msi_bitmap.c

  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
 15int 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;
 33err:
 34	spin_unlock_irqrestore(&bmp->lock, flags);
 35	return -ENOMEM;
 36}
 37EXPORT_SYMBOL(msi_bitmap_alloc_hwirqs);
 38
 39void 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}
 51EXPORT_SYMBOL(msi_bitmap_free_hwirqs);
 52
 53void 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 **/
 75int 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
112int __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_or_panic(size, SMP_CACHE_BYTES);
128		/* the bitmap won't be freed from memblock allocator */
129		kmemleak_not_leak(bmp->bitmap);
130	}
131
132	if (!bmp->bitmap) {
133		pr_debug("msi_bitmap: ENOMEM allocating allocator bitmap!\n");
134		return -ENOMEM;
135	}
136
137	/* We zalloc'ed the bitmap, so all irqs are free by default */
138	spin_lock_init(&bmp->lock);
139	bmp->of_node = of_node_get(of_node);
140	bmp->irq_count = irq_count;
141
142	return 0;
143}
144
145void msi_bitmap_free(struct msi_bitmap *bmp)
146{
147	if (bmp->bitmap_from_slab)
148		kfree(bmp->bitmap);
149	of_node_put(bmp->of_node);
150	bmp->bitmap = NULL;
151}
152
153#ifdef CONFIG_MSI_BITMAP_SELFTEST
154
155static void __init test_basics(void)
156{
157	struct msi_bitmap bmp;
158	int rc, i, size = 512;
159
160	/* Can't allocate a bitmap of 0 irqs */
161	WARN_ON(msi_bitmap_alloc(&bmp, 0, NULL) == 0);
162
163	/* of_node may be NULL */
164	WARN_ON(msi_bitmap_alloc(&bmp, size, NULL));
165
166	/* Should all be free by default */
167	WARN_ON(bitmap_find_free_region(bmp.bitmap, size, get_count_order(size)));
168	bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
169
170	/* With no node, there's no msi-available-ranges, so expect > 0 */
171	WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp) <= 0);
172
173	/* Should all still be free */
174	WARN_ON(bitmap_find_free_region(bmp.bitmap, size, get_count_order(size)));
175	bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
176
177	/* Check we can fill it up and then no more */
178	for (i = 0; i < size; i++)
179		WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) < 0);
180
181	WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) >= 0);
182
183	/* Should all be allocated */
184	WARN_ON(bitmap_find_free_region(bmp.bitmap, size, 0) >= 0);
185
186	/* And if we free one we can then allocate another */
187	msi_bitmap_free_hwirqs(&bmp, size / 2, 1);
188	WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) != size / 2);
189
190	/* Free most of them for the alignment tests */
191	msi_bitmap_free_hwirqs(&bmp, 3, size - 3);
192
193	/* Check we get a naturally aligned offset */
194	rc = msi_bitmap_alloc_hwirqs(&bmp, 2);
195	WARN_ON(rc < 0 && rc % 2 != 0);
196	rc = msi_bitmap_alloc_hwirqs(&bmp, 4);
197	WARN_ON(rc < 0 && rc % 4 != 0);
198	rc = msi_bitmap_alloc_hwirqs(&bmp, 8);
199	WARN_ON(rc < 0 && rc % 8 != 0);
200	rc = msi_bitmap_alloc_hwirqs(&bmp, 9);
201	WARN_ON(rc < 0 && rc % 16 != 0);
202	rc = msi_bitmap_alloc_hwirqs(&bmp, 3);
203	WARN_ON(rc < 0 && rc % 4 != 0);
204	rc = msi_bitmap_alloc_hwirqs(&bmp, 7);
205	WARN_ON(rc < 0 && rc % 8 != 0);
206	rc = msi_bitmap_alloc_hwirqs(&bmp, 121);
207	WARN_ON(rc < 0 && rc % 128 != 0);
208
209	msi_bitmap_free(&bmp);
210
211	/* Clients may WARN_ON bitmap == NULL for "not-allocated" */
212	WARN_ON(bmp.bitmap != NULL);
213}
214
215static void __init test_of_node(void)
216{
217	u32 prop_data[] = { 10, 10, 25, 3, 40, 1, 100, 100, 200, 20 };
218	const char *expected_str = "0-9,20-24,28-39,41-99,220-255";
219	char *prop_name = "msi-available-ranges";
220	char *node_name = "/fakenode";
221	struct device_node of_node;
222	struct property prop;
223	struct msi_bitmap bmp;
224#define SIZE_EXPECTED 256
225	DECLARE_BITMAP(expected, SIZE_EXPECTED);
226
227	/* There should really be a struct device_node allocator */
228	memset(&of_node, 0, sizeof(of_node));
229	of_node_init(&of_node);
230	of_node.full_name = node_name;
231
232	WARN_ON(msi_bitmap_alloc(&bmp, SIZE_EXPECTED, &of_node));
233
234	/* No msi-available-ranges, so expect > 0 */
235	WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp) <= 0);
236
237	/* Should all still be free */
238	WARN_ON(bitmap_find_free_region(bmp.bitmap, SIZE_EXPECTED,
239					get_count_order(SIZE_EXPECTED)));
240	bitmap_release_region(bmp.bitmap, 0, get_count_order(SIZE_EXPECTED));
241
242	/* Now create a fake msi-available-ranges property */
243
244	/* There should really .. oh whatever */
245	memset(&prop, 0, sizeof(prop));
246	prop.name = prop_name;
247	prop.value = &prop_data;
248	prop.length = sizeof(prop_data);
249
250	of_node.properties = &prop;
251
252	/* msi-available-ranges, so expect == 0 */
253	WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp));
254
255	/* Check we got the expected result */
256	WARN_ON(bitmap_parselist(expected_str, expected, SIZE_EXPECTED));
257	WARN_ON(!bitmap_equal(expected, bmp.bitmap, SIZE_EXPECTED));
258
259	msi_bitmap_free(&bmp);
260	kfree(bmp.bitmap);
261}
262
263static int __init msi_bitmap_selftest(void)
264{
265	printk(KERN_DEBUG "Running MSI bitmap self-tests ...\n");
266
267	test_basics();
268	test_of_node();
269
270	return 0;
271}
272late_initcall(msi_bitmap_selftest);
273#endif /* CONFIG_MSI_BITMAP_SELFTEST */