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/kernel.h> 12 #include <linux/bitmap.h> 13 #include <asm/msi_bitmap.h> 14 15 int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num) 16 { 17 unsigned long flags; 18 int offset, order = get_count_order(num); 19 20 spin_lock_irqsave(&bmp->lock, flags); 21 /* 22 * This is fast, but stricter than we need. We might want to add 23 * a fallback routine which does a linear search with no alignment. 24 */ 25 offset = bitmap_find_free_region(bmp->bitmap, bmp->irq_count, order); 26 spin_unlock_irqrestore(&bmp->lock, flags); 27 28 pr_debug("msi_bitmap: allocated 0x%x (2^%d) at offset 0x%x\n", 29 num, order, offset); 30 31 return offset; 32 } 33 34 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset, 35 unsigned int num) 36 { 37 unsigned long flags; 38 int order = get_count_order(num); 39 40 pr_debug("msi_bitmap: freeing 0x%x (2^%d) at offset 0x%x\n", 41 num, order, offset); 42 43 spin_lock_irqsave(&bmp->lock, flags); 44 bitmap_release_region(bmp->bitmap, offset, order); 45 spin_unlock_irqrestore(&bmp->lock, flags); 46 } 47 48 void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq) 49 { 50 unsigned long flags; 51 52 pr_debug("msi_bitmap: reserving hwirq 0x%x\n", hwirq); 53 54 spin_lock_irqsave(&bmp->lock, flags); 55 bitmap_allocate_region(bmp->bitmap, hwirq, 0); 56 spin_unlock_irqrestore(&bmp->lock, flags); 57 } 58 59 /** 60 * msi_bitmap_reserve_dt_hwirqs - Reserve irqs specified in the device tree. 61 * @bmp: pointer to the MSI bitmap. 62 * 63 * Looks in the device tree to see if there is a property specifying which 64 * irqs can be used for MSI. If found those irqs reserved in the device tree 65 * are reserved in the bitmap. 66 * 67 * Returns 0 for success, < 0 if there was an error, and > 0 if no property 68 * was found in the device tree. 69 **/ 70 int msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap *bmp) 71 { 72 int i, j, len; 73 const u32 *p; 74 75 if (!bmp->of_node) 76 return 1; 77 78 p = of_get_property(bmp->of_node, "msi-available-ranges", &len); 79 if (!p) { 80 pr_debug("msi_bitmap: no msi-available-ranges property " \ 81 "found on %s\n", bmp->of_node->full_name); 82 return 1; 83 } 84 85 if (len % (2 * sizeof(u32)) != 0) { 86 printk(KERN_WARNING "msi_bitmap: Malformed msi-available-ranges" 87 " property on %s\n", bmp->of_node->full_name); 88 return -EINVAL; 89 } 90 91 bitmap_allocate_region(bmp->bitmap, 0, get_count_order(bmp->irq_count)); 92 93 spin_lock(&bmp->lock); 94 95 /* Format is: (<u32 start> <u32 count>)+ */ 96 len /= 2 * sizeof(u32); 97 for (i = 0; i < len; i++, p += 2) { 98 for (j = 0; j < *(p + 1); j++) 99 bitmap_release_region(bmp->bitmap, *p + j, 0); 100 } 101 102 spin_unlock(&bmp->lock); 103 104 return 0; 105 } 106 107 int msi_bitmap_alloc(struct msi_bitmap *bmp, unsigned int irq_count, 108 struct device_node *of_node) 109 { 110 int size; 111 112 if (!irq_count) 113 return -EINVAL; 114 115 size = BITS_TO_LONGS(irq_count) * sizeof(long); 116 pr_debug("msi_bitmap: allocator bitmap size is 0x%x bytes\n", size); 117 118 bmp->bitmap = zalloc_maybe_bootmem(size, GFP_KERNEL); 119 if (!bmp->bitmap) { 120 pr_debug("msi_bitmap: ENOMEM allocating allocator bitmap!\n"); 121 return -ENOMEM; 122 } 123 124 /* We zalloc'ed the bitmap, so all irqs are free by default */ 125 spin_lock_init(&bmp->lock); 126 bmp->of_node = of_node_get(of_node); 127 bmp->irq_count = irq_count; 128 129 return 0; 130 } 131 132 void msi_bitmap_free(struct msi_bitmap *bmp) 133 { 134 /* we can't free the bitmap we don't know if it's bootmem etc. */ 135 of_node_put(bmp->of_node); 136 bmp->bitmap = NULL; 137 } 138 139 #ifdef CONFIG_MSI_BITMAP_SELFTEST 140 141 #define check(x) \ 142 if (!