Messages in this thread | | | Date | Fri, 9 Apr 2021 10:17:25 +0100 | From | Jonathan Cameron <> | Subject | Re: [RFC PATCH 01/10] genirq: Add chip flag to denote automatic IRQ (un)masking |
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On Thu, 8 Apr 2021 16:43:17 +0100 Valentin Schneider <valentin.schneider@arm.com> wrote:
> Some IRQ chips such as the Arm GICs automagically mask / unmask an > IRQ during the handling of said IRQ. This renders further mask / unmask > operations within the flow handlers redundant, which we do want to leverage > as masking by itself is not cheap (Distributor access via MMIO for GICs). > > This is different from having a chip->irq_mask_ack() callback as this > masking is: > - inherent to the chip->irq_ack() and *cannot* be omitted > - a *different* masking state than chip->irq_mask() (chip->irq_mask() is > idempotent, chip->irq_ack() really isn't) > > Add a chip flag, IRQCHIP_AUTOMASKS_FLOW, to denote chips with such > behaviour. Add a new IRQ data flag, IRQD_IRQ_FLOW_MASKED, to keep this > flow-induced mask state separate from regular mask / unmask operations > (IRQD_IRQ_MASKED). > > Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Hi Valentin,
One totally trivial thing noticed whilst reading.
> --- > include/linux/irq.h | 10 ++++++++++ > kernel/irq/chip.c | 5 +++++ > kernel/irq/debugfs.c | 2 ++ > kernel/irq/internals.h | 5 +++++ > 4 files changed, 22 insertions(+) > > diff --git a/include/linux/irq.h b/include/linux/irq.h > index bee82809107c..580b1b6b1799 100644 > --- a/include/linux/irq.h > +++ b/include/linux/irq.h > @@ -219,6 +219,8 @@ struct irq_data { > * irq_chip::irq_set_affinity() when deactivated. > * IRQD_IRQ_ENABLED_ON_SUSPEND - Interrupt is enabled on suspend by irq pm if > * irqchip have flag IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND set. > + * IRQD_IRQ_FLOW_MASKED - Interrupt is masked by ACK. Only EOI can > + * clear this.
Nitpick of the day : Seems text above is using tabs for white space blocks whereas you have used spaces. Make it consistent. It's not consistent in the file so I guess you could clean that up, or just go with making it consistent in this block.
> */ > enum { > IRQD_TRIGGER_MASK = 0xf, > @@ -245,6 +247,7 @@ enum { > IRQD_HANDLE_ENFORCE_IRQCTX = (1 << 28), > IRQD_AFFINITY_ON_ACTIVATE = (1 << 29), > IRQD_IRQ_ENABLED_ON_SUSPEND = (1 << 30), > + IRQD_IRQ_FLOW_MASKED = (1 << 31), > }; > > #define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors) > @@ -349,6 +352,11 @@ static inline bool irqd_irq_masked(struct irq_data *d) > return __irqd_to_state(d) & IRQD_IRQ_MASKED; > } > > +static inline bool irqd_irq_flow_masked(struct irq_data *d) > +{ > + return __irqd_to_state(d) & IRQD_IRQ_FLOW_MASKED; > +} > + > static inline bool irqd_irq_inprogress(struct irq_data *d) > { > return __irqd_to_state(d) & IRQD_IRQ_INPROGRESS; > @@ -567,6 +575,7 @@ struct irq_chip { > * IRQCHIP_SUPPORTS_NMI: Chip can deliver NMIs, only for root irqchips > * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND: Invokes __enable_irq()/__disable_irq() for wake irqs > * in the suspend path if they are in disabled state > + * IRQCHIP_AUTOMASKS_FLOW: chip->ack() masks and chip->eoi() unmasks > */ > enum { > IRQCHIP_SET_TYPE_MASKED = (1 << 0), > @@ -579,6 +588,7 @@ enum { > IRQCHIP_SUPPORTS_LEVEL_MSI = (1 << 7), > IRQCHIP_SUPPORTS_NMI = (1 << 8), > IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND = (1 << 9), > + IRQCHIP_AUTOMASKS_FLOW = (1 << 10), > }; > > #include <linux/irqdesc.h> > diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c > index 8cc8e5713287..18c3b0e1568a 100644 > --- a/kernel/irq/chip.c > +++ b/kernel/irq/chip.c > @@ -173,6 +173,11 @@ static void irq_state_clr_masked(struct irq_desc *desc) > irqd_clear(&desc->irq_data, IRQD_IRQ_MASKED); > } > > +static void irq_state_clr_flow_masked(struct irq_desc *desc) > +{ > + irqd_clear(&desc->irq_data, IRQD_IRQ_FLOW_MASKED); > +} > + > static void irq_state_clr_started(struct irq_desc *desc) > { > irqd_clear(&desc->irq_data, IRQD_IRQ_STARTED); > diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c > index e4cff358b437..3ae83622d701 100644 > --- a/kernel/irq/debugfs.c > +++ b/kernel/irq/debugfs.c > @@ -58,6 +58,7 @@ static const struct irq_bit_descr irqchip_flags[] = { > BIT_MASK_DESCR(IRQCHIP_SUPPORTS_LEVEL_MSI), > BIT_MASK_DESCR(IRQCHIP_SUPPORTS_NMI), > BIT_MASK_DESCR(IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND), > + BIT_MASK_DESCR(IRQCHIP_AUTOMASKS_FLOW), > }; > > static void > @@ -103,6 +104,7 @@ static const struct irq_bit_descr irqdata_states[] = { > BIT_MASK_DESCR(IRQD_IRQ_STARTED), > BIT_MASK_DESCR(IRQD_IRQ_DISABLED), > BIT_MASK_DESCR(IRQD_IRQ_MASKED), > + BIT_MASK_DESCR(IRQD_IRQ_FLOW_MASKED), > BIT_MASK_DESCR(IRQD_IRQ_INPROGRESS), > > BIT_MASK_DESCR(IRQD_PER_CPU), > diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h > index 54363527feea..b6c1cceddec0 100644 > --- a/kernel/irq/internals.h > +++ b/kernel/irq/internals.h > @@ -245,6 +245,11 @@ static inline void irq_state_set_masked(struct irq_desc *desc) > irqd_set(&desc->irq_data, IRQD_IRQ_MASKED); > } > > +static inline void irq_state_set_flow_masked(struct irq_desc *desc) > +{ > + irqd_set(&desc->irq_data, IRQD_IRQ_FLOW_MASKED); > +} > + > #undef __irqd_to_state > > static inline void __kstat_incr_irqs_this_cpu(struct irq_desc *desc)
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