[PATCH] pinctrl: qcom: Guard irq_eoi()

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

In the commit setting up the qcom/msm pin controller to
be hierarchical some callbacks were careful to check that
d->parent_data on irq_data was valid before calling the
parent function, however irq_chip_eoi_parent() was called
unconditionally which doesn't work with elder Qualcomm
platforms such as APQ8060.

When the drivers/mfd/qcom-pm8xxx.c driver calls
chained_irq_exit() that call will in turn call chip->irq_eoi()
which is set to irq_chip_eoi_parent() by default on a
hierachical IRQ chip, and the parent is pinctrl-msm.c
so that will in turn unconditionally call
irq_chip_eoi_parent() again, but its parent is invalid
so we get the following crash:

 Unnable to handle kernel NULL pointer dereference at
 virtual address 00000010
 pgd = (ptrval)
 [00000010] *pgd=00000000
 Internal error: Oops: 5 [#1] PREEMPT SMP ARM
 (...)
 PC is at irq_chip_eoi_parent+0x4/0x10
 LR is at pm8xxx_irq_handler+0x1b4/0x2d8

Implement a local stub just avoiding to call down to
irq_chip_eoi_parent() if d->parent_data is not set.

Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: e35a6ae0eb3a ("pinctrl/msm: Setup GPIO chip in hierarchy")
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index 9a8daa256a32..511f596cf2c3 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -828,6 +828,12 @@ static void msm_gpio_irq_unmask(struct irq_data *d)
 	msm_gpio_irq_clear_unmask(d, false);
 }
 
+static void msm_gpio_irq_eoi(struct irq_data *d)
+{
+	if (d->parent_data)
+		irq_chip_eoi_parent(d);
+}
+
 static void msm_gpio_irq_ack(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
@@ -1104,7 +1110,7 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	pctrl->irq_chip.irq_mask = msm_gpio_irq_mask;
 	pctrl->irq_chip.irq_unmask = msm_gpio_irq_unmask;
 	pctrl->irq_chip.irq_ack = msm_gpio_irq_ack;
-	pctrl->irq_chip.irq_eoi = irq_chip_eoi_parent;
+	pctrl->irq_chip.irq_eoi = msm_gpio_irq_eoi;
 	pctrl->irq_chip.irq_set_type = msm_gpio_irq_set_type;
 	pctrl->irq_chip.irq_set_wake = msm_gpio_irq_set_wake;
 	pctrl->irq_chip.irq_request_resources = msm_gpio_irq_reqres;
-- 
2.24.1