releases/4.19.35/genirq-respect-irqchip_skip_set_wake-in-irq_chip_set_wake_parent.patch

   1 From 325aa19598e410672175ed50982f902d4e3f31c5 Mon Sep 17 00:00:00 2001
   2 From: Stephen Boyd <swboyd@chromium.org>
   3 Date: Mon, 25 Mar 2019 11:10:26 -0700
   4 Subject: genirq: Respect IRQCHIP_SKIP_SET_WAKE in irq_chip_set_wake_parent()
   5
   6 From: Stephen Boyd <swboyd@chromium.org>
   7
   8 commit 325aa19598e410672175ed50982f902d4e3f31c5 upstream.
   9
  10 If a child irqchip calls irq_chip_set_wake_parent() but its parent irqchip
  11 has the IRQCHIP_SKIP_SET_WAKE flag set an error is returned.
  12
  13 This is inconsistent behaviour vs. set_irq_wake_real() which returns 0 when
  14 the irqchip has the IRQCHIP_SKIP_SET_WAKE flag set. It doesn't attempt to
  15 walk the chain of parents and set irq wake on any chips that don't have the
  16 flag set either. If the intent is to call the .irq_set_wake() callback of
  17 the parent irqchip, then we expect irqchip implementations to omit the
  18 IRQCHIP_SKIP_SET_WAKE flag and implement an .irq_set_wake() function that
  19 calls irq_chip_set_wake_parent().
  20
  21 The problem has been observed on a Qualcomm sdm845 device where set wake
  22 fails on any GPIO interrupts after applying work in progress wakeup irq
  23 patches to the GPIO driver. The chain of chips looks like this:
  24
  25      QCOM GPIO -> QCOM PDC (SKIP) -> ARM GIC (SKIP)
  26
  27 The GPIO controllers parent is the QCOM PDC irqchip which in turn has ARM
  28 GIC as parent.  The QCOM PDC irqchip has the IRQCHIP_SKIP_SET_WAKE flag
  29 set, and so does the grandparent ARM GIC.
  30
  31 The GPIO driver doesn't know if the parent needs to set wake or not, so it
  32 unconditionally calls irq_chip_set_wake_parent() causing this function to
  33 return a failure because the parent irqchip (PDC) doesn't have the
  34 .irq_set_wake() callback set. Returning 0 instead makes everything work and
  35 irqs from the GPIO controller can be configured for wakeup.
  36
  37 Make it consistent by returning 0 (success) from irq_chip_set_wake_parent()
  38 when a parent chip has IRQCHIP_SKIP_SET_WAKE set.
  39
  40 [ tglx: Massaged changelog ]
  41
  42 Fixes: 08b55e2a9208e ("genirq: Add irqchip_set_wake_parent")
  43 Signed-off-by: Stephen Boyd <swboyd@chromium.org>
  44 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  45 Acked-by: Marc Zyngier <marc.zyngier@arm.com>
  46 Cc: linux-arm-kernel@lists.infradead.org
  47 Cc: linux-gpio@vger.kernel.org
  48 Cc: Lina Iyer <ilina@codeaurora.org>
  49 Cc: stable@vger.kernel.org
  50 Link: https://lkml.kernel.org/r/20190325181026.247796-1-swboyd@chromium.org
  51 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  52
  53 ---
  54  kernel/irq/chip.c |    4 ++++
  55  1 file changed, 4 insertions(+)
  56
  57 --- a/kernel/irq/chip.c
  58 +++ b/kernel/irq/chip.c
  59 @@ -1384,6 +1384,10 @@ int irq_chip_set_vcpu_affinity_parent(st
  60  int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on)
  61  {
  62         data = data->parent_data;
  63 +
  64 +       if (data->chip->flags & IRQCHIP_SKIP_SET_WAKE)
  65 +               return 0;
  66 +
  67         if (data->chip->irq_set_wake)
  68                 return data->chip->irq_set_wake(data, on);
  69