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