drm/msm: kexec fixes

In kexec environment, we are more likely to encounter irq's already
enabled from previous environment.  At which point we find that writes
to disable/clear pending irq's are slightly less than useless without
first enabling clocks.

TODO: full blown state read-in so kexec'd kernel can inherit the mode
already setup.
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp4/mdp4_irq.c

@@ -32,7 +32,10 @@ static void mdp4_irq_error_handler(struct mdp_irq *irq, uint32_t irqstatus)
 void mdp4_irq_preinstall(struct msm_kms *kms)
 {
 	struct mdp4_kms *mdp4_kms = to_mdp4_kms(to_mdp_kms(kms));
+	mdp4_enable(mdp4_kms);
 	mdp4_write(mdp4_kms, REG_MDP4_INTR_CLEAR, 0xffffffff);
+	mdp4_write(mdp4_kms, REG_MDP4_INTR_ENABLE, 0x00000000);
+	mdp4_disable(mdp4_kms);
 }
 
 int mdp4_irq_postinstall(struct msm_kms *kms)
@@ -53,7 +56,9 @@ int mdp4_irq_postinstall(struct msm_kms *kms)
 void mdp4_irq_uninstall(struct msm_kms *kms)
 {
 	struct mdp4_kms *mdp4_kms = to_mdp4_kms(to_mdp_kms(kms));
+	mdp4_enable(mdp4_kms);
 	mdp4_write(mdp4_kms, REG_MDP4_INTR_ENABLE, 0x00000000);
+	mdp4_disable(mdp4_kms);
 }
 
 irqreturn_t mdp4_irq(struct msm_kms *kms)

drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c

@@ -34,7 +34,10 @@ static void mdp5_irq_error_handler(struct mdp_irq *irq, uint32_t irqstatus)
 void mdp5_irq_preinstall(struct msm_kms *kms)
 {
 	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(kms));
+	mdp5_enable(mdp5_kms);
 	mdp5_write(mdp5_kms, REG_MDP5_INTR_CLEAR, 0xffffffff);
+	mdp5_write(mdp5_kms, REG_MDP5_INTR_EN, 0x00000000);
+	mdp5_disable(mdp5_kms);
 }
 
 int mdp5_irq_postinstall(struct msm_kms *kms)
@@ -57,7 +60,9 @@ int mdp5_irq_postinstall(struct msm_kms *kms)
 void mdp5_irq_uninstall(struct msm_kms *kms)
 {
 	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(kms));
+	mdp5_enable(mdp5_kms);
 	mdp5_write(mdp5_kms, REG_MDP5_INTR_EN, 0x00000000);
+	mdp5_disable(mdp5_kms);
 }
 
 static void mdp5_irq_mdp(struct mdp_kms *mdp_kms)