Re: [PATCH v3 1/4] genirq: Introduce driver-readable IRQ status word

[Jan Kiszka]

Am 14.12.2010 21:47, Thomas Gleixner wrote:
> On Mon, 13 Dec 2010, Jan Kiszka wrote:
>> +/**
>> + *  get_irq_status - read interrupt line status word
>> + *  @irq: Interrupt line of the status word
>> + *
>> + *  This returns the current content of the status word associated with
>> + *  the given interrupt line. See IRQS_* flags for details.
>> + */
>> +unsigned long get_irq_status(unsigned int irq)
>> +{
>> +struct irq_desc *desc = irq_to_desc(irq);
>> +
>> +return desc ? desc->irq_data.drv_status : 0;
>> +}
>> +EXPORT_SYMBOL_GPL(get_irq_status);
> 
> We should document that this is a snapshot and in no way serialized
> against modifications of drv_status. I'll fix up the kernel doc.

Yeah, I think I had some hint on this in the previous version but
apparently dropped it for this round.

Thanks,
Jan



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Re: [PATCH v3 1/4] genirq: Introduce driver-readable IRQ status word

[Thomas Gleixner]

On Mon, 13 Dec 2010, Jan Kiszka wrote:
> +/**
> + *   get_irq_status - read interrupt line status word
> + *   @irq: Interrupt line of the status word
> + *
> + *   This returns the current content of the status word associated with
> + *   the given interrupt line. See IRQS_* flags for details.
> + */
> +unsigned long get_irq_status(unsigned int irq)
> +{
> + struct irq_desc *desc = irq_to_desc(irq);
> +
> + return desc ? desc->irq_data.drv_status : 0;
> +}
> +EXPORT_SYMBOL_GPL(get_irq_status);

We should document that this is a snapshot and in no way serialized
against modifications of drv_status. I'll fix up the kernel doc.

Thanks,

tglx
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[PATCH v3 1/4] genirq: Introduce driver-readable IRQ status word

[Jan Kiszka]

From: Jan Kiszka 

This associates a status word with every IRQ descriptor. Drivers can obtain
its content via get_irq_status(irq). First use case will be propagating the
interrupt sharing state.

Signed-off-by: Jan Kiszka 
---
 include/linux/interrupt.h |2 ++
 include/linux/irq.h   |2 ++
 kernel/irq/manage.c   |   15 +++
 3 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 79d0c4f..4c1aa72 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -126,6 +126,8 @@ struct irqaction {
 
 extern irqreturn_t no_action(int cpl, void *dev_id);
 
+extern unsigned long get_irq_status(unsigned int irq);
+
 #ifdef CONFIG_GENERIC_HARDIRQS
 extern int __must_check
 request_threaded_irq(unsigned int irq, irq_handler_t handler,
diff --git a/include/linux/irq.h b/include/linux/irq.h
index abde252..8bdb421 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -96,6 +96,7 @@ struct msi_desc;
  * methods, to allow shared chip implementations
  * @msi_desc:  MSI descriptor
  * @affinity:  IRQ affinity on SMP
+ * @drv_status:driver-readable status flags (IRQS_*)
  *
  * The fields here need to overlay the ones in irq_desc until we
  * cleaned up the direct references and switched everything over to
@@ -111,6 +112,7 @@ struct irq_data {
 #ifdef CONFIG_SMP
cpumask_var_t   affinity;
 #endif
+   unsigned long   drv_status;
 };
 
 /**
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 5f92acc..2ea0d30 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1157,3 +1157,18 @@ int request_any_context_irq(unsigned int irq, 
irq_handler_t handler,
return !ret ? IRQC_IS_HARDIRQ : ret;
 }
 EXPORT_SYMBOL_GPL(request_any_context_irq);
+
+/**
+ * get_irq_status - read interrupt line status word
+ * @irq: Interrupt line of the status word
+ *
+ * This returns the current content of the status word associated with
+ * the given interrupt line. See IRQS_* flags for details.
+ */
+unsigned long get_irq_status(unsigned int irq)
+{
+   struct irq_desc *desc = irq_to_desc(irq);
+
+   return desc ? desc->irq_data.drv_status : 0;
+}
+EXPORT_SYMBOL_GPL(get_irq_status);
-- 
1.7.1

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