(x)) printk("msi_bitmap: test failed at line %d\n", __LINE__); 143 144 void __init test_basics(void) 145 { 146 struct msi_bitmap bmp; 147 int i, size = 512; 148 149 /* Can't allocate a bitmap of 0 irqs */ 150 check(msi_bitmap_alloc(&bmp, 0, NULL) != 0); 151 152 /* of_node may be NULL */ 153 check(0 == msi_bitmap_alloc(&bmp, size, NULL)); 154 155 /* Should all be free by default */ 156 check(0 == bitmap_find_free_region(bmp.bitmap, size, 157 get_count_order(size))); 158 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 159 160 /* With no node, there's no msi-available-ranges, so expect > 0 */ 161 check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0); 162 163 /* Should all still be free */ 164 check(0 == bitmap_find_free_region(bmp.bitmap, size, 165 get_count_order(size))); 166 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 167 168 /* Check we can fill it up and then no more */ 169 for (i = 0; i < size; i++) 170 check(msi_bitmap_alloc_hwirqs(&bmp, 1) >= 0); 171 172 check(msi_bitmap_alloc_hwirqs(&bmp, 1) < 0); 173 174 /* Should all be allocated */ 175 check(bitmap_find_free_region(bmp.bitmap, size, 0) < 0); 176 177 /* And if we free one we can then allocate another */ 178 msi_bitmap_free_hwirqs(&bmp, size / 2, 1); 179 check(msi_bitmap_alloc_hwirqs(&bmp, 1) == size / 2); 180 181 msi_bitmap_free(&bmp); 182 183 /* Clients may check bitmap == NULL for "not-allocated" */ 184 check(bmp.bitmap == NULL); 185 186 kfree(bmp.bitmap); 187 } 188 189 void __init test_of_node(void) 190 { 191 u32 prop_data[] = { 10, 10, 25, 3, 40, 1, 100, 100, 200, 20 }; 192 const char *expected_str = "0-9,20-24,28-39,41-99,220-255"; 193 char *prop_name = "msi-available-ranges"; 194 char *node_name = "/fakenode"; 195 struct device_node of_node; 196 struct property prop; 197 struct msi_bitmap bmp; 198 int size = 256; 199 DECLARE_BITMAP(expected, size); 200 201 /* There should really be a struct device_node allocator */ 202 memset(&of_node, 0, sizeof(of_node)); 203 kref_init(&of_node.kref); 204 of_node.full_name = node_name; 205 206 check(0 == msi_bitmap_alloc(&bmp, size, &of_node)); 207 208 /* No msi-available-ranges, so expect > 0 */ 209 check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0); 210 211 /* Should all still be free */ 212 check(0 == bitmap_find_free_region(bmp.bitmap, size, 213 get_count_order(size))); 214 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 215 216 /* Now create a fake msi-available-ranges property */ 217 218 /* There should really .. oh whatever */ 219 memset(&prop, 0, sizeof(prop)); 220 prop.name = prop_name; 221 prop.value = &prop_data; 222 prop.length = sizeof(prop_data); 223 224 of_node.properties = ∝ 225 226 /* msi-available-ranges, so expect == 0 */ 227 check(msi_bitmap_reserve_dt_hwirqs(&bmp) == 0); 228 229 /* Check we got the expected result */ 230 check(0 == bitmap_parselist(expected_str, expected, size)); 231 check(bitmap_equal(expected, bmp.bitmap, size)); 232 233 msi_bitmap_free(&bmp); 234 kfree(bmp.bitmap); 235 } 236 237 int __init msi_bitmap_selftest(void) 238 { 239 printk(KERN_DEBUG "Running MSI bitmap self-tests ...\n"); 240 241 test_basics(); 242 test_of_node(); 243 244 return 0; 245 } 246 late_initcall(msi_bitmap_selftest); 247 #endif /* CONFIG_MSI_BITMAP_SELFTEST */ 248