MSI bitmap.
 *
 * Looks in the device tree to see if there is a property specifying which
 * irqs can be used for MSI. If found those irqs reserved in the device tree
 * are reserved in the bitmap.
 *
 * Returns 0 for success, < 0 if there was an error, and > 0 if no property
 * was found in the device tree.
 **/
int msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap *bmp)
{
	int i, j, len;
	const u32 *p;

	if (!bmp->of_node)
		return 1;

	p = of_get_property(bmp->of_node, "msi-available-ranges", &len);
	if (!p) {
		pr_debug("msi_bitmap: no msi-available-ranges property " \
			 "found on %s\n", bmp->of_node->full_name);
		return 1;
	}

	if (len % (2 * sizeof(u32)) != 0) {
		printk(KERN_WARNING "msi_bitmap: Malformed msi-available-ranges"
		       " property on %s\n", bmp->of_node->full_name);
		return -EINVAL;
	}

	bitmap_allocate_region(bmp->bitmap, 0, get_count_order(bmp->irq_count));

	spin_lock(&bmp->lock);

	/* Format is: (<u32 start> <u32 count>)+ */
	len /= 2 * sizeof(u32);
	for (i = 0; i < len; i++, p += 2) {
		for (j = 0; j < *(p + 1); j++)
			bitmap_release_region(bmp->bitmap, *p + j, 0);
	}

	spin_unlock(&bmp->lock);

	return 0;
}

int msi_bitmap_alloc(struct msi_bitmap *bmp, unsigned int irq_count,
		     struct device_node *of_node)
{
	int size;

	if (!irq_count)
		return -EINVAL;

	size = BITS_TO_LONGS(irq_count) * sizeof(long);
	pr_debug("msi_bitmap: allocator bitmap size is 0x%x bytes\n", size);

	bmp->bitmap = zalloc_maybe_bootmem(size, GFP_KERNEL);
	if (!bmp->bitmap) {
		pr_debug("msi_bitmap: ENOMEM allocating allocator bitmap!\n");
		return -ENOMEM;
	}

	/* We zalloc'ed the bitmap, so all irqs are free by default */
	spin_lock_init(&bmp->lock);
	bmp->of_node = of_node_get(of_node);
	bmp->irq_count = irq_count;

	return 0;
}

void msi_bitmap_free(struct msi_bitmap *bmp)
{
	/* we can't free the bitmap we don't know if it's bootmem etc. */
	of_node_put(bmp->of_node);
	bmp->bitmap = NULL;
}

#ifdef CONFIG_MSI_BITMAP_SELFTEST

#define check(x)	\
	if (!(x)) printk("msi_bitmap: test failed at line %d\n", __LINE__);

void __init test_basics(void)
{
	struct msi_bitmap bmp;
	int i, size = 512;

	/* Can't allocate a bitmap of 0 irqs */
	check(msi_bitmap_alloc(&bmp, 0, NULL) != 0);

	/* of_node may be NULL */
	check(0 == msi_bitmap_alloc(&bmp, size, NULL));

	/* Should all be free by default */
	check(0 == bitmap_find_free_region(bmp.bitmap, size,
					   get_count_order(size)));
	bitmap_release_region(bmp.bitmap, 0, get_count_order(size));

	/* With no node, there's no msi-available-ranges, so expect > 0 */
	check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0);

	/* Should all still be free */
	check(0 == bitmap_find_free_region(bmp.bitmap, size,
					   get_count_order(size)));
	bitmap_release_region(bmp.bitmap, 0, get_count_order(size));

	/* Check we can fill it up and then no more */
	for (i = 0; i < size; i++)
		check(msi_bitmap_alloc_hwirqs(&bmp, 1) >= 0);

	check(msi_bitmap_alloc_hwirqs(&bmp, 1) < 0);

	/* Should all be allocated */
	check(bitmap_find_free_region(bmp.bitmap, size, 0) < 0);

	/* And if we free one we can then allocate another */
	msi_bitmap_free_hwirqs(&bmp, size / 2, 1);
	check(msi_bitmap_alloc_hwirqs(&bmp, 1) == size / 2);

	msi_bitmap_free(&bmp);

	/* Clients may check bitmap == NULL for "not-allocated" */
	check(bmp.bitmap == NULL);

	kfree(bmp.bitmap);
}

void __init test_of_node(void)
{
	u32 prop_data[] = { 10, 10, 25, 3, 40, 1, 100, 100, 200, 20 };
	const char *expected_str = "0-9,20-24,28-39,41-99,220-255";
	char *prop_name = "msi-available-ranges";
	char *node_name = "/fakenode";
	struct device_node of_node;
	struct property prop;
	struct msi_bitmap bmp;
	int size = 256;
	DECLARE_BITMAP(expected, size);

	/* There should really be a struct device_node allocator */
	memset(&of_node, 0, sizeof(of_node));
	of_node_init(&of_node);
	of_node.full_name = node_name;

	check(0 == msi_bitmap_alloc(&bmp, size, &of_node));

	/* No msi-available-ranges, so expect > 0 */
	check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0);

	/* Should all still be free */
	check(0 == bitmap_find_free_region(bmp.bitmap, size,
					   get_count_order(size)));
	bitmap_release_region(bmp.bitmap, 0, get_count_order(size));

	/* Now create a fake msi-available-ranges property */

	/* There should really .. oh whatever */
	memset(&prop, 0, sizeof(prop));
	prop.name = prop_name;
	prop.value = &prop_data;
	prop.length = sizeof(prop_data);

	of_node.properties = &prop;

	/* msi-available-ranges, so expect == 0 */
	check(msi_bitmap_reserve_dt_hwirqs(&bmp) == 0);

	/* Check we got the expected result */
	check(0 == bitmap_parselist(expected_str, expected, size));
	check(bitmap_equal(expected, bmp.bitmap, size));

	msi_bitmap_free(&bmp);
	kfree(bmp.bitmap);
}

int __init msi_bitmap_selftest(void)
{
	printk(KERN_DEBUG "Running MSI bitmap self-tests ...\n");

	test_basics();
	test_of_node();

	return 0;
}
late_initcall(msi_bitmap_selftest);
#endif /* CONFIG_MSI_BITMAP_SELFTEST */