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

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index fc89eeb8a6b47df43cd30392e149847eab89f4ae..2e30d925a40d9b638854949bac95ba209590b98b 100644 (file)
--- 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);
 }
 
 /*