genirq: Avoid unnecessary low level irq function calls

Check irq state in enable/disable/unmask/mask_irq to avoid unnecessary
low level irq function calls.

This has two advantages:
    - Conditionals are faster than hardware access

    - Solves issues with the underlying refcounting of the pinctrl
      infrastructure

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: tfiga@chromium.org
Cc: briannorris@chromium.org
Cc: dianders@chromium.org
Link: http://lkml.kernel.org/r/1498476814-12563-2-git-send-email-jeffy.chen@rock-chips.com

1 files changed, 33 insertions, 20 deletions

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index fc89eeb8a6b4..2e30d925a40d 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -314,22 +314,32 @@ void irq_shutdown(struct irq_desc *desc)
 
 void irq_enable(struct irq_desc *desc)
 {
-        irq_state_clr_disabled(desc);
-        if (desc->irq_data.chip->irq_enable)
-                desc->irq_data.chip->irq_enable(&desc->irq_data);
-        else
-                desc->irq_data.chip->irq_unmask(&desc->irq_data);
-        irq_state_clr_masked(desc);
+        if (!irqd_irq_disabled(&desc->irq_data)) {
+                unmask_irq(desc);
+        } else {
+                irq_state_clr_disabled(desc);
+                if (desc->irq_data.chip->irq_enable) {
+                        desc->irq_data.chip->irq_enable(&desc->irq_data);
+                        irq_state_clr_masked(desc);
+                } else {
+                        unmask_irq(desc);
+                }
+        }
 }
 
 static void __irq_disable(struct irq_desc *desc, bool mask)
 {
-        irq_state_set_disabled(desc);
-        if (desc->irq_data.chip->irq_disable) {
-                desc->irq_data.chip->irq_disable(&desc->irq_data);
-                irq_state_set_masked(desc);
-        } else if (mask) {
-                mask_irq(desc);
+        if (irqd_irq_disabled(&desc->irq_data)) {
+                if (mask)
+                        mask_irq(desc);
+        } else {
+                irq_state_set_disabled(desc);
+                if (desc->irq_data.chip->irq_disable) {
+                        desc->irq_data.chip->irq_disable(&desc->irq_data);
+                        irq_state_set_masked(desc);
+                } else if (mask) {
+                        mask_irq(desc);
+                }
         }
 }
 
@@ -378,18 +388,21 @@ void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu)
 
 static inline void mask_ack_irq(struct irq_desc *desc)
 {
-        if (desc->irq_data.chip->irq_mask_ack)
+        if (desc->irq_data.chip->irq_mask_ack) {
                 desc->irq_data.chip->irq_mask_ack(&desc->irq_data);
-        else {
-                desc->irq_data.chip->irq_mask(&desc->irq_data);
+                irq_state_set_masked(desc);
+        } else {
+                mask_irq(desc);
                 if (desc->irq_data.chip->irq_ack)
                         desc->irq_data.chip->irq_ack(&desc->irq_data);
         }
-        irq_state_set_masked(desc);
 }
 
 void mask_irq(struct irq_desc *desc)
 {
+        if (irqd_irq_masked(&desc->irq_data))
+                return;
+
         if (desc->irq_data.chip->irq_mask) {
                 desc->irq_data.chip->irq_mask(&desc->irq_data);
                 irq_state_set_masked(desc);
@@ -398,6 +411,9 @@ void mask_irq(struct irq_desc *desc)
 
 void unmask_irq(struct irq_desc *desc)
 {
+        if (!irqd_irq_masked(&desc->irq_data))
+                return;
+
         if (desc->irq_data.chip->irq_unmask) {
                 desc->irq_data.chip->irq_unmask(&desc->irq_data);
                 irq_state_clr_masked(desc);
@@ -411,10 +427,7 @@ void unmask_threaded_irq(struct irq_desc *desc)
         if (chip->flags & IRQCHIP_EOI_THREADED)
                 chip->irq_eoi(&desc->irq_data);
 
-        if (chip->irq_unmask) {
-                chip->irq_unmask(&desc->irq_data);
-                irq_state_clr_masked(desc);
-        }
+        unmask_irq(desc);
 }
 
 /*