xref: /linux/arch/powerpc/sysdev/msi_bitmap.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2006-2008, Michael Ellerman, IBM Corporation.
4  */
5 
6 #include <linux/slab.h>
7 #include <linux/kernel.h>
8 #include <linux/kmemleak.h>
9 #include <linux/bitmap.h>
10 #include <linux/memblock.h>
11 #include <linux/of.h>
12 #include <asm/msi_bitmap.h>
13 #include <asm/setup.h>
14 
msi_bitmap_alloc_hwirqs(struct msi_bitmap * bmp,int num)15 int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
16 {
17 	unsigned long flags;
18 	int offset, order = get_count_order(num);
19 
20 	spin_lock_irqsave(&bmp->lock, flags);
21 
22 	offset = bitmap_find_next_zero_area(bmp->bitmap, bmp->irq_count, 0,
23 					    num, (1 << order) - 1);
24 	if (offset > bmp->irq_count)
25 		goto err;
26 
27 	bitmap_set(bmp->bitmap, offset, num);
28 	spin_unlock_irqrestore(&bmp->lock, flags);
29 
30 	pr_debug("msi_bitmap: allocated 0x%x at offset 0x%x\n", num, offset);
31 
32 	return offset;
33 err:
34 	spin_unlock_irqrestore(&bmp->lock, flags);
35 	return -ENOMEM;
36 }
37 EXPORT_SYMBOL(msi_bitmap_alloc_hwirqs);
38 
msi_bitmap_free_hwirqs(struct msi_bitmap * bmp,unsigned int offset,unsigned int num)39 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset,
40 			    unsigned int num)
41 {
42 	unsigned long flags;
43 
44 	pr_debug("msi_bitmap: freeing 0x%x at offset 0x%x\n",
45 		 num, offset);
46 
47 	spin_lock_irqsave(&bmp->lock, flags);
48 	bitmap_clear(bmp->bitmap, offset, num);
49 	spin_unlock_irqrestore(&bmp->lock, flags);
50 }
51 EXPORT_SYMBOL(msi_bitmap_free_hwirqs);
52 
msi_bitmap_reserve_hwirq(struct msi_bitmap * bmp,unsigned int hwirq)53 void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq)
54 {
55 	unsigned long flags;
56 
57 	pr_debug("msi_bitmap: reserving hwirq 0x%x\n", hwirq);
58 
59 	spin_lock_irqsave(&bmp->lock, flags);
60 	bitmap_allocate_region(bmp->bitmap, hwirq, 0);
61 	spin_unlock_irqrestore(&bmp->lock, flags);
62 }
63 
64 /**
65  * msi_bitmap_reserve_dt_hwirqs - Reserve irqs specified in the device tree.
66  * @bmp: pointer to the MSI bitmap.
67  *
68  * Looks in the device tree to see if there is a property specifying which
69  * irqs can be used for MSI. If found those irqs reserved in the device tree
70  * are reserved in the bitmap.
71  *
72  * Returns 0 for success, < 0 if there was an error, and > 0 if no property
73  * was found in the device tree.
