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