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 #define check(x) \ 149 if (!(x)) printk("msi_bitmap: test failed at line %d\n", __LINE__); 150 151 static void __init test_basics(void) 152 { 153 struct msi_bitmap bmp; 154 int i, size = 512; 155 156 /* Can't allocate a bitmap of 0 irqs */ 157 check(msi_bitmap_alloc(&bmp, 0, NULL) != 0); 158 159 /* of_node may be NULL */ 160 check(0 == msi_bitmap_alloc(&bmp, size, NULL)); 161 162 /* Should all be free by default */ 163 check(0 == bitmap_find_free_region(bmp.bitmap, size, 164 get_count_order(size))); 165 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 166 167 /* With no node, there's no msi-available-ranges, so expect > 0 */ 168 check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0); 169 170 /* Should all still be free */ 171 check(0 == bitmap_find_free_region(bmp.bitmap, size, 172 get_count_order(size))); 173 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 174 175 /* Check we can fill it up and then no more */ 176 for (i = 0; i < size; i++) 177 check(msi_bitmap_alloc_hwirqs(&bmp, 1) >= 0); 178 179 check(msi_bitmap_alloc_hwirqs(&bmp, 1) < 0); 180 181 /* Should all be allocated */ 182 check(bitmap_find_free_region(bmp.bitmap, size, 0) < 0); 183 184 /* And if we free one we can then allocate another */ 185 msi_bitmap_free_hwirqs(&bmp, size / 2, 1); 186 check(msi_bitmap_alloc_hwirqs(&bmp, 1) == size / 2); 187 188 /* Check we get a naturally aligned offset */ 189 check(msi_bitmap_alloc_hwirqs(&bmp, 2) % 2 == 0); 190 check(msi_bitmap_alloc_hwirqs(&bmp, 4) % 4 == 0); 191 check(msi_bitmap_alloc_hwirqs(&bmp, 8) % 8 == 0); 192 check(msi_bitmap_alloc_hwirqs(&bmp, 9) % 16 == 0); 193 check(msi_bitmap_alloc_hwirqs(&bmp, 3) % 4 == 0); 194 check(msi_bitmap_alloc_hwirqs(&bmp, 7) % 8 == 0); 195 check(msi_bitmap_alloc_hwirqs(&bmp, 121) % 128 == 0); 196 197 msi_bitmap_free(&bmp); 198 199 /* Clients may check bitmap == NULL for "not-allocated" */ 200 check(bmp.bitmap == NULL); 201 202 kfree(bmp.bitmap); 203 } 204 205 static void __init test_of_node(void) 206 { 207 u32 prop_data[] = { 10, 10, 25, 3, 40, 1, 100, 100, 200, 20 }; 208 const char *expected_str = "0-9,20-24,28-39,41-99,220-255"; 209 char *prop_name = "msi-available-ranges"; 210 char *node_name = "/fakenode"; 211 struct device_node of_node; 212 struct property prop; 213 struct msi_bitmap bmp; 214 int size = 256; 215 DECLARE_BITMAP(expected, size); 216 217 /* There should really be a struct device_node allocator */ 218 memset(&of_node, 0, sizeof(of_node)); 219 of_node_init(&of_node); 220 of_node.full_name = node_name; 221 222 check(0 == msi_bitmap_alloc(&bmp, size, &of_node)); 223 224 /* No msi-available-ranges, so expect > 0 */ 225 check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0); 226 227 /* Should all still be free */ 228 check(0 == bitmap_find_free_region(bmp.bitmap, size, 229 get_count_order(size))); 230 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 231 232 /* Now create a fake msi-available-ranges property */ 233 234 /* There should really .. oh whatever */ 235 memset(&prop, 0, sizeof(prop)); 236 prop.name = prop_name; 237 prop.value = &prop_data; 238 prop.length = sizeof(prop_data); 239 240 of_node.properties = ∝ 241 242 /* msi-available-ranges, so expect == 0 */ 243 check(msi_bitmap_reserve_dt_hwirqs(&bmp) == 0); 244 245 /* Check we got the expected result */ 246 check(0 == bitmap_parselist(expected_str, expected, size)); 247 check(bitmap_equal(expected, bmp.bitmap, size)); 248 249 msi_bitmap_free(&bmp); 250 kfree(bmp.bitmap); 251 } 252 253 static int __init msi_bitmap_selftest(void) 254 { 255 printk(KERN_DEBUG "Running MSI bitmap self-tests ...\n"); 256 257 test_basics(); 258 test_of_node(); 259 260 return 0; 261 } 262 late_initcall(msi_bitmap_selftest); 263 #endif /* CONFIG_MSI_BITMAP_SELFTEST */ 264