Merge tag 'irq-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq updates from Thomas Gleixner:
 "Updates for the interrupt subsystem:

  Core:
   - Allow trimming of interrupt hierarchy to support odd hardware
     setups where only a subset of the interrupts requires the full
     hierarchy.

   - Allow the retrigger mechanism to follow a hierarchy to simplify
     driver code.

   - Provide a mechanism to force enable wakeup interrrupts on suspend.

   - More infrastructure to handle IPIs in the core code

  Architectures:
   - Convert ARM/ARM64 IPI handling to utilize the interrupt core code.

  Drivers:
   - The usual pile of new interrupt chips (MStar, Actions Owl, TI
     PRUSS, Designware ICTL)

   - ARM(64) IPI related conversions

   - Wakeup support for Qualcom PDC

   - Prevent hierarchy corruption in the NVIDIA Tegra driver

   - The usual small fixes, improvements and cleanups all over the
     place"

* tag 'irq-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (59 commits)
  dt-bindings: interrupt-controller: Add MStar interrupt controller
  irqchip/irq-mst: Add MStar interrupt controller support
  soc/tegra: pmc: Don't create fake interrupt hierarchy levels
  soc/tegra: pmc: Allow optional irq parent callbacks
  gpio: tegra186: Allow optional irq parent callbacks
  genirq/irqdomain: Allow partial trimming of irq_data hierarchy
  irqchip/qcom-pdc: Reset PDC interrupts during init
  irqchip/qcom-pdc: Set IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag
  pinctrl: qcom: Set IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag
  genirq/PM: Introduce IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag
  pinctrl: qcom: Use return value from irq_set_wake() call
  pinctrl: qcom: Set IRQCHIP_SET_TYPE_MASKED and IRQCHIP_MASK_ON_SUSPEND flags
  ARM: Handle no IPI being registered in show_ipi_list()
  MAINTAINERS: Add entries for Actions Semi Owl SIRQ controller
  irqchip: Add Actions Semi Owl SIRQ controller
  dt-bindings: interrupt-controller: Add Actions SIRQ controller binding
  dt-bindings: dw-apb-ictl: Update binding to describe use as primary interrupt controller
  irqchip/dw-apb-ictl: Add primary interrupt controller support
  irqchip/dw-apb-ictl: Refactor priot to introducing hierarchical irq domains
  genirq: Add stub for set_handle_irq() when !GENERIC_IRQ_MULTI_HANDLER
  ...

1 files changed, 95 insertions, 4 deletions

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 76cd7ebd1178..cf8b374b892d 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1136,6 +1136,17 @@ static struct irq_data *irq_domain_insert_irq_data(struct irq_domain *domain,
 	return irq_data;
 }
 
+static void __irq_domain_free_hierarchy(struct irq_data *irq_data)
+{
+	struct irq_data *tmp;
+
+	while (irq_data) {
+		tmp = irq_data;
+		irq_data = irq_data->parent_data;
+		kfree(tmp);
+	}
+}
+
 static void irq_domain_free_irq_data(unsigned int virq, unsigned int nr_irqs)
 {
 	struct irq_data *irq_data, *tmp;
@@ -1147,12 +1158,83 @@ static void irq_domain_free_irq_data(unsigned int virq, unsigned int nr_irqs)
 		irq_data->parent_data = NULL;
 		irq_data->domain = NULL;
 
-		while (tmp) {
-			irq_data = tmp;
-			tmp = tmp->parent_data;
-			kfree(irq_data);
+		__irq_domain_free_hierarchy(tmp);
+	}
+}
+
+/**
+ * irq_domain_disconnect_hierarchy - Mark the first unused level of a hierarchy
+ * @domain:	IRQ domain from which the hierarchy is to be disconnected
+ * @virq:	IRQ number where the hierarchy is to be trimmed
+ *
+ * Marks the @virq level belonging to @domain as disconnected.
+ * Returns -EINVAL if @virq doesn't have a valid irq_data pointing
+ * to @domain.
+ *
+ * Its only use is to be able to trim levels of hierarchy that do not
+ * have any real meaning for this interrupt, and that the driver marks
+ * as such from its .alloc() callback.
+ */
+int irq_domain_disconnect_hierarchy(struct irq_domain *domain,
+				    unsigned int virq)
+{
+	struct irq_data *irqd;
+
+	irqd = irq_domain_get_irq_data(domain, virq);
+	if (!irqd)
+		return -EINVAL;
+
+	irqd->chip = ERR_PTR(-ENOTCONN);
+	return 0;
+}
+
+static int irq_domain_trim_hierarchy(unsigned int virq)
+{
+	struct irq_data *tail, *irqd, *irq_data;
+
+	irq_data = irq_get_irq_data(virq);
+	tail = NULL;
+
+	/* The first entry must have a valid irqchip */
+	if (!irq_data->chip || IS_ERR(irq_data->chip))
+		return -EINVAL;
+
+	/*
+	 * Validate that the irq_data chain is sane in the presence of
+	 * a hierarchy trimming marker.
+	 */
+	for (irqd = irq_data->parent_data; irqd; irq_data = irqd, irqd = irqd->parent_data) {
+		/* Can't have a valid irqchip after a trim marker */
+		if (irqd->chip && tail)
+			return -EINVAL;
+
+		/* Can't have an empty irqchip before a trim marker */
+		if (!irqd->chip && !tail)
+			return -EINVAL;
+
+		if (IS_ERR(irqd->chip)) {
+			/* Only -ENOTCONN is a valid trim marker */
+			if (PTR_ERR(irqd->chip) != -ENOTCONN)
+				return -EINVAL;
+
+			tail = irq_data;
 		}
 	}
+
+	/* No trim marker, nothing to do */
+	if (!tail)
+		return 0;
+
+	pr_info("IRQ%d: trimming hierarchy from %s\n",
+		virq, tail->parent_data->domain->name);
+
+	/* Sever the inner part of the hierarchy...  */
+	irqd = tail;
+	tail = tail->parent_data;
+	irqd->parent_data = NULL;
+	__irq_domain_free_hierarchy(tail);
+
+	return 0;
 }
 
 static int irq_domain_alloc_irq_data(struct irq_domain *domain,
@@ -1362,6 +1444,15 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 		mutex_unlock(&irq_domain_mutex);
 		goto out_free_irq_data;
 	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = irq_domain_trim_hierarchy(virq + i);
+		if (ret) {
+			mutex_unlock(&irq_domain_mutex);
+			goto out_free_irq_data;
+		}
+	}
+	
 	for (i = 0; i < nr_irqs; i++)
 		irq_domain_insert_irq(virq + i);
 	mutex_unlock(&irq_domain_mutex);