| Message ID | 20130729142600.63eeab50@skate |
|---|---|
| State | Not Applicable |
| Headers | show |
On Mon, Jul 29, 2013 at 02:26:00PM +0200, Thomas Petazzoni wrote: > Dear Thierry Reding, > > On Mon, 29 Jul 2013 08:54:31 +0200, Thierry Reding wrote: > > > > So what is your suggestion to allow the PCIe controller to retrieve the > > > correct irq_domain if we have only one DT node for the IRQ controller > > > that registers two irq_domains ? > > > > If I understand correctly, Grant isn't objecting to the introduction of > > the lookup function, but rather its implementation. You could add a > > pointer to a struct msi_chip within struct irq_domain and then iterate > > over all irq_domain instances (see irq_find_host()) and find one which > > has the correct device_node pointer and the msi_chip pointer set. > > Ah ok. The only trick is that we have to change irq_find_host() to > *not* match on MSI domains. Can you check the below patch to see if it > matches what Grant suggested? It works for me, and it allows to completely > remove the registry of msi_chip in drivers/of, as well as the of_node > pointer in struct msi_chip. > > Thanks! > > Thomas > > From c2c0137cb110270f96e1e0fa298a5d585b8d829e Mon Sep 17 00:00:00 2001 > From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> > Date: Mon, 29 Jul 2013 14:12:31 +0200 > Subject: [PATCHv6 05/11] irqdomain: add support to associate an irq_domain > with a msi_chip > > Message Signaled Interrupts are a PCI-specific mechanism that allows > PCI devices to notify interrupts to the CPU using in-band > messages. The PCI subsystem represents an MSI-capable interrupt > controller as an msi_chip structure, and this patch improves the > irqdomain subsystem with a new pointer associating an irq_domain with > the corresponding msi_chip. > > The __irq_domain_add() function is augmented with an additional > argument, the 'msi_chip' pointer, and all callers of this function are > updated. > > A new function irq_domain_add_msi() function is added to allow the > registration of an MSI-type irq domain. > > The irq_find_host() function is modified to not match on MSI-type irq > domains: a given DT device node may represent both a normal interrupt > controller and a MSI interrupt controller. irq_find_host() should > return the irq_domain that corresponds to the normal interupt "interupt" -> "interrupt" > controller. > > An irq_find_msi() function is added to get the MSI_type irq domain "MSI_type" -> "MSI-type". > given a DT device node. And "irq domain" -> "IRQ domain" in all of the above. > diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h [...] > @@ -162,7 +167,16 @@ static inline struct irq_domain *irq_domain_add_tree(struct device_node *of_node > const struct irq_domain_ops *ops, > void *host_data) > { > - return __irq_domain_add(of_node, 0, ~0, 0, ops, host_data); > + return __irq_domain_add(of_node, 0, ~0, 0, ops, NULL, host_data); > +} > +static inline struct irq_domain *irq_domain_add_msi(struct device_node *of_node, > + unsigned int size, > + const struct irq_domain_ops *ops, > + struct msi_chip *msi_chip, > + void *host_data) > +{ > + return __irq_domain_add(of_node, size, size, 0, ops, > + msi_chip, host_data); > } Given that the majority of interrupt controllers probably don't have any MSI functionality, I wonder if perhaps this should be done in a more helper-oriented way, see below... > diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c [...] > @@ -198,6 +201,12 @@ struct irq_domain *irq_find_host(struct device_node *node) > */ > mutex_lock(&irq_domain_mutex); > list_for_each_entry(h, &irq_domain_list, link) { > + /* > + * We only want to match normal interrupt domains, not > + * MSI domains > + */ > + if (h->msi_chip) > + continue; > if (h->ops->match) > rc = h->ops->match(h, node); > else > @@ -214,6 +223,28 @@ struct irq_domain *irq_find_host(struct device_node *node) > EXPORT_SYMBOL_GPL(irq_find_host); > > /** > + * irq_find_msi() - Locates a MSI domain for a given device node > + * @node: device-tree node of the interrupt controller > + */ > +struct irq_domain *irq_find_msi(struct device_node *node) > +{ > + struct irq_domain *h, *found = NULL; > + > + mutex_lock(&irq_domain_mutex); > + list_for_each_entry(h, &irq_domain_list, link) { > + if (!h->msi_chip) > + continue; > + if (h->of_node && h->of_node == node) { > + found = h; > + break; > + } > + } > + mutex_unlock(&irq_domain_mutex); > + return found; > +} > +EXPORT_SYMBOL_GPL(irq_find_msi); This doesn't quite copy what irq_find_host() does, since it ignores the associated ops->match(). But given that ops->match() already provides a way to hook into the lookup, perhaps we could add a function such as this: int irq_domain_supports_msi(struct irq_domain *d, struct device_node *node) { if ((d->of_node == NULL) || (d->of_node != node)) return 0; return d->msi_chip != NULL; } Then use that in drivers that expose MSI functionality via an IRQ domain like this: static const struct irq_domain_ops foo_irq_domain_ops = { ... .match = irq_domain_supports_msi, ... }; One problem with this is that it doesn't solve your problem where two different IRQ domains are exposed by the same device, because the irq_find_host() will still match the MSI IRQ domain for the non-MSI device node as well. This could be solved by adding another match function... This goes in hand with the helper-style API that I mentioned above. But it's really up to Grant to decide which way he wants this to go. Thierry
Dear Thierry Reding, On Mon, 29 Jul 2013 14:58:27 +0200, Thierry Reding wrote: > > /** > > + * irq_find_msi() - Locates a MSI domain for a given device node > > + * @node: device-tree node of the interrupt controller > > + */ > > +struct irq_domain *irq_find_msi(struct device_node *node) > > +{ > > + struct irq_domain *h, *found = NULL; > > + > > + mutex_lock(&irq_domain_mutex); > > + list_for_each_entry(h, &irq_domain_list, link) { > > + if (!h->msi_chip) > > + continue; > > + if (h->of_node && h->of_node == node) { > > + found = h; > > + break; > > + } > > + } > > + mutex_unlock(&irq_domain_mutex); > > + return found; > > +} > > +EXPORT_SYMBOL_GPL(irq_find_msi); > > This doesn't quite copy what irq_find_host() does, since it ignores the > associated ops->match(). Correct. > But given that ops->match() already provides a way to hook into the > lookup, perhaps we could add a function such as this: > > int irq_domain_supports_msi(struct irq_domain *d, struct device_node *node) > { > if ((d->of_node == NULL) || (d->of_node != node)) > return 0; > > return d->msi_chip != NULL; > } > > Then use that in drivers that expose MSI functionality via an IRQ domain > like this: > > static const struct irq_domain_ops foo_irq_domain_ops = { > ... > .match = irq_domain_supports_msi, > ... > }; > > One problem with this is that it doesn't solve your problem where two > different IRQ domains are exposed by the same device, because the > irq_find_host() will still match the MSI IRQ domain for the non-MSI > device node as well. Indeed. > This could be solved by adding another match function... But this would involve changing all the users of irq_find_host(), no? > This goes in hand with the helper-style API that I mentioned above. But > it's really up to Grant to decide which way he wants this to go. Yes, Grant, your suggestions are welcome on this. Thanks! Thomas
Grant, Would it be possible to get your opinion on the patch below? You're the one who disagreed about the "of: pci: add registry of MSI chips", so I implemented something that hopefully is more in line with what you expected, so it'd be great if you could take some time to review it. This MSI stuff has been around for quite some time, the specific patch you NAKed had originally been posted on June, 6th, and was thought to be ready for merging thanks to the ACK of Rob Herring. While I certainly understand that patches can continue to be discussed by other maintainers, it'd be nice to have quick feedback from you after this NAK so that we can converge towards an accepted solution to be merged in 3.12. Thanks a lot, Thomas On Mon, 29 Jul 2013 14:26:00 +0200, Thomas Petazzoni wrote: > Dear Thierry Reding, > > On