Merge branch 'nfs-server-stable' of git://linux-nfs.org/~bfields/linux
[linux-2.6] / arch / powerpc / sysdev / mpic_msi.c
1 /*
2  * Copyright 2006-2007, 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/irq.h>
12 #include <linux/bitmap.h>
13 #include <linux/msi.h>
14 #include <asm/mpic.h>
15 #include <asm/prom.h>
16 #include <asm/hw_irq.h>
17 #include <asm/ppc-pci.h>
18
19
20 static void __mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
21 {
22         pr_debug("mpic: reserving hwirq 0x%lx\n", hwirq);
23         bitmap_allocate_region(mpic->hwirq_bitmap, hwirq, 0);
24 }
25
26 void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
27 {
28         unsigned long flags;
29
30         /* The mpic calls this even when there is no allocator setup */
31         if (!mpic->hwirq_bitmap)
32                 return;
33
34         spin_lock_irqsave(&mpic->bitmap_lock, flags);
35         __mpic_msi_reserve_hwirq(mpic, hwirq);
36         spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
37 }
38
39 irq_hw_number_t mpic_msi_alloc_hwirqs(struct mpic *mpic, int num)
40 {
41         unsigned long flags;
42         int offset, order = get_count_order(num);
43
44         spin_lock_irqsave(&mpic->bitmap_lock, flags);
45         /*
46          * This is fast, but stricter than we need. We might want to add
47          * a fallback routine which does a linear search with no alignment.
48          */
49         offset = bitmap_find_free_region(mpic->hwirq_bitmap, mpic->irq_count,
50                                          order);
51         spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
52
53         pr_debug("mpic: allocated 0x%x (2^%d) at offset 0x%x\n",
54                  num, order, offset);
55
56         return offset;
57 }
58
59 void mpic_msi_free_hwirqs(struct mpic *mpic, int offset, int num)
60 {
61         unsigned long flags;
62         int order = get_count_order(num);
63
64         pr_debug("mpic: freeing 0x%x (2^%d) at offset 0x%x\n",
65                  num, order, offset);
66
67         spin_lock_irqsave(&mpic->bitmap_lock, flags);
68         bitmap_release_region(mpic->hwirq_bitmap, offset, order);
69         spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
70 }
71
72 #ifdef CONFIG_MPIC_U3_HT_IRQS
73 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
74 {
75         irq_hw_number_t hwirq;
76         struct irq_host_ops *ops = mpic->irqhost->ops;
77         struct device_node *np;
78         int flags, index, i;
79         struct of_irq oirq;
80
81         pr_debug("mpic: found U3, guessing msi allocator setup\n");
82
83         /* Reserve source numbers we know are reserved in the HW */
84         for (i = 0;   i < 8;   i++)
85                 __mpic_msi_reserve_hwirq(mpic, i);
86
87         for (i = 42;  i < 46;  i++)
88                 __mpic_msi_reserve_hwirq(mpic, i);
89
90         for (i = 100; i < 105; i++)
91                 __mpic_msi_reserve_hwirq(mpic, i);
92
93         np = NULL;
94         while ((np = of_find_all_nodes(np))) {
95                 pr_debug("mpic: mapping hwirqs for %s\n", np->full_name);
96
97                 index = 0;
98                 while (of_irq_map_one(np, index++, &oirq) == 0) {
99                         ops->xlate(mpic->irqhost, NULL, oirq.specifier,
100                                                 oirq.size, &hwirq, &flags);
101                         __mpic_msi_reserve_hwirq(mpic, hwirq);
102                 }
103         }
104
105         return 0;
106 }
107 #else
108 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
109 {
110         return -1;
111 }
112 #endif
113
114 static int mpic_msi_reserve_dt_hwirqs(struct mpic *mpic)
115 {
116         int i, len;
117         const u32 *p;
118
119         p = of_get_property(mpic->irqhost->of_node,
120                             "msi-available-ranges", &len);
121         if (!p) {
122                 pr_debug("mpic: no msi-available-ranges property found on %s\n",
123                           mpic->irqhost->of_node->full_name);
124                 return -ENODEV;
125         }
126
127         if (len % 8 != 0) {
128                 printk(KERN_WARNING "mpic: Malformed msi-available-ranges "
129                        "property on %s\n", mpic->irqhost->of_node->full_name);
130                 return -EINVAL;
131         }
132
133         bitmap_allocate_region(mpic->hwirq_bitmap, 0,
134                                get_count_order(mpic->irq_count));
135
136         /* Format is: (<u32 start> <u32 count>)+ */
137         len /= sizeof(u32);
138         for (i = 0; i < len / 2; i++, p += 2)
139                 mpic_msi_free_hwirqs(mpic, *p, *(p + 1));
140
141         return 0;
142 }
143
144 int mpic_msi_init_allocator(struct mpic *mpic)
145 {
146         int rc, size;
147
148         BUG_ON(mpic->hwirq_bitmap);
149         spin_lock_init(&mpic->bitmap_lock);
150
151         size = BITS_TO_LONGS(mpic->irq_count) * sizeof(long);
152         pr_debug("mpic: allocator bitmap size is 0x%x bytes\n", size);
153
154         mpic->hwirq_bitmap = alloc_maybe_bootmem(size, GFP_KERNEL);
155
156         if (!mpic->hwirq_bitmap) {
157                 pr_debug("mpic: ENOMEM allocating allocator bitmap!\n");
158                 return -ENOMEM;
159         }
160
161         memset(mpic->hwirq_bitmap, 0, size);
162
163         rc = mpic_msi_reserve_dt_hwirqs(mpic);
164         if (rc) {
165                 if (mpic->flags & MPIC_U3_HT_IRQS)
166                         rc = mpic_msi_reserve_u3_hwirqs(mpic);
167
168                 if (rc)
169                         goto out_free;
170         }
171
172         return 0;
173
174  out_free:
175         if (mem_init_done)
176                 kfree(mpic->hwirq_bitmap);
177
178         mpic->hwirq_bitmap = NULL;
179         return rc;
180 }