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[V4,05/16] irqchip: crossbar: Change allocation logic by reversing search for free irqs

Message ID 1403766634-18543-6-git-send-email-r.sricharan@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

R Sricharan June 26, 2014, 7:10 a.m. UTC 
From: Nishanth Menon <nm@ti.com>

Reverse the search algorithm to ensure that address mapping and IRQ
allocation logics are proper. This makes the below bugs visible sooner.

class 1. address space errors -> example:
reg = <a size_b>
ti,max-irqs =  is a wrong parameter

class 2: irq-reserved list - which decides which entries in the
address space is not actually wired in

class 3: wrong list of routable-irqs.

In general allocating from max to min tends to have benefits in
ensuring the different issues that may be present in dts is easily
caught at definition time, rather than at a later point in time.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
 drivers/irqchip/irq-crossbar.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c
index 4be30c0..a39cb31 100644
--- a/drivers/irqchip/irq-crossbar.c
+++ b/drivers/irqchip/irq-crossbar.c
@@ -58,7 +58,7 @@  static inline int get_prev_map_irq(int cb_no)
 {
 	int i;
 
-	for (i = 0; i < cb->int_max; i++)
+	for (i = cb->int_max - 1; i >= 0; i--)
 		if (cb->irq_map[i] == cb_no)
 			return i;
 
@@ -69,7 +69,7 @@  static inline int allocate_free_irq(int cb_no)
 {
 	int i;
 
-	for (i = 0; i < cb->int_max; i++) {
+	for (i = cb->int_max - 1; i >= 0; i--) {
 		if (cb->irq_map[i] == IRQ_FREE) {
 			cb->irq_map[i] = cb_no;
 			return i;