Some (admittedly odd) irqchips perform functions that are not directly
related to any of their child IRQ lines, and therefore need to perform
some tasks during suspend/resume regardless of whether there are
any "installed" interrupts for the irqchip. However, the current
generic-chip framework does not call the chip's irq_{suspend,resume}
when there are no interrupts installed (this makes sense, because there
are no irq_data objects for such a call to be made).
More specifically, irq-bcm7120-l2 configures both a forwarding mask
(which affects other top-level GIC IRQs) and a second-level interrupt
mask (for managing its own child interrupts). The former must be
saved/restored on suspend/resume, even when there's nothing to do for
the latter.
This patch adds a new set of suspend/resume hooks to irq_chip_generic,
to help represent *chip* suspend/resume, rather than IRQ suspend/resume.
These callbacks will always be called for an IRQ chip (regardless of the
installed interrupts) and are based on the per-chip irq_chip_generic
struct, rather than the per-IRQ irq_data struct.
The original problem report is described in extra detail here:
http://lkml.kernel.org/g/20150619224123.GL4917@ld-irv-0074
Signed-off-by: Brian Norris <computersforpeace@xxxxxxxxx>
Tested-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
v1: https://lkml.org/lkml/2015/6/19/760
v1 -> v2:
* clarify the comments on irq_chip::irq_{suspend,resume}
* add new suspend/resume hooks to the irq_chip_generic instead of irq_chip,
since that is the right level of abstraction (see v1 discussion)
include/linux/irq.h | 14 ++++++++++++--
kernel/irq/generic-chip.c | 6 ++++++
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 92188b0225bb..9fd346e605ff 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -324,8 +324,10 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
* @irq_bus_sync_unlock:function to sync and unlock slow bus (i2c) chips
* @irq_cpu_online: configure an interrupt source for a secondary CPU
* @irq_cpu_offline: un-configure an interrupt source for a secondary CPU
- * @irq_suspend: function called from core code on suspend once per chip
- * @irq_resume: function called from core code on resume once per chip
+ * @irq_suspend: function called from core code on suspend once per
+ * chip, when one or more interrupts are installed
+ * @irq_resume: function called from core code on resume once per chip,
+ * when one ore more interrupts are installed
* @irq_pm_shutdown: function called from core code on shutdown once per chip
* @irq_calc_mask: Optional function to set irq_data.mask for special cases
* @irq_print_chip: optional to print special chip info in show_interrupts
@@ -761,6 +763,12 @@ struct irq_chip_type {
* @reg_base: Register base address (virtual)
* @reg_readl: Alternate I/O accessor (defaults to readl if NULL)
* @reg_writel: Alternate I/O accessor (defaults to writel if NULL)
+ * @suspend: Function called from core code on suspend once per
+ * chip; can be useful instead of irq_chip::suspend to
+ * handle chip details even when no interrupts are in use
+ * @resume: Function called from core code on resume once per chip;
+ * can be useful instead of irq_chip::suspend to handle
+ * chip details even when no interrupts are in use
* @irq_base: Interrupt base nr for this chip
* @irq_cnt: Number of interrupts handled by this chip
* @mask_cache: Cached mask register shared between all chip types
@@ -787,6 +795,8 @@ struct irq_chip_generic {
void __iomem *reg_base;
u32 (*reg_readl)(void __iomem *addr);
void (*reg_writel)(u32 val, void __iomem *addr);
+ void (*suspend)(struct irq_chip_generic *gc);
+ void (*resume)(struct irq_chip_generic *gc);
unsigned int irq_base;
unsigned int irq_cnt;
u32 mask_cache;
diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index 15b370daf234..abd286afbd27 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -553,6 +553,9 @@ static int irq_gc_suspend(void)
if (data)
ct->chip.irq_suspend(data);
}
+
+ if (gc->suspend)
+ gc->suspend(gc);
}
return 0;
}
@@ -564,6 +567,9 @@ static void irq_gc_resume(void)
list_for_each_entry(gc, &gc_list, list) {
struct irq_chip_type *ct = gc->chip_types;
+ if (gc->resume)
+ gc->resume(gc);
+
if (ct->chip.irq_resume) {
struct irq_data *data = irq_gc_get_irq_data(gc);
--
2.4.3.573.g4eafbef