Mon, 29 Jul 2013 08:54:31 +0200, Thierry Reding wrote: > > > > So what is your suggestion to allow the PCIe controller to retrieve the > > > correct irq_domain if we have only one DT node for the IRQ controller > > > that registers two irq_domains ? > > > > If I understand correctly, Grant isn't objecting to the introduction of > > the lookup function, but rather its implementation. You could add a > > pointer to a struct msi_chip within struct irq_domain and then iterate > > over all irq_domain instances (see irq_find_host()) and find one which > > has the correct device_node pointer and the msi_chip pointer set. > > Ah ok. The only trick is that we have to change irq_find_host() to > *not* match on MSI domains. Can you check the below patch to see if it > matches what Grant suggested? It works for me, and it allows to completely > remove the registry of msi_chip in drivers/of, as well as the of_node > pointer in struct msi_chip. > > Thanks! > > Thomas > > From c2c0137cb110270f96e1e0fa298a5d585b8d829e Mon Sep 17 00:00:00 2001 > From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> > Date: Mon, 29 Jul 2013 14:12:31 +0200 > Subject: [PATCHv6 05/11] irqdomain: add support to associate an irq_domain > with a msi_chip > > Message Signaled Interrupts are a PCI-specific mechanism that allows > PCI devices to notify interrupts to the CPU using in-band > messages. The PCI subsystem represents an MSI-capable interrupt > controller as an msi_chip structure, and this patch improves the > irqdomain subsystem with a new pointer associating an irq_domain with > the corresponding msi_chip. > > The __irq_domain_add() function is augmented with an additional > argument, the 'msi_chip' pointer, and all callers of this function are > updated. > > A new function irq_domain_add_msi() function is added to allow the > registration of an MSI-type irq domain. > > The irq_find_host() function is modified to not match on MSI-type irq > domains: a given DT device node may represent both a normal interrupt > controller and a MSI interrupt controller. irq_find_host() should > return the irq_domain that corresponds to the normal interupt > controller. > > An irq_find_msi() function is added to get the MSI_type irq domain > given a DT device node. > > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> > --- > include/linux/irqdomain.h | 20 +++++++++++++++++--- > kernel/irq/irqdomain.c | 35 +++++++++++++++++++++++++++++++++-- > 2 files changed, 50 insertions(+), 5 deletions(-) > > diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h > index 1ffa336..f1b11c8 100644 > --- a/include/linux/irqdomain.h > +++ b/include/linux/irqdomain.h > @@ -38,6 +38,7 @@ > struct device_node; > struct irq_domain; > struct of_device_id; > +struct msi_chip; > > /* Number of irqs reserved for a legacy isa controller */ > #define NUM_ISA_INTERRUPTS 16 > @@ -101,6 +102,7 @@ struct irq_domain { > /* Optional data */ > struct device_node *of_node; > struct irq_domain_chip_generic *gc; > + struct msi_chip *msi_chip; > > /* reverse map data. The linear map gets appended to the irq_domain */ > irq_hw_number_t hwirq_max; > @@ -114,6 +116,7 @@ struct irq_domain { > struct irq_domain *__irq_domain_add(struct device_node *of_node, int size, > irq_hw_number_t hwirq_max, int direct_max, > const struct irq_domain_ops *ops, > + struct msi_chip *msi_chip, > void *host_data); > struct irq_domain *irq_domain_add_simple(struct device_node *of_node, > unsigned int size, > @@ -127,6 +130,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, > const struct irq_domain_ops *ops, > void *host_data); > extern struct irq_domain *irq_find_host(struct device_node *node); > +extern struct irq_domain *irq_find_msi(struct device_node *node); > extern void irq_set_default_host(struct irq_domain *host); > > /** > @@ -141,14 +145,15 @@ static inline struct irq_domain *irq_domain_add_linear(struct device_node *of_no > const struct irq_domain_ops *ops, > void *host_data) > { > - return __irq_domain_add(of_node, size, size, 0, ops, host_data); > + return __irq_domain_add(of_node, size, size, 