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 }