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 * This is fast, but stricter than we need. We might want to add 25 * a fallback routine which does a linear search with no alignment. 26 */ 27 offset = bitmap_find_free_region(bmp->bitmap, bmp->irq_count, order); 28 spin_unlock_irqrestore(&bmp->lock, flags); 29 30 pr_debug("msi_bitmap: allocated 0x%x (2^%d) at offset 0x%x\n", 31 num, order, offset); 32 33 return offset; 34 } 35 36 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset, 37 unsigned int num) 38 { 39 unsigned long flags; 40 int order = get_count_order(num); 41 42 pr_debug("msi_bitmap: freeing 0x%x (2^%d) at offset 0x%x\n", 43 num, order, offset); 44 45 spin_lock_irqsave(&bmp->lock, flags); 46 bitmap_release_region(bmp->bitmap, offset, order); 47 spin_unlock_irqrestore(&bmp->lock, flags); 48 } 49 50 void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq) 51 { 52 unsigned long flags; 53 54 pr_debug("msi_bitmap: reserving hwirq 0x%x\n", hwirq); 55 56 spin_lock_irqsave(&bmp->lock, flags); 57 bitmap_allocate_region(bmp->bitmap, hwirq, 0); 58 spin_unlock_irqrestore(&bmp->lock, flags); 59 } 60 61 /** 62 * msi_bitmap_reserve_dt_hwirqs - Reserve irqs specified in the device tree. 63 * @bmp: pointer to the MSI bitmap. 64 * 65 * Looks in the device tree to see if there is a property specifying which 66 * irqs can be used for MSI. If found those irqs reserved in the device tree 67 * are reserved in the bitmap. 68 * 69 * Returns 0 for success, < 0 if there was an error, and > 0 if no property 70 * was found in the device tree. 71 **/ 72 int msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap *bmp) 73 { 74 int i, j, len; 75 const u32 *p; 76 77 if (!bmp->of_node) 78 return 1; 79 80 p = of_get_property(bmp->of_node, "msi-available-ranges", &len); 81 if (!p) { 82 pr_debug("msi_bitmap: no msi-available-ranges property " \ 83 "found on %s\n", bmp->of_node->full_name); 84 return 1; 85 } 86 87 if (len % (2 * sizeof(u32)) != 0) { 88 printk(KERN_WARNING "msi_bitmap: Malformed msi-available-ranges" 89 " property on %s\n", bmp->of_node->full_name); 90 return -EINVAL; 91 } 92 93 bitmap_allocate_region(bmp->bitmap, 0, get_count_order(bmp->irq_count)); 94 95 spin_lock(&bmp->lock); 96 97 /* Format is: (<u32 start> <u32 count>)+ */ 98 len /= 2 * sizeof(u32); 99 for (i = 0; i < len; i++, p += 2) { 100 for (j = 0; j < *(p + 1); j++) 101 bitmap_release_region(bmp->bitmap, *p + j, 0); 102 } 103 104 spin_unlock(&bmp->lock); 105 106 return 0; 107 } 108 109 int msi_bitmap_alloc(struct msi_bitmap *bmp, unsigned int irq_count, 110 struct device_node *of_node) 111 { 112 int size; 113 114 if (!irq_count) 115 return -EINVAL; 116 117 size = BITS_TO_LONGS(irq_count) * sizeof(long); 118 pr_debug("msi_bitmap: allocator bitmap size is 0x%x bytes\n", size); 119 120 bmp->bitmap = zalloc_maybe_bootmem(size, GFP_KERNEL); 121 if (!bmp->bitmap) { 122 pr_debug("msi_bitmap: ENOMEM allocating allocator bitmap!\n"); 123 return -ENOMEM; 124 } 125 126 /* We zalloc'ed the bitmap, so all irqs are free by default */ 127 spin_lock_init(&bmp->lock); 128 bmp->of_node = of_node_get(of_node); 129 bmp->irq_count = irq_count; 130 131 return 0; 132 } 133 134 void msi_bitmap_free(struct msi_bitmap *bmp) 135 { 136 /* we can't free the bitmap we don't know if it's bootmem etc. */ 137 of_node_put(bmp->of_node); 138 bmp->bitmap = NULL; 139 } 140 141 #ifdef CONFIG_MSI_BITMAP_SELFTEST 142 143 #define check(x) \ 144 if (!