0, ops, NULL, host_data); > } > static inline struct irq_domain *irq_domain_add_nomap(struct device_node *of_node, > unsigned int max_irq, > const struct irq_domain_ops *ops, > void *host_data) > { > - return __irq_domain_add(of_node, 0, max_irq, max_irq, ops, host_data); > + return __irq_domain_add(of_node, 0, max_irq, max_irq, ops, NULL, > + host_data); > } > static inline struct irq_domain *irq_domain_add_legacy_isa( > struct device_node *of_node, > @@ -162,7 +167,16 @@ static inline struct irq_domain *irq_domain_add_tree(struct device_node *of_node > const struct irq_domain_ops *ops, > void *host_data) > { > - return __irq_domain_add(of_node, 0, ~0, 0, ops, host_data); > + return __irq_domain_add(of_node, 0, ~0, 0, ops, NULL, host_data); > +} > +static inline struct irq_domain *irq_domain_add_msi(struct device_node *of_node, > + unsigned int size, > + const struct irq_domain_ops *ops, > + struct msi_chip *msi_chip, > + void *host_data) > +{ > + return __irq_domain_add(of_node, size, size, 0, ops, > + msi_chip, host_data); > } > > extern void irq_domain_remove(struct irq_domain *host); > diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c > index b9ddb94..80dc1ca 100644 > --- a/kernel/irq/irqdomain.c > +++ b/kernel/irq/irqdomain.c > @@ -29,6 +29,7 @@ static struct irq_domain *irq_default_domain; > * @direct_max: Maximum value of direct maps; Use ~0 for no limit; 0 for no > * direct mapping > * @ops: map/unmap domain callbacks > + * @msi_chip: pointer to MSI chip structure, for MSI domains > * @host_data: Controller private data pointer > * > * Allocates and initialize and irq_domain structure. Caller is expected to > @@ -38,6 +39,7 @@ static struct irq_domain *irq_default_domain; > struct irq_domain *__irq_domain_add(struct device_node *of_node, int size, > irq_hw_number_t hwirq_max, int direct_max, > const struct irq_domain_ops *ops, > + struct msi_chip *msi_chip, > void *host_data) > { > struct irq_domain *domain; > @@ -52,6 +54,7 @@ struct irq_domain *__irq_domain_add(struct device_node *of_node, int size, > domain->ops = ops; > domain->host_data = host_data; > domain->of_node = of_node_get(of_node); > + domain->msi_chip = msi_chip; > domain->hwirq_max = hwirq_max; > domain->revmap_size = size; > domain->revmap_direct_max_irq = direct_max; > @@ -127,7 +130,7 @@ struct irq_domain *irq_domain_add_simple(struct device_node *of_node, > { > struct irq_domain *domain; > > - domain = __irq_domain_add(of_node, size, size, 0, ops, host_data); > + domain = __irq_domain_add(of_node, size, size, 0, ops, NULL, host_data); > if (!domain) > return NULL; > > @@ -172,7 +175,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, > struct irq_domain *domain; > > domain = __irq_domain_add(of_node, first_hwirq + size, > - first_hwirq + size, 0, ops, host_data); > + first_hwirq + size, 0, ops, NULL, host_data); > if (!domain) > return NULL; > > @@ -198,6 +201,12 @@ struct irq_domain *irq_find_host(struct device_node *node) > */ > mutex_lock(&irq_domain_mutex); > list_for_each_entry(h, &irq_domain_list, link) { > + /* > + * We only want to match normal interrupt domains, not > + * MSI domains > + */ > + if (h->msi_chip) > + continue; > if (h->ops->match) > rc = h->ops->match(h, node); > else > @@ -214,6 +223,28 @@ struct irq_domain *irq_find_host(struct device_node *node) > EXPORT_SYMBOL_GPL(irq_find_host); > > /** > + * irq_find_msi() - Locates a MSI domain for a given device node > + * @node: device-tree node of the interrupt controller > + */ > +struct irq_domain *irq_find_msi(struct device_node *node) > +{ > + struct irq_domain *h, *found = NULL; > + > + mutex_lock(&irq_domain_mutex); > + list_for_each_entry(h, &irq_domain_list, link) { > + if (!h->msi_chip) > + continue; > + if (h->of_node && h->of_node == node) { > + found = h; > + break; > + } > + } > + mutex_unlock(&irq_domain_mutex); > + return found; > +} > +EXPORT_SYMBOL_GPL(irq_find_msi); > + > +/** > * irq_set_default_host() - Set a "default" irq domain > * @domain: default domain pointer > *
