arch/powerpc/sysdev/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
  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
  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
  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  **/
  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
 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_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
 145 void 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
 155 static 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
 215 static 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
 263 static 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 }
 272 late_initcall(msi_bitmap_selftest);
 273 #endif /* CONFIG_MSI_BITMAP_SELFTEST */