(x)) printk("msi_bitmap: test failed at line %d\n", __LINE__); 145 146 void __init test_basics(void) 147 { 148 struct msi_bitmap bmp; 149 int i, size = 512; 150 151 /* Can't allocate a bitmap of 0 irqs */ 152 check(msi_bitmap_alloc(&bmp, 0, NULL) != 0); 153 154 /* of_node may be NULL */ 155 check(0 == msi_bitmap_alloc(&bmp, size, NULL)); 156 157 /* Should all be free by default */ 158 check(0 == bitmap_find_free_region(bmp.bitmap, size, 159 get_count_order(size))); 160 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 161 162 /* With no node, there's no msi-available-ranges, so expect > 0 */ 163 check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0); 164 165 /* Should all still be free */ 166 check(0 == bitmap_find_free_region(bmp.bitmap, size, 167 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 check(msi_bitmap_alloc_hwirqs(&bmp, 1) >= 0); 173 174 check(msi_bitmap_alloc_hwirqs(&bmp, 1) < 0); 175 176 /* Should all be allocated */ 177 check(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 check(msi_bitmap_alloc_hwirqs(&bmp, 1) == size / 2); 182 183 msi_bitmap_free(&bmp); 184 185 /* Clients may check bitmap == NULL for "not-allocated" */ 186 check(bmp.bitmap == NULL); 187 188 kfree(bmp.bitmap); 189 } 190 191 void __init test_of_node(void) 192 { 193 u32 prop_data[] = { 10, 10, 25, 3, 40, 1, 100, 100, 200, 20 }; 194 const char *expected_str = "0-9,20-24,28-39,41-99,220-255"; 195 char *prop_name = "msi-available-ranges"; 196 char *node_name = "/fakenode"; 197 struct device_node of_node; 198 struct property prop; 199 struct msi_bitmap bmp; 200 int size = 256; 201 DECLARE_BITMAP(expected, size); 202 203 /* There should really be a struct device_node allocator */ 204 memset(&of_node, 0, sizeof(of_node)); 205 of_node_init(&of_node); 206 of_node.full_name = node_name; 207 208 check(0 == msi_bitmap_alloc(&bmp, size, &of_node)); 209 210 /* No msi-available-ranges, so expect > 0 */ 211 check(msi_bitmap_reserve_dt_hwirqs(&bmp) > 0); 212 213 /* Should all still be free */ 214 check(0 == bitmap_find_free_region(bmp.bitmap, size, 215 get_count_order(size))); 216 bitmap_release_region(bmp.bitmap, 0, get_count_order(size)); 217 218 /* Now create a fake msi-available-ranges property */ 219 220 /* There should really .. oh whatever */ 221 memset(&prop, 0, sizeof(prop)); 222 prop.name = prop_name; 223 prop.value = &prop_data; 224 prop.length = sizeof(prop_data); 225 226 of_node.properties = ∝ 227 228 /* msi-available-ranges, so expect == 0 */ 229 check(msi_bitmap_reserve_dt_hwirqs(&bmp) == 0); 230 231 /* Check we got the expected result */ 232 check(0 == bitmap_parselist(expected_str, expected, size)); 233 check(bitmap_equal(expected, bmp.bitmap, size)); 234 235 msi_bitmap_free(&bmp); 236 kfree(bmp.bitmap); 237 } 238 239 int __init msi_bitmap_selftest(void) 240 { 241 printk(KERN_DEBUG "Running MSI bitmap self-tests ...\n"); 242 243 test_basics(); 244 test_of_node(); 245 246 return 0; 247 } 248 late_initcall(msi_bitmap_selftest); 249 #endif /* CONFIG_MSI_BITMAP_SELFTEST */ 250