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 #include <sysdev/mpic.h>
  20
  21 static void __mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
  22 {
  23         pr_debug("mpic: reserving hwirq 0x%lx\n", hwirq);
  24         bitmap_allocate_region(mpic->hwirq_bitmap, hwirq, 0);
  25 }
  26
  27 void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
  28 {
  29         unsigned long flags;
  30
  31         /* The mpic calls this even when there is no allocator setup */
  32         if (!mpic->hwirq_bitmap)
  33                 return;
  34
  35         spin_lock_irqsave(&mpic->bitmap_lock, flags);
  36         __mpic_msi_reserve_hwirq(mpic, hwirq);
  37         spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
  38 }
  39
  40 irq_hw_number_t mpic_msi_alloc_hwirqs(struct mpic *mpic, int num)
  41 {
  42         unsigned long flags;
  43         int offset, order = get_count_order(num);
  44
  45         spin_lock_irqsave(&mpic->bitmap_lock, flags);
  46         /*
  47          * This is fast, but stricter than we need. We might want to add
  48          * a fallback routine which does a linear search with no alignment.
  49          */
  50         offset = bitmap_find_free_region(mpic->hwirq_bitmap, mpic->irq_count,
  51                                          order);
  52         spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
  53
  54         pr_debug("mpic: allocated 0x%x (2^%d) at offset 0x%x\n",
  55                  num, order, offset);
  56
  57         return offset;
  58 }
  59
  60 void mpic_msi_free_hwirqs(struct mpic *mpic, int offset, int num)
  61 {
  62         unsigned long flags;
  63         int order = get_count_order(num);
  64
  65         pr_debug("mpic: freeing 0x%x (2^%d) at offset 0x%x\n",
  66                  num, order, offset);
  67
  68         spin_lock_irqsave(&mpic->bitmap_lock, flags);
  69         bitmap_release_region(mpic->hwirq_bitmap, offset, order);
  70         spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
  71 }
  72
  73 #ifdef CONFIG_MPIC_U3_HT_IRQS
  74 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
  75 {
  76         irq_hw_number_t hwirq;
  77         struct irq_host_ops *ops = mpic->irqhost->ops;
  78         struct device_node *np;
  79         int flags, index, i;
  80         struct of_irq oirq;
  81
  82         pr_debug("mpic: found U3, guessing msi allocator setup\n");
  83
  84         /* Reserve source numbers we know are reserved in the HW */
  85         for (i = 0;   i < 8;   i++)
  86                 __mpic_msi_reserve_hwirq(mpic, i);
  87
  88         for (i = 42;  i < 46;  i++)
  89                 __mpic_msi_reserve_hwirq(mpic, i);
  90
  91         for (i = 100; i < 105; i++)
  92                 __mpic_msi_reserve_hwirq(mpic, i);
  93
  94         np = NULL;
  95         while ((np = of_find_all_nodes(np))) {
  96                 pr_debug("mpic: mapping hwirqs for %s\n", np->full_name);
  97
  98                 index = 0;
  99                 while (of_irq_map_one(np, index++, &oirq) == 0) {
 100                         ops->xlate(mpic->irqhost, NULL, oirq.specifier,
 101                                                 oirq.size, &hwirq, &flags);
 102                         __mpic_msi_reserve_hwirq(mpic, hwirq);
 103                 }
 104         }
 105
 106         return 0;
 107 }
 108 #else
 109 static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
 110 {
 111         return -1;
 112 }
 113 #endif
 114
 115 static int mpic_msi_reserve_dt_hwirqs(struct mpic *mpic)
 116 {
 117         int i, len;
 118         const u32 *p;
 119
 120         p = of_get_property(mpic->irqhost->of_node,
 121                             "msi-available-ranges", &len);
 122         if (!p) {
 123                 pr_debug("mpic: no msi-available-ranges property found on %s\n",
 124                           mpic->irqhost->of_node->full_name);
 125                 return -ENODEV;
 126         }
 127
 128         if (len % 8 != 0) {
 129                 printk(KERN_WARNING "mpic: Malformed msi-available-ranges "
 130                        "property on %s\n", mpic->irqhost->of_node->full_name);
 131                 return -EINVAL;
 132         }
 133
 134         bitmap_allocate_region(mpic->hwirq_bitmap, 0,
 135                                get_count_order(mpic->irq_count));
 136
 137         /* Format is: (<u32 start> <u32 count>)+ */
 138         len /= sizeof(u32);
 139         for (i = 0; i < len / 2; i++, p += 2)
 140                 mpic_msi_free_hwirqs(mpic, *p, *(p + 1));
 141
 142         return 0;
 143 }
 144
 145 int mpic_msi_init_allocator(struct mpic *mpic)
 146 {
 147         int rc, size;
 148
 149         BUG_ON(mpic->hwirq_bitmap);
 150         spin_lock_init(&mpic->bitmap_lock);
 151
 152         size = BITS_TO_LONGS(mpic->irq_count) * sizeof(long);
 153         pr_debug("mpic: allocator bitmap size is 0x%x bytes\n", size);
 154
 155         mpic->hwirq_bitmap = alloc_maybe_bootmem(size, GFP_KERNEL);
 156
 157         if (!mpic->hwirq_bitmap) {
 158                 pr_debug("mpic: ENOMEM allocating allocator bitmap!\n");
 159                 return -ENOMEM;
 160         }
 161
 162         memset(mpic->hwirq_bitmap, 0, size);
 163
 164         rc = mpic_msi_reserve_dt_hwirqs(mpic);
 165         if (rc) {
 166                 if (mpic->flags & MPIC_U3_HT_IRQS)
 167                         rc = mpic_msi_reserve_u3_hwirqs(mpic);
 168
 169                 if (rc)
 170                         goto out_free;
 171         }
 172
 173         return 0;
 174
 175  out_free:
 176         if (mem_init_done)
 177                 kfree(mpic->hwirq_bitmap);
 178
 179         mpic->hwirq_bitmap = NULL;
 180         return rc;
 181 }