[PATCH 4.9 69/95] drm/rockchip: Clear all interrupts before requesting the IRQ

From: Greg Kroah-Hartman
Date: Sun Apr 22 2018 - 10:56:45 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Marc Zyngier <marc.zyngier@xxxxxxx>

commit 5f9e93fed4d45e9a8f84728aff1a8f2ab8922902 upstream.

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@xxxxxxxxxxxxxxx
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
[adapted to recent rockchip-drm changes]
Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20180220130120.5254-2-marc.zyngier@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)

--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1386,6 +1386,9 @@ 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);

for (i = 0; i < vop_data->table_size; i++)
@@ -1541,17 +1544,9 @@ static int vop_bind(struct device *dev,

mutex_init(&vop->vsync_mutex);

- 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);

@@ -1561,13 +1556,19 @@ static int vop_bind(struct device *dev,
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;
}