[PATCH 2/3] of: MSI: Simplify irqdomain lookup

From: Marc Zyngier
Date: Tue Jan 26 2016 - 08:52:43 EST


So far, when trying to associate a device with its MSI domain,
we first lookup the domain using a MSI token, and if this
doesn't return anything useful, we pick up any domain matching
the same node.

This logic is broken for two reasons:
1) Only the generic MSI code (PCI or platform) sets this token
to PCI/MSI or platform MSI. So we're guaranteed that if there
is something to be found, we will find it with the first call.
2) If we have a convoluted situation where:
- a single node implements both wired and MSI interrupts
- MSI support for that HW hasn't been compiled in
we'll end up using the wired domain for MSIs anyway, and things
break badly.

So let's just remove __of_get_msi_domain, and replace it by a direct
call to irq_find_matching_host, because that's what we really want.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
drivers/of/irq.c | 18 +++---------------
1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 4fa916d..a9ea552 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -680,18 +680,6 @@ u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in)
return __of_msi_map_rid(dev, &msi_np, rid_in);
}

-static struct irq_domain *__of_get_msi_domain(struct device_node *np,
- enum irq_domain_bus_token token)
-{
- struct irq_domain *d;
-
- d = irq_find_matching_host(np, token);
- if (!d)
- d = irq_find_host(np);
-
- return d;
-}
-
/**
* of_msi_map_get_device_domain - Use msi-map to find the relevant MSI domain
* @dev: device for which the mapping is to be done.
@@ -707,7 +695,7 @@ struct irq_domain *of_msi_map_get_device_domain(struct device *dev, u32 rid)
struct device_node *np = NULL;

__of_msi_map_rid(dev, &np, rid);
- return __of_get_msi_domain(np, DOMAIN_BUS_PCI_MSI);
+ return irq_find_matching_host(np, DOMAIN_BUS_PCI_MSI);
}

/**
@@ -731,7 +719,7 @@ struct irq_domain *of_msi_get_domain(struct device *dev,
/* Check for a single msi-parent property */
msi_np = of_parse_phandle(np, "msi-parent", 0);
if (msi_np && !of_property_read_bool(msi_np, "#msi-cells")) {
- d = __of_get_msi_domain(msi_np, token);
+ d = irq_find_matching_host(msi_np, token);
if (!d)
of_node_put(msi_np);
return d;
@@ -745,7 +733,7 @@ struct irq_domain *of_msi_get_domain(struct device *dev,
while (!of_parse_phandle_with_args(np, "msi-parent",
"#msi-cells",
index, &args)) {
- d = __of_get_msi_domain(args.np, token);
+ d = irq_find_matching_host(args.np, token);
if (d)
return d;

--
2.1.4