Dear Thierry Reding, On Mon, 29 Jul 2013 14:58:27 +0200, Thierry Reding wrote: > > +static inline struct irq_domain *irq_domain_add_msi(struct device_node *of_node, > > + unsigned int size, > > + const struct irq_domain_ops *ops, > > + struct msi_chip *msi_chip, > > + void *host_data) > > +{ > > + return __irq_domain_add(of_node, size, size, 0, ops, > > + msi_chip, host_data); > > } > > Given that the majority of interrupt controllers probably don't have any > MSI functionality, I wonder if perhaps this should be done in a more > helper-oriented way, see below... I'm not sure I get the relation between this comment on this specific part of the code and the match helpers suggestion that you did below. Could you explain? > > +struct irq_domain *irq_find_msi(struct device_node *node) > > +{ > > + struct irq_domain *h, *found = NULL; > > + > > + mutex_lock(&irq_domain_mutex); > > + list_for_each_entry(h, &irq_domain_list, link) { > > + if (!h->msi_chip) > > + continue; > > + if (h->of_node && h->of_node == node) { > > + found = h; > > + break; > > + } > > + } > > + mutex_unlock(&irq_domain_mutex); > > + return found; > > +} > > +EXPORT_SYMBOL_GPL(irq_find_msi); > > This doesn't quite copy what irq_find_host() does, since it ignores the > associated ops->match(). > > But given that ops->match() already provides a way to hook into the > lookup, perhaps we could add a function such as this: > > int irq_domain_supports_msi(struct irq_domain *d, struct device_node *node) > { > if ((d->of_node == NULL) || (d->of_node != node)) > return 0; > > return d->msi_chip != NULL; > } > > Then use that in drivers that expose MSI functionality via an IRQ domain > like this: > > static const struct irq_domain_ops foo_irq_domain_ops = { > ... > .match = irq_domain_supports_msi, > ... > }; > > One problem with this is that it doesn't solve your problem where two > different IRQ domains are exposed by the same device, because the > irq_find_host() will still match the MSI IRQ domain for the non-MSI > device node as well. This could be solved by adding another match > function... I've given this some thought, and I don't see how ->match() functions can solve the problem. The irq_find_host() is simply given as input a DT node, and is asked to find the irqdomain attached to this DT node. To do so, for each irqdomain in the system, it calls the ->match() operation, or does some default DT node equality checking. However, nor the irq_find_host() function, nor a custom ->match() function has a way of knowing whether what you're looking for is the "normal" IRQ controller, or the MSI controller. > This goes in hand with the helper-style API that I mentioned above. But > it's really up to Grant to decide which way he wants this to go. Again, I am not sure what you meant with "helper-style API". I do understand the idea of providing a helper irq_domain_supports_msi() that can be used as the ->match() operation in irq_domain_ops, but I fail to see how this solves the problem. Thanks! Thomas
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h index 1ffa336..f1b11c8 100644 --- a/include/linux/irqdomain.h +++ b/include/linux/irqdomain.h @@ -38,6 +38,7 @@ struct device_node; struct irq_domain; struct of_device_id; +struct msi_chip; /* Number of irqs reserved for a legacy isa controller */ #define NUM_ISA_INTERRUPTS 16 @@ -101,6 +102,7 @@ struct irq_domain { /* Optional data */ struct device_node *of_node; struct irq_domain_chip_generic *gc; + struct msi_chip *msi_chip; /* reverse map data. The linear map gets appended to the irq_domain */ irq_hw_number_t hwirq_max; @@ -114,6 +116,7 @@ struct irq_domain { struct irq_domain *__irq_domain_add(struct device_node *of_node, int size, irq_hw_number_t hwirq_max, int direct_max, const struct irq_domain_ops *ops, + struct msi_chip *msi_chip, void *host_data); struct irq_domain *irq_domain_add_simple(struct device_node *of_node, unsigned int size, @@ -127,6 +130,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, const struct irq_domain_ops *ops, void *host_data); extern struct irq_domain *irq_find_host(struct device_node *node); +extern struct irq_domain *irq_find_msi(struct device_node *node); extern