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of/irq: Add new function of_msi_map_rid()

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The device tree property "msi-map" specifies how to create the PCI
requester id used in some MSI controllers.  Add a new function
of_msi_map_rid() that finds the msi-map property and applies its
translation to a given requester id.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
David Daney 2015-10-08 15:10:48 -07:00 committed by Marc Zyngier
parent b531566e4d
commit 8db02d8b40
2 changed files with 91 additions and 0 deletions
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84
drivers/of/irq.c
View file

@ -598,3 +598,87 @@ void of_msi_configure(struct device *dev, struct device_node *np)
d = irq_find_host(msi_np);
dev_set_msi_domain(dev, d);
}
/**
* of_msi_map_rid - Map a MSI requester ID for a device.
* @dev: device for which the mapping is to be done.
* @msi_np: device node of the expected msi controller.
* @rid_in: unmapped MSI requester ID for the device.
*
* Walk up the device hierarchy looking for devices with a "msi-map"
* property. If found, apply the mapping to @rid_in.
*
* Returns the mapped MSI requester ID.
*/
u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in)
{
struct device *parent_dev;
struct device_node *msi_controller_node;
u32 map_mask, masked_rid, rid_base, msi_base, rid_len, phandle;
int msi_map_len;
bool matched;
u32 rid_out = rid_in;
const __be32 *msi_map = NULL;
/*
* Walk up the device parent links looking for one with a
* "msi-map" property.
*/
for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent) {
if (!parent_dev->of_node)
continue;
msi_map = of_get_property(parent_dev->of_node,
"msi-map", &msi_map_len);
if (!msi_map)
continue;
if (msi_map_len % (4 * sizeof(__be32))) {
dev_err(parent_dev, "Error: Bad msi-map length: %d\n",
msi_map_len);
return rid_out;
}
/* We have a good parent_dev and msi_map, let's use them. */
break;
}
if (!msi_map)
return rid_out;
/* The default is to select all bits. */
map_mask = 0xffffffff;
/*
* Can be overridden by "msi-map-mask" property. If
* of_property_read_u32() fails, the default is used.
*/
of_property_read_u32(parent_dev->of_node, "msi-map-mask", &map_mask);
masked_rid = map_mask & rid_in;
matched = false;
while (!matched && msi_map_len >= 4 * sizeof(__be32)) {
rid_base = be32_to_cpup(msi_map + 0);
phandle = be32_to_cpup(msi_map + 1);
msi_base = be32_to_cpup(msi_map + 2);
rid_len = be32_to_cpup(msi_map + 3);
msi_controller_node = of_find_node_by_phandle(phandle);
matched = masked_rid >= rid_base &&
masked_rid < rid_base + rid_len &&
msi_np == msi_controller_node;
of_node_put(msi_controller_node);
msi_map_len -= 4 * sizeof(__be32);
msi_map += 4;
}
if (!matched)
return rid_out;
rid_out = masked_rid + msi_base;
dev_dbg(dev,
"msi-map at: %s, using mask %08x, rid-base: %08x, msi-base: %08x, length: %08x, rid: %08x -> %08x\n",
dev_name(parent_dev), map_mask, rid_base, msi_base,
rid_len, rid_in, rid_out);
return rid_out;
}

7
include/linux/of_irq.h
View file

@ -75,6 +75,7 @@ static inline int of_irq_to_resource_table(struct device_node *dev,
extern unsigned int irq_of_parse_and_map(struct device_node *node, int index);
extern struct device_node *of_irq_find_parent(struct device_node *child);
extern void of_msi_configure(struct device *dev, struct device_node *np);
u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in);
#else /* !CONFIG_OF */
static inline unsigned int irq_of_parse_and_map(struct device_node *dev,
@ -87,6 +88,12 @@ static inline void *of_irq_find_parent(struct device_node *child)
{
return NULL;
}
static inline u32 of_msi_map_rid(struct device *dev,
struct device_node *msi_np, u32 rid_in)
{
return rid_in;
}
#endif /* !CONFIG_OF */
#endif /* __OF_IRQ_H */