74  **/
msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap * bmp)75 int msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap *bmp)
76 {
77 	int i, j, len;
78 	const u32 *p;
79 
80 	if (!bmp->of_node)
81 		return 1;
82 
83 	p = of_get_property(bmp->of_node, "msi-available-ranges", &len);
84 	if (!p) {
85 		pr_debug("msi_bitmap: no msi-available-ranges property " \
86 			 "found on %pOF\n", bmp->of_node);
87 		return 1;
88 	}
89 
90 	if (len % (2 * sizeof(u32)) != 0) {
91 		printk(KERN_WARNING "msi_bitmap: Malformed msi-available-ranges"
92 		       " property on %pOF\n", bmp->of_node);
93 		return -EINVAL;
94 	}
95 
96 	bitmap_allocate_region(bmp->bitmap, 0, get_count_order(bmp->irq_count));
97 
98 	spin_lock(&bmp->lock);
99 
100 	/* Format is: (<u32 start> <u32 count>)+ */
101 	len /= 2 * sizeof(u32);
102 	for (i = 0; i < len; i++, p += 2) {
103 		for (j = 0; j < *(p + 1); j++)
104 			bitmap_release_region(bmp->bitmap, *p + j, 0);
105 	}
106 
107 	spin_unlock(&bmp->lock);
108 
109 	return 0;
110 }
111 
msi_bitmap_alloc(struct msi_bitmap * bmp,unsigned int irq_count,struct device_node * of_node)112 int __ref msi_bitmap_alloc(struct msi_bitmap *bmp, unsigned int irq_count,
113 		     struct device_node *of_node)
114 {
115 	int size;
116 
117 	if (!irq_count)
118 		return -EINVAL;
119 
120 	size = BITS_TO_LONGS(irq_count) * sizeof(long);
121 	pr_debug("msi_bitmap: allocator bitmap size is 0x%x bytes\n", size);
122 
123 	bmp->bitmap_from_slab = slab_is_available();
124 	if (bmp->bitmap_from_slab)
125 		bmp->bitmap = kzalloc(size, GFP_KERNEL);
126 	else {
127 		bmp->bitmap = memblock_alloc(size, SMP_CACHE_BYTES);
128 		if (!bmp->bitmap)
129 			panic("%s: Failed to allocate %u bytes\n", __func__,
130 			      size);
131 		/* the bitmap won't be freed from memblock allocator */
132 		kmemleak_not_leak(bmp->bitmap);
133 	}
134 
135 	if (!bmp->bitmap) {
136 		pr_debug("msi_bitmap: ENOMEM allocating allocator bitmap!\n");
137 		return -ENOMEM;
138 	}
139 
140 	/* We zalloc'ed the bitmap, so all irqs are free by default */
141 	spin_lock_init(&bmp->lock);
142 	bmp->of_node = of_node_get(of_node);
143 	bmp->irq_count = irq_count;
144 
145 	return 0;
146 }
147 
msi_bitmap_free(struct msi_bitmap * bmp)148 void msi_bitmap_free(struct msi_bitmap *bmp)
149 {
150 	if (bmp->bitmap_from_slab)
151 		kfree(bmp->bitmap);
152 	of_node_put(bmp->of_node);
153 	bmp->bitmap = NULL;
154 }
155 
156 #ifdef CONFIG_MSI_BITMAP_SELFTEST
157 
test_basics(void)158 static void __init test_basics(void)
159 {
160 	struct msi_bitmap bmp;
161 	int rc, i, size = 512;
162 
163 	/* Can't allocate a bitmap of 0 irqs */
164 	WARN_ON(msi_bitmap_alloc(&bmp, 0, NULL) == 0);
165 
166 	/* of_node may be NULL */
167 	WARN_ON(msi_bitmap_alloc(&bmp, size, NULL));
168 
169 	/* Should all be free by default */
170 	WARN_ON(bitmap_find_free_region(bmp.bitmap, size, get_count_order(size)));
171 	bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
172 
173 	/* With no node, there's no msi-available-ranges, so expect > 0 */
174 	WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp) <= 0);
175 
176 	/* Should all still be free */
177 	WARN_ON(bitmap_find_free_region(bmp.bitmap, size, get_count_order(size)));
178 	bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
179 
180 	/* Check we can fill it up and then no more */
