drm/rockchip: Clear all interrupts before requesting the IRQ

Calling request_irq() followed by disable_irq() is usually a bad idea,
specially if the interrupt can be pending, and you're not yet in a
position to handle it.

This is exactly what happens on my kevin system when rebooting in a
second kernel using kexec: Some interrupt is left pending from
the previous kernel, and we take it too early, before disable_irq()
could do anything.

Let's clear the pending interrupts as we initialize the HW, and move
the interrupt request after that point. This ensures that we're in
a sane state when the interrupt is requested.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
[adapted to recent rockchip-drm changes]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20180220130120.5254-2-marc.zyngier@arm.com

1 files changed, 12 insertions, 11 deletions

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index b601c59e76a8..7a1de09d45d8 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1401,6 +1401,9 @@ static int vop_initial(struct vop *vop)
         usleep_range(10, 20);
         reset_control_deassert(ahb_rst);
 
+        VOP_INTR_SET_TYPE(vop, clear, INTR_MASK, 1);
+        VOP_INTR_SET_TYPE(vop, enable, INTR_MASK, 0);
+
         memcpy(vop->regsbak, vop->regs, vop->len);
 
         VOP_REG_SET(vop, misc, global_regdone_en, 1);
@@ -1564,17 +1567,9 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
         spin_lock_init(&vop->irq_lock);
         mutex_init(&vop->vop_lock);
 
-        ret = devm_request_irq(dev, vop->irq, vop_isr,
-                               IRQF_SHARED, dev_name(dev), vop);
-        if (ret)
-                return ret;
-
-        /* IRQ is initially disabled; it gets enabled in power_on */
-        disable_irq(vop->irq);
-
         ret = vop_create_crtc(vop);
         if (ret)
-                goto err_enable_irq;
+                return ret;
 
         pm_runtime_enable(&pdev->dev);
 
@@ -1585,13 +1580,19 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
                 goto err_disable_pm_runtime;
         }
 
+        ret = devm_request_irq(dev, vop->irq, vop_isr,
+                               IRQF_SHARED, dev_name(dev), vop);
+        if (ret)
+                goto err_disable_pm_runtime;
+
+        /* IRQ is initially disabled; it gets enabled in power_on */
+        disable_irq(vop->irq);
+
         return 0;
 
 err_disable_pm_runtime:
         pm_runtime_disable(&pdev->dev);
         vop_destroy_crtc(vop);
-err_enable_irq:
-        enable_irq(vop->irq); /* To balance out the disable_irq above */
         return ret;
 }