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Date: Wed, 31 May 2017 14:54:19 +0100
From: Marc Zyngier <marc.zyngier@....com>
To: Thomas Gleixner <tglx@...utronix.de>,
LKML <linux-kernel@...r.kernel.org>
Cc: jeffy <jeffy.chen@...k-chips.com>,
Brian Norris <briannorris@...omium.org>, dianders@...omium.org,
tfiga@...omium.org
Subject: Re: [patch 1/2] genirq: Handle NOAUTOEN interrupt setup proper
Hi Thomas,
On 31/05/17 10:58, Thomas Gleixner wrote:
> If an interrupt is marked NOAUTOEN then request_irq() installs the action,
> but does not enable the interrupt via startup_irq(). The interrupt is
> enabled via enable_irq() later from the driver. enable_irq() calls
> irq_enable().
>
> That means that for interrupts which have a irq_startup() callback this
> callback is never invoked. Neither is irq_domain_activate_irq() invoked for
> such interrupts.
>
> If an interrupt depends on irq_startup() or irq_domain_activate_irq() then
> the enable via irq_enable() is not enough.
>
> Add a status flag IRQD_IRQ_STARTED_UP and use this to select the proper
> mechanism in enable_irq(). Use the flag also to avoid pointless calls into
> the low level functions.
>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
> include/linux/irq.h | 6 ++++
> kernel/irq/chip.c | 73 +++++++++++++++++++++++++++++++++++++------------
> kernel/irq/internals.h | 1
> kernel/irq/manage.c | 2 -
> 4 files changed, 64 insertions(+), 18 deletions(-)
>
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -216,6 +216,7 @@ enum {
> IRQD_WAKEUP_ARMED = (1 << 19),
> IRQD_FORWARDED_TO_VCPU = (1 << 20),
> IRQD_AFFINITY_MANAGED = (1 << 21),
> + IRQD_IRQ_STARTED_UP = (1 << 22),
> };
>
> #define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors)
> @@ -329,6 +330,11 @@ static inline void irqd_clr_activated(st
> __irqd_to_state(d) &= ~IRQD_ACTIVATED;
> }
>
> +static inline bool irqd_is_started_up(struct irq_data *d)
nit: since we have set/clr_started, consider making this is_started
(without the up)? Or add the _up to clr/set?
> +{
> + return __irqd_to_state(d) & IRQD_IRQ_STARTED_UP;
> +}
> +
> #undef __irqd_to_state
>
> static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -185,37 +185,71 @@ static void irq_state_set_masked(struct
> irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);
> }
>
> +static void irq_state_clr_started(struct irq_desc *desc)
> +{
> + irqd_clear(&desc->irq_data, IRQD_IRQ_STARTED_UP);
> +}
> +
> +static void irq_state_set_started(struct irq_desc *desc)
> +{
> + irqd_set(&desc->irq_data, IRQD_IRQ_STARTED_UP);
> +}
> +
> int irq_startup(struct irq_desc *desc, bool resend)
> {
> int ret = 0;
>
> - irq_state_clr_disabled(desc);
> + if (irqd_is_started_up(&desc->irq_data))
> + return 0;
> +
How about:
if (irqd_is_started_up(&desc->irq_data)) {
irq_enable(desc);
return 0;
}
> desc->depth = 0;
>
> irq_domain_activate_irq(&desc->irq_data);
> if (desc->irq_data.chip->irq_startup) {
> ret = desc->irq_data.chip->irq_startup(&desc->irq_data);
> + irq_state_clr_disabled(desc);
> irq_state_clr_masked(desc);
> } else {
> irq_enable(desc);
> }
> + irq_state_set_started(desc);
> +
> if (resend)
> check_irq_resend(desc);
> +
> return ret;
> }
>
> +static void __irq_disable(struct irq_desc *desc, bool mask);
> +
> void irq_shutdown(struct irq_desc *desc)
> {
> - irq_state_set_disabled(desc);
> - desc->depth = 1;
> - if (desc->irq_data.chip->irq_shutdown)
> - desc->irq_data.chip->irq_shutdown(&desc->irq_data);
> - else if (desc->irq_data.chip->irq_disable)
> - desc->irq_data.chip->irq_disable(&desc->irq_data);
> - else
> - desc->irq_data.chip->irq_mask(&desc->irq_data);
> + if (irqd_is_started_up(&desc->irq_data)) {
> + desc->depth = 1;
> + if (desc->irq_data.chip->irq_shutdown) {
> + desc->irq_data.chip->irq_shutdown(&desc->irq_data);
> + irq_state_set_disabled(desc);
> + irq_state_set_masked(desc);
> + } else {
> + __irq_disable(desc, true);
> + }
> + irq_state_clr_started(desc);
> + }
> + /*
> + * This must be called even if the interrupt was never started up,
> + * because the activation can happen before the interrupt is
> + * available for request/startup. It has it's own state tracking so
> + * it's safe to call it unconditonally.
unconditionally?
> + */
> irq_domain_deactivate_irq(&desc->irq_data);
> - irq_state_set_masked(desc);
> +}
> +
> +void irq_enable_or_startup(struct irq_desc *desc)
> +{
> + if (!irqd_is_started_up(&desc->irq_data))
> + irq_startup(desc, false);
> + else
> + irq_enable(desc);
get rid of this new function...
> }
>
> void irq_enable(struct irq_desc *desc)
> @@ -228,6 +262,17 @@ void irq_enable(struct irq_desc *desc)
> irq_state_clr_masked(desc);
> }
>
> +static void __irq_disable(struct irq_desc *desc, bool mask)
> +{
> + irq_state_set_disabled(desc);
> + if (desc->irq_data.chip->irq_disable) {
> + desc->irq_data.chip->irq_disable(&desc->irq_data);
> + irq_state_set_masked(desc);
> + } else if (mask) {
> + mask_irq(desc);
> + }
> +}
> +
> /**
> * irq_disable - Mark interrupt disabled
> * @desc: irq descriptor which should be disabled
> @@ -250,13 +295,7 @@ void irq_enable(struct irq_desc *desc)
> */
> void irq_disable(struct irq_desc *desc)
> {
> - irq_state_set_disabled(desc);
> - if (desc->irq_data.chip->irq_disable) {
> - desc->irq_data.chip->irq_disable(&desc->irq_data);
> - irq_state_set_masked(desc);
> - } else if (irq_settings_disable_unlazy(desc)) {
> - mask_irq(desc);
> - }
> + __irq_disable(desc, irq_settings_disable_unlazy(desc));
> }
>
> void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu)
> --- a/kernel/irq/internals.h
> +++ b/kernel/irq/internals.h
> @@ -68,6 +68,7 @@ extern void __enable_irq(struct irq_desc
>
> extern int irq_startup(struct irq_desc *desc, bool resend);
> extern void irq_shutdown(struct irq_desc *desc);
> +extern void irq_enable_or_startup(struct irq_desc *desc);
> extern void irq_enable(struct irq_desc *desc);
> extern void irq_disable(struct irq_desc *desc);
> extern void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu);
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -533,7 +533,7 @@ void __enable_irq(struct irq_desc *desc)
> goto err_out;
> /* Prevent probing on this irq: */
> irq_settings_set_noprobe(desc);
> - irq_enable(desc);
> + irq_enable_or_startup(desc);
and make this irq_startup(desc, false)?
> check_irq_resend(desc);
> /* fall-through */
> }
>
>
Otherwise:
Acked-by: Marc Zyngier <marc.zyngier@....com>
M.
--
Jazz is not dead. It just smells funny...
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