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/kmemleak.h>
  14 #include <linux/bitmap.h>
  15 #include <linux/bootmem.h>
  16 #include <asm/msi_bitmap.h>
  17 #include <asm/setup.h>
  18
  19 int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
  20 {
  21         unsigned long flags;
  22         int offset, order = get_count_order(num);
  23
  24         spin_lock_irqsave(&bmp->lock, flags);
  25
  26         offset = bitmap_find_next_zero_area(bmp->bitmap, bmp->irq_count, 0,
  27                                             num, (1 << order) - 1);
  28         if (offset > bmp->irq_count)
  29                 goto err;
  30
  31         bitmap_set(bmp->bitmap, offset, num);
  32         spin_unlock_irqrestore(&bmp->lock, flags);
  33
  34         pr_debug("msi_bitmap: allocated 0x%x at offset 0x%x\n", num, offset);
  35
  36         return offset;
  37 err:
  38         spin_unlock_irqrestore(&bmp->lock, flags);
  39         return -ENOMEM;
  40 }
  41 EXPORT_SYMBOL(msi_bitmap_alloc_hwirqs);
  42
  43 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset,
  44                             unsigned int num)
  45 {
  46         unsigned long flags;
  47
  48         pr_debug("msi_bitmap: freeing 0x%x at offset 0x%x\n",
  49                  num, offset);
  50
  51         spin_lock_irqsave(&bmp->lock, flags);
  52         bitmap_clear(bmp->bitmap, offset, num);
  53         spin_unlock_irqrestore(&bmp->lock, flags);
  54 }
  55 EXPORT_SYMBOL(msi_bitmap_free_hwirqs);
  56
  57 void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq)
  58 {
  59         unsigned long flags;
  60
  61         pr_debug("msi_bitmap: reserving hwirq 0x%x\n", hwirq);
  62
  63         spin_lock_irqsave(&bmp->lock, flags);
  64         bitmap_allocate_region(bmp->bitmap, hwirq, 0);
  65         spin_unlock_irqrestore(&bmp->lock, flags);
  66 }
  67
  68 /**
  69  * msi_bitmap_reserve_dt_hwirqs - Reserve irqs specified in the device tree.
  70  * @bmp: pointer to the MSI bitmap.
  71  *
  72  * Looks in the device tree to see if there is a property specifying which
  73  * irqs can be used for MSI. If found those irqs reserved in the device tree
  74  * are reserved in the bitmap.
  75  *
  76  * Returns 0 for success, < 0 if there was an error, and > 0 if no property
  77  * was found in the device tree.
  78  **/
  79 int msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap *bmp)
  80 {
  81         int i, j, len;
  82         const u32 *p;
  83
  84         if (!bmp->of_node)
  85                 return 1;
  86
  87         p = of_get_property(bmp->of_node, "msi-available-ranges", &len);
  88         if (!p) {
  89                 pr_debug("msi_bitmap: no msi-available-ranges property " \
  90                          "found on %pOF\n", bmp->of_node);
  91                 return 1;
  92         }
  93
  94         if (len % (2 * sizeof(u32)) != 0) {
  95                 printk(KERN_WARNING "msi_bitmap: Malformed msi-available-ranges"
  96                        " property on %pOF\n", bmp->of_node);
  97                 return -EINVAL;
  98         }
  99
 100         bitmap_allocate_region(bmp->bitmap, 0, get_count_order(bmp->irq_count));
 101
 102         spin_lock(&bmp->lock);
 103
 104         /* Format is: (<u32 start> <u32 count>)+ */
 105         len /= 2 * sizeof(u32);
 106         for (i = 0; i < len; i++, p += 2) {
 107                 for (j = 0; j < *(p + 1); j++)
 108                         bitmap_release_region(bmp->bitmap, *p + j, 0);
 109         }
 110
 111         spin_unlock(&bmp->lock);
 112
 113         return 0;
 114 }
 115
 116 int __ref msi_bitmap_alloc(struct msi_bitmap *bmp, unsigned int irq_count,
 117                      struct device_node *of_node)
 118 {
 119         int size;
 120
 121         if (!irq_count)
 122                 return -EINVAL;
 123
 124         size = BITS_TO_LONGS(irq_count) * sizeof(long);
 125         pr_debug("msi_bitmap: allocator bitmap size is 0x%x bytes\n", size);
 126
 127         bmp->bitmap_from_slab = slab_is_available();
 128         if (bmp->bitmap_from_slab)
 129                 bmp->bitmap = kzalloc(size, GFP_KERNEL);
 130         else {
 131                 bmp->bitmap = memblock_virt_alloc(size, 0);
 132                 /* the bitmap won't be freed from memblock allocator */
 133                 kmemleak_not_leak(bmp->bitmap);
 134         }
 135
 136         if (!bmp->bitmap) {
 137                 pr_debug("msi_bitmap: ENOMEM allocating allocator bitmap!\n");
 138                 return -ENOMEM;
 139         }
 140
 141         /* We zalloc'ed the bitmap, so all irqs are free by default */
 142         spin_lock_init(&bmp->lock);
 143         bmp->of_node = of_node_get(of_node);
 144         bmp->irq_count = irq_count;
 145
 146         return 0;
 147 }
 148
 149 void msi_bitmap_free(struct msi_bitmap *bmp)
 150 {
 151         if (bmp->bitmap_from_slab)