void irq_set_default_host(struct irq_domain *host); /** @@ -141,14 +145,15 @@ static inline struct irq_domain *irq_domain_add_linear(struct device_node *of_no const struct irq_domain_ops *ops, void *host_data) { - return __irq_domain_add(of_node, size, size, 0, ops, host_data); + return __irq_domain_add(of_node, size, size, 0, ops, NULL, host_data); } static inline struct irq_domain *irq_domain_add_nomap(struct device_node *of_node, unsigned int max_irq, const struct irq_domain_ops *ops, void *host_data) { - return __irq_domain_add(of_node, 0, max_irq, max_irq, ops, host_data); + return __irq_domain_add(of_node, 0, max_irq, max_irq, ops, NULL, + host_data); } static inline struct irq_domain *irq_domain_add_legacy_isa( struct device_node *of_node, @@ -162,7 +167,16 @@ static inline struct irq_domain *irq_domain_add_tree(struct device_node *of_node const struct irq_domain_ops *ops, void *host_data) { - return __irq_domain_add(of_node, 0, ~0, 0, ops, host_data); + return __irq_domain_add(of_node, 0, ~0, 0, ops, NULL, host_data); +} +static inline struct irq_domain *irq_domain_add_msi(struct device_node *of_node, + unsigned int size, + const struct irq_domain_ops *ops, + struct msi_chip *msi_chip, + void *host_data) +{ + return __irq_domain_add(of_node, size, size, 0, ops, + msi_chip, host_data); } extern void irq_domain_remove(struct irq_domain *host); diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index b9ddb94..80dc1ca 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -29,6 +29,7 @@ static struct irq_domain *irq_default_domain; * @direct_max: Maximum value of direct maps; Use ~0 for no limit; 0 for no * direct mapping * @ops: map/unmap domain callbacks + * @msi_chip: pointer to MSI chip structure, for MSI domains * @host_data: Controller private data pointer * * Allocates and initialize and irq_domain structure. Caller is expected to @@ -38,6 +39,7 @@ static struct irq_domain *irq_default_domain; struct irq_domain *__irq_domain_add(struct device_node *of_node, int size, irq_hw_number_t hwirq_max, int direct_max, const struct irq_domain_ops *ops, + struct msi_chip *msi_chip, void *host_data) { struct irq_domain *domain; @@ -52,6 +54,7 @@ struct irq_domain *__irq_domain_add(struct device_node *of_node, int size, domain->ops = ops; domain->host_data = host_data; domain->of_node = of_node_get(of_node); + domain->msi_chip = msi_chip; domain->hwirq_max = hwirq_max; domain->revmap_size = size; domain->revmap_direct_max_irq = direct_max; @@ -127,7 +130,7 @@ struct irq_domain *irq_domain_add_simple(struct device_node *of_node, { struct irq_domain *domain; - domain = __irq_domain_add(of_node, size, size, 0, ops, host_data); + domain = __irq_domain_add(of_node, size, size, 0, ops, NULL, host_data); if (!domain) return NULL; @@ -172,7 +175,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, struct irq_domain *domain; domain = __irq_domain_add(of_node, first_hwirq + size, - first_hwirq + size, 0, ops, host_data); + first_hwirq + size, 0, ops, NULL, host_data); if (!domain) return NULL; @@ -198,6 +201,12 @@ struct irq_domain *irq_find_host(struct device_node *node) */ mutex_lock(&irq_domain_mutex); list_for_each_entry(h, &irq_domain_list, link) { + /* + * We only want to match normal interrupt domains, not + * MSI domains + */ + if (h->msi_chip) + continue; if (h->ops->match) rc = h->ops->match(h, node); else @@ -214,6 +223,28 @@ struct irq_domain *irq_find_host(struct device_node *node) EXPORT_SYMBOL_GPL(irq_find_host); /** + * irq_find_msi() - Locates a MSI domain for a given device node + * @node: device-tree node of the interrupt controller + */ +struct irq_domain *irq_find_msi(struct device_node *node) +{ + struct irq_domain *h, *found = NULL; + + mutex_lock(&irq_domain_mutex); + list_for_each_entry(h, &irq_domain_list, link) { + if (!h->msi_chip) + continue; + if (h->of_node && h->of_node == node) { + found = h; + break; + } + } + mutex_unlock(&irq_domain_mutex); + return found; +} +EXPORT_SYMBOL_GPL(irq_find_msi); + +/** * irq_set_default_host() - Set a "default" irq domain * @domain: default domain pointer *