[POWERPC] MPIC MSI allocator
To support MSI on MPIC we need a way to reserve and allocate hardware irq
numbers, this patch implements an allocator for that purpose.
New firmware platforms must define a "msi-available-ranges" property on their
MPIC node for MSI to work. For U3/U4 we do a best-guess setup.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/sysdev/mpic_msi.c b/arch/powerpc/sysdev/mpic_msi.c
new file mode 100644
index 0000000..b076793
--- /dev/null
+++ b/arch/powerpc/sysdev/mpic_msi.c
@@ -0,0 +1,183 @@
+/*
+ * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2 of the
+ * License.
+ *
+ */
+
+#include <linux/irq.h>
+#include <linux/bootmem.h>
+#include <linux/bitmap.h>
+#include <linux/msi.h>
+#include <asm/mpic.h>
+#include <asm/prom.h>
+#include <asm/hw_irq.h>
+#include <asm/ppc-pci.h>
+
+
+static void __mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
+{
+ pr_debug("mpic: reserving hwirq 0x%lx\n", hwirq);
+ bitmap_allocate_region(mpic->hwirq_bitmap, hwirq, 0);
+}
+
+void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
+{
+ unsigned long flags;
+
+ /* The mpic calls this even when there is no allocator setup */
+ if (!mpic->hwirq_bitmap)
+ return;
+
+ spin_lock_irqsave(&mpic->bitmap_lock, flags);
+ __mpic_msi_reserve_hwirq(mpic, hwirq);
+ spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
+}
+
+irq_hw_number_t mpic_msi_alloc_hwirqs(struct mpic *mpic, int num)
+{
+ unsigned long flags;
+ int offset, order = get_count_order(num);
+
+ spin_lock_irqsave(&mpic->bitmap_lock, flags);
+ /*
+ * This is fast, but stricter than we need. We might want to add
+ * a fallback routine which does a linear search with no alignment.
+ */
+ offset = bitmap_find_free_region(mpic->hwirq_bitmap, mpic->irq_count,
+ order);
+ spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
+
+ pr_debug("mpic: allocated 0x%x (2^%d) at offset 0x%x\n",
+ num, order, offset);
+
+ return offset;
+}
+
+void mpic_msi_free_hwirqs(struct mpic *mpic, int offset, int num)
+{
+ unsigned long flags;
+ int order = get_count_order(num);
+
+ pr_debug("mpic: freeing 0x%x (2^%d) at offset 0x%x\n",
+ num, order, offset);
+
+ spin_lock_irqsave(&mpic->bitmap_lock, flags);
+ bitmap_release_region(mpic->hwirq_bitmap, offset, order);
+ spin_unlock_irqrestore(&mpic->bitmap_lock, flags);
+}
+
+#ifdef CONFIG_MPIC_U3_HT_IRQS
+static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
+{
+ irq_hw_number_t hwirq;
+ struct irq_host_ops *ops = mpic->irqhost->ops;
+ struct device_node *np;
+ int flags, index, i;
+ struct of_irq oirq;
+
+ pr_debug("mpic: found U3, guessing msi allocator setup\n");
+
+ /* Reserve source numbers we know are reserved in the HW */
+ for (i = 0; i < 8; i++)
+ __mpic_msi_reserve_hwirq(mpic, i);
+
+ for (i = 42; i < 46; i++)
+ __mpic_msi_reserve_hwirq(mpic, i);
+
+ for (i = 100; i < 105; i++)
+ __mpic_msi_reserve_hwirq(mpic, i);
+
+ np = NULL;
+ while ((np = of_find_all_nodes(np))) {
+ pr_debug("mpic: mapping hwirqs for %s\n", np->full_name);
+
+ index = 0;
+ while (of_irq_map_one(np, index++, &oirq) == 0) {
+ ops->xlate(mpic->irqhost, NULL, oirq.specifier,
+ oirq.size, &hwirq, &flags);
+ __mpic_msi_reserve_hwirq(mpic, hwirq);
+ }
+ }
+
+ return 0;
+}
+#else
+static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
+{
+ return -1;
+}
+#endif
+
+static int mpic_msi_reserve_dt_hwirqs(struct mpic *mpic)
+{
+ int i, len;
+ const u32 *p;
+
+ p = of_get_property(mpic->of_node, "msi-available-ranges", &len);
+ if (!p) {
+ pr_debug("mpic: no msi-available-ranges property found on %s\n",
+ mpic->of_node->full_name);
+ return -ENODEV;
+ }
+
+ if (len % 8 != 0) {
+ printk(KERN_WARNING "mpic: Malformed msi-available-ranges "
+ "property on %s\n", mpic->of_node->full_name);
+ return -EINVAL;
+ }
+
+ bitmap_allocate_region(mpic->hwirq_bitmap, 0,
+ get_count_order(mpic->irq_count));
+
+ /* Format is: (<u32 start> <u32 count>)+ */
+ len /= sizeof(u32);
+ for (i = 0; i < len / 2; i++, p += 2)
+ mpic_msi_free_hwirqs(mpic, *p, *(p + 1));
+
+ return 0;
+}
+
+int mpic_msi_init_allocator(struct mpic *mpic)
+{
+ int rc, size;
+
+ BUG_ON(mpic->hwirq_bitmap);
+ spin_lock_init(&mpic->bitmap_lock);
+
+ size = BITS_TO_LONGS(mpic->irq_count) * sizeof(long);
+ pr_debug("mpic: allocator bitmap size is 0x%x bytes\n", size);
+
+ if (mem_init_done)
+ mpic->hwirq_bitmap = kmalloc(size, GFP_KERNEL);
+ else
+ mpic->hwirq_bitmap = alloc_bootmem(size);
+
+ if (!mpic->hwirq_bitmap) {
+ pr_debug("mpic: ENOMEM allocating allocator bitmap!\n");
+ return -ENOMEM;
+ }
+
+ memset(mpic->hwirq_bitmap, 0, size);
+
+ rc = mpic_msi_reserve_dt_hwirqs(mpic);
+ if (rc) {
+ if (mpic->flags & MPIC_U3_HT_IRQS)
+ rc = mpic_msi_reserve_u3_hwirqs(mpic);
+
+ if (rc)
+ goto out_free;
+ }
+
+ return 0;
+
+ out_free:
+ if (mem_init_done)
+ kfree(mpic->hwirq_bitmap);
+
+ mpic->hwirq_bitmap = NULL;
+ return rc;
+}