181 	for (i = 0; i < size; i++)
182 		WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) < 0);
183 
184 	WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) >= 0);
185 
186 	/* Should all be allocated */
187 	WARN_ON(bitmap_find_free_region(bmp.bitmap, size, 0) >= 0);
188 
189 	/* And if we free one we can then allocate another */
190 	msi_bitmap_free_hwirqs(&bmp, size / 2, 1);
191 	WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) != size / 2);
192 
193 	/* Free most of them for the alignment tests */
194 	msi_bitmap_free_hwirqs(&bmp, 3, size - 3);
195 
196 	/* Check we get a naturally aligned offset */
197 	rc = msi_bitmap_alloc_hwirqs(&bmp, 2);
198 	WARN_ON(rc < 0 && rc % 2 != 0);
199 	rc = msi_bitmap_alloc_hwirqs(&bmp, 4);
200 	WARN_ON(rc < 0 && rc % 4 != 0);
201 	rc = msi_bitmap_alloc_hwirqs(&bmp, 8);
202 	WARN_ON(rc < 0 && rc % 8 != 0);
203 	rc = msi_bitmap_alloc_hwirqs(&bmp, 9);
204 	WARN_ON(rc < 0 && rc % 16 != 0);
205 	rc = msi_bitmap_alloc_hwirqs(&bmp, 3);
206 	WARN_ON(rc < 0 && rc % 4 != 0);
207 	rc = msi_bitmap_alloc_hwirqs(&bmp, 7);
208 	WARN_ON(rc < 0 && rc % 8 != 0);
209 	rc = msi_bitmap_alloc_hwirqs(&bmp, 121);
210 	WARN_ON(rc < 0 && rc % 128 != 0);
211 
212 	msi_bitmap_free(&bmp);
213 
214 	/* Clients may WARN_ON bitmap == NULL for "not-allocated" */
215 	WARN_ON(bmp.bitmap != NULL);
216 }
217 
test_of_node(void)218 static void __init test_of_node(void)
219 {
220 	u32 prop_data[] = { 10, 10, 25, 3, 40, 1, 100, 100, 200, 20 };
221 	const char *expected_str = "0-9,20-24,28-39,41-99,220-255";
222 	char *prop_name = "msi-available-ranges";
223 	char *node_name = "/fakenode";
224 	struct device_node of_node;
225 	struct property prop;
226 	struct msi_bitmap bmp;
227 #define SIZE_EXPECTED 256
228 	DECLARE_BITMAP(expected, SIZE_EXPECTED);
229 
230 	/* There should really be a struct device_node allocator */
231 	memset(&of_node, 0, sizeof(of_node));
232 	of_node_init(&of_node);
233 	of_node.full_name = node_name;
234 
235 	WARN_ON(msi_bitmap_alloc(&bmp, SIZE_EXPECTED, &of_node));
236 
237 	/* No msi-available-ranges, so expect > 0 */
238 	WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp) <= 0);
239 
240 	/* Should all still be free */
241 	WARN_ON(bitmap_find_free_region(bmp.bitmap, SIZE_EXPECTED,
242 					get_count_order(SIZE_EXPECTED)));
243 	bitmap_release_region(bmp.bitmap, 0, get_count_order(SIZE_EXPECTED));
244 
245 	/* Now create a fake msi-available-ranges property */
246 
247 	/* There should really .. oh whatever */
248 	memset(&prop, 0, sizeof(prop));
249 	prop.name = prop_name;
250 	prop.value = &prop_data;
251 	prop.length = sizeof(prop_data);
252 
253 	of_node.properties = &prop;
254 
255 	/* msi-available-ranges, so expect == 0 */
256 	WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp));
257 
258 	/* Check we got the expected result */
259 	WARN_ON(bitmap_parselist(expected_str, expected, SIZE_EXPECTED));
260 	WARN_ON(!bitmap_equal(expected, bmp.bitmap, SIZE_EXPECTED));
261 
262 	msi_bitmap_free(&bmp);
263 	kfree(bmp.bitmap);
264 }
265 
msi_bitmap_selftest(void)266 static int __init msi_bitmap_selftest(void)
267 {
268 	printk(KERN_DEBUG "Running MSI bitmap self-tests ...\n");
269 
270 	test_basics();
271 	test_of_node();
272 
273 	return 0;
274 }
275 late_initcall(msi_bitmap_selftest);
276 #endif /* CONFIG_MSI_BITMAP_SELFTEST */
277