 152                 kfree(bmp->bitmap);
 153         of_node_put(bmp->of_node);
 154         bmp->bitmap = NULL;
 155 }
 156
 157 #ifdef CONFIG_MSI_BITMAP_SELFTEST
 158
 159 static void __init test_basics(void)
 160 {
 161         struct msi_bitmap bmp;
 162         int rc, i, size = 512;
 163
 164         /* Can't allocate a bitmap of 0 irqs */
 165         WARN_ON(msi_bitmap_alloc(&bmp, 0, NULL) == 0);
 166
 167         /* of_node may be NULL */
 168         WARN_ON(msi_bitmap_alloc(&bmp, size, NULL));
 169
 170         /* Should all be free by default */
 171         WARN_ON(bitmap_find_free_region(bmp.bitmap, size, get_count_order(size)));
 172         bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
 173
 174         /* With no node, there's no msi-available-ranges, so expect > 0 */
 175         WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp) <= 0);
 176
 177         /* Should all still be free */
 178         WARN_ON(bitmap_find_free_region(bmp.bitmap, size, get_count_order(size)));
 179         bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
 180
 181         /* Check we can fill it up and then no more */
 182         for (i = 0; i < size; i++)
 183                 WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) < 0);
 184
 185         WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) >= 0);
 186
 187         /* Should all be allocated */
 188         WARN_ON(bitmap_find_free_region(bmp.bitmap, size, 0) >= 0);
 189
 190         /* And if we free one we can then allocate another */
 191         msi_bitmap_free_hwirqs(&bmp, size / 2, 1);
 192         WARN_ON(msi_bitmap_alloc_hwirqs(&bmp, 1) != size / 2);
 193
 194         /* Free most of them for the alignment tests */
 195         msi_bitmap_free_hwirqs(&bmp, 3, size - 3);
 196
 197         /* Check we get a naturally aligned offset */
 198         rc = msi_bitmap_alloc_hwirqs(&bmp, 2);
 199         WARN_ON(rc < 0 && rc % 2 != 0);
 200         rc = msi_bitmap_alloc_hwirqs(&bmp, 4);
 201         WARN_ON(rc < 0 && rc % 4 != 0);
 202         rc = msi_bitmap_alloc_hwirqs(&bmp, 8);
 203         WARN_ON(rc < 0 && rc % 8 != 0);
 204         rc = msi_bitmap_alloc_hwirqs(&bmp, 9);
 205         WARN_ON(rc < 0 && rc % 16 != 0);
 206         rc = msi_bitmap_alloc_hwirqs(&bmp, 3);
 207         WARN_ON(rc < 0 && rc % 4 != 0);
 208         rc = msi_bitmap_alloc_hwirqs(&bmp, 7);
 209         WARN_ON(rc < 0 && rc % 8 != 0);
 210         rc = msi_bitmap_alloc_hwirqs(&bmp, 121);
 211         WARN_ON(rc < 0 && rc % 128 != 0);
 212
 213         msi_bitmap_free(&bmp);
 214
 215         /* Clients may WARN_ON bitmap == NULL for "not-allocated" */
 216         WARN_ON(bmp.bitmap != NULL);
 217 }
 218
 219 static void __init test_of_node(void)
 220 {
 221         u32 prop_data[] = { 10, 10, 25, 3, 40, 1, 100, 100, 200, 20 };
 222         const char *expected_str = "0-9,20-24,28-39,41-99,220-255";
 223         char *prop_name = "msi-available-ranges";
 224         char *node_name = "/fakenode";
 225         struct device_node of_node;
 226         struct property prop;
 227         struct msi_bitmap bmp;
 228         int size = 256;
 229         DECLARE_BITMAP(expected, size);
 230
 231         /* There should really be a struct device_node allocator */
 232         memset(&of_node, 0, sizeof(of_node));
 233         of_node_init(&of_node);
 234         of_node.full_name = node_name;
 235
 236         WARN_ON(msi_bitmap_alloc(&bmp, size, &of_node));
 237
 238         /* No msi-available-ranges, so expect > 0 */
 239         WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp) <= 0);
 240
 241         /* Should all still be free */
 242         WARN_ON(bitmap_find_free_region(bmp.bitmap, size, get_count_order(size)));
 243         bitmap_release_region(bmp.bitmap, 0, get_count_order(size));
 244
 245         /* Now create a fake msi-available-ranges property */
 246
 247         /* There should really .. oh whatever */
 248         memset(&prop, 0, sizeof(prop));
 249         prop.name = prop_name;
 250         prop.value = &prop_data;
 251         prop.length = sizeof(prop_data);
 252
 253         of_node.properties = &prop;
 254
 255         /* msi-available-ranges, so expect == 0 */
 256         WARN_ON(msi_bitmap_reserve_dt_hwirqs(&bmp));
 257
 258         /* Check we got the expected result */
 259         WARN_ON(bitmap_parselist(expected_str, expected, size));
 260         WARN_ON(!bitmap_equal(expected, bmp.bitmap, size));
 261
 262         msi_bitmap_free(&bmp);
 263         kfree(bmp.bitmap);
 264 }
 265
 266 static int __init msi_bitmap_selftest(void)
 267 {
 268         printk(KERN_DEBUG "Running MSI bitmap self-tests ...\n");
 269
 270         test_basics();
 271         test_of_node();
 272
 273         return 0;
 274 }
 275 late_initcall(msi_bitmap_selftest);
 276 #endif /* CONFIG_MSI_BITMAP_SELFTEST */