Re: [patch V2 43/46] genirq/msi: Provide and use msi_domain_set_default_info_flags()

2020-08-28 Thread Thomas Gleixner
On Thu, Aug 27 2020 at 09:17, Marc Zyngier wrote:
> On 2020-08-26 12:17, Thomas Gleixner wrote:
>>  #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
>> +void msi_domain_set_default_info_flags(struct msi_domain_info *info)
>> +{
>> +/* Required so that a device latches a valid MSI message on startup 
>> */
>> +info->flags |= MSI_FLAG_ACTIVATE_EARLY;
>
> As far as I remember the story behind this flag (it's been a while),
> it was working around a PCI-specific issue, hence being located in
> the PCI code.

Yes. Some cards misbehave when there is no valid message programmed and
MSI is enabled.

> Now, the "program the MSI before enabling it" concept makes sense no
> matter what bus this is on, and I wonder why we are even keeping this
> flag around.

> Can't we just drop it together with the check in
> msi_domain_alloc_irqs()?

I'm fine with that.

Thanks,

tglx
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Re: [patch V2 43/46] genirq/msi: Provide and use msi_domain_set_default_info_flags()

2020-08-27 Thread Marc Zyngier

On 2020-08-26 12:17, Thomas Gleixner wrote:

MSI interrupts have some common flags which should be set not only for
PCI/MSI interrupts.

Move the PCI/MSI flag setting into a common function so it can be 
reused.


Signed-off-by: Thomas Gleixner 
---
V2: New patch
---
 drivers/pci/msi.c   |7 +--
 include/linux/msi.h |1 +
 kernel/irq/msi.c|   24 
 3 files changed, 26 insertions(+), 6 deletions(-)

--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1469,12 +1469,7 @@ struct irq_domain *pci_msi_create_irq_do
if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
pci_msi_domain_update_chip_ops(info);

-   info->flags |= MSI_FLAG_ACTIVATE_EARLY;
-   if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
-   info->flags |= MSI_FLAG_MUST_REACTIVATE;
-
-   /* PCI-MSI is oneshot-safe */
-   info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
+   msi_domain_set_default_info_flags(info);

domain = msi_create_irq_domain(fwnode, info, parent);
if (!domain)
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -410,6 +410,7 @@ int platform_msi_domain_alloc(struct irq
 void platform_msi_domain_free(struct irq_domain *domain, unsigned int 
virq,

  unsigned int nvec);
 void *platform_msi_get_host_data(struct irq_domain *domain);
+void msi_domain_set_default_info_flags(struct msi_domain_info *info);
 #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */

 #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -70,6 +70,30 @@ void get_cached_msi_msg(unsigned int irq
 EXPORT_SYMBOL_GPL(get_cached_msi_msg);

 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
+void msi_domain_set_default_info_flags(struct msi_domain_info *info)
+{
+	/* Required so that a device latches a valid MSI message on startup 
*/

+   info->flags |= MSI_FLAG_ACTIVATE_EARLY;


As far as I remember the story behind this flag (it's been a while),
it was working around a PCI-specific issue, hence being located in
the PCI code.

Now, the "program the MSI before enabling it" concept makes sense no 
matter
what bus this is on, and I wonder why we are even keeping this flag 
around.
Can't we just drop it together with the check in 
msi_domain_alloc_irqs()?


Thanks,

M.
--
Jazz is not dead. It just smells funny...
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