Commit-ID: 06f6c3399e9f9ff6eafc200e80f9226c3cee0eaf
Gitweb: http://git.kernel.org/tip/06f6c3399e9f9ff6eafc200e80f9226c3cee0eaf
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 12 Oct 2010 12:31:46 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 12 Oct 2010 16:39:07 +0200
genirq: Implement irq reservation
Mark a range of interrupts as allocated. In the SPARSE_IRQ=n case we
need this to update the bitmap for the legacy irqs so the enumerator
via irq_get_next_irq() works.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
include/linux/irq.h | 1 +
kernel/irq/irqdesc.c | 26 ++++++++++++++++++++++++++
2 files changed, 27 insertions(+), 0 deletions(-)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index cefacf9..096b74d 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -400,6 +400,7 @@ static inline struct irq_2_iommu *irq_data_get_iommu(struct irq_data *d)
int irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node);
void irq_free_descs(unsigned int irq, unsigned int cnt);
+int irq_reserve_irqs(unsigned int from, unsigned int cnt);
static inline int irq_alloc_desc(int node)
{
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 2e7e94e..35d9052 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -464,6 +464,32 @@ err:
}
/**
+ * irq_reserve_irqs - mark irqs allocated
+ * @from: mark from irq number
+ * @cnt: number of irqs to mark
+ *
+ * Returns 0 on success or an appropriate error code
+ */
+int irq_reserve_irqs(unsigned int from, unsigned int cnt)
+{
+ unsigned long flags;
+ unsigned int start;
+ int ret = 0;
+
+ if (!cnt || (from + cnt) > nr_irqs)
+ return -EINVAL;
+
+ raw_spin_lock_irqsave(&sparse_irq_lock, flags);
+ start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
+ if (start == from)
+ bitmap_set(allocated_irqs, start, cnt);
+ else
+ ret = -EEXIST;
+ raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
+ return ret;
+}
+
+/**
* irq_get_next_irq - get next allocated irq number
* @offset: where to start the search
*
--
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