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 <asm/msi_bitmap.h>
  12 #include <asm/setup.h>
  13
  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
  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
  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  **/
  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
 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
 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
 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
 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 = &prop;
 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
 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 */