arch/powerpc/sysdev/msi_bitmap.c

   1 /*
   2  * Copyright 2006-2008, Michael Ellerman, IBM Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; version 2 of the
   7  * License.
   8  *
   9  */
  10
  11 #include <linux/slab.h>
  12 #include <linux/kernel.h>
  13 #include <linux/bitmap.h>
  14 #include <linux/bootmem.h>
  15 #include <asm/msi_bitmap.h>
  16 #include <asm/setup.h>
  17
  18 int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
  19 {
  20         unsigned long flags;
  21         int offset, order = get_count_order(num);
  22
  23         spin_lock_irqsave(&bmp->lock, flags);
  24
  25         offset = bitmap_find_next_zero_area(bmp->bitmap, bmp->irq_count, 0,
  26                                             num, (1 << order) - 1);
  27         if (offset > bmp->irq_count)
  28                 goto err;
  29
  30         bitmap_set(bmp->bitmap, offset, num);
  31         spin_unlock_irqrestore(&bmp->lock, flags);
  32
  33         pr_debug("msi_bitmap: allocated 0x%x at offset 0x%x\n", num, offset);
  34
  35         return offset;
  36 err:
  37         spin_unlock_irqrestore(&bmp->lock, flags);
  38         return -ENOMEM;
  39 }
  40 EXPORT_SYMBOL(msi_bitmap_alloc_hwirqs);
  41
  42 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset,
  43                             unsigned int num)
  44 {
  45         unsigned long flags;
  46
  47         pr_debug("msi_bitmap: freeing 0x%x at offset 0x%x\n",
  48                  num, offset);
  49
  50         spin_lock_irqsave(&bmp->lock, flags);
  51         bitmap_clear(bmp->bitmap, offset, num);
  52         spin_unlock_irqrestore(&bmp->lock, flags);
  53 }
  54 EXPORT_SYMBOL(msi_bitmap_free_hwirqs);
  55
  56 void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq)
  57 {
  58         unsigned long flags;
  59
  60         pr_debug("msi_bitmap: reserving hwirq 0x%x\n", hwirq);
  61
  62         spin_lock_irqsave(&bmp->lock, flags);
  63         bitmap_allocate_region(bmp->bitmap, hwirq, 0);
  64         spin_unlock_irqrestore(&bmp->lock, flags);
  65 }
  66
  67 /**
  68  * msi_bitmap_reserve_dt_hwirqs - Reserve irqs specified in the device tree.
  69  * @bmp: pointer to the MSI bitmap.
  70  *
  71  * Looks in the device tree to see if there is a property specifying which
  72  * irqs can be used for MSI. If found those irqs reserved in the device tree
  73  * are reserved in the bitmap.
  74  *
  75  * Returns 0 for success, < 0 if there was an error, and > 0 if no property
  76  * was found in the device tree.
  77  **/
  78 int msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap *bmp)
  79 {
  80         int i, j, len;
  81         const u32 *p;
  82
  83         if (!bmp->of_node)
  84                 return 1;
  85
  86         p = of_get_property(bmp->of_node, "msi-available-ranges", &len);
  87         if (!p) {
  88                 pr_debug("msi_bitmap: no msi-available-ranges property " \
  89                          "found on %s\n", bmp->of_node->full_name);
  90                 return 1;
  91         }
  92
  93         if (len % (2 * sizeof(u32)) != 0) {
  94                 printk(KERN_WARNING "msi_bitmap: Malformed msi-available-ranges"
  95                        " property on %s\n", bmp->of_node->full_name);
  96                 return -EINVAL;
  97         }
  98
  99         bitmap_allocate_region(bmp->bitmap, 0, get_count_order(bmp->irq_count));
 100
 101         spin_lock(&bmp->lock);
 102
 103         /* Format is: (<u32 start> <u32 count>)+ */
 104         len /= 2 * sizeof(u32);
 105         for (i = 0; i < len; i++, p += 2) {
 106                 for (j = 0; j < *(p + 1); j++)
 107                         bitmap_release_region(bmp->bitmap, *p + j, 0);
 108         }
 109
 110         spin_unlock(&bmp->lock);
 111
 112         return 0;
 113 }
 114
 115 int __init_refok msi_bitmap_alloc(struct msi_bitmap *bmp, unsigned int irq_count,
 116                      struct device_node *of_node)
 117 {
 118         int size;
 119
 120         if (!irq_count)
 121                 return -EINVAL;
 122
 123         size = BITS_TO_LONGS(irq_count) * sizeof(long);
 124         pr_debug("msi_bitmap: allocator bitmap size is 0x%x bytes\n", size);
 125
 126         bmp->bitmap_from_slab = slab_is_available();
 127         if (bmp->bitmap_from_slab)
 128                 bmp->bitmap = kzalloc(size, GFP_KERNEL);
 129         else {
 130                 bmp->bitmap = memblock_virt_alloc(size, 0);
 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
 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
 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
 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         int size = 256;
 228         DECLARE_BITMAP(expected, size);
 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, &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, get_count_order(size)));
 242         bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
 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));
 259         WARN_ON(!bitmap_equal(expected, bmp.bitmap, size));
 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 */